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Mediavilla A, Silgado A, Febrer-Sendra B, Crego-Vicente B, Martínez-Vallejo P, Maturana CR, Goterris L, Nindia A, Martínez-Campreciós J, Aixut S, Aznar-Ruiz-de-Alegría ML, Fernández-Soto P, Muro A, Salvador F, Molina I, Berzosa P, Oliveira-Souto I, Sulleiro E. Real-time PCR for malaria diagnosis and identification of Plasmodium species in febrile patients in Cubal, Angola. Parasit Vectors 2024; 17:384. [PMID: 39261971 PMCID: PMC11389249 DOI: 10.1186/s13071-024-06467-3] [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: 03/08/2024] [Accepted: 08/24/2024] [Indexed: 09/13/2024] Open
Abstract
BACKGROUND Malaria is the parasitic disease with the highest morbimortality worldwide. The World Health Organization (WHO) estimates that there were approximately 249 million cases in 2022, of which 3.4% were in Angola. Diagnosis is based on parasite identification by microscopy examination, antigen detection, and/or molecular tests, such as polymerase chain reaction (PCR). This study aimed to evaluate the usefulness of real-time PCR as a diagnostic method for malaria in an endemic area (Cubal, Angola). METHODS A cross-sectional study was carried out at the Hospital Nossa Senhora da Paz in Cubal, Angola, including 200 patients who consulted for febrile syndrome between May and July 2022. From each patient, a capillary blood sample was obtained by finger prick for malaria field diagnosis [microscopy and rapid diagnostic test (RDT)] and venous blood sample for real-time PCR performed at the Hospital Universitario Vall d'Hebron in Barcelona, Spain. Any participant with a positive result from at least one of these three methods was diagnosed with malaria. RESULTS Of the 200 participants included, 54% were female and the median age was 7 years. Malaria was diagnosed by at least one of the three techniques (microscopy, RDT, and/or real-time PCR) in 58% of the participants, with RDT having the highest percentage of positivity (49%), followed by real-time PCR (39.5%) and microscopy (33.5%). Of the 61 discordant samples, 4 were only positive by microscopy, 13 by real-time PCR, and 26 by RDT. Plasmodium falciparum was the most frequent species detected (90.63%), followed by P. malariae (17.19%) and P. ovale (9.38%). Coinfections were detected in ten participants (15.63%): six (60%) were caused by P. falciparum and P. malariae, three (30%) by P. falciparum and P. ovale, and one (10%) triple infection with these three species. In addition, it was observed that P. falciparum and P. malariae coinfection significantly increased the parasite density of the latter. CONCLUSIONS RDT was the technique with the highest positivity rate, followed by real-time PCR and microscopy. The results of the real-time PCR may have been underestimated due to suboptimal storage conditions during the transportation of the DNA eluates. However, real-time PCR techniques have an important role in the surveillance of circulating Plasmodium species, given the epidemiological importance of the increase in non-falciparum species in the country, and can provide an estimate of the intensity of infection.
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Affiliation(s)
- Alejandro Mediavilla
- Microbiology Department, Vall d'Hebron University Hospital, Autonomous University of Barcelona, PROSICS Barcelona, Barcelona, Spain
- Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
| | - Aroa Silgado
- Microbiology Department, Vall d'Hebron University Hospital, Autonomous University of Barcelona, PROSICS Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Begoña Febrer-Sendra
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Center for Research in Tropical Diseases of the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Beatriz Crego-Vicente
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Center for Research in Tropical Diseases of the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Patricia Martínez-Vallejo
- Microbiology Department, Vall d'Hebron University Hospital, Autonomous University of Barcelona, PROSICS Barcelona, Barcelona, Spain
- Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
| | - Carles Rubio Maturana
- Microbiology Department, Vall d'Hebron University Hospital, Autonomous University of Barcelona, PROSICS Barcelona, Barcelona, Spain
- Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
| | - Lidia Goterris
- Microbiology Department, Vall d'Hebron University Hospital, Autonomous University of Barcelona, PROSICS Barcelona, Barcelona, Spain
| | | | - Joan Martínez-Campreciós
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
- International Health Unit Vall d'Hebron-Drassanes, Infectious Diseases Department, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain
| | - Sandra Aixut
- International Health Unit Vall d'Hebron-Drassanes, Infectious Diseases Department, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain
| | - María Luisa Aznar-Ruiz-de-Alegría
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
- International Health Unit Vall d'Hebron-Drassanes, Infectious Diseases Department, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain
| | - Pedro Fernández-Soto
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Center for Research in Tropical Diseases of the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Antonio Muro
- Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Center for Research in Tropical Diseases of the University of Salamanca (IBSAL-CIETUS), Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Fernando Salvador
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
- International Health Unit Vall d'Hebron-Drassanes, Infectious Diseases Department, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain
| | - Israel Molina
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
- International Health Unit Vall d'Hebron-Drassanes, Infectious Diseases Department, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain
| | - Pedro Berzosa
- Malaria and Neglected Tropical Diseases Laboratory, National Centre for Tropical Medicine, Carlos III Health Institute, CIBER de Enfermedades Infecciosas, Madrid, Spain
| | - Inés Oliveira-Souto
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain.
- International Health Unit Vall d'Hebron-Drassanes, Infectious Diseases Department, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain.
| | - Elena Sulleiro
- Microbiology Department, Vall d'Hebron University Hospital, Autonomous University of Barcelona, PROSICS Barcelona, Barcelona, Spain.
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain.
- International Health Unit Vall d'Hebron-Drassanes, Infectious Diseases Department, Vall d'Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain.
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Djuidje Chatue IA, Nyegue MA, Kamdem SD, Maloba F, Taliy Junaid I, Malhotra P, Masumbe Netongo P. Association between Epstein-Barr virus reactivation and severe malaria in pregnant women living in a malaria-endemic region of Cameroon. PLOS GLOBAL PUBLIC HEALTH 2024; 4:e0003556. [PMID: 39133703 PMCID: PMC11318859 DOI: 10.1371/journal.pgph.0003556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 07/10/2024] [Indexed: 08/15/2024]
Abstract
Malaria kills nearly 619,000 people each year. Despite the natural immunity acquired to malaria, pregnant women and children under five die from severe forms of the disease in sub-Saharan Africa. Co-infection with acute Epstein-Barr Virus (EBV) infection has been shown to suppress the anti-malarial humoral responses, but little is known about the impact of EBV reactivation on malaria-associated morbidity. This study investigated the association between EBV reactivation and malaria severity in pregnant women living in a malaria-endemic region in Cameroon. A cross-sectional study was conducted on 220 pregnant women attending antenatal consultations in three health facilities in the West region of Cameroon. Malaria was diagnosed by microscopy, and Plasmodium species were identified by Nested PCR. Plasma samples were analyzed by ELISA for the presence of EBV nuclear antigen, EBV viral capsid antigen, and EBV early antigen to determine EBV reactivation. All statistics were performed using GraphPad Prism and SPSS software. The prevalence of malaria among pregnant women was 23.2%, of which 18.6% were P. falciparum mono-infections and 4.5% mixed infections (3.6% P. falciparum and P. malariae; 0.9% P. falciparum and P. ovale). 99.5% of the women were EBV seropositive, and 13.2% had EBV reactivation. Pregnant women with reactivated EBV were more likely to develop severe malaria than pregnant women with latent EBV (OR 4.33, 95% CI 1.08-17.25, p = 0.03). The median parasitemia in pregnant women with latent EBV was lower than in those with EBV reactivation (2816 vs. 19002 parasites/μL, p = 0.02). Our study revealed that lytic reactivation of EBV may be associated with the severity of malaria in pregnant women. Suggesting that, like acute infection, EBV reactivation should be considered a risk factor for severe malaria in pregnant women in malaria-endemic regions or could serve as a hallmark of malaria severity during pregnancy. Further detailed studies are needed.
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Affiliation(s)
- Ide Armelle Djuidje Chatue
- Department of Microbiology, University of Yaounde I, Yaounde, Centre, Cameroon
- Molecular Diagnostics Research Group, Biotechnology Centre-University of Yaounde I (BTC-UYI), Yaounde, Centre, Cameroon
- Malaria Biology, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, Delhi, India
| | | | - Severin Donald Kamdem
- Molecular Diagnostics Research Group, Biotechnology Centre-University of Yaounde I (BTC-UYI), Yaounde, Centre, Cameroon
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Franklin Maloba
- Molecular Diagnostics Research Group, Biotechnology Centre-University of Yaounde I (BTC-UYI), Yaounde, Centre, Cameroon
- Department of Microbiology and Parasitology, University of Buea, Buea, Southwest Cameroon
- Biology Program, School of Science, Navajo Technical University, Crownpoint, New Mexico, United States of America
| | - Iqbal Taliy Junaid
- Malaria Biology, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, Delhi, India
| | - Pawan Malhotra
- Malaria Biology, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, Delhi, India
| | - Palmer Masumbe Netongo
- Molecular Diagnostics Research Group, Biotechnology Centre-University of Yaounde I (BTC-UYI), Yaounde, Centre, Cameroon
- Biology Program, School of Science, Navajo Technical University, Crownpoint, New Mexico, United States of America
- Department of Biochemistry, University of Yaounde I, Yaounde, Centre, Cameroon
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Omondi P, Musyoka B, Okai T, Kongere J, Kagaya W, Chan CW, Ngara M, Kanoi BN, Kido Y, Gitaka J, Kaneko A. Non-random distribution of Plasmodium Species infections and associated clinical features in children in the lake Victoria region, Kenya, 2012-2018. Trop Med Health 2024; 52:52. [PMID: 39103954 PMCID: PMC11299388 DOI: 10.1186/s41182-024-00622-3] [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: 05/21/2024] [Accepted: 07/25/2024] [Indexed: 08/07/2024] Open
Abstract
BACKGROUND While Plasmodium falciparum (Pf) stands out as the most lethal malaria parasite species in humans, the impact of other species should not be dismissed. Moreover, there is a notable lack of understanding of mixed-species infections and their clinical implications. METHODS We conducted eight school-based cross-sectional malariometric surveys in the Lake Victoria region of western Kenya between January-February 2012 and September-October 2018. In each survey, a minimum of 100 children aged 3 to 15 years were randomly chosen from a school in Ungoye village on the mainland and as well as from each school selected in every catchment area on Mfangano island. Plasmodium infection was determined by microscopy and nested polymerase chain reaction (PCR). The multiple-kind lottery (MKL) model calculated the expected distribution of Plasmodium infections in the population and compared it to observed values using a chi-squared test (χ2). RESULTS The Plasmodium prevalence was 25.9% (2521/9724) by microscopy and 51.1% (4969/9724) by PCR. Among all infections detected by PCR, Pf, P. malariae (Pm), and P. ovale (Po) mono-infections were 58.6%, 3.1%, and 1.8%, respectively. Pf/Pm, Pf/Po, Pm/Po, and Pf/Pm/Po co-infections were 23.5%, 4.3%, 0.1%, and 8.6%, respectively. MKL modelling revealed non-random distributions, with frequencies of Pf/Pm and Pf/Pm/Po co-infections being significantly higher than expected (χ2 = 3385.60, p < 0.001). Pf co-infections with Pm and Po were associated with a decreased risk of fever (aOR 0.64, 95% CI 0.46-0.83; p = 0.01) and increased risks of splenomegaly (aOR 12.79, 95% CI 9.69-16.9; p < 0.001) and anaemia (aOR 2.57, 95% CI 2.09-3.15; p < 0.001), compared to single-species infections. CONCLUSION This study sheds light on the potential interaction between Pf and Pm and/or Po. Given the clinical significance of mixed-species infections, improved diagnostics, and case management of Pm and Po are urgently needed.
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Affiliation(s)
- Protus Omondi
- Department of Virology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Brian Musyoka
- Department of Virology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Takatsugu Okai
- Department of Virology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - James Kongere
- Department of Parasitology/ Osaka International Research Center for Infectious Diseases, Osaka Metropolitan University, Osaka, Japan
| | - Wataru Kagaya
- Department of Eco-Epidemiology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Chim W Chan
- Department of Parasitology/ Osaka International Research Center for Infectious Diseases, Osaka Metropolitan University, Osaka, Japan
| | - Mtakai Ngara
- Department of Clinical Medicine, Mount Kenya University, Thika, Kenya
- Island Malaria Group, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Bernard N Kanoi
- Department of Clinical Medicine, Mount Kenya University, Thika, Kenya
| | - Yasutoshi Kido
- Department of Virology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Jesse Gitaka
- Department of Clinical Medicine, Mount Kenya University, Thika, Kenya
| | - Akira Kaneko
- Department of Parasitology/ Osaka International Research Center for Infectious Diseases, Osaka Metropolitan University, Osaka, Japan.
- Island Malaria Group, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
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4
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Patel P, Mishra KK, Ghosh K. Confirmatory Assay for Laboratory Diagnosis of Malaria Using Molecular Approach. Acta Parasitol 2024; 69:1000-1004. [PMID: 38498250 DOI: 10.1007/s11686-024-00831-0] [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: 10/12/2022] [Accepted: 02/26/2024] [Indexed: 03/20/2024]
Abstract
BACKGROUND Prompt malarial treatment and surveillance is crucial for accurate diagnosis of Plasmodium Sp. Gold standard microscopic examination has been widely applied for diagnosis of malaria in most part of the endemic areas. But in case of submicroscopic and asymptomatic microscopic diagnosis is questioned. The study aims to develop a simple, cost effective & robust nucleic acid amplification technique for the detection of malaria parasite. METHODS Study population included 50 clinically diagnosed positive malaria patient samples from various pathological laboratories. Microscopy by preparing thick film was carried out of every sample for primary screening in the available facility of Surat Raktadan Kendra & Research Centre- Blood Bank. The conventional PCR (Polymerase Chain Reaction) was applied for genus-specific amplification targeting the 18 S rRNA gene of Plasmodium. Agarose gel electrophoresis was used to separate and analyze the amplified PCR product using 2% Agarose gel. RESULTS AND CONCLUSION The study shows that nested PCR not only detected all microscopic positive samples, but also detected submicroscopic infections that were missed or misread by microscopy. Hence, the sensitivity of molecular based detection technique is proved to be more compared to microscopic examination.
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Affiliation(s)
- Parizad Patel
- Surat Raktadan Kendra & Research Centre (Regional Blood Transfusion & Research Centre), Khatodara Health Centre, 1st Floor, Udhana Magdalla Road, Khatodara, Surat, Gujarat, 395002, India
| | - Kanchan Kumar Mishra
- Surat Raktadan Kendra & Research Centre (Regional Blood Transfusion & Research Centre), Khatodara Health Centre, 1st Floor, Udhana Magdalla Road, Khatodara, Surat, Gujarat, 395002, India
| | - Kanjaksha Ghosh
- Surat Raktadan Kendra & Research Centre (Regional Blood Transfusion & Research Centre), Khatodara Health Centre, 1st Floor, Udhana Magdalla Road, Khatodara, Surat, Gujarat, 395002, India
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Ojurongbe TA, Afolabi HA, Bashiru KA, Sule WF, Akinde SB, Ojurongbe O, Adegoke NA. Prediction of malaria positivity using patients' demographic and environmental features and clinical symptoms to complement parasitological confirmation before treatment. Trop Dis Travel Med Vaccines 2023; 9:24. [PMID: 38098124 PMCID: PMC10722830 DOI: 10.1186/s40794-023-00208-7] [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: 04/25/2023] [Accepted: 09/28/2023] [Indexed: 12/17/2023] Open
Abstract
BACKGROUND Current malaria diagnosis methods that rely on microscopy and Histidine Rich Protein-2 (HRP2)-based rapid diagnostic tests (RDT) have drawbacks that necessitate the development of improved and complementary malaria diagnostic methods to overcome some or all these limitations. Consequently, the addition of automated detection and classification of malaria using laboratory methods can provide patients with more accurate and faster diagnosis. Therefore, this study used a machine-learning model to predict Plasmodium falciparum (Pf) antigen positivity (presence of malaria) based on sociodemographic behaviour, environment, and clinical features. METHOD Data from 200 Nigerian patients were used to develop predictive models using nested cross-validation and sequential backward feature selection (SBFS), with 80% of the dataset randomly selected for training and optimisation and the remaining 20% for testing the models. Outcomes were classified as Pf-positive or Pf-negative, corresponding to the presence or absence of malaria, respectively. RESULTS Among the three machine learning models examined, the penalised logistic regression model had the best area under the receiver operating characteristic curve for the training set (AUC = 84%; 95% confidence interval [CI]: 75-93%) and test set (AUC = 83%; 95% CI: 63-100%). Increased odds of malaria were associated with higher body weight (adjusted odds ratio (AOR) = 4.50, 95% CI: 2.27 to 8.01, p < 0.0001). Even though the association between the odds of having malaria and body temperature was not significant, patients with high body temperature had higher odds of testing positive for the Pf antigen than those who did not have high body temperature (AOR = 1.40, 95% CI: 0.99 to 1.91, p = 0.068). In addition, patients who had bushes in their surroundings (AOR = 2.60, 95% CI: 1.30 to 4.66, p = 0.006) or experienced fever (AOR = 2.10, 95% CI: 0.88 to 4.24, p = 0.099), headache (AOR = 2.07; 95% CI: 0.95 to 3.95, p = 0.068), muscle pain (AOR = 1.49; 95% CI: 0.66 to 3.39, p = 0.333), and vomiting (AOR = 2.32; 95% CI: 0.85 to 6.82, p = 0.097) were more likely to experience malaria. In contrast, decreased odds of malaria were associated with age (AOR = 0.62, 95% CI: 0.41 to 0.90, p = 0.012) and BMI (AOR = 0.47, 95% CI: 0.26 to 0.80, p = 0.006). CONCLUSION Newly developed routinely collected baseline sociodemographic, environmental, and clinical features to predict Pf antigen positivity may be a valuable tool for clinical decision-making.
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Affiliation(s)
| | | | | | | | | | - Olusola Ojurongbe
- Department of Medical Microbiology and Parasitology, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
- Center for Emerging and Re-emerging Infectious Diseases, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Nurudeen A Adegoke
- Melanoma Institute Australia, The University of Sydney, Sydney, Australia
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Orimadegun AE, Dada-Adegbola HO, Michael OS, Adepoju AA, Funwei RI, Olusola FI, Ajayi IO, Ogunkunle OO, Ademowo OG, Jegede AS, Baba E, Hamade P, Webster J, Chandramohan D, Falade CO. SD-Bioline malaria rapid diagnostic test performance and time to become negative after treatment of malaria infection in Southwest Nigerian Children. Ann Afr Med 2023; 22:470-480. [PMID: 38358148 PMCID: PMC10775936 DOI: 10.4103/aam.aam_220_21] [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: 10/18/2021] [Revised: 10/10/2022] [Accepted: 12/09/2022] [Indexed: 02/16/2024] Open
Abstract
Context and Aim Given the challenges of microscopy, we compared its performance with SD-Bioline malaria rapid diagnostic test (MRDT) and polymerase chain reaction (PCR) and evaluated the time it took for positive results to become negative after treatment of children with acute uncomplicated malaria. Subjects and Methods We present the report of 485 participants with complete MRDT, microscopy, and PCR data out of 511 febrile children aged 3-59 months who participated in a cohort study over a 12-month period in rural and urban areas of Ibadan, Nigeria. MRDT-positive children received antimalaria and tested at every visit over 28 days. Speciation was also carried out by PCR. Results With microscopy as the gold standard, SD-Bioline™ had 95.2% sensitivity, 66.4% specificity, 67.5% positive predictive value (PPV), and 94.9 negative predictive value (NPV), while with PCR the findings were 84.3% sensitivity, 66.5% specificity, 72.7% PPV, and 80.1% NPV. PCR speciation of malaria parasites revealed 91.6% Plasmodium falciparum, 18.9% Plasmodium malariae, and 4.4% Plasmodium ovale. Among the 47 children with P. malariae infections, 66.0% were coinfected with P. falciparum, while 54.6% cases of P. ovale occurred as coinfections with P. falciparum. The median time to a negative MRDT was 23.2 days, while the median time to a negative malaria microscopy was 3.8 days. The two survival curves were significantly different. Conclusions The SD-BiolineTM MRDT performed well, with remarkable persistence of rapid test-positive for an average of 23 days post treatment. The prevalence of P. malaria is somewhat greater than expected.
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Affiliation(s)
| | | | - Obaro S. Michael
- Department of Pharmacology and Therapeutics, College of Medicine, Ibadan, Nigeria
| | | | | | | | - IkeOluwapo O. Ajayi
- Department of Epidemiology and Biostatistics, College of Medicine, Ibadan, Nigeria
| | | | - Olusegun George Ademowo
- Department of Pharmacology and Therapeutics, College of Medicine, Ibadan, Nigeria
- Institute for Advanced Medical Research and Training, College of Medicine, Ibadan, Nigeria
| | - Ayodele Samuel Jegede
- Department of Sociology, Faculty of the Social Sciences, University of Ibadan, Ibadan, Nigeria
| | - Ebenezer Baba
- Malaria Consortium Regional Office for Africa, Kampala, Uganda
| | | | - Jayne Webster
- London School of Tropical Medicine and Hygiene, London, United Kingdom
| | | | - Catherine Olufunke Falade
- Department of Pharmacology and Therapeutics, College of Medicine, Ibadan, Nigeria
- Institute for Advanced Medical Research and Training, College of Medicine, Ibadan, Nigeria
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7
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Gossner CM, Hallmaier-Wacker L, Briet O, Haussig JM, de Valk H, Wijermans A, Bakonyi T, Madubuko T, Frank C, Noel H, Abdulaziz M. Arthropod-borne diseases among travellers arriving in Europe from Africa, 2015 to 2019. Euro Surveill 2023; 28:2200270. [PMID: 36795503 PMCID: PMC9936595 DOI: 10.2807/1560-7917.es.2023.28.7.2200270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
BackgroundTravellers are generally considered good sentinels for infectious disease surveillance.AimTo investigate whether health data from travellers arriving from Africa to Europe could provide evidence to support surveillance systems in Africa.MethodsWe examined disease occurrence and estimated risk of infection among travellers arriving from Africa to Europe from 2015 to 2019 using surveillance data of arthropod-borne disease cases collected through The European Surveillance System (TESSy) and flight passenger volumes from the International Air Transport Association.ResultsMalaria was the most common arthropod-borne disease reported among travellers from Africa, with 34,235 cases. The malaria travellers' infection rate (TIR) was 28.8 cases per 100,000 travellers, which is 36 and 144 times higher than the TIR for dengue and chikungunya, respectively. The malaria TIR was highest among travellers arriving from Central and Western Africa. There were 956 and 161 diagnosed imported cases of dengue and chikungunya, respectively. The highest TIR was among travellers arriving from Central, Eastern and Western Africa for dengue and from Central Africa for chikungunya in this period. Limited numbers of cases of Zika virus disease, West Nile virus infection, Rift Valley fever and yellow fever were reported.ConclusionsDespite some limitations, travellers' health data can efficiently complement local surveillance data in Africa, particularly when the country or region has a sub-optimal surveillance system. The sharing of anonymised traveller health data between regions/continents should be encouraged.
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Affiliation(s)
- Céline M Gossner
- European Centre for Disease Prevention and Control, Stockholm, Sweden
| | | | - Olivier Briet
- European Centre for Disease Prevention and Control, Stockholm, Sweden
| | - Joana M Haussig
- European Centre for Disease Prevention and Control, Stockholm, Sweden
| | | | - Ariana Wijermans
- European Centre for Disease Prevention and Control, Stockholm, Sweden
| | - Tamas Bakonyi
- European Centre for Disease Prevention and Control, Stockholm, Sweden
| | - Theresa Madubuko
- Africa Centres for Disease Control and Prevention, Addis Ababa, Ethiopia
| | | | - Harold Noel
- Santé publique France, Saint Maurice, France
| | - Mohammed Abdulaziz
- Africa Centres for Disease Control and Prevention, Addis Ababa, Ethiopia
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8
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Ippolito MM, Gebhardt ME, Ferriss E, Schue JL, Kobayashi T, Chaponda M, Kabuya JB, Muleba M, Mburu M, Matoba J, Musonda M, Katowa B, Lubinda M, Hamapumbu H, Simubali L, Mudenda T, Wesolowski A, Shields TM, Hackman A, Shiff C, Coetzee M, Koekemoer LL, Munyati S, Gwanzura L, Mutambu S, Stevenson JC, Thuma PE, Norris DE, Bailey JA, Juliano JJ, Chongwe G, Mulenga M, Simulundu E, Mharakurwa S, Agre PC, Moss WJ. Scientific Findings of the Southern and Central Africa International Center of Excellence for Malaria Research: Ten Years of Malaria Control Impact Assessments in Hypo-, Meso-, and Holoendemic Transmission Zones in Zambia and Zimbabwe. Am J Trop Med Hyg 2022; 107:55-67. [PMID: 36228903 PMCID: PMC9662223 DOI: 10.4269/ajtmh.21-1287] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 04/08/2022] [Indexed: 11/07/2022] Open
Abstract
For a decade, the Southern and Central Africa International Center of Excellence for Malaria Research has operated with local partners across study sites in Zambia and Zimbabwe that range from hypo- to holoendemic and vary ecologically and entomologically. The burden of malaria and the impact of control measures were assessed in longitudinal cohorts, cross-sectional surveys, passive and reactive case detection, and other observational designs that incorporated multidisciplinary scientific approaches: classical epidemiology, geospatial science, serosurveillance, parasite and mosquito genetics, and vector bionomics. Findings to date have helped elaborate the patterns and possible causes of sustained low-to-moderate transmission in southern Zambia and eastern Zimbabwe and recalcitrant high transmission and fatality in northern Zambia. Cryptic and novel mosquito vectors, asymptomatic parasite reservoirs in older children, residual parasitemia and gametocytemia after treatment, indoor residual spraying timed dyssynchronously to vector abundance, and stockouts of essential malaria commodities, all in the context of intractable rural poverty, appear to explain the persistent malaria burden despite current interventions. Ongoing studies of high-resolution transmission chains, parasite population structures, long-term malaria periodicity, and molecular entomology are further helping to lay new avenues for malaria control in southern and central Africa and similar settings.
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Affiliation(s)
- Matthew M. Ippolito
- Johns Hopkins University School of Medicine, Baltimore, Maryland
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Mary E. Gebhardt
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Ellen Ferriss
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Jessica L. Schue
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Tamaki Kobayashi
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | | | | | | | | | | | | | | | | | | | | | - Amy Wesolowski
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | - Andre Hackman
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Clive Shiff
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Maureen Coetzee
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand and National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Lizette L. Koekemoer
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand and National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Shungu Munyati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Lovemore Gwanzura
- Biomedical Research and Training Institute, Harare, Zimbabwe
- University of Zimbabwe Faculty of Medicine and Health Sciences, Harare, Zimbabwe
| | | | - Jennifer C. Stevenson
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Macha Research Trust, Choma, Zambia
| | | | - Douglas E. Norris
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | - Jonathan J. Juliano
- University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | | | - Modest Mulenga
- Directorate of Research and Postgraduate Studies, Lusaka Apex Medical University, Lusaka, Zambia
| | | | - Sungano Mharakurwa
- Biomedical Research and Training Institute, Harare, Zimbabwe
- Africa University, Mutare, Zimbabwe
| | - Peter C. Agre
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - William J. Moss
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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Akinyi MY, Chifwete M, Ndwiga L, Kimenyi KM, Osoti V, Ochola-Oyier LI. A cross-sectional analysis identifies a low prevalence of Plasmodium ovale curtisi infections in symptomatic and asymptomatic individuals in Kilifi county, Kenya. Wellcome Open Res 2022. [DOI: 10.12688/wellcomeopenres.17972.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: The focus on P. falciparum diagnosis has led to an underestimation of the global burden of malaria resulting from neglected Plasmodium species. However, there is still scarce data on the prevalence of P. ovale globally. To address this knowledge gap, data collected from cross-sectional studies in Kilifi county were used to: 1) determine the prevalence of P. ovale curtisi infections; and 2) determine the sensitivity of different diagnostic assays in detecting P. ovale curtisi infections. Methods: A total of 531 individuals were sampled across three study sites in Kilifi County, Kenya between 2009 and 2020. Blood smears were prepared from peripheral blood and screened for Plasmodium parasite stages using light microscopy. Molecular screening involved DNA extraction of dried blood spots and blood in ethylenediaminetetraacetic acid, polymerase chain reaction (PCR) using primers targeting the 18 small ribosomal subunit and sequencing. Results: Microscopy screening revealed that the most prevalent species was P. falciparum (32.0%) followed by P. malariae (9.0%) and then P. ovale (1.5%). PCR screening identified additional P. ovale curtisi positives cases. Overall, 48 (8.2%) out of the 531 individuals harbored P. ovale curtisi infection with the highest prevalence reported in the tertiary health facility, (14.6%, 95% CI 8-23.6%), followed by the primary health facility (8.6%, 95% CI 5.4-11.9%), and the community from a cross-sectional blood survey, (6.5%, 95% CI 3.0-11.8%). Microscopy screening for P. ovale had a low sensitivity of 7% (95% CI 1-19-30%) and a high specificity of 99% (95% CI 98-100%). Sequencing results confirmed the presence of P.ovale curtisi. Conclusions: This study provides baseline data for P.ovale curtisi surveillance in Kilifi County, primarily using PCR to improve diagnosis. These results suggest that malaria elimination and eradication efforts should not only concentrate on P. falciparum but should embrace a holistic approach towards elimination of all Plasmodium species.
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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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11
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The Pan African Vivax and Ovale Network (PAVON): Refocusing on Plasmodium vivax, ovale and asymptomatic malaria in sub-Saharan Africa. Parasitol Int 2021; 84:102415. [PMID: 34216801 DOI: 10.1016/j.parint.2021.102415] [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: 02/01/2021] [Revised: 06/26/2021] [Accepted: 06/28/2021] [Indexed: 11/20/2022]
Abstract
The recent World Malaria report shows that progress in malaria elimination has stalled. Current data acquisition by NMCPs depend on passive case detection and clinical reports focused mainly on Plasmodium falciparum (Pf). In recent times, several countries in sub-Saharan Africa have reported cases of Plasmodium vivax (Pv) with a considerable number being Duffy negative. The burden of Pv and Plasmodium ovale (Po) appear to be more than acknowledged. Similarly, the contribution of asymptomatic malaria in transmission is hardly considered by NMCPs in Africa. Inclusion of these as targets in malaria elimination agenda is necessary to achieve elimination goal, as these harbor hypnozoites. The Pan African Vivax and Ovale Network (PAVON) is a new consortium of African Scientists working in Africa on the transmission profile of Pv and Po. The group collaborates with African NMCPs to train in Plasmodium molecular diagnostics, microscopy, and interpretation of molecular data from active surveys to translate into policy. Details of the mission, rational and modus operandi of the group are outlined.
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12
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Mitchell CL, Brazeau NF, Keeler C, Mwandagalirwa MK, Tshefu AK, Juliano JJ, Meshnick SR. Under the Radar: Epidemiology of Plasmodium ovale in the Democratic Republic of the Congo. J Infect Dis 2021; 223:1005-1014. [PMID: 32766832 PMCID: PMC8006425 DOI: 10.1093/infdis/jiaa478] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 07/28/2020] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Plasmodium ovale is an understudied malaria species prevalent throughout much of sub-Saharan Africa. Little is known about the distribution of ovale malaria and risk factors for infection in areas of high malaria endemicity. METHODS Using the 2013 Democratic Republic of the Congo (DRC) Demographic and Health Survey, we conducted a risk factor analysis for P. ovale infections. We evaluated geographic clustering of infections and speciated to P. ovale curtisi and P. ovale wallikeri through deep sequencing. RESULTS Of 18 149 adults tested, we detected 143 prevalent P. ovale infections (prevalence estimate 0.8%; 95% confidence interval [CI], .59%-.98%). Prevalence ratios (PR) for significant risk factors were: male sex PR = 2.12 (95% CI, 1.38-3.26), coprevalent P. falciparum PR = 3.52 (95% CI, 2.06-5.99), and rural residence PR = 2.19 (95% CI, 1.31-3.66). P. ovale was broadly distributed throughout the DRC; an elevated cluster of infections was detected in the south-central region. Speciation revealed P. ovale curtisi and P. ovale wallikeri circulating throughout the country. CONCLUSIONS P. ovale persists broadly in the DRC, a high malaria burden country. For successful elimination of all malaria species, P. ovale needs to be on the radar of malaria control programs.
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Affiliation(s)
- Cedar L Mitchell
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Nicholas F Brazeau
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Corinna Keeler
- Department of Geography, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Melchior Kashamuka Mwandagalirwa
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
- Kinshasa School of Public Health, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Antoinette K Tshefu
- Kinshasa School of Public Health, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Jonathan J Juliano
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
- Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
- Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
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13
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Oriero EC, Amenga-Etego L, Ishengoma DS, Amambua-Ngwa A. Plasmodium malariae, current knowledge and future research opportunities on a neglected malaria parasite species. Crit Rev Microbiol 2021; 47:44-56. [PMID: 33507842 DOI: 10.1080/1040841x.2020.1838440] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Plasmodium malariae is often reported as a benign malaria parasite. There are limited data on its biology and disease burden in sub-Saharan Africa (sSA) possibly due to the unavailability of specific and affordable tools for routine diagnosis and large epidemiology studies. In addition, P. malariae occurs at low parasite densities and in co-infections with other species, predominately P. falciparum. The paucity of data on P. malariae infections limits the capacity to accurately determine its contribution to malaria and the effect of control interventions against P. falciparum on its prevalence. Here, we summarise the current knowledge on P. malariae epidemiology in sSA - overall prevalence ranging from 0-32%, as detected by different diagnostic methods; seroprevalence ranging from 0-56% in three countries (Mozambique, Benin and Zimbabwe), and explore the future application of next-generation sequencing technologies as a tool for enriching P. malariae genomic epidemiology. This will provide insights into important adaptive mechanisms of this neglected non-falciparum species, including antimalarial drug resistance, local and regional parasite transmission patterns and genomic signatures of selection. Improved diagnosis and genomic surveillance of non-falciparum malaria parasites in Africa would be helpful in evaluating progress towards elimination of all human Plasmodium species.
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Affiliation(s)
- Eniyou C Oriero
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at LSHTM, Fajara, The Gambia
| | - Lucas Amenga-Etego
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Ghana
| | - Deus S Ishengoma
- Tanga Research Centre, National Institute for Medical Research, Tanga, Tanzania
| | - Alfred Amambua-Ngwa
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at LSHTM, Fajara, The Gambia
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14
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Chipoya MN, Shimaponda-Mataa NM. Prevalence, characteristics and risk factors of imported and local malaria cases in North-Western Province, Zambia: a cross-sectional study. Malar J 2020; 19:430. [PMID: 33228684 PMCID: PMC7686676 DOI: 10.1186/s12936-020-03504-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 11/17/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Imported malaria is a major challenge for countries that are in malaria elimination stage such as Zambia. Legitimate cross-border activities add to the risk of transmission, necessitating determination of prevalence, characteristics and risk factors of imported and local malaria. METHODS This cross-sectional study was conducted in 103 consented child and adult patients with clinical malaria symptoms, from selected health facilities in north-western Zambia. Patient demographic data and blood samples for malaria microscopy and full blood count were obtained. Chi-square and penalized logistic regression were performed to describe the characteristics and assess the risk factors of imported and local malaria in North-Western Province. RESULTS Overall, malaria prevalence was 78.6% with 93.8% Plasmodium falciparum and 6.2% other species. The local cases were 72 (88.9%) while the imported were 9 (11.1%) out of the 81 positive participants. About 98.6% of the local cases were P. falciparum compared to 55.6% (χ2 = 52.4; p < 0.01) P. falciparum among the imported cases. Among the imported cases, 44% were species other than P. falciparum (χ2 = 48; p < 0.01) while among the local cases only 1.4% were. Gametocytes were present in 44% of the imported malaria cases and only in 2.8% of the local cases (χ2 = 48; p < 0.01). About 48.6% of local participants had severe anaemia compared to 33.3% of participants from the two neighbouring countries who had (χ2 = 4.9; p = 0.03). In the final model, only country of residence related positively to presence of species other than P. falciparum (OR = 39.0, CI [5.9, 445.9]; p < 0.01) and presence of gametocytes (OR = 23.1, CI [4.2, 161.6]; p < 0.01). CONCLUSION Malaria prevalence in North-Western Province is high, with P. falciparum as the predominant species although importation of Plasmodium ovale and Plasmodium malariae is happening as well. Country of residence of patients is a major risk factor for malaria species and gametocyte presence. The need for enhanced malaria control with specific focus on border controls to detect and treat, for specific diagnosis and treatment according to species obtaining, for further research in the role of species and gametocytaemia in imported malaria, cannot be overemphasized.
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Affiliation(s)
- Maureen N Chipoya
- Department of Biomedical Sciences, School of Health Sciences, University of Zambia, Ridgeway Campus, Lusaka, Zambia
| | - Nzooma M Shimaponda-Mataa
- Department of Biomedical Sciences, School of Health Sciences, University of Zambia, Ridgeway Campus, Lusaka, Zambia.
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15
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Oboh MA, Oyebola KM, Idowu ET, Badiane AS, Otubanjo OA, Ndiaye D. Rising report of Plasmodium vivax in sub-Saharan Africa: Implications for malaria elimination agenda. SCIENTIFIC AFRICAN 2020. [DOI: 10.1016/j.sciaf.2020.e00596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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16
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Plasmodium spp. mixed infection leading to severe malaria: a systematic review and meta-analysis. Sci Rep 2020; 10:11068. [PMID: 32632180 PMCID: PMC7338391 DOI: 10.1038/s41598-020-68082-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 05/21/2020] [Indexed: 12/11/2022] Open
Abstract
Mixed Plasmodium malaria infections can lead to severe malaria. This systematic review and meta-analysis aimed to explore the prevalence of severe mixed Plasmodium malaria infection and to compare it with the prevalence of severe P. falciparum malaria mono-infection across the included studies. Original English-language research articles from PubMed, Scopus, and ISI Web of Science were identified and screened. Articles reporting the number of mixed infections and the number of severe mixed infections were used to determine the main outcome of this study, while the number of P. falciparum infections and the number of severe P. falciparum infections were used to determine the secondary outcome of this study. For the main outcome, the pooled prevalence and 95% confidence interval (CI) of severe mixed infections was analysed using STATA software version 15.0 (Stata Corp, College Station, TX, USA). For the secondary outcome, the rate of severe mixed infections compared to severe P. falciparum infections was analysed using the meta-analysis approach, and summary odds ratios (ORs) and 95% CIs were calculated. Random-effects models were used to produce the summary ORs. The Mantel–Haenszel method and calculated I2 were also reported to test whether there was heterogeneity among the included studies. Publication bias was also assessed using funnel plots. The meta-analysis of secondary outcomes was conducted using Review Manager 5.3 software (Cochrane Community). A total of 894,561 malaria patients were reported in all 16 included studies. Overall, a pooled analysis showed that 9% (2,006/35,768, 95% CI 7.0–12.0%) of patients with mixed Plasmodium infection had severe mixed infection. A meta-analysis of 14 studies demonstrated that patients with mixed Plasmodium infection (1,999/35,755) and patients with P. falciparum malaria (9,249/294,397) had an equal risk of developing severe malaria (OR 0.93, 95% CI 0.59–1.44). Both mixed infection and P. falciparum mono-infection showed a similar trend of complications in which severe anaemia, pulmonary failure, and renal impairment were the three most common complications found. However, patients with mixed infection had a higher proportion of severe anaemia and pulmonary complications than those with P. falciparum infection. Moreover, patients with mixed infection had a higher proportion of multiple organ failure than those with P. falciparum mono-infection. Mixed Plasmodium spp. infections were common but often unrecognized or underestimated, leading to severe complications among these malaria patients. Therefore, in routine clinical laboratories, using an accurate combination of diagnostic procedures to identify suspected patients with mixed infections is crucial for therapeutic decisions, prompt treatment, and effective patient management.
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Kotepui M, Kotepui KU, Milanez GD, Masangkay FR. Prevalence and proportion of Plasmodium spp. triple mixed infections compared with double mixed infections: a systematic review and meta-analysis. Malar J 2020; 19:224. [PMID: 32580721 PMCID: PMC7315477 DOI: 10.1186/s12936-020-03292-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 06/17/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Although mixed infection by two Plasmodium species has been recognized, mixed infection by three different Plasmodium species within one individual has not been clarified. This study sought to determine the pooled prevalence and proportion of triple mixed Plasmodium spp. infection compared with double mixed infection. METHODS Articles from PubMed, Scopus, and Web of Science were searched for cross-sectional studies of triple mixed infection by Plasmodium species and then were retrieved and extracted. The pooled proportion and prevalence of triple mixed infection by Plasmodium species were subjected to random-effects analysis. The secondary outcomes were differences in the pooled proportion between triple mixed infection and double mixed infection by Plasmodium species reported in the included studies. RESULTS Of 5621 identified studies, triple mixed infection data were available for 35 records, including 601 patients from 22 countries. The overall pooled prevalence of triple mixed infection was 4% (95% Confidence Interval (CI) 3-5%; I2 = 92.5%). The pooled proportion of triple mixed infection compared with double mixed infection was 12% (95% CI 9-18; I2 = 91%). Most of the included studies (29/35; 82.9%) presented a lower proportion of triple mixed infection than double mixed infection. Subgroup analysis demonstrated that the proportion of triple mixed infection was the highest in Oceania (23%; 95% CI 15-36%) and Europe (21%; 95% CI 5-86%), but the lowest in the USA (3%; 95% CI 2-4%). Moreover, the proportion of triple mixed infection was higher in residents (20%; 95% CI 14-29%) than in febrile patients (7%; 95% CI 4-13%), when compared with the proportion of double mixed infection. Subgroup analysis of the age groups demonstrated that, compared with the proportion of double mixed infection, triple mixed infection was lower in patients aged ≤ 5 years (OR = 0.27; 95% CI 0.13-0.56; I2 = 31%) and > 5 years (OR = 0.09; 95% CI 0.04-0.25, I2 = 78%). CONCLUSIONS The present study suggested that, in areas where triple mixed infection were endemic, PCR or molecular diagnosis for all residents in communities where malaria is submicroscopic can provide prevalence data and intervention measures, as well as prevent disease transmission and enhance malaria elimination efforts.
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Affiliation(s)
- Manas Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand.
| | - Kwuntida Uthaisar Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand
| | - Giovanni D Milanez
- Department of Medical Technology, Far Eastern University-Manila, Manila, Philippines
| | - Frederick R Masangkay
- Department of Medical Technology, Far Eastern University-Manila, Manila, Philippines
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Woday A, Mohammed A, Gebre A, Urmale K. Prevalence and Associated Factors of Malaria among Febrile Children in Afar Region, Ethiopia: A Health Facility Based Study. Ethiop J Health Sci 2020; 29:613-622. [PMID: 31666783 PMCID: PMC6813264 DOI: 10.4314/ejhs.v29i5.12] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background Malaria is a major public health problem in Sub-Saharan Africa including Ethiopia and it affects children under five and pregnant mothers. Theprevalence of malaria is not well studied though the burden is expected to be high in low lands of Afar region.Therefore, this study attempts to assess the prevalence and associated factors of malaria among under five children in the pastoral community. Methods Cross-sectional study design was employed from April 15th to 15th May 2018 on a sample of 484 under-five children who visited the randomly selected health facilities of Dubti district, Afar region.The study participants were recruited randomly with the basic assumption that their arrival at health facilities is random. The main outcome variable was parasitological confirmed malaria among under five children and it was measured using either microscopy blood film examination. Binary logistic regression model was done to measure the association between confirmed malaria infection and its predictors. Independent variables with p-value less than 0.25 in the bivariate analysis were entered into multivariable logistic regression analysis model. Statistical significance level was declared at p-value less than 0.05. Results The prevalence of malaria among febrile under-five children was 64% (95% CI 59.5%–68.4%). Of these, more than half (66.5%) and one-fifth (22. 2%) of the cases were caused by p.falciparum and p.vivax respectively. The multivariable logistic regression analysis showed thatliving in rural residence [AOR=1.77: 95% CI 1.10–2.85], having educated mother [AOR=0.406: 95% CI 0.26–0.63], age of child ([AOR=2.98: 95% CI 1.41–6.32], sex of child [AOR=1.99: 95% CI 1.29–3.08], not sleep under ITN [AOR=9.10: 95% CI 1.01- 82.58], ITN availability [AOR=2.23: 95% CI 1.01- 4.89] and history of malaria infection among family members [AOR=9.10: 95% CI 1.01–82.58] were the independent predictors of malaria infection among under five children. Conclusion The overall prevalence of malaria among under-five children was high compared to the national prevalence of malaria among the general population. Health care providers (HCPs) should educate parents/guardians regarding proper utilization of ITN at night. In addiotion, they should provide early treatment for febrile family members to halt the transmission of malaria. The regional government should give due attention to supply of ITN and enhance the awareness of the community. Additional longitudinal studies are recommended.
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Affiliation(s)
- Abay Woday
- Department of Public Health, College of Health Science, Samara University, Samara, Ethiopia
| | - Ahmed Mohammed
- Department of Malaria Prevention and Control, Dubti District Health Office, Dubti, Ethiopia
| | - Abel Gebre
- Department of Public Health, College of Health Science, Samara University, Samara, Ethiopia
| | - Kusse Urmale
- Department of Nursing, College of Health Science, Samara University, Samara, Ethiopia
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19
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Sears KP, Kappmeyer LS, Wise LN, Silva M, Ueti MW, White S, Reif KE, Knowles DP. Infection dynamics of Theileria equi and Theileria haneyi, a newly discovered apicomplexan of the horse. Vet Parasitol 2019; 271:68-75. [PMID: 31303207 DOI: 10.1016/j.vetpar.2019.06.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 11/15/2022]
Abstract
Theileria equi infection, exotic to the United States has reemerged through intravenous (iatrogenic) and tick-borne transmission. Surveillance at the US-Mexico border identified a new species, Theileria haneyi, (T. haneyiEP) (EP = Eagle Pass, Texas) which warranted additional investigation due to inability to detect by PCR targeting of T. equi ema-1 and EMA-1-cELISA validated for T. equi. Infection dynamics of T. haneyiEP were evaluated, including ability to superinfect in the presence of T. equi-Texas (T. equiTX), the isolate responsible for the reemergence of T. equi in the U S. Experimental infection with T. equiTX or T. haneyiEP revealed minimal clinical disease however, T. equiTX infection led to significantly greater neutropenia. Comparison of time to antibody detection following inoculation revealed significantly greater time to detectable anti-T. haneyiEP antibody (26.67 days post-inoculation (DPI)) than T. equiTX (11.67 DPI). Regardless of initial infection with either T. equiTX or T. haneyiEP, superinfection was established. Comparative analysis of antibody responses from a splenectomized horse infected with T. haneyiEP to that of a spleen intact horse infected with T. equiFL revealed a different antibody binding profile to T. haneyiEP, T. equiTX and T. equiFL merozoite antigen and limited shared antigen/cross-reactive antibody(s). Affinity purified T. equi EMA-1 and EMA-2 from T. equiFL were shown as targets for horse antibodies against T. haneyi. Data presented here show (1) T. haneyiEP can superinfect in the presence of T. equiTX infection and co-persists for minimally 25 months, (2) intravenous challenge with T. haneyi is subclinical, and (3) limited cross-reactive antibody between T. haneyiEP and T. equi includes reactivity to EMA-1 and EMA-2.
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Affiliation(s)
- Kelly P Sears
- Veterinary Clinical Sciences, Washington State University, Pullman, WA, USA.
| | - Lowell S Kappmeyer
- Animal Disease Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, WA, USA
| | - Lauren N Wise
- Animal Disease Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, WA, USA; St. George's University, School of Veterinary Medicine True Blue Campus, St. George's, Grenada West Indies, Grenada
| | - Marta Silva
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | - Massaro W Ueti
- Animal Disease Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, WA, USA
| | - Stephen White
- Animal Disease Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, WA, USA; Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | - Kathryn E Reif
- Animal Disease Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, WA, USA; Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | - Donald P Knowles
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
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20
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Sitali L, Miller JM, Mwenda MC, Bridges DJ, Hawela MB, Hamainza B, Chizema-Kawesha E, Eisele TP, Chipeta J, Lindtjørn B. Distribution of Plasmodium species and assessment of performance of diagnostic tools used during a malaria survey in Southern and Western Provinces of Zambia. Malar J 2019; 18:130. [PMID: 30971231 PMCID: PMC6458729 DOI: 10.1186/s12936-019-2766-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 04/04/2019] [Indexed: 11/10/2022] Open
Abstract
Background Zambia continues to make strides in reducing malaria burden through the use of proven malaria interventions and has recently pledged to eliminate malaria by 2021. Case management services have been scaled up at community level with rapid diagnostic tests (RDTs) providing antigen-based detection of falciparum malaria only. Key to national malaria elimination goals is the ability to identify, treat and eliminate all Plasmodium species. This study sought to determine the distribution of non-falciparum malaria and assess the performance of diagnostic tests for Plasmodium falciparum in Western and Southern Provinces of Zambia, two provinces planned for early malaria elimination. Methods A sub-set of individuals’ data and samples from a cross-sectional household survey, conducted during peak malaria transmission season in April and May 2017, was used. The survey collected socio-demographic information on household members and coverage of malaria interventions. Malaria testing was done on respondents of all ages using blood smears and RDTs while dried blood spots were collected on filter papers for analysis using photo-induced electron transfer polymerase chain reaction (PET-PCR). Slides were stained using Giemsa stain and examined by microscopy for malaria parasites. Results From the 1567 individuals included, the overall prevalence of malaria was 19.4% (CI 17.5–21.4) by PCR, 19.3% (CI 17.4–21.4) by RDT and 12.9% (CI 11.3–14.7) by microscopy. Using PET-PCR as the gold standard, RDTs showed a sensitivity of 75.7% (CI 70.4–80.4) and specificity of 94.2% (CI 92.8–95.4). The positive predictive value (PPV) was 75.9% (CI 70.7–80.6) and negative predictive value (NPV) was 94.1% (CI 92.1–95.4). In contrast, microscopy for sensitivity, specificity, PPV, and NPV values were 56.9% (CI 51.1–62.5), 97.7% (CI 96.7–98.5), 85.6% (CI 80.0–90.2), 90.4% (CI 88.7–91.9), respectively. Non-falciparum infections were found only in Western Province, where 11.6% of P. falciparum infections were co-infections with Plasmodium ovale or Plasmodium malariae. Conclusion From the sub-set of survey data analysed, non-falciparum species are present and occurred as mixed infections. As expected, PET-PCR was slightly more sensitive than both malaria RDTs and microscopy to detecting malaria infections.
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Affiliation(s)
- Lungowe Sitali
- Centre for International Health, Faculty of Medicine, University of Bergen, Bergen, Norway. .,Department of Biomedical Science, School of Health Sciences, University of Zambia, Lusaka, Zambia. .,School of Medicine and University Teaching Hospital Malaria Research Unit (SMUTH-MRU), Lusaka, Zambia.
| | - John M Miller
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Mulenga C Mwenda
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Daniel J Bridges
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Moonga B Hawela
- National Malaria Elimination Centre, Ministry of Health, Chainama Hospital and College Grounds, Lusaka, Zambia
| | - Busiku Hamainza
- National Malaria Elimination Centre, Ministry of Health, Chainama Hospital and College Grounds, Lusaka, Zambia
| | - Elizabeth Chizema-Kawesha
- National Malaria Elimination Centre, Ministry of Health, Chainama Hospital and College Grounds, Lusaka, Zambia
| | - Thomas P Eisele
- Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA.,Center for Applied Malaria Research and Evaluation, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - James Chipeta
- School of Medicine and University Teaching Hospital Malaria Research Unit (SMUTH-MRU), Lusaka, Zambia.,Department of Paediatrics and Child Health, University of Zambia School of Medicine, Lusaka, Zambia
| | - Bernt Lindtjørn
- Centre for International Health, Faculty of Medicine, University of Bergen, Bergen, Norway
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21
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Betson M, Clifford S, Stanton M, Kabatereine NB, Stothard JR. Emergence of Nonfalciparum Plasmodium Infection Despite Regular Artemisinin Combination Therapy in an 18-Month Longitudinal Study of Ugandan Children and Their Mothers. J Infect Dis 2018; 217:1099-1109. [PMID: 29325068 PMCID: PMC5939692 DOI: 10.1093/infdis/jix686] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 01/05/2018] [Indexed: 12/04/2022] Open
Abstract
As part of a longitudinal cohort investigation of intestinal schistosomiasis and malaria in Ugandan children and their mothers on the shorelines of Lakes Victoria and Albert, we documented risk factors and morbidity associated with nonfalciparum Plasmodium infections and the longitudinal dynamics of Plasmodium species in children. Host age, household location, and Plasmodium falciparum infection were strongly associated with nonfalciparum Plasmodium infections, and Plasmodium malariae infection was associated with splenomegaly. Despite regular artemisinin combination therapy treatment, there was a 3-fold rise in P. malariae prevalence, which was not accountable for by increasing age of the child. Worryingly, our findings reveal the consistent emergence of nonfalciparum infections in children, highlighting the complex dynamics underlying multispecies infections here. Given the growing body of evidence that nonfalciparum malaria infections cause significant morbidity, we encourage better surveillance for nonfalciparum Plasmodium infections, particularly in children, with more sensitive DNA detection methods and improved field-based diagnostics.
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Affiliation(s)
- Martha Betson
- School of Veterinary Medicine, University of Surrey, Guildford
| | - Sarah Clifford
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Michelle Stanton
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - J Russell Stothard
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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22
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Amir A, Cheong FW, De Silva JR, Lau YL. Diagnostic tools in childhood malaria. Parasit Vectors 2018; 11:53. [PMID: 29361963 PMCID: PMC5781272 DOI: 10.1186/s13071-018-2617-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 01/02/2018] [Indexed: 01/05/2023] Open
Abstract
Every year, millions of people are burdened with malaria. An estimated 429,000 casualties were reported in 2015, with the majority made up of children under five years old. Early and accurate diagnosis of malaria is of paramount importance to ensure appropriate administration of treatment. This minimizes the risk of parasite resistance development, reduces drug wastage and unnecessary adverse reaction to antimalarial drugs. Malaria diagnostic tools have expanded beyond the conventional microscopic examination of Giemsa-stained blood films. Contemporary and innovative techniques have emerged, mainly the rapid diagnostic tests (RDT) and other molecular diagnostic methods such as PCR, qPCR and loop-mediated isothermal amplification (LAMP). Even microscopic diagnosis has gone through a paradigm shift with the development of new techniques such as the quantitative buffy coat (QBC) method and the Partec rapid malaria test. This review explores the different diagnostic tools available for childhood malaria, each with their characteristic strengths and limitations. These tools play an important role in making an accurate malaria diagnosis to ensure that the use of anti-malaria are rationalized and that presumptive diagnosis would only be a thing of the past.
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Affiliation(s)
- Amirah Amir
- Department of Parasitology, Faculty of Medicine, University Malaya, 50603, Kuala Lumpur, Malaysia
| | - Fei-Wen Cheong
- Department of Parasitology, Faculty of Medicine, University Malaya, 50603, Kuala Lumpur, Malaysia
| | - Jeremy R De Silva
- Department of Parasitology, Faculty of Medicine, University Malaya, 50603, Kuala Lumpur, Malaysia
| | - Yee-Ling Lau
- Department of Parasitology, Faculty of Medicine, University Malaya, 50603, Kuala Lumpur, Malaysia.
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23
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Asua V, Tukwasibwe S, Conrad M, Walakira A, Nankabirwa JI, Mugenyi L, Kamya MR, Nsobya SL, Rosenthal PJ. Plasmodium Species Infecting Children Presenting with Malaria in Uganda. Am J Trop Med Hyg 2017; 97:753-757. [PMID: 28990911 DOI: 10.4269/ajtmh.17-0345] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Contributions of species other than Plasmodium falciparum to human malaria in sub-Saharan Africa are uncertain. We collected blood from children aged 6 months to 10 years diagnosed with malaria by Giemsa-stained blood smears (176 subjects) or histidine rich protein-2-based rapid diagnostic tests (323 subjects) in 2016; 50 samples from each of 10 sites across Uganda were studied to identify infecting species. Of 499 available samples, 474 demonstrated plasmodial infection by polymerase chain reaction amplification of 18S ribosomal RNA genes, including P. falciparum in 472, Plasmodium malariae in 22, Plasmodium ovale in 15, and Plasmodium vivax in four; 435 were pure P. falciparum, two did not contain P. falciparum, and the remainder were mixed infections including P. falciparum. The prevalence of nonfalciparum species varied geographically. Stratifying based on recent history of indoor residual spraying (IRS) of insecticides, nonfalciparum infections were seen in 27/189 (14.8%) samples from sites that received and 13/285 (4.6%) samples from sites that did not receive IRS since 2010 (P = 0.0013). Overall, 39/474 (8.2%) samples from individuals diagnosed with malaria included nonfalciparum infections. Thus, a substantial proportion of episodes of malaria in Uganda include infections with plasmodial species other than P. falciparum.
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Affiliation(s)
- Victor Asua
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Melissa Conrad
- Department of Medicine, University of California, San Francisco, San Francisco, California; 3Department of Medicine, Makerere University, Kampala, Uganda
| | | | - Joaniter I Nankabirwa
- Deparment of Pathology, Makerere University, Kampala, Uganda.,Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Moses R Kamya
- Deparment of Pathology, Makerere University, Kampala, Uganda.,Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Samuel L Nsobya
- Deparment of Pathology, Makerere University, Kampala, Uganda.,Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Philip J Rosenthal
- Department of Medicine, University of California, San Francisco, San Francisco, California; 3Department of Medicine, Makerere University, Kampala, Uganda
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24
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Kang JM, Cho PY, Moe M, Lee J, Jun H, Lee HW, Ahn SK, Kim TI, Pak JH, Myint MK, Lin K, Kim TS, Na BK. Comparison of the diagnostic performance of microscopic examination with nested polymerase chain reaction for optimum malaria diagnosis in Upper Myanmar. Malar J 2017; 16:119. [PMID: 28302168 PMCID: PMC5356273 DOI: 10.1186/s12936-017-1765-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 02/28/2017] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Accurate diagnosis of Plasmodium infection is crucial for prompt malaria treatment and surveillance. Microscopic examination has been widely applied as the gold standard for malaria diagnosis in most part of malaria endemic areas, but its diagnostic value has been questioned, particularly in submicroscopic malaria. In this study, the diagnostic performance of microscopic examination and nested polymerase chain reaction (PCR) was evaluated to establish optimal malaria diagnosis method in Myanmar. METHODS A total of 1125 blood samples collected from residents in the villages and towns located in Naung Cho, Pyin Oo Lwin, Tha Beik Kyin townships and Mandalay of Upper Myanmar were screened by microscopic examination and species-specific nested PCR method. RESULTS Among the 1125 blood samples, 261 samples were confirmed to be infected with malaria by microscopic examination. Evaluation of the 1125 samples by species-specific nested PCR analysis revealed that the agreement between microscopic examination and nested PCR was 87.3% (261/299). Nested PCR successfully detected 38 Plasmodium falciparum or Plasmodium vivax infections, which were missed in microscopic examination. Microscopic examinations also either misdiagnosed the infected Plasmodium species, or did not detect mixed infections with different Plasmodium species in 31 cases. CONCLUSIONS The nested PCR method is more reliable than conventional microscopic examination for the diagnosis of malaria infections, and this is particularly true in cases of mixed infections and submicroscopic infections. Given the observed higher sensitivity and specificity of nested PCR, the molecular method holds enormous promise in malaria diagnosis and species differentiation, and can be applied as an effective monitoring tool for malaria surveillance, control and elimination in Myanmar.
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Affiliation(s)
- Jung-Mi Kang
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-Aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Pyo-Yun Cho
- Department of Tropical Medicine and Inha Research Institute for Medical Sciences, Inha University School of Medicine, Incheon, 22212, Republic of Korea
| | - Mya Moe
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar
| | - Jinyoung Lee
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, 52727, Republic of Korea
| | - Hojong Jun
- Department of Tropical Medicine and Inha Research Institute for Medical Sciences, Inha University School of Medicine, Incheon, 22212, Republic of Korea
| | - Hyeong-Woo Lee
- Department of Tropical Medicine and Inha Research Institute for Medical Sciences, Inha University School of Medicine, Incheon, 22212, Republic of Korea
| | - Seong Kyu Ahn
- Department of Tropical Medicine and Inha Research Institute for Medical Sciences, Inha University School of Medicine, Incheon, 22212, Republic of Korea
| | - Tae Im Kim
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, 52727, Republic of Korea
| | - Jhang Ho Pak
- Department of Convergence Medicine, University of Ulsan College of Medicine and Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, Republic of Korea
| | - Moe Kyaw Myint
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar
| | - Khin Lin
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar.
| | - Tong-Soo Kim
- Department of Tropical Medicine and Inha Research Institute for Medical Sciences, Inha University School of Medicine, Incheon, 22212, Republic of Korea.
| | - Byoung-Kuk Na
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, 52727, Republic of Korea. .,BK21Plus Team for Anti-Aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea.
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25
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Hayashida K, Kajino K, Simukoko H, Simuunza M, Ndebe J, Chota A, Namangala B, Sugimoto C. Direct detection of falciparum and non-falciparum malaria DNA from a drop of blood with high sensitivity by the dried-LAMP system. Parasit Vectors 2017; 10:26. [PMID: 28086864 PMCID: PMC5237333 DOI: 10.1186/s13071-016-1949-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 12/21/2016] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Because of the low sensitivity of conventional rapid diagnostic tests (RDTs) for malaria infections, the actual prevalence of the diseases, especially those caused by non-Plasmodium falciparum (non-Pf) species, in asymptomatic populations remain less defined in countries lacking in well-equipped facilities for accurate diagnoses. Our direct blood dry LAMP system (CZC-LAMP) was applied to the diagnosis of malaria as simple, rapid and highly sensitive method as an alternative for conventional RDTs in malaria endemic areas where laboratory resources are limited. RESULTS LAMP primer sets for mitochondria DNAs of Plasmodium falciparum (Pf) and human-infective species other than Pf (non-Pf; P. vivax, P. ovale, P. malariae) were designed and tested by using human blood DNA samples from 74 residents from a malaria endemic area in eastern Zambia. These malaria dry-LAMPs were optimized for field or point-of-care operations, and evaluated in the field at a malaria endemic area in Zambia with 96 human blood samples. To determine the sensitivities and specificities, results obtained by the on-site LAMP diagnosis were compared with those by the nested PCR and nucleotide sequencing of its product. The dry LAMPs showed the sensitivities of 89.7% for Pf and 85.7% for non-Pf, and the specificities of 97.2% for Pf and 100% for non-Pf, with purified blood DNA samples. The direct blood LAMP diagnostic methods, in which 1 μl of anticoagulated blood were used as the template, showed the sensitivities of 98.1% for Pf, 92.1% for non-Pf, and the specificities of 98.1% for Pf, 100% for non-Pf. The prevalences of P. falciparum, P. malariae and P. ovale in the surveyed area were 52.4, 25.3 and 10.6%, respectively, indicating high prevalence of asymptomatic carriers in endemic areas in Zambia. CONCLUSIONS We have developed new field-applicable malaria diagnostic tests. The malaria CZC-LAMPs showed high sensitivity and specificity to both P. falciparum and non-P. falciparum. These malaria CZC-LAMPs provide new means for rapid, sensitive and reliable point-of-care diagnosis for low-density malaria infections, and are expected to help update current knowledge of malaria epidemiology, and can contribute to the elimination of malaria from endemic areas.
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Affiliation(s)
- Kyoko Hayashida
- Division of Collaboration and Education, Hokkaido University Research Center for Zoonosis Control, Sapporo, 001-0020, Japan
| | - Kiichi Kajino
- Division of Collaboration and Education, Hokkaido University Research Center for Zoonosis Control, Sapporo, 001-0020, Japan.
| | - Humphrey Simukoko
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka, Zambia
| | - Martin Simuunza
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka, Zambia
| | - Joseph Ndebe
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka, Zambia
| | - Amos Chota
- Department of Paraclinical Studies, School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka, Zambia
| | - Boniface Namangala
- Department of Paraclinical Studies, School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka, Zambia
| | - Chihiro Sugimoto
- Division of Collaboration and Education, Hokkaido University Research Center for Zoonosis Control, Sapporo, 001-0020, Japan.,Global Station for Zoonosis Control, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, 001-0020, Japan
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26
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Li P, Zhao Z, Xing H, Li W, Zhu X, Cao Y, Yang Z, Sattabongkot J, Yan G, Fan Q, Cui L. Plasmodium malariae and Plasmodium ovale infections in the China-Myanmar border area. Malar J 2016; 15:557. [PMID: 27846879 PMCID: PMC5111346 DOI: 10.1186/s12936-016-1605-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/07/2016] [Indexed: 01/28/2023] Open
Abstract
Background The Greater Mekong Subregion is aiming to achieve regional malaria elimination by 2030. Though a shift in malaria parasite species predominance by Plasmodium vivax has been recently documented, the transmission of the two minor Plasmodium species, Plasmodium malariae and Plasmodium ovale spp., is poorly characterized in the region. This study aims to determine the prevalence of these minor species in the China–Myanmar border area and their genetic diversity. Methods Epidemiology study was conducted during passive case detection in hospitals and clinics in Myanmar and four counties in China along the China–Myanmar border. Cross-sectional surveys were conducted in villages and camps for internally displaced persons to determine the prevalence of malaria infections. Malaria infections were diagnosed initially by microscopy and later in the laboratory using nested PCR for the SSU rRNA genes. Plasmodium malariae and P. ovale infections were confirmed by sequencing the PCR products. The P. ovale subtypes were determined by sequencing the Pocytb, Pocox1 and Pog3p genes. Parasite populations were evaluated by PCR amplification and sequencing of the MSP-1 genes. Antifolate sensitivity was assessed by sequencing the dhfr-ts and dhps genes from the P. malariae and P. ovale isolates. Results Analysis of 2701 blood samples collected from the China–Myanmar border by nested PCR targeting the parasite SSU rRNA genes identified 561 malaria cases, including 161 Plasmodium falciparum, 327 P. vivax, 66 P. falciparum/P. vivax mixed infections, 4 P. malariae and 3 P. ovale spp. P. vivax and P. falciparum accounted for >60 and ~30% of all malaria cases, respectively. In comparison, the prevalence of P. malariae and P. ovale spp. was very low and only made up ~1% of all PCR-positive cases. Nevertheless, these two species were often misidentified as P. vivax infections or completely missed by microscopy even among symptomatic patients. Phylogenetic analysis of the SSU rRNA, Pocytb, Pocox1 and Pog3p genes confirmed that the three P. ovale spp. isolates belonged to the subtype P. ovale curtisi. Low-level genetic diversity was detected in the MSP-1, dhfr and dhps genes of these minor parasite species, potentially stemming from the low prevalence of these parasites preventing their mixing. Whereas most of the dhfr and dhps positions equivalent to those conferring antifolate resistance in P. falciparum and P. vivax were wild type, a new mutation S113C corresponding to the S108 position in pfdhfr was identified in two P. ovale curtisi isolates. Conclusions The four human malaria parasite species all occurred sympatrically at the China–Myanmar border. While P. vivax has become the predominant species, the two minor parasite species also occurred at very low prevalence but were often misidentified or missed by conventional microscopy. These minor parasite species displayed low levels of polymorphisms in the msp-1, dhfr and dhps genes. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1605-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Peipei Li
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Zhenjun Zhao
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Hua Xing
- Dalian University of Technology, Dalian, Liaoning, China
| | - Wenli Li
- Dalian University of Technology, Dalian, Liaoning, China
| | - Xiaotong Zhu
- Department of Immunology, China Medical University, Shenyang, Liaoning, China
| | - Yaming Cao
- Department of Immunology, China Medical University, Shenyang, Liaoning, China
| | - Zhaoqing Yang
- Department of Parasitology, Kunming Medical University, Kunming, Yunnan, China
| | | | - Guiyun Yan
- University of California, Irvine, CA, USA
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China.
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, PA, USA.
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27
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Idris ZM, Chan CW, Kongere J, Gitaka J, Logedi J, Omar A, Obonyo C, Machini BK, Isozumi R, Teramoto I, Kimura M, Kaneko A. High and Heterogeneous Prevalence of Asymptomatic and Sub-microscopic Malaria Infections on Islands in Lake Victoria, Kenya. Sci Rep 2016; 6:36958. [PMID: 27841361 PMCID: PMC5107902 DOI: 10.1038/srep36958] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/24/2016] [Indexed: 11/17/2022] Open
Abstract
Kenya is intensifying its national efforts in malaria control to achieve malaria elimination. Detailed characterization of malaria infection among populations living in the areas where the disease is endemic in Kenya is a crucial priority, especially for planning and evaluating future malaria elimination strategy. This study aimed to investigate the distribution and extent of malaria infection on islands in Lake Victoria of Kenya to aid in designing new interventions for malaria elimination. Five cross-sectional surveys were conducted between January 2012 and August 2014 on four islands (Mfangano, Takawiri, Kibuogi and Ngodhe) in Lake Victoria and a coastal mainland (Ungoye). Malaria prevalence varied significantly among settings: highest in Ungoye, followed by the large island of Mfangano and lowest in the three remaining small islands. Of the 3867 malaria infections detected by PCR, 91.8% were asymptomatic, 50.3% were sub-microscopic, of which 94% were also asymptomatic. We observed geographical differences and age dependency in both proportion of sub-microscopic infections and asymptomatic parasite carriage. Our findings highlighted the local heterogeneity in malaria prevalence on islands and a coastal area in Lake Victoria, and provided support for the inclusion of mass drug administration as a component of the intervention package to eliminate malaria on islands.
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Affiliation(s)
- Zulkarnain Md Idris
- Island Malaria Group, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, 17177, Sweden.,Department of Parasitology and Medical Entomology, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, 56000, Malaysia
| | - Chim W Chan
- Island Malaria Group, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, 17177, Sweden
| | - James Kongere
- Nagasaki University Nairobi Research Station, NUITM-KEMRI Project, Nairobi, 00202, Kenya
| | - Jesse Gitaka
- Department of Clinical Medicine, Mount Kenya University, Thika, 01000, Kenya
| | - John Logedi
- National Malaria Control Programme, Ministry of Public Health and Sanitation, Nairobi, 00100, Kenya
| | - Ahmeddin Omar
- National Malaria Control Programme, Ministry of Public Health and Sanitation, Nairobi, 00100, Kenya
| | - Charles Obonyo
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, 40100, Kenya
| | - Beatrice Kemunto Machini
- National Malaria Control Programme, Ministry of Public Health and Sanitation, Nairobi, 00100, Kenya
| | - Rie Isozumi
- Department of Parasitology, Graduate School of Medicine, Osaka City University, Osaka, 558-8585, Japan
| | - Isao Teramoto
- Department of Parasitology, Graduate School of Medicine, Osaka City University, Osaka, 558-8585, Japan
| | - Masatsugu Kimura
- Department of Parasitology, Graduate School of Medicine, Osaka City University, Osaka, 558-8585, Japan
| | - Akira Kaneko
- Island Malaria Group, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, 17177, Sweden.,Department of Parasitology, Graduate School of Medicine, Osaka City University, Osaka, 558-8585, Japan.,Institute of Tropical Medicine, Nagasaki University, Nagasaki, 852-8102, Japan
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28
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Sutherland CJ. Persistent Parasitism: The Adaptive Biology of Malariae and Ovale Malaria. Trends Parasitol 2016; 32:808-819. [PMID: 27480365 DOI: 10.1016/j.pt.2016.07.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 06/17/2016] [Accepted: 07/12/2016] [Indexed: 12/29/2022]
Abstract
Plasmodium malariae causes malaria in humans throughout the tropics and subtropics. Plasmodium ovale curtisi and Plasmodium ovale wallikeri are sympatric sibling species common in sub-Saharan Africa and also found in Oceania and Asia. Although rarely identified as the cause of malaria cases in endemic countries, PCR detection has confirmed all three parasite species to be more prevalent, and persistent, than previously thought. Chronic, low-density, multispecies asymptomatic infection is a successful biological adaptation by these Plasmodium spp., a pattern also observed among malaria parasites of wild primates. Current whole-genome analyses are illuminating the species barrier separating the ovale parasite species and reveal substantial expansion of subtelomeric gene families. The evidence for and against a quiescent pre-erythrocytic form of P. malariae is reviewed.
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Affiliation(s)
- Colin J Sutherland
- Department of Immunology and Infection and Public Health England Malaria Reference Laboratory, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK; Department of Clinical Parasitology, Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, Mortimer Market Centre, Capper Street, London WC1E 6JB, UK.
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29
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Doctor SM, Liu Y, Anderson OG, Whitesell AN, Mwandagalirwa MK, Muwonga J, Keeler C, Emch M, Likwela JL, Tshefu A, Meshnick SR. Low prevalence of Plasmodium malariae and Plasmodium ovale mono-infections among children in the Democratic Republic of the Congo: a population-based, cross-sectional study. Malar J 2016; 15:350. [PMID: 27392905 PMCID: PMC4938993 DOI: 10.1186/s12936-016-1409-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 06/21/2016] [Indexed: 11/10/2022] Open
Abstract
Background In an effort to improve surveillance for epidemiological and clinical outcomes, rapid diagnostic tests (RDTs) have become increasingly widespread as cost-effective and field-ready methods of malaria diagnosis. However, there are concerns that using RDTs specific to Plasmodium falciparum may lead to missed detection of other malaria species such as Plasmodium malariae and Plasmodium ovale. Methods Four hundred and sixty six samples were selected from children under 5 years old in the Democratic Republic of the Congo (DRC) who took part in a Demographic and Health Survey (DHS) in 2013–14. These samples were first tested for all Plasmodium species using an 18S ribosomal RNA-targeted real-time PCR; malaria-positive samples were then tested for P. falciparum, P. malariae and P.ovale using a highly sensitive nested PCR. Results The prevalence of P. falciparum, P. malariae and P. ovale were 46.6, 12.9 and 8.3 %, respectively. Most P. malariae and P. ovale infections were co-infected with P. falciparum—the prevalence of mono-infections of these species were only 1.0 and 0.6 %, respectively. Six out of these eight mono-infections were negative by RDT. The prevalence of P. falciparum by the more sensitive nested PCR was higher than that found previously by real-time PCR. Conclusions Plasmodium malariae and P. ovale remain endemic at a low rate in the DRC, but the risk of missing malarial infections of these species due to falciparum-specific RDT use is low. The observed prevalence of P. falciparum is higher with a more sensitive PCR method. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1409-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Stephanie M Doctor
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27599-7435, USA
| | - Yunhao Liu
- Department of Statistics and Operations Research, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Olivia G Anderson
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27599-7435, USA
| | - Amy N Whitesell
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27599-7435, USA
| | - Melchior Kashamuka Mwandagalirwa
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27599-7435, USA.,Ecole de Santé Publique, Faculté de Medecine, Université de Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Jérémie Muwonga
- Programme National de Lutte contre le SIDA et les IST, Kinshasa, Democratic Republic of the Congo
| | - Corinna Keeler
- Department of Geography, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Michael Emch
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27599-7435, USA.,Department of Geography, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Joris L Likwela
- Programme National de Lutte contre le Paludisme, Kinshasa, Democratic Republic of the Congo
| | - Antoinette Tshefu
- Ecole de Santé Publique, Faculté de Medecine, Université de Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27599-7435, USA.
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