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Patiño LH, Castañeda S, Camargo M, Cao LY, Liggayu B, Paniz-Mondolfi A, Ramírez JD. Validation of real-time PCR assays for detecting Plasmodium and Babesia DNA species in blood samples. Acta Trop 2024; 258:107350. [PMID: 39134111 DOI: 10.1016/j.actatropica.2024.107350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 07/11/2024] [Accepted: 08/02/2024] [Indexed: 08/17/2024]
Abstract
Malaria and babesiosis are global health threats affecting humans, wildlife, and domestic animals, particularly in Africa, the Americas, and Europe. Malaria can lead to severe outcomes, while babesiosis usually resembles a mild illness but can be severe and fatal in individuals with weakened immune systems. Swift, accurate detection of these parasites is crucial for treatment and control. We evaluated a real-time PCR assay for diagnosing five Plasmodium and three Babesia species from blood samples, assessing its sensitivity, specificity, and analytical performance by analyzing 46 malaria-positive and 32 Babesia spp-positive samples diagnosed through microscopy. The limit of detection for Plasmodium species ranged from 30 to 0.0003 copies/µL. For mixed infections, it was 0.3 copies/µL for P. falciparum/P. vivax and 3 copies/µL for P. malariae/P. knowlesi. Babesia species had a detection limit of 0.2 copies/µL. No cross-reactivity was observed among 64 DNA samples from various microorganisms. The assay showed good sensitivity, detecting Plasmodium and Babesia species with 100 % accuracy overall, except for P. falciparum (97.7 %) and B. microti (12.5 %). The low sensitivity of detecting B. microti was attributed to limitations in microscopy for species identification. This technique heavily relies on the proficiency of the examiner, as species within the genus cannot be distinguished under a microscope. Additionally, Babesia can be confused with the early trophozoite stage (ring forms) of Plasmodium parasites. The findings support multiplex qPCR's diagnostic superiority over the gold standard, despite higher costs. It offers enhanced sensitivity, specificity, and detects mixed infections, crucial for effective monitoring and diagnosis of malaria and babesiosis in endemic regions with significant public health challenges.
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Affiliation(s)
- Luz Helena Patiño
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia; Molecular Microbiology Laboratory, Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Sergio Castañeda
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia
| | - Milena Camargo
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia
| | - Li Yong Cao
- Molecular Microbiology Laboratory, Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Bernadette Liggayu
- Molecular Microbiology Laboratory, Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Alberto Paniz-Mondolfi
- Molecular Microbiology Laboratory, Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Juan David Ramírez
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia; Molecular Microbiology Laboratory, Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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Abad P, Coronado M, Vincelle-Nieto Á, Pérez-Benavente S, Fobil JN, Puyet A, Diez A, Reyes-Palomares A, Azcárate IG, Bautista JM. Shotgun Characterization of the Circulating IgM Antigenome of an Infectious Pathogen by Immunocapture-LC-MS/MS from Dried Serum Spots. J Proteome Res 2024; 23:633-643. [PMID: 38183416 DOI: 10.1021/acs.jproteome.3c00439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2024]
Abstract
One of the main challenges in compiling the complete collection of protein antigens from pathogens for the selection of vaccine candidates or intervention targets is to acquire a broad enough representation of them to be recognized by the highly diversified immunoglobulin repertoire in human populations. Dried serum spot sampling (DSS) retains a large repertoire of circulating immunoglobulins from each individual that can be representative of a population, according to the sample size. In this work, shotgun proteomics of an infectious pathogen based on DSS sampling coupled with IgM immunoprecipitation, liquid chromatography-mass spectrometry (LC-MS/MS), and bioinformatic analyses was combined to characterize the circulating IgM antigenome. Serum samples from a malaria endemic region at different clinical statuses were studied to optimize IgM binding efficiency and antibody leaching by varying serum/immunomagnetic bead ratios and elution conditions. The method was validated using Plasmodium falciparum extracts identifying 110 of its IgM-reactive antigens while minimizing the presence of human proteins and antibodies. Furthermore, the IgM antigen recognition profile differentiated between malaria-infected and noninfected individuals at the time of sampling. We conclude that a shotgun proteomics approach offers advantages in providing a high-throughput, reliable, and clean way to identify IgM-recognized antigens from trace amounts of serum. The mass spectrometry raw data and metadata have been deposited with ProteomeXchange via MassIVE with the PXD identifier PXD043800.
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Affiliation(s)
- Paloma Abad
- Department of Biochemistry and Molecular Biology, Universidad Complutense de Madrid, Faculty of Veterinary Sciences, 28040 Madrid, Spain
| | - Montserrat Coronado
- Department of Biochemistry and Molecular Biology, Universidad Complutense de Madrid, Faculty of Veterinary Sciences, 28040 Madrid, Spain
| | - África Vincelle-Nieto
- Department of Biochemistry and Molecular Biology, Universidad Complutense de Madrid, Faculty of Veterinary Sciences, 28040 Madrid, Spain
| | - Susana Pérez-Benavente
- Department of Biochemistry and Molecular Biology, Universidad Complutense de Madrid, Faculty of Veterinary Sciences, 28040 Madrid, Spain
| | - Julius N Fobil
- Department of Biological, Environmental & Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, P.O. Box LG 13, G-4381 Legon, Ghana
| | - Antonio Puyet
- Department of Biochemistry and Molecular Biology, Universidad Complutense de Madrid, Faculty of Veterinary Sciences, 28040 Madrid, Spain
- 12 de Octubre Health Research Institute (imas12), 28041 Madrid, Spain
| | - Amalia Diez
- Department of Biochemistry and Molecular Biology, Universidad Complutense de Madrid, Faculty of Veterinary Sciences, 28040 Madrid, Spain
- 12 de Octubre Health Research Institute (imas12), 28041 Madrid, Spain
| | - Armando Reyes-Palomares
- Department of Biochemistry and Molecular Biology, Universidad Complutense de Madrid, Faculty of Veterinary Sciences, 28040 Madrid, Spain
- 12 de Octubre Health Research Institute (imas12), 28041 Madrid, Spain
| | - Isabel G Azcárate
- Faculty of Health Sciences, Rey Juan Carlos University, Alcorcón, 28922 Madrid, Spain
| | - José M Bautista
- Department of Biochemistry and Molecular Biology, Universidad Complutense de Madrid, Faculty of Veterinary Sciences, 28040 Madrid, Spain
- 12 de Octubre Health Research Institute (imas12), 28041 Madrid, Spain
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Zedda L, Loddo A, Di Ruberto C. YOLO-PAM: Parasite-Attention-Based Model for Efficient Malaria Detection. J Imaging 2023; 9:266. [PMID: 38132684 PMCID: PMC10744183 DOI: 10.3390/jimaging9120266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/14/2023] [Accepted: 11/24/2023] [Indexed: 12/23/2023] Open
Abstract
Malaria is a potentially fatal infectious disease caused by the Plasmodium parasite. The mortality rate can be significantly reduced if the condition is diagnosed and treated early. However, in many underdeveloped countries, the detection of malaria parasites from blood smears is still performed manually by experienced hematologists. This process is time-consuming and error-prone. In recent years, deep-learning-based object-detection methods have shown promising results in automating this task, which is critical to ensure diagnosis and treatment in the shortest possible time. In this paper, we propose a novel Transformer- and attention-based object-detection architecture designed to detect malaria parasites with high efficiency and precision, focusing on detecting several parasite sizes. The proposed method was tested on two public datasets, namely MP-IDB and IML. The evaluation results demonstrated a mean average precision exceeding 83.6% on distinct Plasmodium species within MP-IDB and reaching nearly 60% on IML. These findings underscore the effectiveness of our proposed architecture in automating malaria parasite detection, offering a potential breakthrough in expediting diagnosis and treatment processes.
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Affiliation(s)
- Luca Zedda
- Department of Mathematics and Computer Science, University of Cagliari, Via Ospedale 72, 09124 Cagliari, Italy;
| | - Andrea Loddo
- Department of Mathematics and Computer Science, University of Cagliari, Via Ospedale 72, 09124 Cagliari, Italy;
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Cardona-Arias JA, Higuita-Gutiérrez LF, Carmona-Fonseca J. Clinical and Parasitological Profiles of Gestational, Placental and Congenital Malaria in Northwestern Colombia. Trop Med Infect Dis 2023; 8:292. [PMID: 37368710 DOI: 10.3390/tropicalmed8060292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/19/2023] [Accepted: 05/23/2023] [Indexed: 06/29/2023] Open
Abstract
This study compared the clinical-parasitological profiles of gestational (GM), placental (PM), and congenital (CM) malaria in northwestern Colombia. A cross-sectional study with 829 pregnant women, 549 placentas, and 547 newborns was conducted. The frequency of GM was 35.8%, PM 20.9%, and CM 8.5%. P. vivax predominated in GM; in PM, the proportion of P. vivax and P. falciparum was similar; in CM, P. falciparum predominated. The main clinical findings were headache (49%), anemia (32%), fever (24%), and musculoskeletal pain (13%). The clinical manifestations were statistically higher in P. vivax infections. In submicroscopic GM (positive with qPCR and negative with thick blood smear), the frequency of anemia, sore throat, and a headache was statistically higher compared with pregnant women without malaria. GM, PM, and CM reduce birth weight and head circumference. In Colombia, this is the first research on the clinical characteristics of GM, PM, and CM; contrary to evidence from other countries, P. vivax and submicroscopic infections are associated with clinical outcomes.
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Affiliation(s)
| | - Luis Felipe Higuita-Gutiérrez
- School of Microbiology, Universidad de Antioquia (UdeA), Medellín 050010, Colombia
- School of Medicine, Universidad Cooperativa de Colombia, Medellín 050012, Colombia
| | - Jaime Carmona-Fonseca
- Grupo de Investigación Salud y Comunidad César Uribe Piedrahíta, Universidad de Antioquia, Medellín 050010, Colombia
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Bal M, Ghosal J, Das A, Sandeepta S, Pati S, Dutta A, Ranjit M. Impact of Sub-patent Malaria During Pregnancy on Birth-Weight in Odisha, India: Time-to-Event Analysis of Prospective Longitudinal Follow-Up of a Survey. J Epidemiol Glob Health 2023; 13:23-31. [PMID: 36650337 PMCID: PMC10006379 DOI: 10.1007/s44197-022-00082-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 11/18/2022] [Indexed: 01/18/2023] Open
Abstract
OBJECTIVE The current study aimed to estimate prevalence of malaria infection, especially sub-patent infection, in pregnant women residing in high malaria-endemic, hard-to-reach pockets of the Indian state of Odisha; and also measure its impact on birth-weight of their new-borns. METHOD A time-to-event analysis of prospective longitudinal follow-up study nested within a cross-sectional survey of people residing in high malaria-endemic six districts of Odisha was conducted during July-November 2019. Malaria status in pregnant mothers was categorized as malaria free; sub-patent, and patent. Hazards Ratio (HR) of low birth-weight (LBW; birth-weight < 2500 gms) was estimated in these three categories (n = 308) adjusted for residence (block), gravida, caste, age and gestational age at testing. RESULTS 50.3% pregnant women had sub-patent malaria infection, 3.9% had patent infection. In fully adjusted model, hazards ratio of LBW was 3.76 (95% CI 1.12, 12.64, p = 0.032) in pregnant women with patent infection and 1.82 (95% CI 0.87, 3.81, p = 0.109) in women with sub-patent infection when compared to no malaria group. CONCLUSION The study showed that half of the pregnant women in high-endemic pockets had sub-patent infection which posed deleterious influence on birth-weight of their new-borns. The study thereby flags the prevalence of sub-patent infection as a public health concern, because sub-patent infection in pregnant mothers may persist as a "silent" reservoir, with the potential to derail the malaria control program, especially when the country plans malaria elimination by 2030.
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Affiliation(s)
- Madhusmita Bal
- Indian Council of Medical Research-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar, Odisha, 751023, India
| | - Jyoti Ghosal
- Indian Council of Medical Research-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar, Odisha, 751023, India
- School of Public Health, KIIT Deemed to Be University, Bhubaneswar, Odisha, India
| | - Arundhuti Das
- Indian Council of Medical Research-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar, Odisha, 751023, India
| | - Sonali Sandeepta
- Indian Council of Medical Research-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar, Odisha, 751023, India
| | - Sanghmitra Pati
- Indian Council of Medical Research-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar, Odisha, 751023, India
| | - Ambarish Dutta
- Indian Institute of Public Health, Public Health Foundation of India, Plot No. 267/3408, Jaydev Vihar, Mayfair Lagoon Road, Bhubaneswar, Odisha, 751013, India.
| | - Manoranjan Ranjit
- Indian Council of Medical Research-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar, Odisha, 751023, India.
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Onken A, Haanshuus CG, Miraji MK, Marijani M, Kibwana KO, Abeid KA, Mørch K, Reimers M, Langeland N, Müller F, Jenum PA, Blomberg B. Malaria prevalence and performance of diagnostic tests among patients hospitalized with acute undifferentiated fever in Zanzibar. Malar J 2022; 21:54. [PMID: 35183188 PMCID: PMC8858509 DOI: 10.1186/s12936-022-04067-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 01/31/2022] [Indexed: 12/04/2022] Open
Abstract
Background Control efforts in Zanzibar reduced the burden of malaria substantially from 2000 to 2015, but re-emergence of falciparum malaria has been observed lately. This study evaluated the prevalence of malaria and performance of routine diagnostic tests among hospitalized fever patients in a 1.5 years period in 2015 and 2016. Methods From March 2015 to October 2016, paediatric and adult patients hospitalized with acute undifferentiated fever at Mnazi Mmoja Hospital, Zanzibar were included. The malaria prevalence, and performance of rapid diagnostic test (RDT) and microscopy, were assessed using polymerase chain reaction (PCR) as gold standard. Results The malaria prevalence was 9% (63/731). Children under 5 years old had lower malaria prevalence (5%, 14/260) than older children (15%, 20/131, p = 0.001) and persons aged 16 to 30 years (13%, 15/119, p = 0.02), but not different from persons over 30 years old (6%, 14/217, p = 0.7). All cases had Plasmodium falciparum infection, except for one case of Plasmodium ovale. Ten malaria patients had no history of visiting mainland Tanzania. The RDT had a sensitivity of 64% (36/56) and a specificity of 98% (561/575), and microscopy had a sensitivity of 50% (18/36) and a specificity of 99% (251/254), compared to PCR. The malaria parasitaemia was lower in patients with false negative results on RDT (median 7 × 103 copies/µL, interquartile range [IQR] 2 × 103 – 8 × 104, p = 0.002) and microscopy (median 9 × 103 copies/µL, IQR 8 × 102 – 7 × 104, p = 0.006) compared to those with true positive RDT (median 2 × 105 copies/µL, IQR 3 × 104 – 5 × 105) and microscopy (median 2 × 105 copies/µL, IQR 6 × 104 – 5 × 105). Conclusions The study emphasizes that malaria was a frequent cause of febrile illness in hospitalized patients in Zanzibar in the years 2015-2016, particularly among school age children and young adults. We found evidence of autochthonous malaria transmission in Zanzibar. Compared to PCR, both RDT and microscopy had low sensitivity, and false negative results were associated with low parasitaemia. While low parasitaemia identified only by PCR in a semi-immune individual could be coincidental and without clinical relevance, clinicians should be aware of the risk of false negative results on routine tests.
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Gumbo A, Topazian HM, Mwanza A, Mitchell CL, Puerto-Meredith S, Njiko R, Kayange M, Mwalilino D, Mvula B, Tegha G, Mvalo T, Hoffman I, Juliano JJ. Occurrence and Distribution of Nonfalciparum Malaria Parasite Species Among Adolescents and Adults in Malawi. J Infect Dis 2022; 225:257-268. [PMID: 34244739 PMCID: PMC8763954 DOI: 10.1093/infdis/jiab353] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/08/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Plasmodium falciparum malaria dominates throughout sub-Saharan Africa, but the prevalence of Plasmodium malariae, Plasmodium ovale spp., and Plasmodium vivax increasingly contribute to infection in countries that control malaria using P. falciparum-specific diagnostic and treatment strategies. METHODS We performed quantitative polymerase chain reaction (qPCR) on 2987 dried blood spots from the 2015-2016 Malawi Demographic and Health Survey to identify presence and distribution of nonfalciparum infection. Bivariate models were used to determine species-specific associations with demographic and environmental risk factors. RESULTS Nonfalciparum infections had broad spatial distributions. Weighted prevalence was 0.025 (SE, 0.004) for P. malariae, 0.097 (SE, 0.008) for P. ovale spp., and 0.001 (SE, 0.0005) for P. vivax. Most infections (85.6%) had low-density parasitemias ≤ 10 parasites/µL, and 66.7% of P. malariae, 34.6% of P. ovale spp., and 40.0% of P. vivax infections were coinfected with P. falciparum. Risk factors for P. malariae were like those known for P. falciparum; however, there were few risk factors recognized for P. ovale spp. and P. vivax, perhaps due to the potential for relapsing episodes. CONCLUSIONS The prevalence of any nonfalciparum infection was 11.7%, with infections distributed across Malawi. Continued monitoring of Plasmodium spp. becomes critical as nonfalciparum infections become important sources of ongoing transmission.
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Affiliation(s)
- Austin Gumbo
- National Malaria Control Programme, Malawi Ministry of Health, Lilongwe, Malawi
| | - Hillary M Topazian
- Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Alexis Mwanza
- Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Cedar L Mitchell
- Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Sydney Puerto-Meredith
- Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Ruth Njiko
- University of North Carolina Project-Malawi, Lilongwe, Malawi
| | - Michael Kayange
- National Malaria Control Programme, Malawi Ministry of Health, Lilongwe, Malawi
| | - David Mwalilino
- National HIV Reference Laboratory, Malawi Ministry of Health, Lilongwe, Malawi
| | - Bernard Mvula
- National HIV Reference Laboratory, Malawi Ministry of Health, Lilongwe, Malawi
| | - Gerald Tegha
- University of North Carolina Project-Malawi, Lilongwe, Malawi
| | - Tisungane Mvalo
- University of North Carolina Project-Malawi, Lilongwe, Malawi
- Department of Pediatrics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Irving Hoffman
- University of North Carolina Project-Malawi, Lilongwe, Malawi
- Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Jonathan J Juliano
- Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
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Dahal P, Khanal B, Rai K, Kattel V, Yadav S, Bhattarai NR. Challenges in Laboratory Diagnosis of Malaria in a Low-Resource Country at Tertiary Care in Eastern Nepal: A Comparative Study of Conventional vs. Molecular Methodologies. J Trop Med 2021; 2021:3811318. [PMID: 34992661 PMCID: PMC8727160 DOI: 10.1155/2021/3811318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 12/13/2021] [Indexed: 11/17/2022] Open
Abstract
For ongoing malaria elimination programmes, available methods such as microscopy and rapid diagnostic tests (RDTs) cannot detect all malaria cases in acute febrile illness. These methods are entirely dependent on the course of infection, parasite load, and skilled technical resources. Our study objectives were to estimate the performance of light microscopy and a RDT as well as real-time PCR for the detection of the Plasmodium parasite. Altogether, 52 blood samples collected from patients with acute febrile illness were tested by microscopy, RDT, and real-time PCR. The results were compared in terms of sensitivity and specificity. Microscopy detected the malaria parasite in 5.8% of the blood samples whereas 13.5% were detected by the RDT and 27% by real-time PCR. Considering real-time PCR as the gold standard method, microscopy had a sensitivity of 21.4% and a specificity of 100%, and the RDT had a sensitivity of 28.6% and a specificity of 92.1%. Microscopy together with the RDT successfully detected malaria positive cases in blood samples of Ct value below 20, but both were unable to detect malaria cases between 26-40 Ct value ranges amplified by real-time PCR. Despite various diagnostic tools being available, microscopy still remains the method of choice for diagnosis, while the RDT is user-friendly when applied at the point of care. However, our preliminary results emphasize the need to implement the test with higher sensitivity and specificity in the context of a malaria elimination programme. Such programmes can be a crucial opportunity to understand the species prevalent in a low-endemic region. However, these results should be further verified with a large cohort study to document the submicroscopic infection.
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Affiliation(s)
- Pragyan Dahal
- Department of Microbiology, B. P. Koirala Institute of Health Sciences, Dharan, Nepal
| | - Basudha Khanal
- Department of Microbiology, B. P. Koirala Institute of Health Sciences, Dharan, Nepal
| | - Keshav Rai
- Department of Microbiology, B. P. Koirala Institute of Health Sciences, Dharan, Nepal
| | - Vivek Kattel
- Department of Internal Medicine, B. P. Koirala Institute of Health Sciences, Dharan, Nepal
| | - Satish Yadav
- Department of Pediatrics, B. P. Koirala Institute of Health Sciences, Dharan, Nepal
| | - Narayan Raj Bhattarai
- Department of Microbiology, B. P. Koirala Institute of Health Sciences, Dharan, Nepal
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Weckman AM, Conroy AL, Madanitsa M, Gnaneswaran B, McDonald CR, Kalilani-Phiri L, Chandna J, Ali D, Mwapasa V, Khairallah C, Thwai KL, Meshnick SR, Taylor SM, ter Kuile FO, Kain KC, Gladstone M. Neurocognitive outcomes in Malawian children exposed to malaria during pregnancy: An observational birth cohort study. PLoS Med 2021; 18:e1003701. [PMID: 34582452 PMCID: PMC8478258 DOI: 10.1371/journal.pmed.1003701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 06/17/2021] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Annually 125 million pregnancies are at risk of malaria infection. However, the impact of exposure to malaria in pregnancy on neurodevelopment in children is not well understood. We hypothesized that malaria in pregnancy and associated maternal immune activation result in neurodevelopmental delay in exposed offspring. METHODS AND FINDINGS Between April 2014 and April 2015, we followed 421 Malawian mother-baby dyads (median [IQR] maternal age: 21 [19, 28] years) who were previously enrolled (median [IQR] gestational age at enrollment: 19.7 [17.9, 22.1] weeks) in a randomized controlled malaria prevention trial with 5 or 6 scheduled assessments of antenatal malaria infection by PCR. Children were evaluated at 12, 18, and/or 24 months of age with cognitive tests previously validated in Malawi: the Malawi Developmental Assessment Tool (MDAT) and the MacArthur-Bates Communicative Development Inventories (MCAB-CDI). We assessed the impact of antenatal malaria (n [%] positive: 240 [57.3]), placental malaria (n [%] positive: 112 [29.6]), and maternal immune activation on neurocognitive development in children. Linear mixed-effects analysis showed that children exposed to antenatal malaria between 33 and 37 weeks gestation had delayed language development across the 2-year follow-up, as measured by MCAB-CDI (adjusted beta estimate [95% CI], -7.53 [-13.04, -2.02], p = 0.008). Maternal immune activation, characterized by increased maternal sTNFRII concentration, between 33 and 37 weeks was associated with lower MCAB-CDI language score (adjusted beta estimate [95% CI], -8.57 [-13.09, -4.06], p < 0.001). Main limitations of this study include a relatively short length of follow-up and a potential for residual confounding that is characteristic of observational studies. CONCLUSIONS This mother-baby cohort presents evidence of a relationship between malaria in pregnancy and neurodevelopmental delay in offspring. Malaria in pregnancy may be a modifiable risk factor for neurodevelopmental injury independent of birth weight or prematurity. Successful interventions to prevent malaria during pregnancy may reduce the risk of neurocognitive delay in children.
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Affiliation(s)
- Andrea M. Weckman
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- SAR Laboratories, Sandra Rotman Centre for Global Health, Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Andrea L. Conroy
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Mwayiwawo Madanitsa
- College of Medicine, University of Malawi, Blantyre, Malawi
- Academy of Medical Sciences, Malawi University of Science and Technology, Thyolo, Malawi
| | - Bruno Gnaneswaran
- Women and Children’s Health, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Chloe R. McDonald
- Grand Challenges Canada, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | | | - Jaya Chandna
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Doreen Ali
- Department of Preventive Health Services, Ministry of Health, Lilongwe, Malawi
| | - Victor Mwapasa
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - Carole Khairallah
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Kyaw Lay Thwai
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Steven R. Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Steve M. Taylor
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Division of Infectious Diseases, Duke University, Durham, North Carolina, United States of America
- Duke Global Health Institute, Duke University, Durham, North Carolina, United States of America
| | - Feiko O. ter Kuile
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Kevin C. Kain
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- SAR Laboratories, Sandra Rotman Centre for Global Health, Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Tropical Disease Unit, Division of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Melissa Gladstone
- Women and Children’s Health, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
- * E-mail:
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Xuan MNT, Kaewlamun W, Saiwichai T, Thanee S, Poofery J, Tiawsirisup S, Channumsin M, Kaewthamasorn M. Development and application of a novel multiplex PCR assay for the differentiation of four haemosporidian parasites in the chicken Gallus gallus domesticus. Vet Parasitol 2021; 293:109431. [PMID: 33906095 DOI: 10.1016/j.vetpar.2021.109431] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/16/2021] [Accepted: 04/16/2021] [Indexed: 10/21/2022]
Abstract
Haemosporidian infections in domestic chickens (Gallus gallus domesticus) are not only widely prevalent but also cause economic loss. Diagnosis is usually made by microscopic examination; however, the method has several drawbacks such as requiring an experienced microscopist, being unreliable when parasitemia is low and being unable to accurately differentiate between co-infections from multiple parasite species. Therefore, the current extent of haemosporidian infections might be underestimated and neglected. We have developed a novel multiplex PCR assay to simultaneously detect and differentiate between four haemosporidian parasites: Leucocytozoon caulleryi, Leucocytozoon sabrazesi, Plasmodium juxtanucleare and Plasmodium gallinaceum. Primers in the present study specifically amplified the corresponding targets with no cross-species amplification detected. The multiplex PCR exhibited a significantly greater detection rate when compared with microscopic examination (p = 0.0001). The results demonstrate that the detection rate of multiplex PCR for L. sabrazesi, P. juxtanucleare, and P. gallinaceum are all greater than that of microscopic examination with p = 0.002, 0.0001 and 0.004, respectively. Co-infections were also detected more effectively by multiplex PCR. We applied the current method to field samples originating from Nan, Prachinburi, and Chachoengsao Provinces. The current study revealed that positive rates of haemosporidian parasites in chickens in the three study sites ranging from 39.5%-93.8%. The present assay offers a timesaving option for molecular diagnosis instead of using singleplex PCRs for detecting the parasites individually. Within a single reaction, this assay would be a useful tool for the detection of avian haemosporidian parasites either single or under co-infection conditions and for large-scale epidemiology studies.
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Affiliation(s)
- Mai Nguyen Thi Xuan
- The International Graduate Course of Veterinary Science and Technology (VST), Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Winai Kaewlamun
- School of Agricultural Resources, Chulalongkorn University, Phayathai Rd., Pathumwan, Bangkok, 10330, Thailand
| | - Tawee Saiwichai
- Department of Parasitology and Entomology, Faculty of Public Health, Mahidol University, Bangkok, 10400, Thailand
| | - Suchansa Thanee
- Veterinary Parasitology Research Unit, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Juthathip Poofery
- Veterinary Parasitology Research Unit, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Sonthaya Tiawsirisup
- Animal Vector-Borne Disease Research Unit, The Veterinary Parasitology Unit, Department of Veterinary Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Manun Channumsin
- Faculty of Veterinary Medicine, Rajamangala University of Technology Tawan-Ok, Bangpra, Sriracha District, Chonburi, 20110, Thailand
| | - Morakot Kaewthamasorn
- Veterinary Parasitology Research Unit, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand.
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11
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Hounkonnou CPA, Briand V, Fievet N, Accrombessi M, Yovo E, Mama A, Sossou D, Vianou B, Massougbodji A, Ndam NT, Cot M, Cottrell G. Dynamics of Submicroscopic Plasmodium falciparum Infections Throughout Pregnancy: A Preconception Cohort Study in Benin. Clin Infect Dis 2021; 71:166-174. [PMID: 32215629 PMCID: PMC7312237 DOI: 10.1093/cid/ciz748] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 08/05/2019] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND In the context of global malaria elimination efforts, special attention is being paid to submicroscopic Plasmodium falciparum infections. In pregnant, sub-Saharan African women, such infections are more prevalent than microscopic infections, and are thought to have adverse effects on both mothers' and newborns' health. However, no study has studied the dynamics and determinants of these infections throughout pregnancy. Retard de Croissance Intra-uterin et Paludisme (RECIPAL), a preconception cohort study carried out in Benin between 2014 and 2017, represented a unique opportunity to assess this issue. METHODS We used data from 273 pregnant Beninese women who were followed-up from preconception to delivery. We studied the dynamics of and factors influencing submicroscopic (and microscopic) P. falciparum infections during the 3 trimesters of pregnancy, using an ordinal logistic mixed model. RESULTS The incidence rate of submicroscopic P. falciparum infections during pregnancy was 12.7 per 100 person-months (95% confidence interval [CI] 10.8-14.9), compared to 6.7 per 100 person-months (95% CI 5.5-8.1) for microscopic infections. The prevalences were highest in the first trimester for both submicroscopic and microscopic infections. After adjustment for potential confounding factors, we found that those of young age and those with a submicroscopic P. falciparum infection prior to pregnancy were at significantly higher risks of submicroscopic and microscopic infections throughout pregnancy, with a more pronounced effect in the first trimester of pregnancy. CONCLUSIONS The first trimester of pregnancy is a particularly high-risk period for P. falciparum infection during pregnancy, especially for the youngest women. Malaria prevention tools covering the preconception period and early pregnancy are urgently needed to better protect pregnant women and their newborns.
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Affiliation(s)
- Cornélia P A Hounkonnou
- Université de Paris, Mère et enfant en milieu tropical: pathogènes, système de santé et transition épidémiologique, Institut de Recherche pour le Développement, Paris, France.,Sorbonne Université, Université Pierre et Marie-Curie, Paris, France
| | - Valérie Briand
- Université de Paris, Mère et enfant en milieu tropical: pathogènes, système de santé et transition épidémiologique, Institut de Recherche pour le Développement, Paris, France
| | - Nadine Fievet
- Université de Paris, Mère et enfant en milieu tropical: pathogènes, système de santé et transition épidémiologique, Institut de Recherche pour le Développement, Paris, France
| | | | - Emmanuel Yovo
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Cotonou, Bénin
| | - Atikatou Mama
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Cotonou, Bénin
| | - Darius Sossou
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Cotonou, Bénin
| | - Bertin Vianou
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Cotonou, Bénin
| | - Achille Massougbodji
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Cotonou, Bénin
| | - Nicaise Tuikue Ndam
- Université de Paris, Mère et enfant en milieu tropical: pathogènes, système de santé et transition épidémiologique, Institut de Recherche pour le Développement, Paris, France
| | - Michel Cot
- Université de Paris, Mère et enfant en milieu tropical: pathogènes, système de santé et transition épidémiologique, Institut de Recherche pour le Développement, Paris, France
| | - Gilles Cottrell
- Université de Paris, Mère et enfant en milieu tropical: pathogènes, système de santé et transition épidémiologique, Institut de Recherche pour le Développement, Paris, France.,Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Cotonou, Bénin
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12
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Taylor SM, Levitt B, Freedman B, Madanitsa M, Thwai KL, Kalilani-Phiri L, Khairallah C, Mwapasa V, Ter Kuile FO, Meshnick SR. Interactions Between Antenatal Sulfadoxine-Pyrimethamine, Drug-Resistant Plasmodium falciparum Parasites, and Delivery Outcomes in Malawi. J Infect Dis 2021; 222:661-669. [PMID: 32221555 DOI: 10.1093/infdis/jiaa145] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 03/25/2020] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Sulfadoxine-pyrimethamine (SP) is used as intermittent preventive therapy in pregnancy (IPTp) for malaria in sub-Saharan Africa. The resistance marker dhps A581G has been associated with reduced IPTp-SP efficacy and enhanced morbidity in SP recipients. METHODS We measured SP-resistance allele frequencies in Malawian women participating in a trial comparing IPTp with SP against intermittent screening by rapid diagnostic tests (ISTp). We genotyped polymerase chain reaction-detected parasites using deep sequencing of SP-resistance alleles. RESULTS Among 125 placental infections, A581G-bearing parasites were associated with reduced birth weight (mean difference [MD], 252 g; 95% confidence interval [CI], 46-457; P = .017). Relative to ISTp, IPTp-SP was associated with higher birth weights in women with wild-type parasites (MD, 116 g; 95% CI, -40 to 272; P = .142) and lower birth weights in women with A581G-bearing parasites (MD, 192 g; 95% CI, -264 to 648; P = .385) (Pinteraction = .033). Similar associations were noted on gestational age (Pinteraction = .075). Amongst only IPTp-SP recipients, relative to women who last received SP > 4 weeks before delivery, recent SP receipt was associated with lower birth weight in women with wild-type parasites (MD, 118 g; 95% CI, -376 to 139; P = .361) and higher birth weight in women with A581G-bearing parasites (MD, 783 g; 95% CI, -20 to 1586; P = .054) (Pinteraction = .005). CONCLUSIONS The effectiveness in birth weight of IPTp-SP is compromised by A581G-bearing parasites, but there was no evidence that the adverse effects of these parasites are exacerbated by antenatal SP. ISRCTN REGISTRY www.isrctn.com/ISRCTN69800930.
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Affiliation(s)
- Steve M Taylor
- Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina, USA.,Duke Global Health Institute, Durham, North Carolina, USA.,Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Brandt Levitt
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA
| | - Betsy Freedman
- Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina, USA
| | - Mwayiwawo Madanitsa
- Department of Public Health, School of Public Health and Family Medicine, College of Medicine, Blantyre, Malawi.,Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Kyaw-Lay Thwai
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Linda Kalilani-Phiri
- Department of Public Health, School of Public Health and Family Medicine, College of Medicine, Blantyre, Malawi
| | - Carole Khairallah
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Victor Mwapasa
- Department of Public Health, School of Public Health and Family Medicine, College of Medicine, Blantyre, Malawi
| | - Feiko O Ter Kuile
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
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13
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Solomon A, Kahase D, Alemayhu M. Prevalence of placental malaria among asymptomatic pregnant women in Wolkite health center, Gurage zone, Southern Ethiopia. Trop Dis Travel Med Vaccines 2020; 6:20. [PMID: 33062290 PMCID: PMC7552502 DOI: 10.1186/s40794-020-00121-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 09/28/2020] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Placental malaria (PM) is a major public health problem associated with adverse pregnancy outcomes such as low birth weight (LBW), preterm delivery and maternal anemia. The present study is aimed to determine the prevalence of placental malaria among asymptomatic pregnant women in Wolkite health center, Gurage zone, Southern Ethiopia. METHOD Facility-based cross-sectional study was carried out from June 2019 to August 2019. A total of 230 pregnant women were involved in the study where socio-demographic data, medical and obstetric history were collected using pretested structured questionnaires. Blood samples were collected at delivery from maternal capillary, placenta and umbilical cord for the detection of malarial parasite. Maternal hematocrit was determined to screen for anemia. RESULT In this study, the prevalence of placental malaria, peripheral malaria and umbilical cord malaria was 3.9% (9/230), 15.2% (35/230) and 2.6% (6/230) respectively. Plasmodium falciparum and Plasmodium vivax were detected by microscopy. All babies with positive umbilical cord blood films were born from a mother with placental malaria. Maternal anemia was recorded in 58.3% of the women. In univariate analysis, placental malaria was significantly associated with LBW (p < 0.001) unlike parity and maternal anemia. CONCLUSION Placental malaria among asymptomatic pregnant women is low in Wolkite health centre, Gurage zone in Southern Ethiopia. Moreover, placental malaria was strongly associated with LBW. Thus, further strengthening the existing prevention and control activities and screening of asymptomatic pregnant women as part of routine antenatal care service is very essential.
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Affiliation(s)
- Absra Solomon
- Department of Medical Laboratory Science, College of Medicine and Health Science, Wolkite University, Wolkite, Ethiopia
| | - Daniel Kahase
- Department of Medical Laboratory Science, College of Medicine and Health Science, Wolkite University, Wolkite, Ethiopia
| | - Mihret Alemayhu
- Department of Medical Laboratory Science, College of Medicine and Health Science, Wolkite University, Wolkite, Ethiopia
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14
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Nsiah K, Bahaah B, Afranie BO, Acheampong E. Evaluation of red blood cell count as an ancillary index to hemoglobin level in defining the severe falciparum malarial anemia among Ghanaian children in low-resource communities. Heliyon 2020; 6:e04605. [PMID: 32904347 PMCID: PMC7452483 DOI: 10.1016/j.heliyon.2020.e04605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/10/2020] [Accepted: 07/28/2020] [Indexed: 01/15/2023] Open
Abstract
Our study evaluated red blood cell count as supporting hematological index to hematocrit level in predicting severe malarial anemia instead of the hemoglobin levels among malaria-infected children in Ghana. This case-control study was conducted at the Komfo Anokye Teaching Hospital (KATH) in Kumasi, Ghana. The study recruited 139 children, of which 45 were Controls (C), 43 with severe malaria (SM), and 51 with mild malaria (MM). Validated questionnaires were administered to obtain the socio-demographic data from each respondent. Venous blood was obtained for parasitemia count and to determine the hematological profile of each participant. With point of observation, data analysis was done. The mean age of the children was 4.22 ± 2.65 years. Median levels of hemoglobin (Hb) decreased in the order; C > MM > SM (P < 0.0001). There was a reduction in median levels of hematocrit (HCT) (P < 0.0001), RBC (red blood cells count) (<0.0001), from the MM to the SM. Among patients with severe malaria, there were a positive significant spearmen's co-efficient correlations between median levels of RBC (r = 0.652, P = 0.005) and HB (r = 0.640, P = 0.006) individually against HCT. However among the mild malaria patients only RBC (r = 0.884, P < 0.001) was positively correlated against HCT. At a cut-off of <4.0×106/uL for RBC and <8.8 g/dL for Hb, RBC (90.4%) recorded a slightly high accuracy in predicting severe falciparum malarial anemia than Hb (86.9%) among the cases. Red blood cell count may be a promising indicator to support hematocrit (<15%) in defining severe malarial anemia than hemoglobin level (<5 g/dL) among malaria-infected children from endemic areas in Ghana.
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Affiliation(s)
- Kwabena Nsiah
- Department of Biochemistry and Biotechnology, Faculty of Biosciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Bernard Bahaah
- Department of Biochemistry and Biotechnology, Faculty of Biosciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Bright Oppong Afranie
- Department of Molecular Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Emmanuel Acheampong
- Department of Molecular Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.,School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
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15
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Submicroscopic malaria infection is not associated with fever in cross-sectional studies in Malawi. Malar J 2020; 19:233. [PMID: 32600362 PMCID: PMC7322713 DOI: 10.1186/s12936-020-03296-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 06/17/2020] [Indexed: 11/10/2022] Open
Abstract
Background Submicroscopic Plasmodium falciparum infections are widespread in many areas. However, the contribution of these infections to symptomatic malaria is not well understood. This study evaluated whether participants with submicroscopic P. falciparum infections have higher prevalence of fever than uninfected participants in southern Malawi. Methods A total of 16,650 children and adults were enrolled in the course of six cross-sectional surveys during the dry season (October–November) and after the rainy season (April–May) between 2012 and 2014 in three districts in southern Malawi. Demographic and socioeconomic data were collected in conjunction with data on clinical histories, use of malaria preventive measures, and anti-malarial medication taken within 2 weeks of the survey. Axillary temperatures were measured, and blood samples were collected for P. falciparum detection by microscopy and PCR. Participants without malaria parasites detected on microscopy but with a positive PCR for P. falciparum were defined as having submicroscopic infection. Fever was defined as having any one of: reported fever in the past 2 weeks, reported fever in the past 48 h, or a temperature of ≥ 37.5 °C measured at the time of interview. Results Submicroscopic P. falciparum infections and fever were both detected in 9% of the study population. In the final analysis adjusted for clustering within household and enumeration area, having submicroscopic P. falciparum infection was associated with reduced odds of fever in the dry season (odds ratio = 0.52; 95% CI 0.33–0.82); the association in the rainy season did not achieve statistical significance (odds ratio = 1.20; 95% CI 0.91–1.59). The association between submicroscopic infection and fever was consistent across all age groups. When the definition of fever was limited to temperature of ≥ 37.5 °C measured at the time of interview, the association was not statistically significant in either the rainy or dry season. Conclusions In this series of cross-sectional studies in southern Malawi, submicroscopic P. falciparum infection was not associated with increased risk of fever. Submicroscopic detection of the malaria parasite is important in efforts to decrease transmission but is not essential for the clinical recognition of malaria disease.
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16
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Taylor SM, Sumner KM, Freedman B, Mangeni JN, Obala AA, Prudhomme O'Meara W. Direct Estimation of Sensitivity of Plasmodium falciparum Rapid Diagnostic Test for Active Case Detection in a High-Transmission Community Setting. Am J Trop Med Hyg 2020; 101:1416-1423. [PMID: 31674301 DOI: 10.4269/ajtmh.19-0558] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Community-based active case detection of malaria parasites with conventional rapid diagnostic tests (cRDTs) is a strategy used most commonly in low-transmission settings. We estimated the sensitivity of this approach in a high-transmission setting in Western Kenya. We tested 3,547 members of 912 households identified in 2013-2014 by index children with (case) and without (control) cRDT-positive malaria. All were tested for Plasmodium falciparum with both a cRDT targeting histidine-rich protein 2 and with an ultrasensitive real-time polymerase chain reaction (PCR). We computed cRDT sensitivity against PCR as the referent, compared prevalence between participant types, and estimated cRDT detectability as a function of PCR-estimated parasite density. Parasite prevalence was 22.9% by cRDTs and 61.5% by PCR. Compared with children aged < 5 years or adults aged > 15 years, geometric mean parasite densities (95% CI) were highest in school-age children aged 5-15 years (8.4 p/uL; 6.6-10.6). The overall sensitivity of cRDT was 36%; among asymptomatic household members, cRDT sensitivity was 25.5% and lowest in adults aged > 15 years (15.8%). When modeled as a function of parasite density, relative to school-age children, the probability of cRDT positivity was reduced in both children aged < 5 years (odds ratio [OR] 0.48; 95% CI: 0.34-0.69) and in adults aged > 15 years (OR: 0.35; 95% CI: 0.27-0.47). An HRP2-detecting cRDT had poor sensitivity for active P. falciparum case detection in asymptomatic community members, and sensitivity was lowest in highly prevalent low-density infections and in adults. Future studies can model the incremental effects of high-sensitivity rapid diagnostic tests and the impacts on transmission.
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Affiliation(s)
- Steve M Taylor
- Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina.,Department of Epidemiology, University of North Carolina Gillings School of Global Public Health, Chapel Hill, North Carolina.,Duke Global Health Institute, Durham, North Carolina
| | - Kelsey M Sumner
- Department of Epidemiology, University of North Carolina Gillings School of Global Public Health, Chapel Hill, North Carolina.,Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina
| | - Betsy Freedman
- Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina
| | | | - Andrew A Obala
- College of Health Sciences, Moi University, Eldoret, Kenya
| | - Wendy Prudhomme O'Meara
- College of Health Sciences, Moi University, Eldoret, Kenya.,Duke Global Health Institute, Durham, North Carolina.,Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina
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17
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Khaemba EN, Ogwang C, Kinyanjui S, Muindi JM, Koske JK, Kimani D, Ngoi J, Mwacharo J, Shangala J, Njuguna P, Mutinda D, Nyatichi E, Peshu J, Mutinda B, Ndungu FM, Farnert A, Bashraheil MM, Bejon P, Kapulu MC. Comparing drug regimens for clearance of malaria parasites in asymptomatic adults using PCR in Kilifi County, Kenya: an open-label randomised controlled clinical trial (MalPaC). Wellcome Open Res 2020. [DOI: 10.12688/wellcomeopenres.15627.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: To restrict trial endpoints to infections acquired after vaccination in Phase IIb trials of candidate malaria vaccines, participants are treated with anti-malarial drugs to clear existing infections. Anti-malarial drugs with a long half-life may inhibit the acquisition of new infections. This study evaluated the effects of three anti-malarial drug regimens on the clearance of existing infections and acquisition of new infections. Methods: An open-label randomised controlled trial (MalPaC) was conducted between November 2013 and February 2014. Ninety adults were randomised 1:1:1 to receive one of three treatments: atovaquone/proguanil and artesunate (AP+AS); artesunate (AS); or sulphadoxine-pyrimethamine, artesunate, and primaquine (SP+AS+PQ). Parasite monitoring was determined over 84-day follow-up by assessing Plasmodium falciparum positivity by 18s qPCR, live and sexual stage parasites by RT-PCR, and recrudescence of infections by msp2 genotyping. Results: At enrolment, parasite prevalence by qPCR was 44% (40/90, day 0), which fell to 10% (9/90, day 16), then rose to almost the initial rates by day 84 (39%, 35/90). Individuals treated with AS and SP+AS+PQ were more likely to have higher qPCR positive rates compared to participants treated with AP+AS in the immediate post-treatment phase (days 16-28) (OR=7.7 [95%CI 4.6-12.8] p<0.0005 and OR=4.2 [95%CI 2.6-6.8] p<0.0005, respectively). In the immediate post-treatment phase, qPCR positivity was less likely associated with evidence of live parasites and gametocytaemia. Prevalence of “old”, “new” or “undetectable” infections did not differ significantly over time or drug regimen. However, participants on the AP+AS drug regimen were less likely to have parasite infection recrudescence compared to participants treated with AS and SP+AS+PQ. Conclusion: Falciparum DNA remained detectable by PCR post-treatment with incomplete parasite clearance regardless of drug regimen. Though AP+AS drug regimen may also have partially suppressed the acquisition of new infections during post-treatment follow-up. Trial registration: Pan African Clinical Trials Registry, 22nd of August 2013, PACTR201309000625311.
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18
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Buchwald AG, Sixpence A, Chimenya M, Damson M, Sorkin JD, Wilson ML, Seydel K, Hochman S, Mathanga DP, Taylor TE, Laufer MK. Clinical Implications of Asymptomatic Plasmodium falciparum Infections in Malawi. Clin Infect Dis 2020; 68:106-112. [PMID: 29788054 DOI: 10.1093/cid/ciy427] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 05/15/2018] [Indexed: 11/14/2022] Open
Abstract
Background Asymptomatic Plasmodium falciparum infections are common in Malawi; however, the implications of these infections for the burden of malaria illness are unknown. Whether asymptomatic infections eventually progress to malaria illness, persist without causing symptoms, or clear spontaneously remains undetermined. We identified asymptomatic infections and evaluated the associations between persistent asymptomatic infections and malaria illness. Methods Children and adults (N = 120) who presented at a health facility with uncomplicated malaria were followed monthly for 2 years. During follow-up visits, participants with malaria symptoms were tested and, if positive, treated. Samples from all visits were tested for parasites using both microscopy and polymerase chain reaction, and all malaria infections underwent genotyping. Cox frailty models were used to estimate the temporal association between asymptomatic infections and malaria illness episodes. Mixed models were used to estimate the odds of clinical symptoms associated with new versus persistent infections. Results Participants had a median follow-up time of 720 days. Asymptomatic infections were detected during 23% of visits. Persistent asymptomatic infections were associated with decreased risk of malaria illness in all ages (hazard ratio 0.50, P < .001). When asymptomatic infections preceded malaria illness, newly-acquired infections were detected at 92% of subsequent clinical episodes, independent of presence of persistent infections. Malaria illness among children was more likely due to newly-acquired infections (odds ratio, 1.4; 95% confidence interval, 1.3-1.5) than to persistent infections. Conclusions Asymptomatic P. falciparum infections are associated with decreased incidence of malaria illness, but do not protect against disease when new infection occurs.
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Affiliation(s)
- Andrea G Buchwald
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore
| | - Alick Sixpence
- Malaria Alert Center, University of Malawi College of Medicine, Blantyre
| | - Mabvuto Chimenya
- Malaria Alert Center, University of Malawi College of Medicine, Blantyre
| | - Milius Damson
- Malaria Alert Center, University of Malawi College of Medicine, Blantyre
| | - John D Sorkin
- Department of Veterans Affairs, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore
| | - Mark L Wilson
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor
| | - Karl Seydel
- College of Osteopathic Medicine, Michigan State University, East Lansing
| | - Sarah Hochman
- Department of Medicine, New York University School of Medicine
| | - Don P Mathanga
- Malaria Alert Center, University of Malawi College of Medicine, Blantyre
| | - Terrie E Taylor
- College of Osteopathic Medicine, Michigan State University, East Lansing
| | - Miriam K Laufer
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore
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19
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Andronescu LR, Buchwald AG, Coalson JE, Cohee L, Bauleni A, Walldorf JA, Kandangwe C, Mzilahowa T, Taylor TE, Mathanga DP, Laufer MK. Net age, but not integrity, may be associated with decreased protection against Plasmodium falciparum infection in southern Malawi. Malar J 2019; 18:329. [PMID: 31551076 PMCID: PMC6760057 DOI: 10.1186/s12936-019-2930-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 08/22/2019] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Distribution campaigns for insecticide-treated nets (ITN) have increased the use of ITNs in Malawi, but malaria prevalence remains high even among those using the nets. Previous studies have addressed ITN ownership, insecticide resistance, and frequency of ITN use as possible contributing factors to the high prevalence of malaria infection despite high ITN coverage, but have rarely considered whether the condition of the ITN, or how many people use it, impacts efficacy. This study assessed how ITN integrity, ITN age, and the number of persons sharing a net might mitigate or reduce protective efficacy among self-identified ITN users in Malawi. METHODS From 2012 to 2014, six cross-sectional surveys were conducted in both the rainy and dry seasons in southern Malawi. Data were collected on ITN use, integrity (number and size of holes), and age. Blood samples for detecting Plasmodium falciparum infection were obtained from reported ITN users over 6 months of age. Generalized linear mixed models were used to account for clustering at the household and community level. The final model controlled for gender, household eaves, and community-level infection prevalence during the rainy season. RESULTS There were 9646 ITN users with blood samples across six surveys, 15% of whom tested positive for P. falciparum infection. Among children under 5 years old, there was a 50% increased odds of P. falciparum infection among those sleeping under an ITN older than two years, compared to those using an ITN less than 2 years old (OR = 1.50; 95% CI 1.07-2.08). ITN integrity and number of individuals sharing an ITN were not associated with P. falciparum infection. CONCLUSIONS Older ITNs were associated with higher rates of P. falciparum in young children, which may indicate that insecticide concentrations play a larger role in infection prevention than the physical barrier of an ITN. ITN use was self-reported and the integrity measures lacked the precision of newer methods, suggesting a need for objective measures of ITN use and more precise assessment of ITN integrity.
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Affiliation(s)
- Liana R. Andronescu
- 0000 0001 2175 4264grid.411024.2Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 W, Baltimore Street, Baltimore, MD 21201 USA
| | - Andrea G. Buchwald
- 0000 0001 2175 4264grid.411024.2Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 W, Baltimore Street, Baltimore, MD 21201 USA ,0000 0001 0703 675Xgrid.430503.1Present Address: University of Colorado School of Public Health, University of Colorado, 13001 E, 17th Place, Mail Stop B119, Aurora, CO 80045 USA
| | - Jenna E. Coalson
- 0000 0001 2168 186Xgrid.134563.6Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295N Martin Ave, Tucson, AZ 85724 USA
| | - Lauren Cohee
- 0000 0001 2175 4264grid.411024.2Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 W, Baltimore Street, Baltimore, MD 21201 USA
| | - Andy Bauleni
- 0000 0001 2113 2211grid.10595.38Malaria Alert Centre, University of Malawi College of Medicine, Blantyre, Malawi
| | - Jenny A. Walldorf
- 0000 0001 2175 4264grid.411024.2Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 W, Baltimore Street, Baltimore, MD 21201 USA ,0000 0001 2163 0069grid.416738.fPresent Address: Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA USA
| | - Chifundo Kandangwe
- 0000 0001 2113 2211grid.10595.38Malaria Alert Centre, University of Malawi College of Medicine, Blantyre, Malawi
| | - Themba Mzilahowa
- 0000 0001 2113 2211grid.10595.38Malaria Alert Centre, University of Malawi College of Medicine, Blantyre, Malawi
| | - Terrie E. Taylor
- 0000 0001 2150 1785grid.17088.36Department of Osteopathic Medical Specialties, Michigan State University, 909 Fee Road, East Lansing, MI 48824 USA
| | - Don P. Mathanga
- 0000 0001 2113 2211grid.10595.38Malaria Alert Centre, University of Malawi College of Medicine, Blantyre, Malawi
| | - Miriam K. Laufer
- 0000 0001 2175 4264grid.411024.2Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 W, Baltimore Street, Baltimore, MD 21201 USA
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Impact of Submicroscopic Plasmodium falciparum Parasitaemia on Maternal Anaemia and Low Birth Weight in Blue Nile State, Sudan. J Trop Med 2019; 2019:3162378. [PMID: 31485236 PMCID: PMC6702852 DOI: 10.1155/2019/3162378] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/20/2019] [Accepted: 07/15/2019] [Indexed: 12/25/2022] Open
Abstract
The aim of the present study was to investigate the prevalence of submicroscopic infections and to assess its impact on maternal anaemia and low birth weight. A cross-sectional study was carried out with 1149 consented pregnant women who delivered at 3 main hospitals in the Blue Nile State, between January 2012 and December 2015. From a matched maternal peripheral, placental maternal side, and cord blood sample, blood films and dried spots were prepared for microscopic examination and nested polymerase chain reaction (n-PCR), respectively. 107 out of 447 negative blood films were found to have submicroscopic infection detected using n-PCR in any of the three compartments. Placental samples had a significantly higher prevalence (142) of submicroscopic infections compared with the peripheral (6.5%) and cord (8.1%) samples. The mean (SD) of the maternal haemoglobin (Hb) was significantly lower in cases with submicroscopic parasitaemia (10.9 (0.8) vs. 12.1 (0.7) g/dl, P < 0.001) compared with those who had no submicroscopic parasitaemia. Submicroscopic malaria infection was associated with anaemia (OR 19.7, (95% CI, 10.3–37.8)). Thirty-eight babies born to women with submicroscopic infections were low birth weight (LBW) and was significantly lower in submicroscopic parasitaemia (2.663 (0.235) vs. 2.926 (0.341) kg, P < 0.001). Submicroscopic malaria infection was associated with LBW (OR = 2.7, (95% CI, 1.2–5.6)). There is a high incidence of submicroscopic infections in any of the three compartments regardless of age or parity. Submicroscopic infection is a risk of maternal anaemia and low birth weight in women in this area of high seasonal malaria transmission.
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Haanshuus CG, Mørch K, Blomberg B, Strøm GEA, Langeland N, Hanevik K, Mohn SC. Assessment of malaria real-time PCR methods and application with focus on low-level parasitaemia. PLoS One 2019; 14:e0218982. [PMID: 31276473 PMCID: PMC6611585 DOI: 10.1371/journal.pone.0218982] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 06/04/2019] [Indexed: 01/04/2023] Open
Abstract
In epidemiological surveys and surveillance the application of molecular tools is essential in detecting submicroscopic malaria. A genus-specific conventional cytochrome b (cytb) PCR has shown high sensitivity in field studies, detecting 70% submicroscopic malaria. The main objective of this study was to assess the conversion from conventional to real-time PCR testing both SYBR and probe protocols, and including quantitative (q) PCR. The protocols were assessed applying well-defined clinical patient material consisting of 33 positive and 80 negative samples. Sequencing of positive PCR products was performed. In addition, a sensitivity comparison of real-time PCR methods was done by including five relevant assays investigating the effect of amplification target and platform. Sensitivity was further examined using field material consisting of 111 P.falciparum positive samples from Tanzanian children (< 5 years), as well as using related patient data to assess the application of q-PCR with focus on low-level parasitaemia. Both the cytb SYBR and probe PCR protocols showed as high sensitivity and specificity as their conventional counterpart, except missing one P. malariae sample. The SYBR protocol was more sensitive and specific than using probe. Overall, choice of amplification target applied is relevant for achieving ultra-sensitivity, and using intercalating fluorescence dye rather than labelled hydrolysis probes is favourable. Application of q-PCR analysis in field projects is important for the awareness and understanding of low-level parasitaemia. For use in clinical diagnosis and epidemiological studies the highly sensitive and user-friendly cytb SYBR q-PCR method is a relevant tool. The genus-specific method has the advantage that species identification by sequencing can be performed as an alternative to species-specific PCR.
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Affiliation(s)
- Christel Gill Haanshuus
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
- * E-mail:
| | - Kristine Mørch
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Bjørn Blomberg
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | | | - Nina Langeland
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Haraldsplass Deaconess Hospital, Bergen, Norway
| | - Kurt Hanevik
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Stein Christian Mohn
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
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Jahan F, Khan NH, Wahid S, Ullah Z, Kausar A, Ali N. Malaria epidemiology and comparative reliability of diagnostic tools in Bannu; an endemic malaria focus in south of Khyber Pakhtunkhwa, Pakistan. Pathog Glob Health 2019; 113:75-85. [PMID: 30894081 DOI: 10.1080/20477724.2019.1595904] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
The present study was aimed at elucidation of malaria epidemiology and comparing performance of several diagnostic procedures in Bannu, a highly endemic district of Khyber Pakhtunkhwa, Pakistan. Dried blood spots were collected from patients suspected of malaria visiting a hospital and two private laboratories in district Bannu and processed for species-specific PCR (rRNA). Patients were also screened for malaria through microscopy and RDT. A well-structured questionnaire was used to collect patient information to assess risk factors for malaria. Of 2033 individuals recruited, 21.1% (N = 429) were positive for malaria by at least one method. Overall, positivity detected by PCR was 30.5% (95/311) followed by 17.7% by microscopy (359/2033) and 16.4% by RDT (266/1618). Plasmodium vivax (16.9%, N = 343) was detected as the dominant species followed by Plasmodium falciparum (2.3%, N = 47) and mixed infections (1.2%, N = 39). Microscopy and RDT (Cohen's kappa k = 0.968, p = <0.0001, McNemar test p = 0.069) displayed significant agreement with each other. Satisfactory health, sleeping indoors, presence of health-care facility in vicinity (at an accessible range from home), living in upper middle class and in concrete houses significantly reduced malaria risk; whereas, low literacy level, presence of domestic animals indoors and malaria diagnosis recommended by clinician increased the disease risk. Overall, findings from the study provide reasonable basis for use of RDT as a cost-effective screening tool in field and for clinicians who can proceed with timely treatment of malaria patients. Appropriate management of identified risk factors could contribute to reduction of malaria prevalence in Bannu and its peripheries.
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Affiliation(s)
- Fatima Jahan
- a Department of Zoology , University of Peshawar , Peshawar , Pakistan
| | - Nazma Habib Khan
- a Department of Zoology , University of Peshawar , Peshawar , Pakistan
| | - Sobia Wahid
- a Department of Zoology , University of Peshawar , Peshawar , Pakistan
| | - Zaki Ullah
- b Department of Pharmacy , University of Peshawar , Peshawar , Pakistan
| | - Aisha Kausar
- a Department of Zoology , University of Peshawar , Peshawar , Pakistan
| | - Naheed Ali
- a Department of Zoology , University of Peshawar , Peshawar , Pakistan
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Buchwald AG, Sorkin JD, Sixpence A, Chimenya M, Damson M, Wilson ML, Seydel K, Hochman S, Mathanga D, Taylor TE, Laufer MK. Association Between Age and Plasmodium falciparum Infection Dynamics. Am J Epidemiol 2019; 188:169-176. [PMID: 30252032 DOI: 10.1093/aje/kwy213] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 09/12/2018] [Indexed: 11/12/2022] Open
Abstract
Few data exist on the incidence or duration of natural Plasmodium falciparum infections in high-transmission settings. School-aged children (SAC) carry a disproportionate burden of infections, suggesting either increased incidence or increased duration. We estimated the incidence and duration of unique infections according to age groups. The Mfera Cohort Study (2014-2017) in Malawi had 2 years of follow-up, with 120 participants tested monthly and during sick visits. Blood samples were collected to detect P. falciparum by microscopy and polymerase chain reaction. Positive samples underwent genotyping. Simulation was used to account for high rates of nondetection of infection among low-parasitemia infections, which increase in frequency with age. Adults had significantly fewer unique infections per person per year (median, 2.5) compared with SAC and children younger than 5 years of age (6.3 and 6.6, respectively). Over half of all genotypes were persistent. Infections lasted significantly longer in adults (median, 180 days) and SAC (median, 163 days) compared with children younger than 5 years of age (median, 97 days), after accounting for age-dependent nondetection of infection. SAC acquired new infections at the same rate as children younger than 5 years, but they maintained these infections for longer periods of time, similar to adults. This study provides new insights into P. falciparum infection dynamics that should be considered when designing malaria control strategies.
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Affiliation(s)
- Andrea G Buchwald
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - John D Sorkin
- Geriatrics Research, Education, and Clinical Center, Baltimore Veterans Affairs Medical Center, Baltimore, Maryland
- Division of Geriatrics and Gerontology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Alick Sixpence
- Malaria Alert Center, University of Malawi College of Medicine, Blantyre, Malawi
| | - Mabvuto Chimenya
- Malaria Alert Center, University of Malawi College of Medicine, Blantyre, Malawi
| | - Milius Damson
- Malaria Alert Center, University of Malawi College of Medicine, Blantyre, Malawi
| | - Mark L Wilson
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, Michigan
| | - Karl Seydel
- College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan
| | - Sarah Hochman
- Department of Medicine, New York University School of Medicine, New York, New York
| | - Don Mathanga
- Malaria Alert Center, University of Malawi College of Medicine, Blantyre, Malawi
| | - Terrie E Taylor
- College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan
| | - Miriam K Laufer
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
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24
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Mirahmadi H, Shahrakipour A, Mehravaran A, Khorashad AS, Rahmati-Balaghaleh M, Zarean M. Evaluation of malaria multiplex/nested PCR performance at low parasite densities and mixed infection in Iran: A country close to malaria elimination. INFECTION GENETICS AND EVOLUTION 2018; 65:283-287. [PMID: 30096462 DOI: 10.1016/j.meegid.2018.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/06/2018] [Accepted: 08/06/2018] [Indexed: 11/30/2022]
Abstract
BACKGROUND Malaria is still a major public health problem in subtropical and tropical regions. The rapid and accurate diagnosis of malaria remains a challenge in most of the endemic areas. The primary objective of the present study was to evaluate the performance of multiplex/nested PCR in detecting Plasmodium falciparum at low parasite densities and mixed infection. METHODS The study was performed in the Sistan-Baluchestan province of the southeastern Iran, from May 2015 to July 2016. A total of 105 patients suspected to malaria infection were enrolled in the study. The obtained DNA products, extracted from the thick/thin films, were analyzed by multiplex/nested PCR using genus-specific primers and compared with light microscopy. RESULTS 43 samples were confirmed to be infected by microscopic examination. Among 43 microscopically diagnosed P. falciparum cases, 11.4% (12/105) were confirmed by multiplex/nested PCR, 36.2% (38/105) were confirmed as P. vivax, 1.9% (2/105) had mixed infections with P. falciparum and P. vivax. Among microscopy-negative samples, 10 samples turned malaria-positive in nPCR. In multiplex/nested PCR, the rate of mixed infections was 8.6% (9/105). When compared to LM, the sensitivity, specificity, positive predictive value and negative predictive value of multiplex/nested PCR were calculated to be 82.8, 91.5, 92.3 and 81.1%, respectively. CONCLUSION In this study, we showed that microscopic examination of blood smears does not reliably distinguish Plasmodium species in the case of mixed infections. Therefore, it seems that multiplex/nested PCR is a good candidate for examining the presence of malaria parasites in clinically suspected but microscopically negative cases.
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Affiliation(s)
- Hadi Mirahmadi
- Infectious Diseases and Tropical Medicine Research Center, Resistant Tuberculosis Institute, Zahedan University of Medical Sciences, Zahedan, Iran; Department of Parasitology and Mycology, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Azam Shahrakipour
- Infectious Diseases and Tropical Medicine Research Center, Resistant Tuberculosis Institute, Zahedan University of Medical Sciences, Zahedan, Iran; Department of Parasitology and Mycology, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Ahmad Mehravaran
- Infectious Diseases and Tropical Medicine Research Center, Resistant Tuberculosis Institute, Zahedan University of Medical Sciences, Zahedan, Iran; Department of Parasitology and Mycology, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Alireza Salami Khorashad
- Infectious Diseases and Tropical Medicine Research Center, Resistant Tuberculosis Institute, Zahedan University of Medical Sciences, Zahedan, Iran; Department of Parasitology and Mycology, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Mansour Rahmati-Balaghaleh
- Infectious Diseases and Tropical Medicine Research Center, Resistant Tuberculosis Institute, Zahedan University of Medical Sciences, Zahedan, Iran; Department of Parasitology and Mycology, Zahedan University of Medical Sciences, Zahedan, Iran.
| | - Mehdi Zarean
- Department of Parasitology and Mycology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran; Cutaneous Leishmaniasis Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
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Abstract
Malaria is the major cause of mortality and morbidity in tropical countries. The causative agent, Plasmodium sp., has a complex life cycle and is armed with various mechanisms which ensure its continuous transmission. Gametocytes represent the sexual stage of the parasite and are indispensable for the transmission of the parasite from the human host to the mosquito. Despite its vital role in the parasite's success, it is the least understood stage in the parasite's life cycle. The presence of gametocytes in asymptomatic populations and induction of gametocytogenesis by most antimalarial drugs warrants further investigation into its biology. With a renewed focus on malaria elimination and advent of modern technology available to biologists today, the field of gametocyte biology has developed swiftly, providing crucial insights into the molecular mechanisms driving sexual commitment. This review will summarise key current findings in the field of gametocyte biology and address the associated challenges faced in malaria detection, control and elimination.
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Coalson JE, Cohee LM, Buchwald AG, Nyambalo A, Kubale J, Seydel KB, Mathanga D, Taylor TE, Laufer MK, Wilson ML. Simulation models predict that school-age children are responsible for most human-to-mosquito Plasmodium falciparum transmission in southern Malawi. Malar J 2018; 17:147. [PMID: 29615044 PMCID: PMC5883608 DOI: 10.1186/s12936-018-2295-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/24/2018] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Malaria persists in some high-transmission areas despite extensive control efforts. Progress toward elimination may require effective targeting of specific human populations that act as key transmission reservoirs. METHODS Parameterized using molecular-based Plasmodium falciparum infection data from cross-sectional community studies in southern Malawi, a simulation model was developed to predict the proportions of human-to-mosquito transmission arising from (a) children under 5 years old (U5s), (b) school-age children (SAC, 5-15 years), (c) young adults (16-30 years), and (d) adults > 30 years. The model incorporates mosquito biting heterogeneity and differential infectivity (i.e. probability that a blood-fed mosquito develops oocysts) by age and gametocyte density. RESULTS The model predicted that SAC were responsible for more than 60% of new mosquito infections in both dry and rainy seasons, even though they comprise only 30% of this southern Malawi population. Young adults were the second largest contributors, while U5s and adults over 30 were each responsible for < 10% of transmission. While the specific predicted values are sensitive to the relative infectiousness of SAC, this group remained the most important contributor to mosquito infections under all realistic estimates. CONCLUSIONS These results suggest that U5 children play a small role compared to SAC in maintaining P. falciparum transmission in southern Malawi. Models that assume biting homogeneity overestimate the importance of U5s. To reduce transmission, interventions will need to reach more SAC and young adults. This publicly available model can be used by others to estimate age-specific transmission contributions in epidemiologically similar sites with local parameter estimates of P. falciparum prevalence and bed net use.
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Affiliation(s)
- Jenna E Coalson
- Department of Epidemiology, School of Public Health, University of Michigan, M5507 SPH II, 1415 Washington Heights, Ann Arbor, MI, 48109, USA. .,Center for Insect Science and Department of Epidemiology and Biostatistics, University of Arizona, Tucson, AZ, USA.
| | - Lauren M Cohee
- Division of Malaria Research, Institute of Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Andrea G Buchwald
- Division of Malaria Research, Institute of Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Andrew Nyambalo
- Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre, Malawi
| | - John Kubale
- Department of Epidemiology, School of Public Health, University of Michigan, M5507 SPH II, 1415 Washington Heights, Ann Arbor, MI, 48109, USA
| | - Karl B Seydel
- College of Osteopathic Medicine, Michigan State University, East Lansing, USA
| | - Don Mathanga
- Malaria Alert Centre, University of Malawi College of Medicine, Blantyre, Malawi
| | - Terrie E Taylor
- College of Osteopathic Medicine, Michigan State University, East Lansing, USA
| | - Miriam K Laufer
- Division of Malaria Research, Institute of Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mark L Wilson
- Department of Epidemiology, School of Public Health, University of Michigan, M5507 SPH II, 1415 Washington Heights, Ann Arbor, MI, 48109, USA.
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Arnaldo P, Rovira-Vallbona E, Langa JS, Salvador C, Guetens P, Chiheb D, Xavier B, Kestens L, Enosse SM, Rosanas-Urgell A. Uptake of intermittent preventive treatment and pregnancy outcomes: health facilities and community surveys in Chókwè district, southern Mozambique. Malar J 2018. [PMID: 29530044 PMCID: PMC5848514 DOI: 10.1186/s12936-018-2255-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background Malaria in pregnancy leads to serious adverse effects on the mother and the child and accounts for 75,000–200,000 infant deaths every year. Currently, the World Health Organization recommends intermittent preventive treatment of malaria in pregnancy (IPTp) with sulfadoxine–pyrimethamine (SP) at each scheduled antenatal care (ANC) visit. This study aimed to assess IPTp-SP coverage in mothers delivering in health facilities and at the community. In addition, factors associated with low IPTp-SP uptake and malaria adverse outcomes in pregnancy were investigated. Methods A community and a health facility-based surveys were conducted in mothers delivering in Chókwè district, southern Mozambique. Social-demographic data, malaria prevention practices and obstetric history were recorded through self-report and antenatal records. For women delivering at health facilities, a clinical examination of mother and child was performed, and malaria infection at delivery was determined by rapid diagnostic test, microscopy, quantitative PCR and placental histology. Results Of 1141 participants, 46.6, 30.2, 13.5 and 9.6% reported taking ≥ 3, two, one and none SP doses, respectively. Low IPTp uptake (< 3 doses) was associated with non-institutional deliveries (AOR = 2.9, P < 0.001), first ANC visit after week 28 (AOR = 5.4, P < 0.001), low awareness of IPTp-SP (AOR = 1.6, P < 0.002) and having no or only primary education (AOR = 1.3, P = 0.041). The overall prevalence of maternal malaria (peripheral and/or placental) was 16.8% and was higher among women from rural areas compared to those from urban areas (AOR = 1.9, P < 0.001). Younger age (< 20 years; AOR = 1.6, P = 0.042) and living in rural areas (AOR = 1.9, P < 0.001) were predictors of maternal malaria at delivery. Being primigravidae (AOR = 2.2, P = 0.023) and preterm delivery (AOR = 2.6, P < 0.001) predicted low birth weight while younger age was also associated with premature delivery (AOR = 1.4, P = 0.031). Conclusion The coverage for two and ≥ 3 doses of IPTp-SP is moderately higher than estimates from routine health facility records in Gaza province in 2015. However, this is still far below the national target of 80% for ≥ 3 doses. Ongoing campaigns aiming to increase the use of malaria prevention strategies during pregnancy should particularly target rural populations, increasing IPTp-SP knowledge, stimulate early visits to ANC, improve access to health services and the quality of the service provided. Electronic supplementary material The online version of this article (10.1186/s12936-018-2255-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Paulo Arnaldo
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium.,Plataforma de Parasitologia Molecular, Instituto Nacional de Saúde, Maputo, Mozambique.,University of Antwerp, Antwerp, Belgium
| | - Eduard Rovira-Vallbona
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
| | - Jerónimo S Langa
- Plataforma de Parasitologia Molecular, Instituto Nacional de Saúde, Maputo, Mozambique
| | - Crizolgo Salvador
- Plataforma de Parasitologia Molecular, Instituto Nacional de Saúde, Maputo, Mozambique
| | - Pieter Guetens
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
| | - Driss Chiheb
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
| | - Bernardete Xavier
- Plataforma de Parasitologia Molecular, Instituto Nacional de Saúde, Maputo, Mozambique
| | - Luc Kestens
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium.,University of Antwerp, Antwerp, Belgium
| | - Sónia M Enosse
- Plataforma de Parasitologia Molecular, Instituto Nacional de Saúde, Maputo, Mozambique
| | - Anna Rosanas-Urgell
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium.
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Majors CE, Smith CA, Natoli ME, Kundrod KA, Richards-Kortum R. Point-of-care diagnostics to improve maternal and neonatal health in low-resource settings. LAB ON A CHIP 2017; 17:3351-3387. [PMID: 28832061 PMCID: PMC5636680 DOI: 10.1039/c7lc00374a] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Each day, approximately 830 women and 7400 newborns die from complications during pregnancy and childbirth. Improving maternal and neonatal health will require bringing rapid diagnosis and treatment to the point of care in low-resource settings. However, to date there are few diagnostic tools available that can be used at the point of care to detect the leading causes of maternal and neonatal mortality in low-resource settings. Here we review both commercially available diagnostics and technologies that are currently in development to detect the leading causes of maternal and neonatal mortality, highlighting key gaps in development where innovative design could increase access to technology and enable rapid diagnosis at the bedside.
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Affiliation(s)
- Catherine E Majors
- Department of Bioengineering, Rice University, 6100 Main Street, MS-142, Houston, TX 77005, USA.
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Weerakoon KG, Gordon CA, Williams GM, Cai P, Gobert GN, Olveda RM, Ross AG, Olveda DU, McManus DP. Droplet Digital PCR Diagnosis of Human Schistosomiasis: Parasite Cell-Free DNA Detection in Diverse Clinical Samples. J Infect Dis 2017; 216:1611-1622. [DOI: 10.1093/infdis/jix521] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 09/22/2017] [Indexed: 11/12/2022] Open
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Taylor SM, Madanitsa M, Thwai KL, Khairallah C, Kalilani-Phiri L, van Eijk AM, Mwapasa V, Ter Kuile FO, Meshnick SR. Minimal Impact by Antenatal Subpatent Plasmodium falciparum Infections on Delivery Outcomes in Malawian Women: A Cohort Study. J Infect Dis 2017; 216:296-304. [PMID: 28658935 DOI: 10.1093/infdis/jix304] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Antenatal malaria screening with a rapid diagnostic test (RDT) and treatment only of women with positive RDT findings may potentially prevent low birth weight resulting from malaria. The consequences of subpatent antenatal infections below the detection limit of RDTs are incompletely understood. In Malawi, pregnant women of any gravidity status were tested at each antenatal visit for Plasmodium falciparum, using an RDT and polymerase chain reaction analysis, and were followed until delivery. Associations between antenatal infections and delivery outcomes were assessed with Poisson regression or analysis of variance. Compared with women with no detected antenatal P. falciparum infection, women with positive RDT findings delivered babies with a lower mean birth weight (2960 vs 2867 g; mean difference, -93 g [95% confidence interval {CI}, -27 to -159]; P = .006); this was not observed among women with only subpatent infections (mean birth weight, 3013 g; mean difference, 54 [95% CI, -33-140]; P = .2268). These differences were apparent early in pregnancy, during the second trimester: compared with uninfected women, women with positive RDT findings delivered babies with a lower mean birth weight (mean difference, -94 g [95% CI, -31 to -156]; P = .003), but women with subpatent infections did not (mean difference, 36 g [95% CI, -49-122]; P = .409). Subpatent antenatal P. falciparum infections were not associated with adverse delivery outcomes. The association of patent infections at enrollment with low birth weight suggests the importance of preventing P. falciparum infection early in pregnancy.
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Affiliation(s)
- Steve M Taylor
- Division of Infectious Diseases, Duke University Medical Center.,Duke Global Health Institute, Duke University, Durham.,Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill
| | - Mwayiwawo Madanitsa
- Department of Community Health, College of Medicine, Blantyre, Malawi.,Department of Clinical Sciences, Liverpool School of Tropical Medicine, United Kingdom
| | - Kyaw-Lay Thwai
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill
| | - Carole Khairallah
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, United Kingdom
| | | | - Anna M van Eijk
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, United Kingdom
| | - Victor Mwapasa
- Department of Community Health, College of Medicine, Blantyre, Malawi
| | - Feiko O Ter Kuile
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, United Kingdom
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill
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Deep Sequencing of RNA from Blood and Oral Swab Samples Reveals the Presence of Nucleic Acid from a Number of Pathogens in Patients with Acute Ebola Virus Disease and Is Consistent with Bacterial Translocation across the Gut. mSphere 2017; 2:mSphere00325-17. [PMID: 28861524 PMCID: PMC5566839 DOI: 10.1128/mspheredirect.00325-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 07/28/2017] [Indexed: 01/08/2023] Open
Abstract
In this study, samples from the 2013-2016 West African Ebola virus outbreak from patients in Guinea with Ebola virus disease (EVD) were analyzed to discover and classify what other pathogens were present. Throat swabs were taken from deceased EVD patients, and peripheral blood samples were analyzed that had been taken from patients when they presented at the treatment center with acute illness. High-throughput RNA sequencing (RNA-seq) and bioinformatics were used to identify the potential microorganisms. This approach confirmed Ebola virus (EBOV) in all samples from patients diagnosed as acute positive for the virus by quantitative reverse transcription-PCR in deployed field laboratories. Nucleic acid mapping to Plasmodium was also used on the patient samples, confirming results obtained with an antigen-based rapid diagnostic test (RDT) conducted in the field laboratories. The data suggested that a high Plasmodium load, as determined by sequence read depth, was associated with mortality and influenced the host response, whereas a lower parasite load did not appear to affect outcome. The identifications of selected bacteria from throat swabs via RNA-seq were confirmed by culture. The data indicated that the potential pathogens identified in the blood samples were associated with translocation from the gut, suggesting the presence of bacteremia, which transcriptome data suggested may induce or aggravate the acute-phase response observed during EVD. Transcripts mapping to different viruses were also identified, including those indicative of lytic infections. The development of high-resolution analysis of samples from patients with EVD will help inform care pathways and the most appropriate general antimicrobial therapy to be used in a resource-poor setting. IMPORTANCE Our results highlight the identification of an array of pathogens in the blood of patients with Ebola virus disease (EVD). This has not been done before, and the data have important implications for the treatment of patients with EVD, particularly considering antibiotic stewardship. We show that EVD patients who were also infected with Plasmodium, particularly at higher loads, had more adverse outcomes than patients with lower levels of Plasmodium. However, the presence of Plasmodium did not influence the innate immune response, and it is likely that the presence of EBOV dominated this response. Several viruses other than EBOV were identified, and bacteria associated with sepsis were also identified. These findings were indicative of bacterial translocation across the gut during the acute phase of EVD.
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Waggoner J, Brichard J, Mutuku F, Ndenga B, Heath CJ, Mohamed-Hadley A, Sahoo MK, Vulule J, Lefterova M, Banaei N, Mukoko D, Pinsky BA, LaBeaud AD. Malaria and Chikungunya Detected Using Molecular Diagnostics Among Febrile Kenyan Children. Open Forum Infect Dis 2017; 4:ofx110. [PMID: 28702473 PMCID: PMC5505337 DOI: 10.1093/ofid/ofx110] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 05/02/2017] [Accepted: 05/23/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND In sub-Saharan Africa, malaria is frequently overdiagnosed as the cause of an undifferentiated febrile illness, whereas arboviral illnesses are presumed to be underdiagnosed. METHODS Sera from 385 febrile Kenyan children, who presented to 1 of 4 clinical sites, were tested using microscopy and real-time molecular assays for dengue virus (DENV), chikungunya virus (CHIKV), malaria, and Leptospira. RESULTS Malaria was the primary clinical diagnosis for 254 patients, and an arboviral infection (DENV or CHIKV) was the primary diagnosis for 93 patients. In total, 158 patients (41.0%) had malaria and 32 patients (8.3%) had CHIKV infections. Compared with real-time polymerase chain reaction, microscopy demonstrated a percent positive agreement of 49.7%. The percentage of malaria cases detected by microscopy varied significantly between clinical sites. Arboviral infections were the clinical diagnosis for patients on the Indian Ocean coast (91 of 238, 38.2%) significantly more often than patients in the Lake Victoria region (2 of 145, 1.4%; P < .001). However, detection of CHIKV infections was significantly higher in the Lake Victoria region (19 of 145 [13.1%] vs 13 of 239 [5.4%]; P = .012). CONCLUSIONS The clinical diagnosis of patients with an acute febrile illness, even when aided by microscopy, remains inaccurate in malaria-endemic areas, contributing to inappropriate management decisions.
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Affiliation(s)
- Jesse Waggoner
- Department of Medicine, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia
| | - Julie Brichard
- Department of Pediatrics, Division of Infectious Diseases
| | | | | | | | | | | | | | | | - Niaz Banaei
- Department of Pathology, and.,Ministry of Health, Nairobi, Kenya
| | | | - Benjamin A Pinsky
- Department of Pathology, and.,Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, California
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Pholwat S, Liu J, Stroup S, Jacob ST, Banura P, Moore CC, Huang F, Laufer MK, Houpt E, Guler JL. The Malaria TaqMan Array Card Includes 87 Assays for Plasmodium falciparum Drug Resistance, Identification of Species, and Genotyping in a Single Reaction. Antimicrob Agents Chemother 2017; 61:e00110-17. [PMID: 28264857 PMCID: PMC5404514 DOI: 10.1128/aac.00110-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 03/02/2017] [Indexed: 11/20/2022] Open
Abstract
Antimalarial drug resistance exacerbates the global disease burden and complicates eradication efforts. To facilitate the surveillance of resistance markers in countries of malaria endemicity, we developed a suite of TaqMan assays for known resistance markers and compartmentalized them into a single array card (TaqMan array card, TAC). We included 87 assays for species identification, for the detection of Plasmodium falciparum mutations associated with chloroquine, atovaquone, pyrimethamine, sulfadoxine, and artemisinin resistance, and for neutral single nucleotide polymorphism (SNP) genotyping. Assay performance was first optimized using DNA from common laboratory parasite lines and plasmid controls. The limit of detection was 0.1 to 10 pg of DNA and yielded 100% accuracy compared to sequencing. The tool was then evaluated on 87 clinical blood samples from around the world, and the malaria TAC once again achieved 100% accuracy compared to sequencing and in addition detected the presence of mixed infections in clinical samples. With its streamlined protocol and high accuracy, this malaria TAC should be a useful tool for large-scale antimalarial resistance surveillance.
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Affiliation(s)
- Suporn Pholwat
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Jie Liu
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Suzanne Stroup
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Shevin T Jacob
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Patrick Banura
- Department of Community Health, Masaka Regional Referral Hospital, Masaka, Uganda
| | - Christopher C Moore
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Fang Huang
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Miriam K Laufer
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Eric Houpt
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Jennifer L Guler
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
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Requena P, Arévalo-Herrera M, Menegon M, Martínez-Espinosa FE, Padilla N, Bôtto-Menezes C, Malheiro A, Hans D, Castellanos ME, Robinson L, Samol P, Kochar S, Kochar SK, Kochar DK, Desai M, Sanz S, Quintó L, Mayor A, Rogerson S, Mueller I, Severini C, Del Portillo HA, Bardají A, Chitnis CC, Menéndez C, Dobaño C. Naturally Acquired Binding-Inhibitory Antibodies to Plasmodium vivax Duffy Binding Protein in Pregnant Women Are Associated with Higher Birth Weight in a Multicenter Study. Front Immunol 2017; 8:163. [PMID: 28261219 PMCID: PMC5313505 DOI: 10.3389/fimmu.2017.00163] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/31/2017] [Indexed: 12/11/2022] Open
Abstract
A vaccine to eliminate malaria would need a multi-stage and multi-species composition to achieve robust protection, but the lack of knowledge about antigen targets and mechanisms of protection precludes the development of fully efficacious malaria vaccines, especially for Plasmodium vivax (Pv). Pregnant women constitute a risk population who would greatly benefit from a vaccine preventing the adverse events of Plasmodium infection during gestation. We hypothesized that functional immune responses against putative targets of naturally acquired immunity to malaria and vaccine candidates will be associated with protection against malaria infection and/or poor outcomes during pregnancy. We measured (i) IgG responses to a large panel of Pv and Plasmodium falciparum (Pf) antigens, (ii) the capacity of anti-Pv ligand Duffy binding protein (PvDBP) antibodies to inhibit binding to Duffy antigen, and (iii) cellular immune responses to two Pv antigens, in a subset of 1,056 pregnant women from Brazil, Colombia, Guatemala, India, and Papua New Guinea (PNG). There were significant intraspecies and interspecies correlations for most antibody responses (e.g., PfMSP119 versus PfAMA1, Spearman’s rho = 0.81). Women from PNG and Colombia had the highest levels of IgG overall. Submicroscopic infections seemed sufficient to boost antibody responses in Guatemala but not antigen-specific cellular responses in PNG. Brazil had the highest percentage of Duffy binding inhibition (p-values versus Colombia: 0.040; Guatemala: 0.047; India: 0.003, and PNG: 0.153) despite having low anti-PvDBP IgG levels. Almost all antibodies had a positive association with present infection, and coinfection with the other species increased this association. Anti-PvDBP, anti-PfMSP1, and anti-PfAMA1 IgG levels at recruitment were positively associated with infection at delivery (p-values: 0.010, 0.003, and 0.023, respectively), suggesting that they are markers of malaria exposure. Peripheral blood mononuclear cells from Pv-infected women presented fewer CD8+IFN-γ+ T cells and secreted more G-CSF and IL-4 independently of the stimulus used in vitro. Functional anti-PvDBP levels at recruitment had a positive association with birth weight (difference per doubling antibody levels: 45 g, p-value: 0.046). Thus, naturally acquired binding-inhibitory antibodies to PvDBP might confer protection against poor outcomes of Pv malaria in pregnancy.
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Affiliation(s)
- Pilar Requena
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona , Barcelona, Catalonia , Spain
| | | | | | - Flor E Martínez-Espinosa
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil; Instituto Leônidas e Maria Deane (ILMD/Fiocruz Amazonia), Amazonia, Brazil
| | - Norma Padilla
- Centro de Estudios en Salud, Universidad del Valle de Guatemala , Guatemala City , Guatemala
| | - Camila Bôtto-Menezes
- Instituto Leônidas e Maria Deane (ILMD/Fiocruz Amazonia), Amazonia, Brazil; Universidade do Estado do Amazonas, Manaus, Amazonas, Brazil
| | - Adriana Malheiro
- Instituto de Ciências Biológicas, Universidade Federal do Amazonas , Manaus , Brazil
| | - Dhiraj Hans
- International Center for Genetic Engineering and Biotechnology , Delhi , India
| | | | - Leanne Robinson
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea; Macfarlane Burnet Institute of Medical Research, Melbourne, VIC, Australia; Walter and Eliza Hall Institute, Parkville, VIC, Australia
| | - Paula Samol
- Papua New Guinea Institute of Medical Research , Madang , Papua New Guinea
| | - Swati Kochar
- Medical College Bikaner , Bikaner, Rajasthan , India
| | | | | | - Meghna Desai
- Centers for Disease Control and Prevention, Division of Parasitic Diseases and Malaria, Malaria Branch , Atlanta, GA , USA
| | - Sergi Sanz
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona , Barcelona, Catalonia , Spain
| | - Llorenç Quintó
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona , Barcelona, Catalonia , Spain
| | - Alfredo Mayor
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona , Barcelona, Catalonia , Spain
| | | | - Ivo Mueller
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Catalonia, Spain; Walter and Eliza Hall Institute, Parkville, VIC, Australia
| | | | - Hernando A Del Portillo
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Catalonia, Spain; ICREA, Barcelona, Spain
| | - Azucena Bardají
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona , Barcelona, Catalonia , Spain
| | - Chetan C Chitnis
- International Center for Genetic Engineering and Biotechnology , Delhi , India
| | - Clara Menéndez
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona , Barcelona, Catalonia , Spain
| | - Carlota Dobaño
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona , Barcelona, Catalonia , Spain
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Buchwald AG, Coalson JE, Cohee LM, Walldorf JA, Chimbiya N, Bauleni A, Nkanaunena K, Ngwira A, Sorkin JD, Mathanga DP, Taylor TE, Laufer MK. Insecticide-treated net effectiveness at preventing Plasmodium falciparum infection varies by age and season. Malar J 2017; 16:32. [PMID: 28095916 PMCID: PMC5240228 DOI: 10.1186/s12936-017-1686-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 01/07/2017] [Indexed: 11/10/2022] Open
Abstract
Background After increasing coverage of malaria interventions, malaria prevalence remains high in Malawi. Previous studies focus on the impact of malaria interventions among children under 5 years old. However, in Malawi, the prevalence of infection is highest in school-aged children (SAC), ages 5 to 15 years. This study examined the interaction between age group and insecticide-treated net (ITN) use for preventing individual and community-level infection in Malawi. Methods Six cross-sectional surveys were conducted in the rainy and dry seasons in southern Malawi from 2012 to 2014. Data were collected on household ITN usage and demographics. Blood samples for detection of Plasmodium falciparum infection were obtained from all household members present and over 6 months of age. Generalized linear mixed models were used to account for clustering at the household and community level. Results There were 17,538 observations from six surveys. The association between ITN use and infection varied by season in SAC, but not in other age groups. The adjusted odds ratio (OR) for infection comparing ITN users to non-users among SAC in the rainy season and dry season was 0.78 (95% CI 0.56, 1.10) and 0.51 (0.35, 0.74), respectively. The effect of ITN use did not differ between children under five and adults. Among all non-SACs the OR for infection was 0.78 (0.64, 0.95) in those who used ITNs compared to those that did not. Community net use did not protect against infection. Conclusions Protection against infection with ITN use varies by age group and season. Individual estimates of protection are moderate and a community-level effect was not detected. Additional interventions to decrease malaria prevalence are needed in Malawi. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1686-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Andrea G Buchwald
- Institute for Global Health, University of Maryland School of Medicine, 685W, Baltimore St. HSF-1 Room 480, Baltimore, MD, 21201, USA
| | - Jenna E Coalson
- University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI, 48109, USA
| | - Lauren M Cohee
- Institute for Global Health, University of Maryland School of Medicine, 685W, Baltimore St. HSF-1 Room 480, Baltimore, MD, 21201, USA
| | - Jenny A Walldorf
- Institute for Global Health, University of Maryland School of Medicine, 685W, Baltimore St. HSF-1 Room 480, Baltimore, MD, 21201, USA
| | - Nelson Chimbiya
- University of Malawi College of Medicine, Chichiri, Private Bag 360, Blantyre, Malawi
| | - Andy Bauleni
- University of Malawi College of Medicine, Chichiri, Private Bag 360, Blantyre, Malawi
| | - Kondwani Nkanaunena
- University of Malawi College of Medicine, Chichiri, Private Bag 360, Blantyre, Malawi
| | - Andrew Ngwira
- University of Malawi College of Medicine, Chichiri, Private Bag 360, Blantyre, Malawi
| | - John D Sorkin
- Institute for Global Health, University of Maryland School of Medicine, 685W, Baltimore St. HSF-1 Room 480, Baltimore, MD, 21201, USA
| | - Don P Mathanga
- University of Malawi College of Medicine, Chichiri, Private Bag 360, Blantyre, Malawi
| | - Terrie E Taylor
- Department of Osteopathic Medicine, Michigan State University, West Fee Hall, 909 Fee Road, Room B305, East Lansing, MI, 48824, USA
| | - Miriam K Laufer
- Institute for Global Health, University of Maryland School of Medicine, 685W, Baltimore St. HSF-1 Room 480, Baltimore, MD, 21201, USA.
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Nkhoma M, Ashorn P, Ashorn U, Dewey KG, Gondwe A, Mbotwa J, Rogerson S, Taylor SM, Maleta K. Providing lipid-based nutrient supplement during pregnancy does not reduce the risk of maternal P falciparum parasitaemia and reproductive tract infections: a randomised controlled trial. BMC Pregnancy Childbirth 2017; 17:35. [PMID: 28095801 PMCID: PMC5240436 DOI: 10.1186/s12884-016-1215-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 12/29/2016] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Maternal infections are associated with maternal and foetal adverse outcomes. Nutrient supplementation during pregnancy may reduce the occurrence of infections by improving maternal immunity. We aimed to investigate the impact of small-quantity lipid-based nutrient supplement (SQ-LNS) on the occurrence of Plasmodium falciparum parasitaemia during pregnancy and trichomoniasis, vaginal candidiasis and urinary tract infection (UTI) after delivery. METHODS Pregnant Malawian women enrolled in the iLiNS-DYAD trial receiving daily supplementation with SQ-LNS, multiple micronutrients (MMN) or iron & folic acid (IFA) from <20 gestation weeks (gw) were assessed for P. falciparum parasitaemia at 32 gw using rapid diagnostic testing (RDT), at 36 gw using polymerase chain reaction (PCR) and at delivery using both RDT and PCR; and at one week after delivery for trichomoniasis and vaginal candidiasis using wet mount microscopy and for UTI using urine dipstick analysis. The prevalence of each infection by intervention group was estimated at the prescribed time points and the global null hypothesis was tested using logistic regression. Adjusted analyses were performed using preselected covariates. RESULTS The prevalence of P. falciparum parasitaemia was 10.7% at 32 gw, 9% at 36 gw, and 8.3% by RDT and 20.2% by PCR at delivery. After delivery the prevalence of trichomoniasis was 10.5%, vaginal candidiasis was 0.5%, and UTI was 3.1%. There were no differences between intervention groups in the prevalence of any of the infections. CONCLUSION In this population, SQ-LNS did not influence the occurrence of maternal P. falciparum parasitaemia, trichomoniasis, vaginal candidiasis or UTI. TRIAL REGISTRATION Identifier: NCT01239693 (10 November 2010).
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Affiliation(s)
- Minyanga Nkhoma
- University of Tampere School of Medicine, University of Tampere, Arvo building, FI-33014 Tampere, Finland
| | - Per Ashorn
- University of Tampere School of Medicine, University of Tampere, Arvo building, FI-33014 Tampere, Finland
- Department of Pediatrics, Tampere University Hospital, FI-33521 Tampere, Finland
| | - Ulla Ashorn
- University of Tampere School of Medicine, University of Tampere, Arvo building, FI-33014 Tampere, Finland
| | - Kathryn G. Dewey
- Department of Nutrition, University of California, One Shields Ave., Davis, CA 95616-8669 USA
| | - Austrida Gondwe
- University of Tampere School of Medicine, University of Tampere, Arvo building, FI-33014 Tampere, Finland
| | - John Mbotwa
- School of Public Health and Family Medicine, College of Medicine, Mahatma Gandhi Road, Blantyre, Malawi
| | - Stephen Rogerson
- Department of Medicine at the Peter Doherty Institute, 792 Elizabeth Street, Melbourne, VIC 3000 Australia
| | - Steve M. Taylor
- Division of Infectious Diseases and International Health, Duke University Medical Center, Box 102359 DUMC, Durham, NC 27705 USA
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC 27599-7435 USA
| | - Kenneth Maleta
- School of Public Health and Family Medicine, College of Medicine, Mahatma Gandhi Road, Blantyre, Malawi
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Unger HW, Cates JE, Gutman J, Briand V, Fievet N, Valea I, Tinto H, d'Alessandro U, Landis SH, Adu-Afarwuah S, Dewey KG, Ter Kuile F, Dellicour S, Ouma P, Slutsker L, Terlouw DJ, Kariuki S, Ayisi J, Nahlen B, Desai M, Madanitsa M, Kalilani-Phiri L, Ashorn P, Maleta K, Mueller I, Stanisic D, Schmiegelow C, Lusingu J, Westreich D, van Eijk AM, Meshnick S, Rogerson S. Maternal Malaria and Malnutrition (M3) initiative, a pooled birth cohort of 13 pregnancy studies in Africa and the Western Pacific. BMJ Open 2016; 6:e012697. [PMID: 28003287 PMCID: PMC5223676 DOI: 10.1136/bmjopen-2016-012697] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
PURPOSE The Maternal Malaria and Malnutrition (M3) initiative has pooled together 13 studies with the hope of improving understanding of malaria-nutrition interactions during pregnancy and to foster collaboration between nutritionists and malariologists. PARTICIPANTS Data were pooled on 14 635 singleton, live birth pregnancies from women who had participated in 1 of 13 pregnancy studies. The 13 studies cover 8 countries in Africa and Papua New Guinea in the Western Pacific conducted from 1996 to 2015. FINDINGS TO DATE Data are available at the time of antenatal enrolment of women into their respective parent study and at delivery. The data set comprises essential data such as malaria infection status, anthropometric assessments of maternal nutritional status, presence of anaemia and birth weight, as well as additional variables such gestational age at delivery for a subset of women. Participating studies are described in detail with regard to setting and primary outcome measures, and summarised data are available from each contributing cohort. FUTURE PLANS This pooled birth cohort is the largest pregnancy data set to date to permit a more definite evaluation of the impact of plausible interactions between poor nutritional status and malaria infection in pregnant women on fetal growth and gestational length. Given the current comparative lack of large pregnancy cohorts in malaria-endemic settings, compilation of suitable pregnancy cohorts is likely to provide adequate statistical power to assess malaria-nutrition interactions, and could point towards settings where such interactions are most relevant. The M3 cohort may thus help to identify pregnant women at high risk of adverse outcomes who may benefit from tailored intensive antenatal care including nutritional supplements and alternative or intensified malaria prevention regimens, and the settings in which these interventions would be most effective.
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Affiliation(s)
- Holger W Unger
- Department of Obstetrics and Gynaecology, Edinburgh Royal Infirmary, Edinburgh, UK
- Department of Medicine at the Doherty Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Jordan E Cates
- Department of Epidemiology, UNC-Chapel Hill, Chapel Hill, North Carolina, USA
| | - Julie Gutman
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Valerie Briand
- Institut de Recherche pour le Développement (IRD), Mère et enfant face aux infections tropicales (UMR216), Paris, France
- COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France
| | - Nadine Fievet
- Institut de Recherche pour le Développement (IRD), Mère et enfant face aux infections tropicales (UMR216), Paris, France
- COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes, Paris, France
| | - Innocent Valea
- Unite de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé-DRO, Bobo-Dioulasso, Burkina Faso
- Departement de Recherche Clinique, Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Halidou Tinto
- Unite de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé-DRO, Bobo-Dioulasso, Burkina Faso
- Departement de Recherche Clinique, Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Umberto d'Alessandro
- Medical Research Council Unit, The Gambia
- London School of Hygiene and Tropical Medicine, UK
- Institute of Tropical Medicine, Antwerp, Belgium
| | | | - Seth Adu-Afarwuah
- Department of Nutrition and Food Science, University of Ghana, Legon, Accra, Ghana
| | - Kathryn G Dewey
- Department of Nutrition, University of California, Davis, California, USA
| | - Feiko Ter Kuile
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Stephanie Dellicour
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Peter Ouma
- Kenya Medical Research Institute (KEMRI)/Center for Global Health Research, Kisumu, Kenya
| | - Laurence Slutsker
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Dianne J Terlouw
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme Liverpool School of Tropical Medicine, Liverpool, UK
| | - Simon Kariuki
- Kenya Medical Research Institute (KEMRI)/Center for Global Health Research, Kisumu, Kenya
| | - John Ayisi
- Kenya Medical Research Institute (KEMRI)/Center for Global Health Research, Kisumu, Kenya
| | | | - Meghna Desai
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Mwayi Madanitsa
- School of Public Health and Family Medicine, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Linda Kalilani-Phiri
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- School of Public Health and Family Medicine, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Per Ashorn
- Tampere Center for Child Health Research, Tampere, Finland
- Department for Pediatrics, University of Tampere and Tampere University Hospital, Tampere, Finland
| | - Kenneth Maleta
- School of Public Health and Family Medicine, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Ivo Mueller
- Walter and Eliza Hall Institute, Parkville, Victoria, Australia
| | - Danielle Stanisic
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Christentze Schmiegelow
- Faculty of Health Science, Department of Immunology and Microbiology, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
| | - John Lusingu
- Faculty of Health Science, Department of Immunology and Microbiology, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
- National Institute for Medical Research, Tanga Centre, Tanga, Tanzania
| | - Daniel Westreich
- Department of Epidemiology, UNC-Chapel Hill, Chapel Hill, North Carolina, USA
| | - Anna Maria van Eijk
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Steven Meshnick
- Department of Epidemiology, UNC-Chapel Hill, Chapel Hill, North Carolina, USA
| | - Stephen Rogerson
- Department of Medicine at the Doherty Institute, The University of Melbourne, Parkville, Victoria, Australia
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Haanshuus CG, Chandy S, Manoharan A, Vivek R, Mathai D, Xena D, Singh A, Langeland N, Blomberg B, Vasanthan G, Sitaram U, Appasamy J, Nesaraj J, Henry A, Patil S, Alvarez-Uria G, Armstrong L, Mørch K. A High Malaria Prevalence Identified by PCR among Patients with Acute Undifferentiated Fever in India. PLoS One 2016; 11:e0158816. [PMID: 27389396 PMCID: PMC4936667 DOI: 10.1371/journal.pone.0158816] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/22/2016] [Indexed: 11/29/2022] Open
Abstract
Background Approximately one million malaria cases were reported in India in 2015, based on microscopy. This study aims to assess the malaria prevalence among hospitalised fever patients in India identified by PCR, and to evaluate the performance of routine diagnostic methods. Methods During June 2011-December 2012, patients admitted with acute undifferentiated fever to seven secondary level community hospitals in Assam (Tezpur), Bihar (Raxaul), Chhattisgarh (Mungeli), Maharashtra (Ratnagiri), Andhra Pradesh (Anantapur) and Tamil Nadu (Oddanchatram and Ambur) were included. The malaria prevalence was assessed by polymerase chain reaction (PCR), routine microscopy, and a rapid diagnostic test (RDT) with PCR as a reference method. Results The malaria prevalence by PCR was 19% (268/1412) ranging from 6% (Oddanchatram, South India) to 35% (Ratnagiri, West India). Among malaria positive patients P. falciparum single infection was detected in 46%, while 38% had P. vivax, 11% mixed infections with P. falciparum and P. vivax, and 5% P. malariae. Compared to PCR, microscopy had sensitivity of 29% and specificity of 98%, while the RDT had sensitivity of 24% and specificity of 99%. Conclusions High malaria prevalence was identified by PCR in this cohort. Routine diagnostic methods had low sensitivity compared to PCR. The results suggest that malaria is underdiagnosed in rural India. However, low parasitaemia controlled by immunity may constitute a proportion of PCR positive cases, which calls for awareness of the fact that other pathogens could be responsible for the febrile disease in submicroscopic malaria.
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Affiliation(s)
- Christel Gill Haanshuus
- National Centre for Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Sara Chandy
- Infectious Diseases Training and Research Center, Department of Medicine Unit-1 and Infectious Diseases, Christian Medical College, Vellore, India
| | - Anand Manoharan
- Infectious Diseases Training and Research Center, Department of Medicine Unit-1 and Infectious Diseases, Christian Medical College, Vellore, India
- * E-mail:
| | - Rosario Vivek
- Infectious Diseases Training and Research Center, Department of Medicine Unit-1 and Infectious Diseases, Christian Medical College, Vellore, India
| | - Dilip Mathai
- Infectious Diseases Training and Research Center, Department of Medicine Unit-1 and Infectious Diseases, Christian Medical College, Vellore, India
| | - Deepika Xena
- Infectious Diseases Training and Research Center, Department of Medicine Unit-1 and Infectious Diseases, Christian Medical College, Vellore, India
| | - Ashita Singh
- Baptist Christian Hospital, Tezpur, Assam, India
| | - Nina Langeland
- National Centre for Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Bjørn Blomberg
- National Centre for Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - George Vasanthan
- Infectious Diseases Training and Research Center, Department of Medicine Unit-1 and Infectious Diseases, Christian Medical College, Vellore, India
| | - Usha Sitaram
- Infectious Diseases Training and Research Center, Department of Medicine Unit-1 and Infectious Diseases, Christian Medical College, Vellore, India
| | | | | | - Anil Henry
- Christian Hospital, Mungeli, Chhattisgarh, India
| | - Suvarna Patil
- B.K.L. Walawalkar Hospital, Ratnagiri, Maharashtra, India
| | | | | | - Kristine Mørch
- National Centre for Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
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Mourembou G, Nzondo SM, Ndjoyi-Mbiguino A, Lekana-Douki JB, Kouna LC, Matsiegui PB, Manego RZ, Moukandja IP, Keïta AK, Tissot-Dupont H, Fenollar F, Raoult D. Co-circulation of Plasmodium and Bacterial DNAs in Blood of Febrile and Afebrile Children from Urban and Rural Areas in Gabon. Am J Trop Med Hyg 2016; 95:123-32. [PMID: 27114297 DOI: 10.4269/ajtmh.15-0751] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 03/13/2016] [Indexed: 12/11/2022] Open
Abstract
Malaria is considered to be the most common etiology of fever in sub-Saharan Africa while bacteremias exist but are under assessed. This study aimed to assess bacteremias and malaria in children from urban and rural areas in Gabon. DNA extracts from blood samples of 410 febrile and 60 afebrile children were analyzed using quantitative polymerase chain reaction. Plasmodium spp. was the microorganism most frequently detected in febrile (78.8%, 323/410) and afebrile (13.3%, 8/60) children, (P < 0.001). DNA from one or several bacteria were detected in 15 febrile patients (3.7%) but not in the controls (P = 0.1). This DNA was more frequently detected as co-infections among febrile children tested positive for Plasmodium (4.6%, 15/323) than in those tested negative for Plasmodium (0%, 0/87; P = 0.04). The bacteria detected were Streptococcus pneumoniae 2.4% (10/410), Staphylococcus aureus 1.7% (7/410), Salmonella spp. 0.7% (3/410), Streptococcus pyogenes 0.2% (1/410) and Tropheryma whipplei 0.2% (1/410) only in febrile children. Coxiella burnetii, Borrelia spp., Bartonella spp., Leptospira spp., and Mycobacterium tuberculosis were not observed. This paper reports the first detection of bacteremia related to T. whipplei in Gabon and shows that malaria decreases in urban areas but not in rural areas. Co-infections in febrile patients are common, highlighting the need to improve fever management strategies in Gabon.
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Affiliation(s)
- Gaël Mourembou
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes (URMITE), Aix Marseille Université, Marseille, France. Ecole Doctorale Régionale d'Afrique Centrale, Franceville, Gabon
| | - Sydney Maghendji Nzondo
- Unité de Parasitologie Médicale, Centre International de Recherches Médicales de Franceville (CIRMF), Franceville, Gabon
| | - Angélique Ndjoyi-Mbiguino
- Département de Microbiologie, Laboratoire National de Référence IST/sida, Faculté de Médecine, Université des Sciences de la Santé, Libreville, Gabon
| | - Jean Bernard Lekana-Douki
- Unité de Parasitologie Médicale, Centre International de Recherches Médicales de Franceville (CIRMF), Franceville, Gabon. Département de Parasitologie Mycologie et de Médecine Tropicale, Université des Sciences de la Santé, Libreville, Gabon
| | - Lady Charlène Kouna
- Unité de Parasitologie Médicale, Centre International de Recherches Médicales de Franceville (CIRMF), Franceville, Gabon
| | | | | | - Irene Pegha Moukandja
- Unité de Parasitologie Médicale, Centre International de Recherches Médicales de Franceville (CIRMF), Franceville, Gabon
| | - Alpha Kabinet Keïta
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes (URMITE), Aix Marseille Université, Marseille, France
| | - Hervé Tissot-Dupont
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes (URMITE), Aix Marseille Université, Marseille, France
| | - Florence Fenollar
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes (URMITE), Aix Marseille Université, Marseille, France
| | - Didier Raoult
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes (URMITE), Aix Marseille Université, Marseille, France.
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Kumar D, Dhiman S, Rabha B, Goswami D, Yadav K, Deka M, Veer V, Baruah I. Typing of Plasmodium falciparum DNA from 2 years old Giemsa-stained dried blood spots using nested polymerase chain reaction assay. Indian J Med Microbiol 2016; 34:210-2. [PMID: 27080775 DOI: 10.4103/0255-0857.176841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
A panel of 129 Giemsa-stained thick blood spots (TBS) confirmed for Plasmodium falciparum infection having different levels of parasite density were collected from a malaria endemic area. DNA was extracted and nested polymerase chain reaction (PCR) assay was performed to amplify P. falciparum DNA. Nested PCR assay successfully amplified P. falciparum DNA at a very low parasitaemia of ~10 parasites/μl of blood. Current PCR assay is very simple and can be used retrospectively to monitor the invasion and prevalence of different Plasmodium species in endemic areas.
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Affiliation(s)
| | - S Dhiman
- Medical Entomology Division, Defence Research Laboratory, Tezpur, Assam, India
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41
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Patel JC, Mwapasa V, Kalilani L, Ter Kuile FO, Khairallah C, Thwai KL, Meshnick SR, Taylor SM. Absence of Association Between Sickle Trait Hemoglobin and Placental Malaria Outcomes. Am J Trop Med Hyg 2016; 94:1002-7. [PMID: 27001763 DOI: 10.4269/ajtmh.15-0672] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 01/29/2016] [Indexed: 11/07/2022] Open
Abstract
Heterozygous hemoglobin S (HbAS), or sickle trait, protects children from life-threatening falciparum malaria, potentially by attenuating binding of Plasmodium-infected red blood cells (iRBCs) to extracellular ligands. Such binding is central to the pathogenesis of placental malaria (PM). We hypothesized that HbAS would be associated with reduced risks of PM and low birth weight (LBW). We tested this hypothesis in 850 delivering women in southern Malawi. Parasites were detected by polymerase chain reaction in placental and peripheral blood, and placentae were scored histologically for PM. The prevalence of HbAS was 3.7%, and 11.2% of infants were LBW (< 2,500 g). The prevalence of Plasmodium falciparum was 12.7% in placental and 8.5% in peripheral blood; 24.4% of placentae demonstrated histological evidence of P. falciparum HbAS was not associated with reduced prevalence of P. falciparum in placental (odds ratio [OR]: 1.27, 95% confidence interval [CI]: 0.50-3.23, P = 0.61) or peripheral blood (OR: 2.53, 95% CI: 1.08-2.54, P = 0.03), prevalence of histological PM (OR: 0.97, 95% CI: 0.40-2.34, P = 0.95), or prevalence of LBW (OR: 0.82, 95% CI: 0.24-2.73, P = 0.74). Mean (standard deviation) birth weights of infants born to HbAS (2,947 g [563]) and, homozygous hemoglobin A (2,991 g [465]) mothers were similar. Across a range of parasitologic, clinical, and histologic outcomes, HbAS did not confer protection from PM or its adverse effects.
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Affiliation(s)
- Jaymin C Patel
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
| | - Victor Mwapasa
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
| | - Linda Kalilani
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
| | - Feiko O Ter Kuile
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
| | - Carole Khairallah
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
| | - Kyaw L Thwai
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
| | - Steve M Taylor
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
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Yanow SK, Gavina K, Gnidehou S, Maestre A. Impact of Malaria in Pregnancy as Latin America Approaches Elimination. Trends Parasitol 2016; 32:416-427. [PMID: 26875608 DOI: 10.1016/j.pt.2016.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 01/14/2016] [Accepted: 01/19/2016] [Indexed: 11/29/2022]
Abstract
In Latin America, four million pregnancies are at risk of malaria annually, but malaria in pregnancy is largely overlooked. As countries progress toward malaria elimination, targeting reservoirs of transmission is a priority. Pregnant women are an important risk group because they harbor asymptomatic infections and dormant liver stages of Plasmodium vivax that cause relapses. Of significant concern is the discovery that most infections in pregnant women fail to be detected by routine diagnostics. We review here recent findings on malaria in pregnancy within Latin America. We focus on the Amazon basin and Northwest Colombia, areas that harbor the greatest burden of malaria, and propose that more sensitive diagnostics and active surveillance at antenatal clinics will be necessary to eliminate malaria from these final frontiers.
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Affiliation(s)
- Stephanie K Yanow
- School of Public Health, University of Alberta, Edmonton, Alberta, Canada; Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada.
| | - Kenneth Gavina
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - Sedami Gnidehou
- Department of Biology, Campus Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Amanda Maestre
- Grupo Salud y Comunidad, Universidad de Antioquia, Medellín, Colombia
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43
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Dakić Z, Nikolić A, Lavadinović L, Pelemiš M, Klun I, Dulović O, Milošević B, Stevanović G, Ofori-Belić I, Poluga J, Djurković-Djaković2 O, Pavlović M. Imported parasitic infections in Serbia. Eur J Microbiol Immunol (Bp) 2015; 1:80-5. [PMID: 24466436 DOI: 10.1556/eujmi.1.2011.1.10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Travel to the tropics is associated with a risk of parasitic infection, which is increasing in parallel with the rise in travel to these areas. We thus examined the prevalence and trend in the occurrence of parasitic infections in Serbian travelers. METHODS A retrospective analysis of the medical records of all travelers returning from tropical and subtropical areas, who presented at the Institute for Infectious and Tropical Diseases in Belgrade between January 2001 and January 2008, was performed. RESULTS Of a total of 2440 travelers, 169 (6.9%) were diagnosed with a parasitic infection, including malaria in 79, intestinal parasites in 84 (pathogenic species in 30 and non-pathogenic in 54), filariasis in four, and visceral leishmaniasis and fascioliasis in one patient each. Importantly, of the whole series only 583 (23.9%) were symptomatic, of which 19.4% were found to be infected with a parasite. The single pathogenic parasite occurring in asymptomatic patients was Giardia intestinalis. CONCLUSIONS Parasitic infection causing symptomatic disease among travelers returning from tropical areas to Serbia is not infrequent. In view of the expected increase in travel to the tropics, diagnostic protocols for tropical parasitic diseases should take these data into account.
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Molecular Testing for Plasmodium falciparum by Use of Serum or Plasma and Comparison with Microscopy and Rapid Diagnostic Testing in Febrile Nigerian Patients. J Clin Microbiol 2015; 53:3596-600. [PMID: 26354810 DOI: 10.1128/jcm.01876-15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/02/2015] [Indexed: 01/26/2023] Open
Abstract
Plasmodium nucleic acids have been detected in serum and plasma, but there is little published data describing the diagnostic performance of malaria nucleic acid amplification tests (NAATs) using these specimen types. Previously, our group described a multiplex NAAT for the detection of dengue virus, Leptospira, and Plasmodium species with a callout for P. falciparum (the DLM assay) that demonstrated sensitive detection of P. falciparum from plasma samples during initial evaluation. In this study, we evaluated the sensitivity and specificity of P. falciparum detection in febrile Nigerian patients using the DLM assay, microscopy, and a rapid diagnostic test (BinaxNOW Malaria). Assay performances were compared using a composite reference, which was considered positive if malaria was detected by two or more methods. Serum (n = 182) or plasma (n = 148) from 317 patients was tested; the average sample volume was 70 μl (range, 5 to 300 μl). The sensitivity and specificity of the DLM assay were 97.1% and 93.5%, respectively. The sensitivity of the malaria rapid diagnostic test (98.1%) was similar to that of the DLM assay, and both proved significantly more sensitive than microscopy (79%; P < 0.0001). When analysis was limited to samples with ≥75 μl of serum or plasma, the sensitivity of the DLM assay improved to 99% and specificity was 97.5%. For P. falciparum cases, cycle threshold values in the DLM assay correlated with the parasite density detected by microscopy (Spearman's rank correlation coefficient, P < 0.0001). In conclusion, malaria detection using the DLM assay on serum or plasma is more sensitive than and equal in specificity to microscopy in patients with P. falciparum malaria.
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Kobayashi T, Gamboa D, Ndiaye D, Cui L, Sutton PL, Vinetz JM. Malaria Diagnosis Across the International Centers of Excellence for Malaria Research: Platforms, Performance, and Standardization. Am J Trop Med Hyg 2015; 93:99-109. [PMID: 26259937 PMCID: PMC4574279 DOI: 10.4269/ajtmh.15-0004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 06/23/2015] [Indexed: 12/14/2022] Open
Abstract
Diagnosis is “the act of identifying a disease, illness, or problem by examining someone or something.” When an individual with acute fever presents for clinical attention, accurate diagnosis leading to specific, prompt treatment often saves lives. As applied to malaria, not only individual patient diagnosis is important but also assessing population-level malaria prevalence using appropriate diagnostic methods is essential for public health purposes. Similarly, identifying (diagnosing) fake antimalarial medications prevents the use of counterfeit drugs that can have disastrous effects. Therefore, accurate diagnosis in broad areas related to malaria is fundamental to improving health-care delivery, informing funding agencies of current malaria situations, and aiding in the prioritization of regional and national control efforts. The International Centers of Excellence for Malaria Research (ICEMR), supported by the U.S. National Institute of Allergy and Infectious Diseases, has collaborated on global efforts to improve malaria diagnostics by working to harmonize and systematize procedures across different regions where endemicity and financial resources vary. In this article, the different diagnostic methods used across each ICEMR are reviewed and challenges are discussed.
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Affiliation(s)
- Tamaki Kobayashi
- *Address correspondence to Tamaki Kobayashi, Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, W4612, Baltimore, MD 21205, E-mail: or Joseph M. Vinetz, Division of Infectious Diseases, Department of Medicine, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093-0760, E-mail:
| | | | | | | | | | - Joseph M. Vinetz
- *Address correspondence to Tamaki Kobayashi, Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, W4612, Baltimore, MD 21205, E-mail: or Joseph M. Vinetz, Division of Infectious Diseases, Department of Medicine, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093-0760, E-mail:
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Walldorf JA, Cohee LM, Coalson JE, Bauleni A, Nkanaunena K, Kapito-Tembo A, Seydel KB, Ali D, Mathanga D, Taylor TE, Valim C, Laufer MK. School-Age Children Are a Reservoir of Malaria Infection in Malawi. PLoS One 2015. [PMID: 26207758 PMCID: PMC4514805 DOI: 10.1371/journal.pone.0134061] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Malaria surveillance and interventions in endemic countries often target young children at highest risk of malaria morbidity and mortality. We aimed to determine whether school-age children and adults not captured in surveillance serve as a reservoir for malaria infection and may contribute to malaria transmission. Cross-sectional surveys were conducted in one rainy and one dry season in southern Malawi. Demographic and health information was collected for all household members. Blood samples were obtained for microscopic and PCR identification of Plasmodium falciparum. Among 5796 individuals aged greater than six months, PCR prevalence of malaria infection was 5%, 10%, and 20% in dry, and 9%, 15%, and 32% in rainy seasons in Blantyre, Thyolo, and Chikhwawa, respectively. Over 88% of those infected were asymptomatic. Participants aged 6–15 years were at higher risk of infection (OR=4.8; 95%CI, 4.0–5.8) and asymptomatic infection (OR=4.2; 95%CI, 2.7–6.6) than younger children in all settings. School-age children used bednets less frequently than other age groups. Compared to young children, school-age children were brought less often for treatment and more often to unreliable treatment sources. Conclusion: School-age children represent an underappreciated reservoir of malaria infection and have less exposure to antimalarial interventions. Malaria control and elimination strategies may need to expand to include this age group.
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Affiliation(s)
- Jenny A. Walldorf
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Lauren M. Cohee
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Jenna E. Coalson
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, Michigan, United States of America
| | - Andy Bauleni
- Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre, Malawi
| | - Kondwani Nkanaunena
- Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre, Malawi
| | - Atupele Kapito-Tembo
- Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre, Malawi
| | - Karl B. Seydel
- Michigan State University, East Lansing, Michigan, United States of America
| | - Doreen Ali
- National Malaria Control Program, Ministry of Health, Lilongwe, Malawi
| | - Don Mathanga
- Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre, Malawi
| | - Terrie E. Taylor
- Michigan State University, East Lansing, Michigan, United States of America
| | - Clarissa Valim
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Miriam K. Laufer
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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Chandrasiri UP, Fowkes FJI, Richards JS, Langer C, Fan YM, Taylor SM, Beeson JG, Dewey KG, Maleta K, Ashorn P, Rogerson SJ. The impact of lipid-based nutrient supplementation on anti-malarial antibodies in pregnant women in a randomized controlled trial. Malar J 2015; 14:193. [PMID: 25957793 PMCID: PMC4438573 DOI: 10.1186/s12936-015-0707-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 04/16/2015] [Indexed: 11/12/2022] Open
Abstract
Background Malaria and undernutrition frequently coexist, especially in pregnant women and young children. Nutrient supplementation of these vulnerable groups might reduce their susceptibility to malaria by improving immunity. Methods Antibody immunity to antigens expressed by a placental-binding parasite isolate, a non-placental binding parasite isolate, merozoites and schizonts at enrolment (before 20 gestation weeks) and at 36 gestation weeks were measured in 1,009 Malawian pregnant women receiving a daily lipid-based nutrient supplement, multiple micronutrients or iron and folic acid, who were participants in a randomized clinical trial assessing the effects of nutrient supplementation on pregnancy outcomes and child development(registration ID: NCT01239693). Results Antibodies to placental-binding isolates significantly increased while antibodies to most merozoite antigens declined over pregnancy. Overall, after adjustment for covariates, the type of supplementation did not influence antibody levels at 36 gestation weeks or the rate of change in antibody levels from enrolment to 36 weeks. A negative association between maternal body mass index and opsonizing antibodies to placental-binding antigens (coefficient (95% CI) -1.04 (−1.84, −0.24), was observed. Similarly, women with higher socioeconomic status had significantly lower IgG and opsonizing antibodies to placental-binding antigens. Neither of these associations was significantly influenced by the supplementation type. Conclusions In the current cohort nutrient supplementation did not affect anti-malarial antibody responses, but poor and undernourished mothers should be a priority group in future trials. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0707-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Upeksha P Chandrasiri
- Department of Medicine, Clinical Sciences Building, The University of Melbourne, Royal Parade, Parkville, VIC, 3052, Australia.
| | - Freya J I Fowkes
- Macfarlane Burnet Institute of Medical Research, 85 Commercial Road, Melbourne, Australia. .,Centre for Epidemiology and Biostatistics, Department of Epidemiology, The University of Melbourne, Melbourne, Australia. .,Preventive Medicine and Department of Infectious Diseases, Monash University, Melbourne, Australia.
| | - Jack S Richards
- Department of Medicine, Clinical Sciences Building, The University of Melbourne, Royal Parade, Parkville, VIC, 3052, Australia. .,Macfarlane Burnet Institute of Medical Research, 85 Commercial Road, Melbourne, Australia.
| | - Christine Langer
- Macfarlane Burnet Institute of Medical Research, 85 Commercial Road, Melbourne, Australia.
| | - Yue-Mei Fan
- Department for International Health, University of Tampere School of Medicine, Tampere, Finland. .,Department of Paediatrics, Tampere University Hospital, Tampere, Finland.
| | - Steve M Taylor
- Duke University Medical Center, Durham, North Carolina, USA. .,Gillings School of Global Public Health, University of North Carolina, Chapel Hill, USA.
| | - James G Beeson
- Department of Medicine, Clinical Sciences Building, The University of Melbourne, Royal Parade, Parkville, VIC, 3052, Australia. .,Macfarlane Burnet Institute of Medical Research, 85 Commercial Road, Melbourne, Australia.
| | - Kathryn G Dewey
- Department of Nutrition, University of California Davis, Davis, California, USA.
| | - Kenneth Maleta
- College of Medicine, University of Malawi, Blantyre, Malawi.
| | - Per Ashorn
- Department for International Health, University of Tampere School of Medicine, Tampere, Finland. .,Department of Paediatrics, Tampere University Hospital, Tampere, Finland.
| | - Stephen J Rogerson
- Department of Medicine, Clinical Sciences Building, The University of Melbourne, Royal Parade, Parkville, VIC, 3052, Australia.
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Lo E, Zhou G, Oo W, Afrane Y, Githeko A, Yan G. Low parasitemia in submicroscopic infections significantly impacts malaria diagnostic sensitivity in the highlands of Western Kenya. PLoS One 2015; 10:e0121763. [PMID: 25816298 PMCID: PMC4376713 DOI: 10.1371/journal.pone.0121763] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 02/11/2015] [Indexed: 11/30/2022] Open
Abstract
Asymptomatic malaria infections represent a major challenge in malaria control and elimination in Africa. They are reservoirs of malaria parasite that can contribute to disease transmission. Therefore, identification and control of asymptomatic infections are important to make malaria elimination feasible. In this study, we investigated the extent and distribution of asymptomatic malaria in Western Kenya and examined how varying parasitemia affects performance of diagnostic methods including microscopy, conventional PCR, and quantitative PCR. In addition, we compared parasite prevalence rates and parasitemia levels with respect to topography and age in order to explore factors that influence malaria infection. Over 11,000 asymptomatic blood samples from children and adolescents up to 18 years old representing broad areas of Western Kenya were included. Quantitative PCR revealed the highest parasite positive rate among all methods and malaria prevalence in western Kenya varied widely from less than 1% to over 50%. A significantly lower parasitemia was detected in highland than in lowland samples and this contrast was also observed primarily among submicroscopic samples. Although we found no correlation between parasitemia level and age, individuals of younger age group (aged <14) showed significantly higher parasite prevalence. In the lowlands, individuals of aged 5–14 showed significantly higher prevalence than those under age 5. Our findings highlight the need for a more sensitive and time-efficient assay for asymptomatic malaria detection particularly in areas of low-transmission. Combining QPCR with microscopy can enhance the capacity of detecting submicroscopic asymptomatic malaria infections.
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Affiliation(s)
- Eugenia Lo
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, United States of America
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, United States of America
| | - Winny Oo
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, United States of America
| | - Yaw Afrane
- Centre for Vector Biology and Control Research, Kenya Medical Research Institute, Kisumu, 40100, Kenya
| | - Andrew Githeko
- Centre for Vector Biology and Control Research, Kenya Medical Research Institute, Kisumu, 40100, Kenya
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, United States of America
- * E-mail:
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49
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Longwe H, Jambo KC, Phiri KS, Mbeye N, Gondwe T, Hall T, Tetteh KKA, Drakeley C, Mandala WL. The effect of daily co-trimoxazole prophylaxis on natural development of antibody-mediated immunity against P. falciparum malaria infection in HIV-exposed uninfected Malawian children. PLoS One 2015; 10:e0121643. [PMID: 25807475 PMCID: PMC4373908 DOI: 10.1371/journal.pone.0121643] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 02/02/2015] [Indexed: 11/24/2022] Open
Abstract
Background and Objectives Co-trimoxazole prophylaxis, currently recommended in HIV-exposed, uninfected (HEU) children as protection against opportunistic infections, also has some anti-malarial efficacy. We determined whether daily co-trimoxazole prophylaxis affects the natural development of antibody-mediated immunity to blood-stage Plasmodium falciparum malaria infection. Methods Using an enzyme-linked immunosorbent assay, we measured antibodies to 8Plasmodium falciparum antigens (AMA-1, MSP-119, MSP-3, PfSE, EBA-175RII, GLURP R0, GLURP R2 and CSP) in serum samples from 33 HEU children and 31 HIV-unexposed, uninfected (HUU) children, collected at 6, 12 and 18 months of age. Results Compared to HIV-uninfected children, HEU children had significantly lower levels of specific IgG against AMA-1 at 6 months (p = 0.001), MSP-119 at 12 months (p = 0.041) and PfSE at 6 months (p = 0.038), 12 months (p = 0.0012) and 18 months (p = 0.0097). No differences in the IgG antibody responses against the rest of the antigens were observed between the two groups at all time points. The breadth of specificity of IgG response was reduced in HEU children compared to HUU children during the follow up period. Conclusions Co-trimoxazole prophylaxis seems to reduce IgG antibody responses to P. falciparum blood stage antigens, which could be as a result of a reduction in exposure of those children under this regime. Although antibody responses were regarded as markers of exposure in this study, further studies are required to establish whether these responses are correlated in any way to clinical immunity to malaria.
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Affiliation(s)
- Herbert Longwe
- Department of Basic Medical Sciences, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Kondwani C. Jambo
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Kamija S. Phiri
- Tropical Haematology Research Unit, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Nyanyiwe Mbeye
- Department of Public Health, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Thandile Gondwe
- Department of Public Health, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Tom Hall
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Chris Drakeley
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Wilson L. Mandala
- Department of Basic Medical Sciences, College of Medicine, University of Malawi, Blantyre, Malawi
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- * E-mail:
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50
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O'Meara WP, Mott JA, Laktabai J, Wamburu K, Fields B, Armstrong J, Taylor SM, MacIntyre C, Sen R, Menya D, Pan W, Nicholson BP, Woods CW, Holland TL. Etiology of pediatric fever in western Kenya: a case-control study of falciparum malaria, respiratory viruses, and streptococcal pharyngitis. Am J Trop Med Hyg 2015; 92:1030-7. [PMID: 25758648 DOI: 10.4269/ajtmh.14-0560] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 12/31/2014] [Indexed: 02/03/2023] Open
Abstract
In Kenya, more than 10 million episodes of acute febrile illness are treated annually among children under 5 years. Most are clinically managed as malaria without parasitological confirmation. There is an unmet need to describe pathogen-specific etiologies of fever. We enrolled 370 febrile children and 184 healthy controls. We report demographic and clinical characteristics of patients with Plasmodium falciparum, group A streptococcal (GAS) pharyngitis, and respiratory viruses (influenza A and B, respiratory syncytial virus [RSV], parainfluenza [PIV] types 1-3, adenovirus, human metapneumovirus [hMPV]), as well as those with undifferentiated fever. Of febrile children, 79.7% were treated for malaria. However, P. falciparum was detected infrequently in both cases and controls (14/268 [5.2%] versus 3/133 [2.3%], P = 0.165), whereas 41% (117/282) of febrile children had a respiratory viral infection, compared with 24.8% (29/117) of controls (P = 0.002). Only 9/515 (1.7%) children had streptococcal infection. Of febrile children, 22/269 (8.2%) were infected with > 1 pathogen, and 102/275 (37.1%) had fevers of unknown etiology. Respiratory viruses were common in both groups, but only influenza or parainfluenza was more likely to be associated with symptomatic disease (attributable fraction [AF] 67.5% and 59%, respectively). Malaria was overdiagnosed and overtreated. Few children presented to the hospital with GAS pharyngitis. An enhanced understanding of carriage of common pathogens, improved diagnostic capacity, and better-informed clinical algorithms for febrile illness are needed.
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Affiliation(s)
- Wendy P O'Meara
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Duke Global Health Institute, Durham, North Carolina; Moi University School of Public Health, College of Health Sciences, Eldoret, Kenya; Centers for Disease Control and Prevention, Nairobi, Kenya; Moi University School of Medicine, College of Health Sciences, Eldoret, Kenya; Durham Veterans Affairs Medical Center, Durham, North Carolina
| | - Joshua A Mott
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Duke Global Health Institute, Durham, North Carolina; Moi University School of Public Health, College of Health Sciences, Eldoret, Kenya; Centers for Disease Control and Prevention, Nairobi, Kenya; Moi University School of Medicine, College of Health Sciences, Eldoret, Kenya; Durham Veterans Affairs Medical Center, Durham, North Carolina
| | - Jeremiah Laktabai
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Duke Global Health Institute, Durham, North Carolina; Moi University School of Public Health, College of Health Sciences, Eldoret, Kenya; Centers for Disease Control and Prevention, Nairobi, Kenya; Moi University School of Medicine, College of Health Sciences, Eldoret, Kenya; Durham Veterans Affairs Medical Center, Durham, North Carolina
| | - Kabura Wamburu
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Duke Global Health Institute, Durham, North Carolina; Moi University School of Public Health, College of Health Sciences, Eldoret, Kenya; Centers for Disease Control and Prevention, Nairobi, Kenya; Moi University School of Medicine, College of Health Sciences, Eldoret, Kenya; Durham Veterans Affairs Medical Center, Durham, North Carolina
| | - Barry Fields
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Duke Global Health Institute, Durham, North Carolina; Moi University School of Public Health, College of Health Sciences, Eldoret, Kenya; Centers for Disease Control and Prevention, Nairobi, Kenya; Moi University School of Medicine, College of Health Sciences, Eldoret, Kenya; Durham Veterans Affairs Medical Center, Durham, North Carolina
| | - Janice Armstrong
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Duke Global Health Institute, Durham, North Carolina; Moi University School of Public Health, College of Health Sciences, Eldoret, Kenya; Centers for Disease Control and Prevention, Nairobi, Kenya; Moi University School of Medicine, College of Health Sciences, Eldoret, Kenya; Durham Veterans Affairs Medical Center, Durham, North Carolina
| | - Steve M Taylor
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Duke Global Health Institute, Durham, North Carolina; Moi University School of Public Health, College of Health Sciences, Eldoret, Kenya; Centers for Disease Control and Prevention, Nairobi, Kenya; Moi University School of Medicine, College of Health Sciences, Eldoret, Kenya; Durham Veterans Affairs Medical Center, Durham, North Carolina
| | - Charles MacIntyre
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Duke Global Health Institute, Durham, North Carolina; Moi University School of Public Health, College of Health Sciences, Eldoret, Kenya; Centers for Disease Control and Prevention, Nairobi, Kenya; Moi University School of Medicine, College of Health Sciences, Eldoret, Kenya; Durham Veterans Affairs Medical Center, Durham, North Carolina
| | - Reeshi Sen
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Duke Global Health Institute, Durham, North Carolina; Moi University School of Public Health, College of Health Sciences, Eldoret, Kenya; Centers for Disease Control and Prevention, Nairobi, Kenya; Moi University School of Medicine, College of Health Sciences, Eldoret, Kenya; Durham Veterans Affairs Medical Center, Durham, North Carolina
| | - Diana Menya
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Duke Global Health Institute, Durham, North Carolina; Moi University School of Public Health, College of Health Sciences, Eldoret, Kenya; Centers for Disease Control and Prevention, Nairobi, Kenya; Moi University School of Medicine, College of Health Sciences, Eldoret, Kenya; Durham Veterans Affairs Medical Center, Durham, North Carolina
| | - William Pan
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Duke Global Health Institute, Durham, North Carolina; Moi University School of Public Health, College of Health Sciences, Eldoret, Kenya; Centers for Disease Control and Prevention, Nairobi, Kenya; Moi University School of Medicine, College of Health Sciences, Eldoret, Kenya; Durham Veterans Affairs Medical Center, Durham, North Carolina
| | - Bradly P Nicholson
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Duke Global Health Institute, Durham, North Carolina; Moi University School of Public Health, College of Health Sciences, Eldoret, Kenya; Centers for Disease Control and Prevention, Nairobi, Kenya; Moi University School of Medicine, College of Health Sciences, Eldoret, Kenya; Durham Veterans Affairs Medical Center, Durham, North Carolina
| | - Christopher W Woods
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Duke Global Health Institute, Durham, North Carolina; Moi University School of Public Health, College of Health Sciences, Eldoret, Kenya; Centers for Disease Control and Prevention, Nairobi, Kenya; Moi University School of Medicine, College of Health Sciences, Eldoret, Kenya; Durham Veterans Affairs Medical Center, Durham, North Carolina
| | - Thomas L Holland
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina; Duke Global Health Institute, Durham, North Carolina; Moi University School of Public Health, College of Health Sciences, Eldoret, Kenya; Centers for Disease Control and Prevention, Nairobi, Kenya; Moi University School of Medicine, College of Health Sciences, Eldoret, Kenya; Durham Veterans Affairs Medical Center, Durham, North Carolina
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