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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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Saha S, Narang R, Deshmukh P, Pote K, Anvikar A, Narang P. Diagnostic efficacy of microscopy, rapid diagnostic test and polymerase chain reaction for malaria using bayesian latent class analysis. Indian J Med Microbiol 2018; 35:376-380. [PMID: 29063882 DOI: 10.4103/ijmm.ijmm_17_199] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION The diagnostic techniques for malaria are undergoing a change depending on the availability of newer diagnostics and annual parasite index of infection in a particular area. At the country level, guidelines are available for selection of diagnostic tests; however, at the local level, this decision is made based on malaria situation in the area. The tests are evaluated against the gold standard, and if that standard has limitations, it becomes difficult to compare other available tests. Bayesian latent class analysis computes its internal standard rather than using the conventional gold standard and helps comparison of various tests including the conventional gold standard. MATERIALS AND METHODS In a cross-sectional study conducted in a tertiary care hospital setting, we have evaluated smear microscopy, rapid diagnostic test (RDT), and polymerase chain reaction (PCR) for diagnosis of malaria using Bayesian latent class analysis. RESULTS We found the magnitude of malaria to be 17.7% (95% confidence interval: 12.5%-23.9%) among the study subjects. In the present study, the sensitivity of microscopy was 63%, but it had very high specificity (99.4%). Sensitivity and specificity of RDT and PCR were high with RDT having a marginally higher sensitivity (94% vs. 90%) and specificity (99% vs. 95%). On comparison of likelihood ratios (LRs), RDT had the highest LR for positive test result (175) and the lowest LR for negative test result (0.058) among the three tests. CONCLUSION In settings like ours conventional smear microscopy may be replaced with RDT and as we move toward elimination and facilities become available PCR may be roped into detect cases with lower parasitaemia.
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Affiliation(s)
- Sreemanti Saha
- Department of Microbiology, Mahatma Gandhi Institute of Medical Sciences, Wardha, Maharashtra, India
| | - Rahul Narang
- Department of Microbiology, Mahatma Gandhi Institute of Medical Sciences, Wardha, Maharashtra, India
| | - Pradeep Deshmukh
- Department of Community Medicine, Mahatma Gandhi Institute of Medical Sciences, Wardha, Maharashtra, India
| | - Kiran Pote
- Department of Microbiology, Mahatma Gandhi Institute of Medical Sciences, Wardha, Maharashtra, India
| | - Anup Anvikar
- National Institute for Malaria Research, New Delhi, India
| | - Pratibha Narang
- Department of Microbiology, Mahatma Gandhi Institute of Medical Sciences, Wardha, Maharashtra, India
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Lover AA, Dantzer E, Hongvanthong B, Chindavongsa K, Welty S, Reza T, Khim N, Menard D, Bennett A. Prevalence and risk factors for asymptomatic malaria and genotyping of glucose 6-phosphate (G6PD) deficiencies in a vivax-predominant setting, Lao PDR: implications for sub-national elimination goals. Malar J 2018; 17:218. [PMID: 29859089 PMCID: PMC5984820 DOI: 10.1186/s12936-018-2367-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 05/23/2018] [Indexed: 12/27/2022] Open
Abstract
Background Lao People Democratic Republic (PDR; Laos), a landlocked country in Southeast Asia, has made important progress in reducing malaria morbidity and mortality in the past 5–6 years, and the northern provinces have very low reported incidence. To support national progress towards elimination, it is critical to verify and understand these changes in disease burden. Methods A two-stage cluster cross-sectional survey was conducted in four districts within four northern provinces (Khua, Phongsaly Province; Paktha, Bokeo Province; Nambak, Luang Prabang, and Muang Et, Huaphanh Province). During September and October 2016, demographics and malaria risk factors were collected from a total of 1492 households. A total of 5085 persons consented to collection of blood samples for testing, by rapid diagnostic test (RDT) and polymerase chain reaction (PCR)-based testing. Risk factors for infection were examined using logistic regression; and a randomized subset of males was tested for glucose-6-phosphate dehydrogenase (G6PD) deficiencies using a combined PCR and sequencing approach. Results There were zero positives by RDT, and PCR detected Plasmodium infections in 39 (0.77%; 95% CI 0.40–1.47%) of 5082 analysable samples. The species distribution was Plasmodium vivax (28 total); Plasmodium falciparum/P. vivax (5); P. falciparum (3), Plasmodium malariae (2), and P. vivax/P. malariae (1). In multivariable analysis, the main risk factors included having any other cases within the household [aOR 12.83 (95% CI 4.40 to 37.38), p < 0.001]; and lack of bed net ownership within the household [aOR 10.91 (95% 5.42–21.94), p < 0.001]; age, sex and forest-travel were not associated with parasitaemia. A total of 910 males were tested for the six most common G6PDd in SE Asia; and 30 (3.3%; 95% CI 2.1–5.1%) had a G6PD variant allele associated with G6PD deficiency, with the majority being the Union (14) and Viangchan (11) polymorphisms, with smaller numbers of Canton and Mahidol. Conclusion This is the first rigorous PCR-based population survey for malaria infection in Northern Lao PDR, and found a very low prevalence of asymptomatic Plasmodium infections by standard PCR methods, with P. vivax predominating in the surveyed districts. Clustering of cases within households, and lack of a bed nets suggest reactive case detection, and scale-up of coverage should be prioritized. The predominance of infections with P. vivax, combined with moderate levels of serious G6PD deficiencies highlight the need for careful rollout of primaquine towards elimination goals. Electronic supplementary material The online version of this article (10.1186/s12936-018-2367-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Andrew A Lover
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California, San Francisco, CA, USA.
| | - Emily Dantzer
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California, San Francisco, CA, USA
| | - Bouasy Hongvanthong
- Center for Malariology, Parasitology and Entomology (CMPE), Ministry of Health, Vientiane, Lao PDR
| | | | - Susie Welty
- Global Strategic Information, Institute for Global Health Sciences, University of California, San Francisco, CA, USA
| | - Tania Reza
- Global Strategic Information, Institute for Global Health Sciences, University of California, San Francisco, CA, USA
| | | | - Didier Menard
- Malaria Genetic and Resistance Group, Institut Pasteur, Paris, France
| | - Adam Bennett
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California, San Francisco, CA, USA
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Bell D, Fleurent AE, Hegg MC, Boomgard JD, McConnico CC. Development of new malaria diagnostics: matching performance and need. Malar J 2016; 15:406. [PMID: 27515426 PMCID: PMC4981959 DOI: 10.1186/s12936-016-1454-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 07/28/2016] [Indexed: 12/02/2022] Open
Abstract
Despite advances in diagnostic technology, significant gaps remain in access to malaria diagnosis. Accurate diagnosis and misdiagnosis leads to unnecessary waste of resources, poor disease management, and contributes to a cycle of poverty in low-resourced communities. Despite much effort and investment, few new technologies have reached the field in the last 30 years aside from lateral flow assays. This suggests that much diagnostic development effort has been misdirected, and/or that there are fundamental blocks to introduction of new technologies. Malaria diagnosis is a difficult market; resources are broadly donor-dependent, health systems in endemic countries are frequently weak, and the epidemiology of malaria and priorities of malaria programmes and donors are evolving. Success in diagnostic development will require a good understanding of programme gaps, and the sustainability of markets to address them. Targeting assay development to such clearly defined market requirements will improve the outcomes of product development funding. Six market segments are identified: (1) case management in low-resourced countries, (2) parasite screening for low density infections in elimination programmes, (3) surveillance for evidence of continued transmission, (4) clinical research and therapeutic efficacy monitoring, (5) cross-checking for microscopy quality control, and (6) returned traveller markets distinguished primarily by resource availability. While each of these markets is potentially compelling from a public health standpoint, size and scale are highly variable and continue to evolve. Consequently, return on investment in research and development may be limited, highlighting the need for potentially significant donor involvement or the introduction of novel business models to overcome prohibitive economics. Given the rather specific applications, a well-defined set of stakeholders will need to be on board for the successful introduction and scaling of any new technology to these markets.
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Affiliation(s)
- David Bell
- Global Good Fund/Intellectual Ventures Laboratory, 3150 139th Ave SE, Bellevue, WA, 98005, USA.
| | | | | | | | - Caitlin C McConnico
- International Training and Education Center for Health (I-TECH), Gaborone, Botswana
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Phommasone K, Adhikari B, Henriques G, Pongvongsa T, Phongmany P, von Seidlein L, White NJ, Day NPJ, M Dondorp A, Newton PN, Imwong M, Mayxay M. Asymptomatic Plasmodium infections in 18 villages of southern Savannakhet Province, Lao PDR (Laos). Malar J 2016; 15:296. [PMID: 27234446 PMCID: PMC4882819 DOI: 10.1186/s12936-016-1336-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Accepted: 05/10/2016] [Indexed: 11/10/2022] Open
Abstract
Background A large fraction of Plasmodium infections do not cause clinical signs and symptoms of disease and persist at densities in blood that are not detectable by microscopy or rapid diagnostic tests. These infections may be critical as a transmission reservoir in areas of low malaria endemicity. Understanding the epidemiology of these infections would be helpful for malaria elimination. Methods A cross-sectional survey was conducted in Thapangthong and Nong Districts of Savannakhet Province, Lao PDR, to determine the prevalence of parasitaemia. A total of 888 blood samples were collected from afebrile volunteers aged ≥15 years in 18 villages during March and July 2015. Plasmodium infections were diagnosed by rapid diagnostic tests (RDT) and high volume, ultra-sensitive quantitative polymerase chain reaction (uPCR). Results uPCR detected Plasmodium infections in 175 of 888 samples (20 %). The species distribution was Plasmodiumfalciparum 3.6 % (32/888), Plasmodium vivax 11.1 % (99/888), mixed infections with P. falciparum and P. vivax 1.6 % (14/888) and Plasmodium of undetermined species 3.4 % (30/888). RDT identified only 2 % (18/888) positive cases. Using uPCR as reference, the sensitivity and specificity of RDTs were 28 and 100 %, respectively, in detecting P. falciparum infections, and 3 and 99 % in detecting asymptomatic P. vivax infections. The K13 kelch propeller domain C580Y mutation, associated with reduced susceptibility to artemisinin derivatives, was found in 75 % (12/18) of P. falciparum isolates from Thapangthong and in 7 % (2/28) from Nong (p < 0.001). In a multivariate analysis, males were more likely to have P. vivax infections [adjusted odds ratio (aOR) 4.76 (95 % CI 2.84–8.00)] while older villagers were at lower risk for parasitaemia [aOR for increasing age 0.98 (95 % CI 0.96–0.99)]. Conclusion There is a high prevalence of asymptomatic Plasmodium infections in southern Savannakhet. Artemisinin-resistant P. falciparum strains form an increasing proportion of the parasite population in Thapangthong District and are already present in the more remote Nong District. This worrying trend has wider implications for Laos and could reverse the gains achieved by the successful control of malaria in Laos and the Greater Mekong Sub-region (GMS). Rapid elimination of P. falciparum has to be a top priority in Laos as well as in the wider GMS.
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Affiliation(s)
- Koukeo Phommasone
- Microbiology Laboratory, Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Vientiane, Lao PDR
| | - Bipin Adhikari
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Gisela Henriques
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Tiengkham Pongvongsa
- Savannakhet Provincial Health Department, Nakhon Sawan, Savannakhet Province, Lao PDR
| | - Panom Phongmany
- Savannakhet Provincial Health Department, Nakhon Sawan, Savannakhet Province, Lao PDR
| | - Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.
| | - Nicholas J White
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicholas P J Day
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Paul N Newton
- Microbiology Laboratory, Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Vientiane, Lao PDR.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Mallika Imwong
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mayfong Mayxay
- Microbiology Laboratory, Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Vientiane, Lao PDR.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.,Faculty of Postgraduate Studies, University of Health Sciences, Vientiane, Lao PDR
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Ginouves M, Veron V, Musset L, Legrand E, Stefani A, Prevot G, Demar M, Djossou F, Brousse P, Nacher M, Carme B. Frequency and distribution of mixed Plasmodium falciparum-vivax infections in French Guiana between 2000 and 2008. Malar J 2015; 14:446. [PMID: 26555553 PMCID: PMC4641342 DOI: 10.1186/s12936-015-0971-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 10/27/2015] [Indexed: 11/11/2022] Open
Abstract
Background The two main plasmodial species in French Guiana are Plasmodium vivax and Plasmodium falciparum whose respective prevalence influences the frequency of mixed plasmodial infections. The accuracy of their diagnosis is influenced by the sensitivity of the method used, whereas neither microscopy nor rapid diagnostic tests allow a satisfactory evaluation of mixed plasmodial infections. Methods In the present study, the frequency of mixed infections in different part of French Guiana was determined using real time PCR, a sensitive and specific technique. Results From 400 cases of malaria initially diagnosed by microscopy, real time PCR showed that 10.75 % of the cases were mixed infections. Their prevalence varied considerably between geographical areas. The presence, in equivalent proportions, of the two plasmodial species in eastern French Guiana was associated with a much higher prevalence of mixed plasmodial infections than in western French Guiana, where the majority of the population was Duffy negative and thus resistant to vivax malaria. Conclusion Clinicians must be more vigilant regarding mixed infections in co-endemic P. falciparum/P. vivax areas, in order to deliver optimal care for patients suffering from malaria. This may involve the use of rapid diagnostic tests capable of detecting mixed infections or low density single infections. This is important as French Guiana moves towards malaria elimination.
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Affiliation(s)
- Marine Ginouves
- Medicine Department, Ecosystemes Amazoniens et Pathologie Tropicale, EA 3593, Labex CEBA, University of French Guiana, Cayenne, French Guiana.
| | - Vincent Veron
- Medicine Department, Ecosystemes Amazoniens et Pathologie Tropicale, EA 3593, Labex CEBA, University of French Guiana, Cayenne, French Guiana.
| | - Lise Musset
- Laboratoire de Parasitologie, Centre Collaborateur OMS pour la surveillance de la résistance aux antipaludiques, CNR du Paludisme, Institut Pasteur de la Guyane, Cayenne, French Guiana.
| | - Eric Legrand
- Laboratoire de Parasitologie, Centre Collaborateur OMS pour la surveillance de la résistance aux antipaludiques, CNR du Paludisme, Institut Pasteur de la Guyane, Cayenne, French Guiana. .,Research Unit of Genetics and Genomics of Insect Vectors, Institut Pasteur, Paris, France.
| | - Aurélia Stefani
- Medicine Department, Ecosystemes Amazoniens et Pathologie Tropicale, EA 3593, Labex CEBA, University of French Guiana, Cayenne, French Guiana.
| | - Ghislaine Prevot
- Medicine Department, Ecosystemes Amazoniens et Pathologie Tropicale, EA 3593, Labex CEBA, University of French Guiana, Cayenne, French Guiana.
| | - Magalie Demar
- Medicine Department, Ecosystemes Amazoniens et Pathologie Tropicale, EA 3593, Labex CEBA, University of French Guiana, Cayenne, French Guiana.
| | - Félix Djossou
- Unité des Maladies Infectieuses et Tropicales, Centre Hospitalier de Cayenne, Cayenne, French Guiana.
| | - Paul Brousse
- Pôle des Centres Délocalisés de Prévention et de Soins, Centre Hospitalier de Cayenne, Cayenne, French Guiana.
| | - Mathieu Nacher
- Medicine Department, Ecosystemes Amazoniens et Pathologie Tropicale, EA 3593, Labex CEBA, University of French Guiana, Cayenne, French Guiana. .,Centre d'Investigation Clinique Epidémiologie Clinique Antilles Guyane CIC EC 1424, Cayenne General Hospital, Cayenne, French Guiana.
| | - Bernard Carme
- Medicine Department, Ecosystemes Amazoniens et Pathologie Tropicale, EA 3593, Labex CEBA, University of French Guiana, Cayenne, French Guiana.
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Orlov M, Smeaton LM, Kumwenda J, Hosseinipour MC, Campbell TB, Schooley RT. Presence of Plasmodium falciparum DNA in Plasma Does Not Predict Clinical Malaria in an HIV-1 Infected Population. PLoS One 2015; 10:e0129519. [PMID: 26053030 PMCID: PMC4460081 DOI: 10.1371/journal.pone.0129519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 05/08/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND HIV-1 and Plasmodium falciparum malaria cause substantial morbidity in Sub-Saharan Africa, especially as co-infecting pathogens. We examined the relationship between presence of P. falciparum DNA in plasma samples and clinical malaria as well as the impact of atazanavir, an HIV-1 protease inhibitor (PI), on P. falciparum PCR positivity. METHODS ACTG study A5175 compared two NNRTI-based regimens and one PI-based anti-retroviral (ARV) regimen in antiretroviral therapy naïve participants. We performed nested PCR on plasma samples for the P. falciparum 18s rRNA gene to detect the presence of malaria DNA in 215 of the 221 participants enrolled in Blantyre and Lilongwe, Malawi. We also studied the closest sample preceding the first malaria diagnosis from 102 persons with clinical malaria and randomly selected follow up samples from 88 persons without clinical malaria. RESULTS PCR positivity was observed in 18 (8%) baseline samples and was not significantly associated with age, sex, screening CD4+ T-cell count, baseline HIV-1 RNA level or co-trimoxazole use within the first 8 weeks. Neither baseline PCR positivity (p = 0.45) nor PCR positivity after initiation of antiretroviral therapy (p = 1.0) were significantly associated with subsequent clinical malaria. Randomization to the PI versus NNRTI ARV regimens was not significantly associated with either PCR positivity (p = 0.5) or clinical malaria (p = 0.609). Clinical malaria was associated with a history of tuberculosis (p = 0.006) and a lower BMI (p = 0.004). CONCLUSION P. falciparum DNA was detected in 8% of participants at baseline, but was not significantly associated with subsequent development of clinical malaria. HIV PI therapy did not decrease the prevalence of PCR positivity or incidence of clinical disease.
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Affiliation(s)
- Marika Orlov
- School of Medicine, University of California San Diego, San Diego, California, United States of America
| | - Laura M Smeaton
- Center for Biostatistics in AIDS Research, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | | | - Mina C Hosseinipour
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America; University of North Carolina Project, Lilongwe, Malawi
| | - Thomas B Campbell
- School of Medicine, University of Colorado, Aurora, Colorado, United States of America
| | - Robert T Schooley
- School of Medicine, University of California San Diego, San Diego, California, United States of America
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Bosman P, Stassijns J, Nackers F, Canier L, Kim N, Khim S, Alipon SC, Chuor Char M, Chea N, Dysoley L, Van den Bergh R, Etienne W, De Smet M, Ménard D, Kindermans JM. Plasmodium prevalence and artemisinin-resistant falciparum malaria in Preah Vihear Province, Cambodia: a cross-sectional population-based study. Malar J 2014; 13:394. [PMID: 25288380 PMCID: PMC4200124 DOI: 10.1186/1475-2875-13-394] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 09/29/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Intensified efforts are urgently needed to contain and eliminate artemisinin-resistant Plasmodium falciparum in the Greater Mekong subregion. Médecins Sans Frontières plans to support the Ministry of Health in eliminating P. falciparum in an area with artemisinin resistance in the north-east of Cambodia. As a first step, the prevalence of Plasmodium spp. and the presence of mutations associated with artemisinin resistance were evaluated in two districts of Preah Vihear Province. METHODS A cross-sectional population-based study using a two-stage cluster sampling was conducted in the rural districts of Chhaeb and Chey Saen, from September to October 2013. In each district, 30 clusters of 10 households were randomly selected. In total, blood samples were collected for 1,275 participants in Chhaeb and 1,224 in Chey Saen. Prevalence of Plasmodium spp. was assessed by PCR on dried blood spots. Plasmodium falciparum positive samples were screened for mutations in the K13-propeller domain gene (PF3D7_1343700). RESULT The prevalence of Plasmodium spp. was estimated at 1.49% (95% CI 0.71-3.11%) in Chhaeb and 2.61% (95% CI 1.45-4.66%) in Chey Saen. Twenty-seven samples were positive for P. falciparum, giving a prevalence of 0.16% (95% CI 0.04-0.65) in Chhaeb and 2.04% (95% CI 1.04-3.99%) in Chey Saen. Only 4.0% of the participants testing positive presented with fever or history of fever. K13-propeller domain mutant type alleles (C580Y and Y493H) were found, only in Chey Saen district, in seven out of 11 P. falciparum positive samples with enough genetic material to allow testing. CONCLUSION The overall prevalence of P. falciparum was low in both districts but parasites presenting mutations in the K13-propeller domain gene, strongly associated with artemisinin-resistance, are circulating in Chey Saen.The prevalence might be underestimated because of the absentees - mainly forest workers - and the workers of private companies who were not included in the study. These results confirm the need to urgently develop and implement targeted interventions to contain and eliminate P. falciparum malaria in this district before it spreads to other areas.
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Affiliation(s)
| | - Jorgen Stassijns
- Médecins Sans Frontières, Duprestreet 94, 1090 Brussels, Belgium.
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Hopkins H, González IJ, Polley SD, Angutoko P, Ategeka J, Asiimwe C, Agaba B, Kyabayinze DJ, Sutherland CJ, Perkins MD, Bell D. Highly sensitive detection of malaria parasitemia in a malaria-endemic setting: performance of a new loop-mediated isothermal amplification kit in a remote clinic in Uganda. J Infect Dis 2013; 208:645-52. [PMID: 23633405 PMCID: PMC3719898 DOI: 10.1093/infdis/jit184] [Citation(s) in RCA: 210] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Current malaria diagnostic tests, including microscopy and antigen-detecting rapid tests, cannot reliably detect low-density infections. Molecular methods such as polymerase chain reaction (PCR) are highly sensitive but remain too complex for field deployment. A new commercial molecular assay based on loop-mediated isothermal amplification (LAMP) was assessed for field use. METHODS Malaria LAMP (Eiken Chemical, Japan) was evaluated for samples from 272 outpatients at a rural Ugandan clinic and compared with expert microscopy, nested PCR, and quantitative PCR (qPCR). Two technicians performed the assay after 3 days of training, using 2 alternative blood sample-preparation methods and visual interpretation of results by fluorescence assay. RESULTS Compared with 3-well nested PCR, the sensitivity of both LAMP and single-well nested PCR was 90%; the microscopy sensitivity was 51%. For samples with a Plasmodium falciparum qPCR titer of ≥ 2 parasites/µL, LAMP sensitivity was 97.8% (95% confidence interval, 93.7%-99.5%). Most false-negative LAMP results involved samples with parasitemia levels detectable by 3-well nested PCR but very low or undetectable by qPCR. CONCLUSIONS Malaria LAMP in a remote Ugandan clinic achieved sensitivity similar to that of single-well nested PCR in a United Kingdom reference laboratory. LAMP dramatically lowers the detection threshold achievable in malaria-endemic settings, providing a new tool for diagnosis, surveillance, and screening in elimination strategies.
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Affiliation(s)
- Heidi Hopkins
- Foundation for Innovative New Diagnostics, Uganda Ministry of Health, Kampala, Uganda
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Higa F, Tateyama M, Tasato D, Karimata Y, Nakamura H, Miyagi K, Haranaga S, Hirata T, Hokama A, Cash HL, Toma H, Fujita J. Imported malaria cases in Okinawa Prefecture, Japan. Jpn J Infect Dis 2013; 66:32-5. [PMID: 23429082 DOI: 10.7883/yoken.66.32] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
With the increase in global transportation, imported malaria has become a significant public health concern in Japan. In the present study, we retrospectively analyzed all imported malaria cases in Okinawa Prefecture from 1988 to 2012. In that period, 23 patients with imported malaria were admitted to the University of the Ryukyus Hospital. Malaria types observed included Plasmodium falciparum (14 cases), P. vivax (7 cases), combined P. falciparum and P. ovale (1 case), and combined P. vivax and P. malariae (1 case). All cases were resolved by anti-malarial treatment. The clinical data from these patients highlights the importance of collecting patient travel history and ensuring an adequate supply of both diagnostic test and drug treatments in Okinawa.
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Affiliation(s)
- Futoshi Higa
- Department of Infectious, Respiratory, and Digestive Medicine, Control and Prevention of Infectious Diseases, Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan.
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11
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Fuehrer HP, Starzengruber P, Swoboda P, Khan WA, Matt J, Ley B, Thriemer K, Haque R, Yunus EB, Hossain SM, Walochnik J, Noedl H. Indigenous Plasmodium ovale malaria in Bangladesh. Am J Trop Med Hyg 2010; 83:75-8. [PMID: 20595481 DOI: 10.4269/ajtmh.2010.09-0796] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In spite of the high prevalence of malaria in Southeastern Bangladesh, there remains a significant shortage of information regarding the presence of three of five human malaria parasites: Plasmodium ovale, P. malariae, and P. knowlesi. The presence of P. ovale and P. knowlesi has previously never been reported from Bangladesh. We used a genus- and species-specific nested polymerase chain reaction, targeting highly conserved regions of the small subunit ribosomal RNA (SSU rRNA) gene, to investigate the presence of malaria parasites in a total number of 379 patient samples in a survey of patients with febrile illnesses in the Chittagong Hill Tracts in Southeastern Bangladesh. We identified the first cases of P. ovale in Bangladesh. They were confirmed by sequence analysis; 189 of 379 samples (49.9%; 95% confidence interval = 44.9-54.9%) were positive for Plasmodium sp. by PCR. P. falciparum monoinfections accounted for 68.3% (61.3-74.5%), followed by P. vivax (15.3%; 10.9-21.2%), P. malariae (1.6%; 0.5-4.6%), P. ovale (1.6%; 0.5-4.6%), and mixed infections (13.2%; 9.1-18.8%). We found no evidence of P. knowlesi in this region.
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Affiliation(s)
- Hans-Peter Fuehrer
- Department of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
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12
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Steenkeste N, Rogers WO, Okell L, Jeanne I, Incardona S, Duval L, Chy S, Hewitt S, Chou M, Socheat D, Babin FX, Ariey F, Rogier C. Sub-microscopic malaria cases and mixed malaria infection in a remote area of high malaria endemicity in Rattanakiri province, Cambodia: implication for malaria elimination. Malar J 2010; 9:108. [PMID: 20409349 PMCID: PMC2868861 DOI: 10.1186/1475-2875-9-108] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2009] [Accepted: 04/22/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria microscopy and rapid diagnostic tests are insensitive for very low-density parasitaemia. This insensitivity may lead to missed asymptomatic sub-microscopic parasitaemia, a potential reservoir for infection. Similarly, mixed infections and interactions between Plasmodium species may be missed. The objectives were first to develop a rapid and sensitive PCR-based diagnostic method to detect low parasitaemia and mixed infections, and then to investigate the epidemiological importance of sub-microscopic and mixed infections in Rattanakiri Province, Cambodia. METHODS A new malaria diagnostic method, using restriction fragment length polymorphism analysis of the cytochrome b genes of the four human Plasmodium species and denaturing high performance liquid chromatography, has been developed. The results of this RFLP-dHPLC method have been compared to 1) traditional nested PCR amplification of the 18S rRNA gene, 2) sequencing of the amplified fragments of the cytochrome b gene and 3) microscopy. Blood spots on filter paper and Giemsa-stained blood thick smears collected in 2001 from 1,356 inhabitants of eight villages of Rattanakiri Province have been analysed by the RFLP-dHPLC method and microscopy to assess the prevalence of sub-microscopic and mixed infections. RESULTS The sensitivity and specificity of the new RFLP-dHPLC was similar to that of the other molecular methods. The RFLP-dHPLC method was more sensitive and specific than microscopy, particularly for detecting low-level parasitaemia and mixed infections. In Rattanakiri Province, the prevalences of Plasmodium falciparum and Plasmodium vivax were approximately two-fold and three-fold higher, respectively, by RFLP-dHPLC (59% and 15%, respectively) than by microscopy (28% and 5%, respectively). In addition, Plasmodium ovale and Plasmodium malariae were never detected by microscopy, while they were detected by RFLP-dHPLC, in 11.2% and 1.3% of the blood samples, respectively. Moreover, the proportion of mixed infections detected by RFLP-dHPLC was higher (23%) than with microscopy (8%). CONCLUSIONS The rapid and sensitive molecular diagnosis method developed here could be considered for mass screening and ACT treatment of inhabitants of low-endemicity areas of Southeast Asia.
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Affiliation(s)
- Nicolas Steenkeste
- Unité d'Epidémiologie Moléculaire, Institut Pasteur du Cambodge, Phnom Penh, Cambodia.
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13
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Steenkeste N, Incardona S, Chy S, Duval L, Ekala MT, Lim P, Hewitt S, Sochantha T, Socheat D, Rogier C, Mercereau-Puijalon O, Fandeur T, Ariey F. Towards high-throughput molecular detection of Plasmodium: new approaches and molecular markers. Malar J 2009; 8:86. [PMID: 19402894 PMCID: PMC2686730 DOI: 10.1186/1475-2875-8-86] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 04/29/2009] [Indexed: 11/15/2022] Open
Abstract
Background Several strategies are currently deployed in many countries in the tropics to strengthen malaria control toward malaria elimination. To measure the impact of any intervention, there is a need to detect malaria properly. Mostly, decisions still rely on microscopy diagnosis. But sensitive diagnosis tools enabling to deal with a large number of samples are needed. The molecular detection approach offers a much higher sensitivity, and the flexibility to be automated and upgraded. Methods Two new molecular methods were developed: dot18S, a Plasmodium-specific nested PCR based on the 18S rRNA gene followed by dot-blot detection of species by using species-specific probes and CYTB, a Plasmodium-specific nested PCR based on cytochrome b gene followed by species detection using SNP analysis. The results were compared to those obtained with microscopic examination and the "standard" 18S rRNA gene based nested PCR using species specific primers. 337 samples were diagnosed. Results Compared to the microscopy the three molecular methods were more sensitive, greatly increasing the estimated prevalence of Plasmodium infection, including P. malariae and P. ovale. A high rate of mixed infections was uncovered with about one third of the villagers infected with more than one malaria parasite species. Dot18S and CYTB sensitivity outranged the "standard" nested PCR method, CYTB being the most sensitive. As a consequence, compared to the "standard" nested PCR method for the detection of Plasmodium spp., the sensitivity of dot18S and CYTB was respectively 95.3% and 97.3%. Consistent detection of Plasmodium spp. by the three molecular methods was obtained for 83% of tested isolates. Contradictory results were mostly related to detection of Plasmodium malariae and Plasmodium ovale in mixed infections, due to an "all-or-none" detection effect at low-level parasitaemia. Conclusion A large reservoir of asymptomatic infections was uncovered using the molecular methods. Dot18S and CYTB, the new methods reported herein are highly sensitive, allow parasite DNA extraction as well as genus- and species-specific diagnosis of several hundreds of samples, and are amenable to high-throughput scaling up for larger sample sizes. Such methods provide novel information on malaria prevalence and epidemiology and are suited for active malaria detection. The usefulness of such sensitive malaria diagnosis tools, especially in low endemic areas where eradication plans are now on-going, is discussed in this paper.
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Affiliation(s)
- Nicolas Steenkeste
- Institut Pasteur du Cambodge, Laboratoire d'Epidémiologie Moléculaire, Phnom Penh, Cambodia.
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14
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Lorenzetti A, Fornazari PA, Bonini-Domingos AC, de Souza Rodrigues Penhalbel R, Fugikaha E, Bonini-Domingos CR, Fraga VD, Conceição LM, Rossit ARB, Cavasini CE, Couto VSCD, Machado RLD. Mixed Plasmodium falciparum infections and its clinical implications in four areas of the Brazilian Amazon region. Acta Trop 2008; 107:8-12. [PMID: 18468567 DOI: 10.1016/j.actatropica.2008.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 02/26/2008] [Accepted: 03/27/2008] [Indexed: 11/30/2022]
Abstract
The aim of this study was to assess the prevalence pattern of mixed-Plasmodium falciparum malaria infections in Brazil by molecular diagnosis and to address its clinically important features. DNA was extracted from 115 thick blood film P. falciparum human blood positive samples using the phenol-chloroform method, followed by a semi-nested PCR protocol with species-specific primers. Seventy-three percent of P. falciparum single infections and 26.95% of mixed infections were found. Amongst mixed infections, the majority was double infection (96.77%). Our results suggest that the prevalence of one species over the other can be important on weakening P. falciparum malaria clinical symptoms. We confirm that P. falciparum co-infections frequently occur in Brazilian malaria endemic areas, with underestimated diagnosis. The results point to the need of improving microscopy or changing for another accurate diagnosis technique to differentiate among human malaria species, as this is essential to choose the best treatment and control measure for malaria. More investigations are necessary in order to clarify the role of mixed-infections in the severity of P. falciparum disease.
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Affiliation(s)
- Alexandre Lorenzetti
- Centro de Investigação de Microrganismos, Departamento de Doenças Dermatológicas, Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto, Avenida Brigadeiro Faria Lima 5416, 15090-000 São José do Rio Preto, São Paulo, Brazil
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15
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Erlanger TE, Sayasone S, Krieger GR, Kaul S, Sananikhom P, Tanner M, Odermatt P, Utzinger J. Baseline health situation of communities affected by the Nam Theun 2 hydroelectric project in central Lao PDR and indicators for monitoring. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2008; 18:223-242. [PMID: 18569149 DOI: 10.1080/09603120701757815] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Hydroelectric projects offer opportunities for infrastructure development and economic growth; yet, if not well designed, implemented and operated, they have the potential to negatively affect the health and well-being of local and distant downstream communities. Remote rural populations are particularly vulnerable to the sudden influx of men, materials and money, and associated population mixing that accompany project construction phases. Two large-scale baseline health surveys, carried out in 2001/2002 in two communities that were affected by the Nam Theun 2 hydroelectric project in central Lao PDR, were analysed. For the population to be resettled on the Nakai plateau it was observed that access to clean water and basic sanitation facilities was lacking. Faecal examinations revealed a high infection prevalence for Ascaris lumbricoides (67.7%), but relatively low prevalences for hookworm (9.7%), Taenia spp. (4.8%), Enterobius vermicularis (4.4%), Trichuris trichiura (3.9%), Strongyloides stercoralis (1.4%) and Opisthorchis viverrini (0.9%). For the population in the Xe Bang Fai downstream area, rapid diagnostic tests for malaria carried out in the rainy season found a prevalence below 1%, which might be explained by the complete coverage of households with insecticide-treated nets (99.8%). Anthropometric measurements in both populations suggest that wasting, stunting and underweight in under 5-year-old children were moderate to high; 15.9-17.5%, 40.4-55.7% and 35.8-55.7%, respectively. One out of six individuals aged above 14 years were malnourished, most likely as a result of early childhood wasting. Moderate anaemia, assessed by age- and sex-specific haemoglobin levels, was present in 43.8% (Nakai) and 54.9% of the individuals examined (Xe Bang Fai). Several indicators were extracted that can be utilised for monitoring changes in health, well-being and equity, as the project is implemented and operated.
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16
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Khaminsou N, Kritpetcharat O, Daduang J, Kritpetcharat P. A survey of malarial infection in endemic areas of Savannakhet province, Lao PDR and comparative diagnostic efficiencies of Giemsa staining, acridine orange staining, and semi-nested multiplex PCR. Parasitol Int 2007; 57:143-9. [PMID: 18160336 DOI: 10.1016/j.parint.2007.11.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 11/09/2007] [Accepted: 11/17/2007] [Indexed: 10/22/2022]
Abstract
Malaria remains one of the most important parasitic diseases in Lao PDR, especially in forested rural areas. Knowing the rate of infection using highly sensitive and specific methods, and the factors related to malarial infection, may be helpful in reducing the infection and mortality rates. We aimed to study the malarial infection rate by comparing three detection methods, i.e., Giemsa staining, acridine orange (AO) staining and semi-nested multiplex PCR. The study also included some factors related to malarial infection in the endemic areas of Savannakhet province, Lao PDR. The respective malarial infection rates by Giemsa staining, AO staining and semi-nested multiplex PCR in Houy Jang vs. Keng Thong villages were 13.1 vs. 20.8, 16.2 vs. 25.4 and 20.8 vs. 30.8%. The infection rate among children not over 10 years of age was higher than infection rate among the older ages (p=0.002, Z-test for two proportions). The higher infection rates by semi-nested multiplex PCR over Giemsa and AO staining suggest the existence of many subclinical cases with low level parasitemia, undetected by microscopic techniques. We found no mixed infections using Giemsa or AO staining, but using semi-nested multiplex PCR we found 1.2% (3/260) mixed P. falciparum and P. vivax infections, suggesting that semi-nested multiplex PCR is suitable for detecting malarial infection from endemic areas whose cases may have low parasitemia and/or mixed infection. The factors significantly related to malarial infection from 260 questionnaires were: (1) children and young adults, (2) not having lived in the area more than 5 years, and (3) not using a mosquito net over the bed, indicating an increased risk of new residents of contracting malaria and a need to promote bed nets.
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Affiliation(s)
- Naly Khaminsou
- College of Health Technology, Vientiane, Lao Democratic People's Republic
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17
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Calderaro A, Piccolo G, Perandin F, Gorrini C, Peruzzi S, Zuelli C, Ricci L, Manca N, Dettori G, Chezzi C, Snounou G. Genetic polymorphisms influence Plasmodium ovale PCR detection accuracy. J Clin Microbiol 2007; 45:1624-7. [PMID: 17360843 PMCID: PMC1865880 DOI: 10.1128/jcm.02316-06] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Detection of Plasmodium ovale by use of a nested PCR assay with a novel Plasmodium ovale primer set was superior to detection of Plasmodium ovale by real-time PCR assays. Nested PCR was also better at detecting P. malariae. The detection of P. ovale in many patients first admitted >2 months following their return to Italy indicated that P. ovale relapses are common.
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Affiliation(s)
- A Calderaro
- Faculty of Medicine and Surgery, University of Parma, Department of Pathology and Laboratory Medicine, Section of Microbiology, Viale A. Gramsci, 14-43100 Parma, Italy.
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18
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Nash D, Nair S, Mayxay M, Newton PN, Guthmann JP, Nosten F, Anderson TJ. Selection strength and hitchhiking around two anti-malarial resistance genes. Proc Biol Sci 2005; 272:1153-61. [PMID: 16024377 PMCID: PMC1559806 DOI: 10.1098/rspb.2004.3026] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Neutral mutations may hitchhike to high frequency when they are situated close to sites under positive selection, generating local reductions in genetic diversity. This process is thought to be an important determinant of levels of genomic variation in natural populations. The size of genome regions affected by genetic hitchhiking is expected to be dependent on the strength of selection, but there is little empirical data supporting this prediction. Here, we compare microsatellite variation around two drug resistance genes (chloroquine resistance transporter (pfcrt), chromosome 7, and dihydrofolate reductase (dhfr), chromosome 4) in malaria parasite populations exposed to strong (Thailand) or weak selection (Laos) by anti-malarial drugs. In each population, we examined the point mutations underlying resistance and length variation at 22 (chromosome 4) or 25 (chromosome 7) microsatellite markers across these chromosomes. All parasites from Thailand carried the K76T mutation in pfcrt conferring resistance to chloroquine (CQ) and 2-4 mutations in dhfr conferring resistance to pyrimethamine. By contrast, we found both wild-type and resistant alleles at both genes in Laos. There were dramatic differences in the extent of hitchhiking in the two countries. The size of genome regions affected was smaller in Laos than in Thailand. We observed significant reduction in variation relative to sensitive parasites for 34-64 kb (2-4 cM) in Laos on chromosome 4, compared with 98-137 kb (6-8 cM) in Thailand. Similarly, on chromosome 7, we observed reduced variation for 34-69 kb (2-4 cM) around pfcrt in Laos, but for 195-268 kb (11-16 cM) in Thailand. Reduction in genetic variation was also less extreme in Laos than in Thailand. Most loci were monomorphic in a 12 kb region surrounding both genes on resistant chromosomes from Thailand, whereas in Laos, even loci immediately proximal to selective sites showed some variation on resistant chromosomes. Finally, linkage disequilibrium (LD) decayed more rapidly around resistant pfcrt and dhfr alleles from Laos than from Thailand. These results demonstrate that different realizations of the same selective sweeps may vary considerably in size and shape, in a manner broadly consistent with selection history. From a practical perspective, genomic regions containing resistance genes may be most effectively located by genome-wide association in populations exposed to strong drug selection. However, the lower levels of LD surrounding resistance alleles in populations under weak selection may simplify identification of functional mutations.
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Affiliation(s)
- Denae Nash
- Southwest Foundation for Biomedical Research (SFBR)PO Box 760549, San Antonio, TX 78245, USA
- Our Lady of the Lake UniversitySan Antonio, TX 78207, USA
| | - Shalini Nair
- Southwest Foundation for Biomedical Research (SFBR)PO Box 760549, San Antonio, TX 78245, USA
| | - Mayfong Mayxay
- Faculty of MedicineNational University of LaosVientiane, Lao PDR
- Wellcome Trust-Mahosot-Oxford Tropical Medicine Research CollaborationMahosot HospitalVientiane, Lao PDR
| | - Paul N Newton
- Wellcome Trust-Mahosot-Oxford Tropical Medicine Research CollaborationMahosot HospitalVientiane, Lao PDR
| | - Jean-Paul Guthmann
- Epicentre (Médecins Sans Frontières-France)8 rue Saint Sabin, 75011 Paris, France
| | - François Nosten
- 6 Shoklo Malaria Research Unit (SMRU)Mae Sot, Tak, Thailand
- Faculty of Tropical MedicineMahidol UniversityBangkok, Thailand
- Centre for Clinical Vaccinology and Tropical MedicineChurchill HospitalOxford OX3 7LJ, UK
| | - Tim J.C Anderson
- Southwest Foundation for Biomedical Research (SFBR)PO Box 760549, San Antonio, TX 78245, USA
- Author for correspondence ()
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19
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Mayxay M, Phetsouvanh R, Phompida S, Newton PN, Khanthavong M, Vannachone B, Brockmans A, White NJ. A randomized comparison of oral chloroquine and sulfadoxine-pyrimethamine for the treatment of uncomplicated Plasmodium falciparum malaria in Laos. Trans R Soc Trop Med Hyg 2004; 97:343-4. [PMID: 15228256 DOI: 10.1016/s0035-9203(03)90165-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Between June and October 2000 we conducted the first randomized trial in Laos comparing chloroquine (CQ) with sulfadoxine-pyrimethamine (SP) in the treatment of uncomplicated Plasmodium falciparum malaria (n = 29, 42-d follow-up, age > 5 years). The proportion of patients with treatment failure was high (CQ = 78%, RIII 46%; SP = 36%, RIII 15%). The treatment policy for uncomplicated P. falciparum malaria in Laos needs to be reviewed urgently.
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Affiliation(s)
- Mayfong Mayxay
- Department of Medicine, Faculty of Medical Science, National University of Laos, Laos
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20
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Di Santi SM, Kirchgatter K, Brunialti KCS, Oliveira AM, Ferreira SRS, Boulos M. PCR -- based diagnosis to evaluate the performance of malaria reference centers. Rev Inst Med Trop Sao Paulo 2004; 46:183-7. [PMID: 15361968 DOI: 10.1590/s0036-46652004000400002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although the Giemsa-stained thick blood smear (GTS) remains the gold standard for the diagnosis of malaria, molecular methods are more sensitive and specific to detect parasites and can be used at reference centers to evaluate the performance of microscopy. The description of the Plasmodium falciparum, P. vivax, P. malariae and P. ovale ssrRNA gene sequences allowed the development of a polymerase chain reaction (PCR) that had been used to differentiate the four species. The objective of this study was to determine Plasmodium species through PCR in 190 positive smears from patients in order to verify the quality of diagnosis at SUCEN's Malaria Laboratory. Considering only the 131 positive results in both techniques, GTS detected 4.6% of mixed and 3.1% of P. malariae infections whereas PCR identified 19.1% and 13.8%, respectively.
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Affiliation(s)
- Silvia Maria Di Santi
- Núcleo de Estudos em Malária, Superintendência de Controle de Endemias (SUCEN), Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, 05403-000, São Paulo, SP, Brazil.
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21
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Mayxay M, Pukrittayakamee S, Newton PN, White NJ. Mixed-species malaria infections in humans. Trends Parasitol 2004; 20:233-40. [PMID: 15105024 DOI: 10.1016/j.pt.2004.03.006] [Citation(s) in RCA: 174] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Mayfong Mayxay
- Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok 10400, Thailand
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22
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Padley D, Moody AH, Chiodini PL, Saldanha J. Use of a rapid, single-round, multiplex PCR to detect malarial parasites and identify the species present. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2003; 97:131-7. [PMID: 12803868 DOI: 10.1179/000349803125002977] [Citation(s) in RCA: 160] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
A new, rapid assay, based on a single-round, multiplex PCR, can be used to detect Plasmodium falciparum, P. vivax, P. malariae or P. ovale in human blood. The PCR, which targets the conserved 18S small-subunit RNA genes of the parasites, not only permits a malarial infection to be detected but also allows each Plasmodium species present to be identified, even in cases of mixed infection.
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Affiliation(s)
- D Padley
- Division of Virology, National Institute for Biological Standards and Control, Blanche Lane, South Mimms EN6 3QG, UK.
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23
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Patsoula E, Spanakos G, Sofianatou D, Parara M, Vakalis NC. A single-step, PCR-based method for the detection and differentiation of Plasmodium vivax and P. falciparum. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2003; 97:15-21. [PMID: 12662418 DOI: 10.1179/000349803125002535] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The ability to detect and differentiate between Plasmodium falciparum and P. vivax is of great importance for the routine laboratory diagnosis of malaria, donor-blood screening and epidemiological studies. Most PCR-based methods for the discrimination of these two species require nested protocols or an additional hybridization reaction, leading to high labour costs and long turn-around times. A simple, time-effective and yet sensitive and specific technique, based on a multiplex PCR, has now been developed for the simultaneous detection and differentiation of P. falciparum and P. vivax in blood samples. Compared with the 'gold standard' of microscopy, this method had a sensitivity and specificity of 100%, with a detection limit of just one P. falciparum or three P. vivax parasites/microl blood.
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Affiliation(s)
- E Patsoula
- Department of Parasitology, Entomology and Tropical Diseases, National School of Public Health, 196 Alexandras Avenue, 11521, Athens, Greece.
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