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Fuehrer HP, Campino S, Sutherland CJ. The primate malaria parasites Plasmodium malariae, Plasmodium brasilianum and Plasmodium ovale spp.: genomic insights into distribution, dispersal and host transitions. Malar J 2022; 21:138. [PMID: 35505317 PMCID: PMC9066925 DOI: 10.1186/s12936-022-04151-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 04/05/2022] [Indexed: 01/04/2023] Open
Abstract
During the twentieth century, there was an explosion in understanding of the malaria parasites infecting humans and wild primates. This was built on three main data sources: from detailed descriptive morphology, from observational histories of induced infections in captive primates, syphilis patients, prison inmates and volunteers, and from clinical and epidemiological studies in the field. All three were wholly dependent on parasitological information from blood-film microscopy, and The Primate Malarias” by Coatney and colleagues (1971) provides an overview of this knowledge available at that time. Here, 50 years on, a perspective from the third decade of the twenty-first century is presented on two pairs of primate malaria parasite species. Included is a near-exhaustive summary of the recent and current geographical distribution for each of these four species, and of the underlying molecular and genomic evidence for each. The important role of host transitions in the radiation of Plasmodium spp. is discussed, as are any implications for the desired elimination of all malaria species in human populations. Two important questions are posed, requiring further work on these often ignored taxa. Is Plasmodium brasilianum, circulating among wild simian hosts in the Americas, a distinct species from Plasmodium malariae? Can new insights into the genomic differences between Plasmodium ovale curtisi and Plasmodium ovale wallikeri be linked to any important differences in parasite morphology, cell biology or clinical and epidemiological features?
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Affiliation(s)
- Hans-Peter Fuehrer
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Susana Campino
- Department of Infection Biology, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Colin J Sutherland
- Department of Infection Biology, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
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2
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Tu H, Feng J, Yu C, Lin K, Peiyu W, Shaomi X, Lingyun L, Jian L. Asymptomatic malaria infection at the China-Vietnam border: Knowledge and implications for the cross-border migrant population during the COVID-19 pandemic. Travel Med Infect Dis 2022; 47:102307. [PMID: 35276354 PMCID: PMC8902057 DOI: 10.1016/j.tmaid.2022.102307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 03/02/2022] [Accepted: 03/05/2022] [Indexed: 11/28/2022]
Abstract
Background Eliminating malaria along the China-Vietnam border remains one of the greatest challenges in China, especially during the coronavirus disease 2019 (COVID-19) pandemic, which has disrupted the continuity of malaria control and elimination programs. Understanding the factors associated with asymptomatic malaria infection will inform control interventions aimed at elimination of the disease among migrants from Vietnam working in China, who constitute an at-risk population. Methods From March 2018 to September 2019, 108 migrants from Vietnam working in Ningming County, Guangxi, were enrolled in this study. Each person was interviewed using a structured questionnaire. Blood samples were collected and sent for PCR detection and sequencing. The obtained sequences were analyzed using the BLAST program and DNAMAN software. Results The proportion of participants with malaria knowledge was low, with 19.4% (21/108) reporting knowledge about transmission, 23.2% (25/108) reporting knowledge about clinical symptoms, 7.4% (8/108) reporting awareness of the risk of death and 14.8% (16/108) reporting awareness of prevention methods. No significant difference in the malaria knowledge rate was found among occupational groups, except in the migrant worker group, whose knowledge rate was higher than those in the other occupational groups (χ2 = 32.452, p < 0.001). Although most of the participants (80.6%, 87/108) owned mosquito nets, only approximately half of the participants (49.1%, 53/108) reported using bed nets. The parasitological analysis revealed that 5.6% (6/108) of all the participants were positive for malaria, including 5 participants with Plasmodium falciparum and 1 participant with Plasmodium vivax malaria. There were no statistically significant differences in the positivity rates among the different age, sex, family-size, nationality, occupational, and behavior groups. The positivity rates in individuals who did not use mosquito nets, did not use mosquito coils, and did not install mosquito nets were 4.8% (1/21), 6.8% (3/44), and 3.6% (2/55), respectively. Conclusion Health education focused on high-risk populations, such as migrant workers and forest goers, should be strengthened. Verbal communication and information transmission via the internet, radio, and mobile phone platforms may be required during the COVID-19 pandemic. Further risk assessments and proactive case detection should also be performed in Ningming County and other border counties in Guangxi to detect active and asymptomatic infections in a timely manner and prevent re-establishment of the disease in these communities.
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Affiliation(s)
- Hong Tu
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, National Health Commission Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, Shanghai, PR China
| | - Jun Feng
- Shanghai Municipal Center for Diseases Control and Prevention, Shanghai, PR China.
| | - Chenghang Yu
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, National Health Commission Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, Shanghai, PR China
| | - Kangming Lin
- Institute of Parasitic Diseases, Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Guangxi, PR China
| | - Wang Peiyu
- Ningming County Center for Diseases Control and Prevention, Ningming, Guangxi, PR China
| | - Xiang Shaomi
- Ningming County Center for Diseases Control and Prevention, Ningming, Guangxi, PR China
| | - Luo Lingyun
- Ningming County Center for Diseases Control and Prevention, Ningming, Guangxi, PR China
| | - Li Jian
- Ningming County Center for Diseases Control and Prevention, Ningming, Guangxi, PR China
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3
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San NN, Kien NX, Manh ND, Van Thanh N, Chavchich M, Binh NTH, Long TK, Edgel KA, Rovira-Vallbona E, Edstein MD, Martin NJ. Cross-sectional study of asymptomatic malaria and seroepidemiological surveillance of seven districts in Gia Lai province, Vietnam. Malar J 2022; 21:40. [PMID: 35135536 PMCID: PMC8822839 DOI: 10.1186/s12936-022-04060-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 01/23/2022] [Indexed: 11/12/2022] Open
Abstract
Background Malaria elimination by 2030 is an aim of many countries in the Greater Mekong Sub-region, including Vietnam. However, to achieve this goal and accelerate towards malaria elimination, countries need to determine the extent and prevalence of asymptomatic malaria as a potential reservoir for malaria transmission and the intensity of malaria transmission. The purpose of this study was to determine the prevalence of asymptomatic malaria and seropositivity rate in several districts of Gia Lai province in the Central Highlands of Vietnam. Methods A cross-sectional survey of asymptomatic malaria and serological testing was conducted in 3283 people living at 14 communes across seven districts in Gia Lai province in December 2016 to January 2017. Finger prick capillary blood samples were tested for malaria using rapid diagnostic testing and polymerase chain reaction (PCR), as well as detecting antibodies against 3 Plasmodium falciparum and 4 Plasmodium vivax antigens by indirect enzyme-linked immunosorbent assay (ELISA). Age-seroprevalence curves were fitted using reverse catalytic models with maximum likelihood. Results The study population was predominantly male (65.9%, 2165/3283), adults (88.7%, 2911/3283) and of a minority ethnicity (72.2%, 2371/3283), with most participants being farmers and outdoor government workers (90.2%, 2960/3283). Using a small volume of blood (≈ 10 µL) the PCR assay revealed that 1.74% (57/3283) of the participants had asymptomatic malaria (P. falciparum 1.07%, P. vivax 0.40%, Plasmodium malariae 0.15% and mixed infections 0.12%). In contrast, the annual malaria prevalence rates for clinical malaria in the communities where the participants lived were 0.12% (108/90,395) in 2016 and 0.22% (201/93,184) in 2017. Seropositivity for at least one P. falciparum or one P. vivax antigen was 38.5% (1257/3262) and 31.1% (1022/3282), respectively. Age-dependent trends in the proportion of seropositive individuals in five of the districts discriminated the three districts with sustained low malaria prevalence from the two districts with higher transmission. Conclusions Asymptomatic Plasmodium carriers were found to be substantially more prevalent than clinical cases in seven districts of Gia Lai province, and a third of the population had serological evidence of previous malaria exposure. The findings add knowledge on the extent of asymptomatic malaria and transmission for developing malaria elimination strategies for Vietnam. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04060-6.
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Affiliation(s)
| | - Nguyen Xuan Kien
- Vietnam People's Army Military Medical Department, Hanoi, Vietnam
| | - Nguyen Duc Manh
- Vietnam People's Army Military Institute of Preventive Medicine, Hanoi, Vietnam
| | - Nguyen Van Thanh
- Vietnam People's Army Military Institute of Preventive Medicine, Hanoi, Vietnam
| | - Marina Chavchich
- Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Australia
| | | | | | | | | | - Michael D Edstein
- Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Australia
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Quang HH, Chavchich M, Trinh NTM, Manh ND, Edstein MD, Martin NJ, Edgel KA. Cross-sectional survey of asymptomatic malaria in Dak Nong province in the Central Highlands of Vietnam for the malaria elimination roadmap. PLoS One 2021; 16:e0258580. [PMID: 34669697 PMCID: PMC8528296 DOI: 10.1371/journal.pone.0258580] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 09/30/2021] [Indexed: 12/25/2022] Open
Abstract
Asymptomatic parasite carriers represent a "silent" infective reservoir for malaria transmission and contributes to malaria persistence. However, limited data are available on asymptomatic malaria in Vietnam. Between November 2018 and March 2019, we conducted a malaria epidemiological survey of asymptomatic people (children ≥ 10 years old and adults ≥18 years old, n = 2,809) residing in three communes in Tuy Duc district, Dak Nong province in the Central Highlands of Vietnam. Based on the national stratification of malaria risk, Dak Buk So, Dak Ngo and Quang Truc communes were classified by the National Malaria Control Programme as low, moderate and high malaria endemic areas, respectively. Using participants' finger prick blood samples, malaria parasites were detected by one-step reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The median age (Interquartile Range) for adults and children were 35 years (26-50) and 12 years (11-14), respectively. The prevalence of asymptomatic malaria was 1.7% (22/1,328), 3.5% (31/890) and 12.2% (72/591) for participants from Dak Buk So, Dak Ngo and Quang Truc, respectively. The prevalence of asymptomatic malaria was lower in children compared to adults: 2.6% (9/352) versus 4.7% (116/2,457) (Odds Ratio 0.53, 95% Confidence Interval 0.28 to1.02). Ownership of long-lasting insecticide-treated bed nets and hammocks was 97.1%, 99.0% and 94.7% for participants in Dak Buk So, Dak Ngo and Quang Truc, respectively, however, only 66.0%, 57.3% and 42.8% of the participants reported using bed nets every night. Of the several risk factors examined, going to the forest two weeks prior to enrolment into the study and sleeping in the forest had a significant association with participants being infected with asymptomatic malaria in Quang Truc, but not in the other two communes. Knowledge of the prevalence and distribution of asymptomatic malaria will help design and evaluate future intervention strategies for malaria elimination in Vietnam.
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Affiliation(s)
- Huynh Hong Quang
- Institute of Malariology, Parasitology and Entomology, Quy Nhon, Vietnam
| | - Marina Chavchich
- Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Australia
| | | | | | - Michael D. Edstein
- Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Australia
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Abstract
J. Kevin Baird and colleagues, examine and discuss the estimated global burden of vivax malaria and it's biological, clinical, and public health complexity.
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Affiliation(s)
- Katherine E. Battle
- Institute for Disease Modeling, Seattle, Washington, United States of America
| | - J. Kevin Baird
- Eijkman-Oxford Clinical Research Unit, Eijkman Institute of Molecular Biology, Jakarta, Indonesia
- Nuffield Department of Medicine, Centre for Tropical Medicine, University of Oxford, Oxford, United Kingdom
- * E-mail:
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Kigozi SP, Kigozi RN, Epstein A, Mpimbaza A, Sserwanga A, Yeka A, Nankabirwa JI, Halliday K, Pullan RL, Rutazaana D, Sebuguzi CM, Opigo J, Kamya MR, Staedke SG, Dorsey G, Greenhouse B, Rodriguez-Barraquer I. Rapid shifts in the age-specific burden of malaria following successful control interventions in four regions of Uganda. Malar J 2020; 19:128. [PMID: 32228584 PMCID: PMC7106889 DOI: 10.1186/s12936-020-03196-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/20/2020] [Indexed: 12/17/2022] Open
Abstract
Background Malaria control using long-lasting insecticidal nets (LLINs) and indoor residual spraying of insecticide (IRS) has been associated with reduced transmission throughout Africa. However, the impact of transmission reduction on the age distribution of malaria cases remains unclear. Methods Over a 10-year period (January 2009 to July 2018), outpatient surveillance data from four health facilities in Uganda were used to estimate the impact of control interventions on temporal changes in the age distribution of malaria cases using multinomial regression. Interventions included mass distribution of LLINs at all sites and IRS at two sites. Results Overall, 896,550 patient visits were included in the study; 211,632 aged < 5 years, 171,166 aged 5–15 years and 513,752 > 15 years. Over time, the age distribution of patients not suspected of malaria and those malaria negative either declined or remained the same across all sites. In contrast, the age distribution of suspected and confirmed malaria cases increased across all four sites. In the two LLINs-only sites, the proportion of malaria cases in < 5 years decreased from 31 to 16% and 35 to 25%, respectively. In the two sites receiving LLINs plus IRS, these proportions decreased from 58 to 30% and 64 to 47%, respectively. Similarly, in the LLINs-only sites, the proportion of malaria cases > 15 years increased from 40 to 61% and 29 to 39%, respectively. In the sites receiving LLINs plus IRS, these proportions increased from 19 to 44% and 18 to 31%, respectively. Conclusions These findings demonstrate a shift in the burden of malaria from younger to older individuals following implementation of successful control interventions, which has important implications for malaria prevention, surveillance, case management and control strategies.
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Affiliation(s)
- Simon P Kigozi
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. .,Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.
| | - Ruth N Kigozi
- USAID's Malaria Action Program for Districts, PO Box 8045, Kampala, Uganda
| | - Adrienne Epstein
- Department of Epidemiology & Biostatistics, University of California, San Francisco, 550 16th Street, San Francisco, CA, 94158, USA
| | - Arthur Mpimbaza
- Child Health and Development Centre, Makerere University College of Health Sciences, Mulago Hospital Complex, PO Box 7072, Kampala, Uganda
| | - Asadu Sserwanga
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda
| | - Adoke Yeka
- School of Public Health, Makerere University College of Health Sciences, Mulago Hospital Complex, PO Box 7072, Kampala, Uganda
| | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,School of Medicine, Makerere University College of Health Sciences, Mulago Hospital Complex, PO Box 7072, Kampala, Uganda
| | - Katherine Halliday
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Rachel L Pullan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Damian Rutazaana
- National Malaria Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Catherine M Sebuguzi
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,National Malaria Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Jimmy Opigo
- National Malaria Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,School of Medicine, Makerere University College of Health Sciences, Mulago Hospital Complex, PO Box 7072, Kampala, Uganda
| | - Sarah G Staedke
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,Department of Clinical Research, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Grant Dorsey
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.,Department of Medicine, University of California, San Francisco, 1001 Potrero Ave, SFGH Building 30, San Francisco, CA, 94110, USA
| | - Bryan Greenhouse
- Division of HIV, ID, and Global Medicine, University of California, San Francisco, 1001 Potrero Ave, SFGH, Building 3, San Francisco, CA, 94110, USA.,Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Isabel Rodriguez-Barraquer
- Division of HIV, ID, and Global Medicine, University of California, San Francisco, 1001 Potrero Ave, SFGH, Building 3, San Francisco, CA, 94110, USA
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Pham TV, Nguyen HV, Aguirre AR, Nguyen VV, A. Cleves M, Nguyen XX, Nguyen TT, Tran DT, Le HX, Hens N, Rosanas-Urgell A, D’Alessandro U, Speybroeck N, Erhart A. Plasmodium vivax morbidity after radical cure: A cohort study in Central Vietnam. PLoS Med 2019; 16:e1002784. [PMID: 31100064 PMCID: PMC6524795 DOI: 10.1371/journal.pmed.1002784] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 03/19/2019] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND In Vietnam, the importance of vivax malaria relative to falciparum during the past decade has steadily increased to 50%. This, together with the spread of multidrug-resistant Plasmodium falciparum, is a major challenge for malaria elimination. A 2-year prospective cohort study to assess P. vivax morbidity after radical cure treatment and related risk factors was conducted in Central Vietnam. METHODS AND FINDINGS The study was implemented between April 2009 and December 2011 in four neighboring villages in a remote forested area of Quang Nam province. P. vivax-infected patients were treated radically with chloroquine (CQ; 25 mg/kg over 3 days) and primaquine (PQ; 0.5 mg/kg/day for 10 days) and visited monthly (malaria symptoms and blood sampling) for up to 2 years. Time to first vivax recurrence was estimated by Kaplan-Meier survival analysis, and risk factors for first and recurrent infections were identified by Cox regression models. Among the 260 P. vivax patients (61% males [159/260]; age range 3-60) recruited, 240 completed the 10-day treatment, 223 entered the second month of follow-up, and 219 were followed for at least 12 months. Most individuals (76.78%, 171/223) had recurrent vivax infections identified by molecular methods (polymerase chain reaction [PCR]); in about half of them (55.61%, 124/223), infection was detected by microscopy, and 84 individuals (37.67%) had symptomatic recurrences. Median time to first recurrence by PCR was 118 days (IQR 59-208). The estimated probability of remaining free of recurrence by month 24 was 20.40% (95% CI [14.42; 27.13]) by PCR, 42.52% (95% CI [35.41; 49.44]) by microscopy, and 60.69% (95% CI [53.51; 67.11]) for symptomatic recurrences. The main risk factor for recurrence (first or recurrent) was prior P. falciparum infection. The main limitations of this study are the age of the results and the absence of a comparator arm, which does not allow estimating the proportion of vivax relapses among recurrent infections. CONCLUSION A substantial number of P. vivax recurrences, mainly submicroscopic (SM) and asymptomatic, were observed after high-dose PQ treatment (5.0 mg/kg). Prior P. falciparum infection was an important risk factor for all types of vivax recurrences. Malaria elimination efforts need to address this largely undetected P. vivax transmission by simultaneously tackling the reservoir of P. falciparum and P. vivax infections.
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Affiliation(s)
- Thanh Vinh Pham
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam
- Research Institute of Health and Society (IRSS), Université Catholique de Louvain (UCL), Brussels, Belgium
| | - Hong Van Nguyen
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam
| | - Angel Rosas Aguirre
- Research Institute of Health and Society (IRSS), Université Catholique de Louvain (UCL), Brussels, Belgium
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Perú
- Fund for Scientific Research (FNRS), Brussels, Belgium
| | - Van Van Nguyen
- Provincial Health Services, Tam Ky City, Quang Nam Province, Vietnam
| | - Mario A. Cleves
- Department of Pediatrics, University of Arkansas for Medical Sciences (UAMS), College of Medicine, Little Rock, Arkansas, United States of America
| | - Xa Xuan Nguyen
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam
| | - Thao Thanh Nguyen
- Provincial Malaria Station, Tam Ky City, Quang Nam Province, Vietnam
| | - Duong Thanh Tran
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam
| | - Hung Xuan Le
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam
| | - Niel Hens
- Center for Statistics, I-BioStat, Hasselt University, Hasselt, Belgium
- Centre for health economic research and modelling infectious diseases, Vaxinfectio, University of Antwerp, Antwerp, Belgium
| | - Anna Rosanas-Urgell
- Department of Biomedical Sciences, Institute of Tropical Medicine (ITM), Antwerp, Belgium
| | - Umberto D’Alessandro
- Medical Research Council Unit The Gambia (MRCG), the London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Niko Speybroeck
- Research Institute of Health and Society (IRSS), Université Catholique de Louvain (UCL), Brussels, Belgium
| | - Annette Erhart
- Medical Research Council Unit The Gambia (MRCG), the London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Public Health, ITM, Antwerp, Belgium
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8
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Zhong D, Lo E, Wang X, Yewhalaw D, Zhou G, Atieli HE, Githeko A, Hemming-Schroeder E, Lee MC, Afrane Y, Yan G. Multiplicity and molecular epidemiology of Plasmodium vivax and Plasmodium falciparum infections in East Africa. Malar J 2018; 17:185. [PMID: 29720181 PMCID: PMC5932820 DOI: 10.1186/s12936-018-2337-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 04/26/2018] [Indexed: 11/18/2022] Open
Abstract
Background Parasite genetic diversity and multiplicity of infection (MOI) affect clinical outcomes, response to drug treatment and naturally-acquired or vaccine-induced immunity. Traditional methods often underestimate the frequency and diversity of multiclonal infections due to technical sensitivity and specificity. Next-generation sequencing techniques provide a novel opportunity to study complexity of parasite populations and molecular epidemiology. Methods Symptomatic and asymptomatic Plasmodium vivax samples were collected from health centres/hospitals and schools, respectively, from 2011 to 2015 in Ethiopia. Similarly, both symptomatic and asymptomatic Plasmodium falciparum samples were collected, respectively, from hospitals and schools in 2005 and 2015 in Kenya. Finger-pricked blood samples were collected and dried on filter paper. Long amplicon (> 400 bp) deep sequencing of merozoite surface protein 1 (msp1) gene was conducted to determine multiplicity and molecular epidemiology of P. vivax and P. falciparum infections. The results were compared with those based on short amplicon (117 bp) deep sequencing. Results A total of 139 P. vivax and 222 P. falciparum samples were pyro-sequenced for pvmsp1 and pfmsp1, yielding a total of 21 P. vivax and 99 P. falciparum predominant haplotypes. The average MOI for P. vivax and P. falciparum were 2.16 and 2.68, respectively, which were significantly higher than that of microsatellite markers and short amplicon (117 bp) deep sequencing. Multiclonal infections were detected in 62.2% of the samples for P. vivax and 74.8% of the samples for P. falciparum. Four out of the five subjects with recurrent P. vivax malaria were found to be a relapse 44–65 days after clearance of parasites. No difference was observed in MOI among P. vivax patients of different symptoms, ages and genders. Similar patterns were also observed in P. falciparum except for one study site in Kenyan lowland areas with significantly higher MOI. Conclusions The study used a novel method to evaluate Plasmodium MOI and molecular epidemiological patterns by long amplicon ultra-deep sequencing. The complexity of infections were similar among age groups, symptoms, genders, transmission settings (spatial heterogeneity), as well as over years (pre- vs. post-scale-up interventions). This study demonstrated that long amplicon deep sequencing is a useful tool to investigate multiplicity and molecular epidemiology of Plasmodium parasite infections. Electronic supplementary material The online version of this article (10.1186/s12936-018-2337-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daibin Zhong
- Program in Public Health, University of California at Irvine, Irvine, CA, 92617, USA.
| | - Eugenia Lo
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA
| | - Xiaoming Wang
- Program in Public Health, University of California at Irvine, Irvine, CA, 92617, USA
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia.,Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Guofa Zhou
- Program in Public Health, University of California at Irvine, Irvine, CA, 92617, USA
| | - Harrysone E Atieli
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Andrew Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | | | - Ming-Chieh Lee
- Program in Public Health, University of California at Irvine, Irvine, CA, 92617, USA
| | - Yaw Afrane
- Department of Medical Microbiology, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Guiyun Yan
- Program in Public Health, University of California at Irvine, Irvine, CA, 92617, USA.
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9
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Kattenberg JH, Erhart A, Truong MH, Rovira-Vallbona E, Vu KAD, Nguyen THN, Nguyen VH, Nguyen VV, Bannister-Tyrrell M, Theisen M, Bennet A, Lover AA, Tran TD, Nguyen XX, Rosanas-Urgell A. Characterization of Plasmodium falciparum and Plasmodium vivax recent exposure in an area of significantly decreased transmission intensity in Central Vietnam. Malar J 2018; 17:180. [PMID: 29703200 PMCID: PMC5923009 DOI: 10.1186/s12936-018-2326-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/18/2018] [Indexed: 11/30/2022] Open
Abstract
Background In Vietnam, malaria transmission has been reduced to very low levels over the past 20 years, and as a consequence, the country aims to eliminate malaria by 2030. This study aimed to characterize the dynamics and extent of the parasite reservoir in Central Vietnam, in order to further target elimination strategies and surveillance. Methods A 1-year prospective cohort study (n = 429) was performed in three rural communities in Quang Nam province. Six malaria screenings were conducted between November 2014 and November 2015, including systematic clinical examination and blood sampling for malaria parasite identification, as well as molecular and serological analysis of the study population. Malaria infections were detected by light microscopy (LM) and quantitative real time PCR (qPCR), while exposure to Plasmodium falciparum and Plasmodium vivax was measured in the first and last survey by ELISA for PfAMA1, PfGLURP R2, PvAMA1, and PvMSP1-19. Classification and regression trees were used to define seropositivity and recent exposure. Results Four malaria infections (2 P. falciparum, 2 P. vivax) were detected in the same village by qPCR and/or LM. No fever cases were attributable to malaria. At the same time, the commune health centre (serving a larger area) reported few cases of confirmed malaria cases. Nevertheless, serological data proved that 13.5% of the surveyed population was exposed to P. falciparum and/or P. vivax parasites during the study period, of which 32.6% were seronegative at the start of the study, indicating ongoing transmission in the area. Risk factor analysis for seroprevalence and exposure to P. falciparum and/or P. vivax identified structural or economic risk factors and activity/behaviour-related factors, as well as spatial heterogeneity at the village level. Conclusions Previous studies in Central Vietnam demonstrated high occurrence of asymptomatic and sub-microscopic infections. However, in this study very few asymptomatic infections were detected despite serological evidence of continued transmission. Nonetheless, the factors associated with spatial heterogeneity in transmission could be evaluated using serological classification of recent exposure, which supports the usefulness of serological methods to monitor malaria transmission. Electronic supplementary material The online version of this article (10.1186/s12936-018-2326-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Annette Erhart
- Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerp, Belgium.,MRC Unit, Fajara, The Gambia.,Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Minh Hieu Truong
- National Institute of Malariology, Parasitology and Entomology, Vietnam, Luong The Vinh Street 245-Trung Van, BC 10.200 Tu Liem, Hanoi, Vietnam
| | | | - Khac Anh Dung Vu
- National Institute of Malariology, Parasitology and Entomology, Vietnam, Luong The Vinh Street 245-Trung Van, BC 10.200 Tu Liem, Hanoi, Vietnam
| | - Thi Hong Ngoc Nguyen
- National Institute of Malariology, Parasitology and Entomology, Vietnam, Luong The Vinh Street 245-Trung Van, BC 10.200 Tu Liem, Hanoi, Vietnam
| | - Van Hong Nguyen
- National Institute of Malariology, Parasitology and Entomology, Vietnam, Luong The Vinh Street 245-Trung Van, BC 10.200 Tu Liem, Hanoi, Vietnam
| | - Van Van Nguyen
- Provincial Malaria Station Quang Nam/Center for Malaria and Goitre Control, Quang Nam Province, Tam Ky, Vietnam
| | | | | | - Adam Bennet
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California, San Francisco, USA
| | - Andrew A Lover
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California, San Francisco, USA
| | - Thanh Duong Tran
- National Institute of Malariology, Parasitology and Entomology, Vietnam, Luong The Vinh Street 245-Trung Van, BC 10.200 Tu Liem, Hanoi, Vietnam
| | - Xuan Xa Nguyen
- National Institute of Malariology, Parasitology and Entomology, Vietnam, Luong The Vinh Street 245-Trung Van, BC 10.200 Tu Liem, Hanoi, Vietnam
| | - Anna Rosanas-Urgell
- Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerp, Belgium.
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10
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Micro-epidemiology of malaria in an elimination setting in Central Vietnam. Malar J 2018; 17:119. [PMID: 29554901 PMCID: PMC5859719 DOI: 10.1186/s12936-018-2262-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 03/08/2018] [Indexed: 11/10/2022] Open
Abstract
Background In Vietnam, malaria persists in remote forested regions where infections are spatially heterogeneous, mostly asymptomatic and with low parasite density. Previous studies in Vietnam have investigated broad behavioural concepts such as ‘engaging in forest activities’ as risk factors for malaria infection, which may not explain heterogeneity in malaria risk, especially in malaria elimination settings. Methods A mixed methods study combining ethnographic research and a cross-sectional survey was embedded in a 1-year malariometric cohort study in three ethnic minority villages in South Tra My district, Quang Nam Province in Central Vietnam. Qualitative data collection included in-depth interviews, informal conversations and participant observations over a 2-month period, and the findings were used to develop the questionnaire used in the cross-sectional survey. The latter collected data on evening activities, mobility patterns and household characteristics. The primary outcome, recent exposure to malaria, was defined using the classification and regression tree method to determine significant changes in antibody titres during the year preceding the survey. Risk factor analyses for recent exposure to malaria were conducted using logistic regression. Results 22 in-depth interviews and numerous participant observations were recorded during the ethnographic research (April to June 2015), and 160 adults (86% response rate) responded to the cross-sectional survey (November to December 2015). Recent exposure to Plasmodium falciparum malaria was estimated at 22.9 and at 17.1% for Plasmodium vivax. Ongoing malaria transmission appears to be maintained by activities that delay or disrupt sleeping in a permanent structure in which a bed net could be hung, including evening drinking gatherings, fishing, logging in the forest and outdoor TV watching. Conclusions Vector control tools for outdoor evening activities in villages as well as at farms, forest and river locations should be incorporated into current malaria elimination efforts in Central Vietnam. Micro-epidemiology studies using mixed-methods designs can provide a comprehensive understanding of the malaria risk at fine spatial scales and better inform the implementation of targeted interventions for malaria elimination. Electronic supplementary material The online version of this article (10.1186/s12936-018-2262-0) contains supplementary material, which is available to authorized users.
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11
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Bousema T, Drakeley C. Determinants of Malaria Transmission at the Population Level. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a025510. [PMID: 28242786 DOI: 10.1101/cshperspect.a025510] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Transmission of malaria from man to mosquito defines the human infectious reservoir of malaria. At the population level this is influenced by a variety of human, parasite, and mosquito vector factors some or all of which may vary depending on the epidemiological setting. Here, we review our current state of knowledge related to human infectiousness to mosquitoes and how current malaria control strategies might be adapted to focus on reducing this. While much progress has been made in malaria control, we argue that an improved understanding of human infectivity will allow more effective use of current control tools and make elimination a more feasible goal.
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Affiliation(s)
- Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen 6525 GA, The Netherlands.,Department of Immunology & Infection, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Chris Drakeley
- Department of Immunology & Infection, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
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12
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Longley RJ, White MT, Takashima E, Morita M, Kanoi BN, Li Wai Suen CSN, Betuela I, Kuehn A, Sripoorote P, Franca CT, Siba P, Robinson LJ, Lacerda M, Sattabongkot J, Tsuboi T, Mueller I. Naturally acquired antibody responses to more than 300 Plasmodium vivax proteins in three geographic regions. PLoS Negl Trop Dis 2017; 11:e0005888. [PMID: 28892517 PMCID: PMC5614652 DOI: 10.1371/journal.pntd.0005888] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 09/26/2017] [Accepted: 08/21/2017] [Indexed: 01/22/2023] Open
Abstract
Plasmodium vivax remains an important cause of malaria in South America and the Asia-Pacific. Naturally acquired antibody responses against multiple P. vivax proteins have been described in numerous countries, however, direct comparison of these responses has been difficult with different methodologies employed. We measured antibody responses against 307 P. vivax proteins at the time of P. vivax infection, and at 2–3 later time-points in three countries. We observed that seropositivity rates at the time of infection were highest in Thailand, followed by Brazil then PNG, reflecting the level of antigenic input. The majority of sero-reactive antigens in all sites induced short-lived antibody responses with estimated half-lives of less than 6 months, although there was a trend towards longer-lived responses in PNG children. Despite these differences, IgG seropositivity rates, magnitude and longevity were highly and significantly rank-correlated between the different regions, suggesting such features are reflective of the individual protein. In the pursuit of eliminating all species of malaria, Plasmodium vivax presents one of the most substantial challenges, particularly in countries in Asia, the Western-Pacific and South America. This is primarily due to the ability of P. vivax to cause relapse infections months to years after the initial infectious bite. In areas with low levels of malaria transmission, serology has become an increasingly useful tool for surveillance, as anti-Plasmodium antibodies can be detected in individuals long after blood-stage parasites have cleared. In this study, we provide a detailed characterisation of the antibody response generated following P. vivax infection by measuring antibodies to over 300 P. vivax antigens in three different populations in Thailand, Brazil and Papua New Guinea. The individuals in these populations were followed for up to nine months allowing us to estimate the rate at which antibodies decay over time. This improved understanding of the magnitude and dynamics of the antibody response, validated in multiple populations, will contribute to the development of serological surveillance tools needed for enhanced control and elimination of P. vivax.
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Affiliation(s)
- Rhea J. Longley
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Michael T. White
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Masayuki Morita
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Bernard N. Kanoi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Connie S. N. Li Wai Suen
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Inoni Betuela
- Vector Borne Diseases Unit, PNG Institute of Medical Research, Madang, Papua New Guinea
| | - Andrea Kuehn
- ISGlobal, Barcelona Centre for International Health Research (CRESIB), Hospital Clinic-Universitat de Barcelona, Barcelona, Spain
| | - Piyarat Sripoorote
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Camila T. Franca
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Peter Siba
- Vector Borne Diseases Unit, PNG Institute of Medical Research, Madang, Papua New Guinea
| | - Leanne J. Robinson
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
- Vector Borne Diseases Unit, PNG Institute of Medical Research, Madang, Papua New Guinea
| | - Marcus Lacerda
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, Brazil
- Instituto de Pesquisas Leônidas e Maria Deane, Manaus, Amazonas, Brazil
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Ivo Mueller
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
- Malaria: Parasites & Hosts Unit, Department of Parasites & Insect Vectors, Institut Pasteur, Paris, France
- * E-mail:
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13
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Akerele D, Ljolje D, Talundzic E, Udhayakumar V, Lucchi NW. Molecular diagnosis of Plasmodium ovale by photo-induced electron transfer fluorogenic primers: PET-PCR. PLoS One 2017. [PMID: 28640824 PMCID: PMC5480860 DOI: 10.1371/journal.pone.0179178] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Accurate diagnosis of malaria infections continues to be challenging and elusive, especially in the detection of submicroscopic infections. Developing new malaria diagnostic tools that are sensitive enough to detect low-level infections, user friendly, cost effective and capable of performing large scale diagnosis, remains critical. We have designed novel self-quenching photo-induced electron transfer (PET) fluorogenic primers for the detection of P. ovale by real-time PCR. In our study, a total of 173 clinical samples, consisting of different malaria species, were utilized to test this novel PET-PCR primer. The sensitivity and specificity were calculated using nested-PCR as the reference test. The novel primer set demonstrated a sensitivity of 97.5% and a specificity of 99.2% (95% CI 85.2–99.8% and 95.2–99.9% respectively). Furthermore, the limit of detection for P. ovale was found to be 1 parasite/μl. The PET-PCR assay is a new molecular diagnostic tool with comparable performance to other commonly used PCR methods. It is relatively easy to perform, and amiable to large scale malaria surveillance studies and malaria control and elimination programs. Further field validation of this novel primer will be helpful to ascertain the utility for large scale malaria screening programs.
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Affiliation(s)
- David Akerele
- Division of Pediatric Infectious Diseases, Emory Medical Center, Atlanta, Georgia, United States of America
| | - Dragan Ljolje
- Atlanta Research and Education Foundation, Decatur, Georgia, United States of America
| | - Eldin Talundzic
- Atlanta Research and Education Foundation, Decatur, Georgia, United States of America
| | - Venkatachalam Udhayakumar
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Naomi W. Lucchi
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- * E-mail:
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14
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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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15
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Population Genetics of Plasmodium vivax in Four Rural Communities in Central Vietnam. PLoS Negl Trop Dis 2016; 10:e0004434. [PMID: 26872387 PMCID: PMC4752448 DOI: 10.1371/journal.pntd.0004434] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/14/2016] [Indexed: 12/03/2022] Open
Abstract
Background The burden of malaria in Vietnam has drastically reduced, prompting the National Malaria Control Program to officially engage in elimination efforts. Plasmodium vivax is becoming increasingly prevalent, remaining a major problem in the country's central and southern provinces. A better understanding of P. vivax genetic diversity and structure of local parasite populations will provide baseline data for the evaluation and improvement of current efforts for control and elimination. The aim of this study was to examine the population genetics and structure of P. vivax isolates from four communities in Tra Leng commune, Nam Tra My district in Quang Nam, Central Vietnam. Methodology/Principal Findings P. vivax mono infections collected from 234 individuals between April 2009 and December 2010 were successfully analyzed using a panel of 14 microsatellite markers. Isolates displayed moderate genetic diversity (He = 0.68), with no significant differences between study communities. Polyclonal infections were frequent (71.4%) with a mean multiplicity of infection of 1.91 isolates/person. Low but significant genetic differentiation (FST value from -0.05 to 0.18) was observed between the community across the river and the other communities. Strong linkage disequilibrium ( IAS = 0.113, p < 0.001) was detected across all communities, suggesting gene flow within and among them. Using multiple approaches, 101 haplotypes were grouped into two genetic clusters, while 60.4% of haplotypes were admixed. Conclusions/Significance In this area of Central Vietnam, where malaria transmission has decreased significantly over the past decade, there was moderate genetic diversity and high occurrence of polyclonal infections. Local human populations have frequent social and economic interactions that facilitate gene flow and inbreeding among parasite populations, while decreasing population structure. Findings provide important information on parasites populations circulating in the study area and are relevant to current malaria elimination efforts. In Vietnam, Plasmodium vivax (P. vivax) is the second most frequent human malaria parasite and a major obstacle to countrywide malaria elimination. Knowing the local parasite structure is useful for elimination efforts. Therefore, we analyzed, with a panel of 14 microsatellite markers, 234 P. vivax mono infections in blood samples collected from 4 communities in central Vietnam. Genetic diversity in the population was moderate; a high occurrence of polyclonal infections and significant linkage disequilibrium were detected, suggesting inbreeding or recombination between highly related haplotypes. In addition, both genetic differentiation and population structure was low and only detected between communities at each side of the river. Those results suggest gene flow between study communities with the river defining a moderate geographical barrier. Future studies should determine how this genetic variation is maintained in an area of extremely low transmission.
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Abstract
SUMMARYPlasmodium vivaxis the most geographically widespread of the malaria parasites causing human disease, yet it is comparatively understudied compared withPlasmodium falciparum.In this article we review what is known about naturally acquired immunity toP. vivax, and importantly, how this differs to that acquired againstP. falciparum.Immunity to clinicalP. vivaxinfection is acquired more quickly than toP. falciparum, and evidence suggests humans in endemic areas also have a greater capacity to mount a successful immunological memory response to this pathogen. Both of these factors give promise to the idea of a successfulP. vivaxvaccine. We review what is known about both the cellular and humoral immune response, including the role of cytokines, antibodies, immunoregulation, immune memory and immune dysfunction. Furthermore, we discuss where the future lies in terms of advancing our understanding of naturally acquired immunity toP. vivax, through the use of well-designed longitudinal epidemiological studies and modern tools available to immunologists.
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A systematic review of sub-microscopic Plasmodium vivax infection. Malar J 2015; 14:360. [PMID: 26390924 PMCID: PMC4578340 DOI: 10.1186/s12936-015-0884-z] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/02/2015] [Indexed: 12/26/2022] Open
Abstract
Background An accurate estimate of Plasmodiumvivax prevalence is essential for the successful implementation of malaria control and elimination programmes. Prevalence estimates both inform control strategies and are used in their evaluation. Light microscopy is the main method for detecting Plasmodium parasitaemia in the peripheral blood, but compared to molecular diagnostics, such as polymerase chain reaction (PCR), has limited sensitivity. Methods A systematic review and meta-analysis was conducted to assess the effect of detection method on the prevalence of P.vivax and to quantify the extent to which P. vivax infections are undetected by microscopy. Embase, Medline and the Cochrane Database were searched for studies reporting prevalence by PCR and by microscopy and that contained all of the following key words: vivax, PCR, and malaria. Prevalence estimates and study meta-data were extracted systematically from each publication. Combined microscopy:PCR prevalence ratios were estimated by random effects meta-analysis. Sensitivity and specificity of microscopy were calculated using PCR as the gold standard. Results Of 874 studies reviewed, 40 met the criteria for inclusion contributing 54 prevalence pairs. The prevalence of P.vivax infection measured by PCR was consistently higher than the prevalence measured by microscopy with sub-patent parasitaemia. The mean prevalence of infection detected by microscopy was 67 % (95 % CI 59–73 %) lower than the prevalence detected by PCR. The detection of sub-patent parasitaemia did not vary according to the microscopy method (thick or, thick and thin smears), the PCR prevalence (as a measure of the true P.vivax prevalence), the type of blood used or DNA extraction method. Conclusions Quantifying P. vivax parasitaemia by PCR rather than microscopy consistently increased prevalence estimates by a factor of 2.3. Whilst the sensitivity of microscopy can be improved by better methods, molecular methods have potential to be scaled up to improve the detection of P. vivax transmission reservoirs. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0884-z) contains supplementary material, which is available to authorized users.
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Confirmed Plasmodium vivax Resistance to Chloroquine in Central Vietnam. Antimicrob Agents Chemother 2015; 59:7411-9. [PMID: 26392501 PMCID: PMC4649222 DOI: 10.1128/aac.00791-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 09/06/2015] [Indexed: 01/03/2023] Open
Abstract
Plasmodium vivax resistance to chloroquine (CQ) is currently reported in almost all countries where P. vivax is endemic. In Vietnam, despite a first report on P. vivax resistance to chloroquine published in the early 2000s, P. vivax was still considered sensitive to CQ. Between May 2009 and December 2011, a 2-year cohort study was conducted in central Vietnam to assess the recommended radical cure regimen based on a 10-day course of primaquine (0.5 mg/kg/day) together with 3 days of CQ (25 mg/kg). Here we report the results of the first 28-day follow-up estimating the cumulative risk of P. vivax recurrences together with the corresponding CQ blood concentrations, among other endpoints. Out of 260 recruited P. vivax patients, 240 completed treatment and were followed up to day 28 according to the WHO guidelines. Eight patients (3.45%) had a recurrent P. vivax infection, at day 14 (n = 2), day 21 (n = 1), and day 28 (n = 5). Chloroquine blood concentrations, available for 3/8 recurrent infections (days 14, 21, and 28), were above the MIC (>100 ng/ml whole blood) in all of these cases. Fever and parasitemia (both sexual and asexual stages) were cleared by day 3. Anemia was common at day 0 (35.8%), especially in children under 10 years (50%), and hemoglobin (Hb) recovery at day 28 was substantial among anemic patients (median change from day 0 to 28, +1.7 g/dl; interquartile range [IQR], +0.7 to +3.2). This report, based on CQ blood levels measured at the time of recurrences, confirms for the first time P. vivax CQ resistance in central Vietnam and calls for further studies using standardized protocols for accurately monitoring the extent and evolution of P. vivax resistance to chloroquine in Vietnam. These results, together with the mounting evidence of artemisinin resistance in central Vietnam, further highlight the increasing threat of antimalarial drug resistance to malaria elimination in Vietnam.
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Shelton JMG, Corran P, Risley P, Silva N, Hubbart C, Jeffreys A, Rowlands K, Craik R, Cornelius V, Hensmann M, Molloy S, Sepulveda N, Clark TG, Band G, Clarke GM, Spencer CCA, Kerasidou A, Campino S, Auburn S, Tall A, Ly AB, Mercereau-Puijalon O, Sakuntabhai A, Djimdé A, Maiga B, Touré O, Doumbo OK, Dolo A, Troye-Blomberg M, Mangano VD, Verra F, Modiano D, Bougouma E, Sirima SB, Ibrahim M, Hussain A, Eid N, Elzein A, Mohammed H, Elhassan A, Elhassan I, Williams TN, Ndila C, Macharia A, Marsh K, Manjurano A, Reyburn H, Lemnge M, Ishengoma D, Carter R, Karunaweera N, Fernando D, Dewasurendra R, Drakeley CJ, Riley EM, Kwiatkowski DP, Rockett KA. Genetic determinants of anti-malarial acquired immunity in a large multi-centre study. Malar J 2015; 14:333. [PMID: 26314886 PMCID: PMC4552443 DOI: 10.1186/s12936-015-0833-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 08/03/2015] [Indexed: 01/01/2023] Open
Abstract
Background Many studies report associations between human genetic factors and immunity to malaria but few have been reliably replicated. These studies are usually country-specific, use small sample sizes and are
not directly comparable due to differences in methodologies. This study brings together samples and data collected from multiple sites across Africa and Asia to use standardized methods to look for consistent genetic effects on anti-malarial antibody levels. Methods Sera, DNA samples and clinical data were collected from 13,299 individuals from ten sites in Senegal, Mali, Burkina Faso, Sudan, Kenya, Tanzania, and Sri Lanka using standardized methods. DNA was extracted and typed for 202 Single Nucleotide Polymorphisms with known associations to malaria or antibody production, and antibody levels to four clinical grade malarial antigens [AMA1, MSP1, MSP2, and (NANP)4] plus total IgE were measured by ELISA techniques. Regression models were used to investigate the associations of clinical and genetic factors with antibody levels. Results Malaria infection increased levels of antibodies to malaria antigens and, as expected, stable predictors of anti-malarial antibody levels included age, seasonality, location, and ethnicity. Correlations between antibodies to blood-stage antigens AMA1, MSP1 and MSP2 were higher between themselves than with antibodies to the (NANP)4 epitope of the pre-erythrocytic circumsporozoite protein, while there was little or no correlation with total IgE levels. Individuals with sickle cell trait had significantly lower antibody levels to all blood-stage antigens, and recessive homozygotes for CD36 (rs321198) had significantly lower anti-malarial antibody levels to MSP2. Conclusion Although the most significant finding with a consistent effect across sites was for sickle cell trait, its effect is likely to be via reducing a microscopically positive parasitaemia rather than directly on antibody levels. However, this study does demonstrate a framework for the feasibility of combining data from sites with heterogeneous malaria transmission levels across Africa and Asia with which to explore genetic effects on anti-malarial immunity. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0833-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jennifer M G Shelton
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK.
| | - Patrick Corran
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK. .,National Institute for Biological Standards and Controls, South Mimms, Hertfordshire, UK.
| | - Paul Risley
- National Institute for Biological Standards and Controls, South Mimms, Hertfordshire, UK.
| | - Nilupa Silva
- National Institute for Biological Standards and Controls, South Mimms, Hertfordshire, UK.
| | - Christina Hubbart
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK.
| | - Anna Jeffreys
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK.
| | - Kate Rowlands
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK.
| | - Rachel Craik
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK.
| | - Victoria Cornelius
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK.
| | - Meike Hensmann
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK.
| | - Sile Molloy
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK.
| | - Nuno Sepulveda
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK.
| | - Taane G Clark
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK.
| | - Gavin Band
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK.
| | - Geraldine M Clarke
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK.
| | - Christopher C A Spencer
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK.
| | - Angeliki Kerasidou
- Nuffield Department of Population Health, The Ethox Centre, University of Oxford, Richard Doll Building, Old Road Campus, Oxford, OX3 7LF, UK.
| | - Susana Campino
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.
| | - Sarah Auburn
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK.
| | - Adama Tall
- Infectious Diseases Epidemiology Unit, Institut Pasteur, BP 220, Dakar, Senegal.
| | - Alioune Badara Ly
- Infectious Diseases Epidemiology Unit, Institut Pasteur, BP 220, Dakar, Senegal.
| | - Odile Mercereau-Puijalon
- Parasite Molecular Immunology Unit, Institut Pasteur, 28 rue du Docteur Roux, 75724, Paris Cedex 15, France.
| | - Anavaj Sakuntabhai
- Unité de Génétique Fonctionnelle des Maladies Infectieuses, Institut Pasteur, 28 rue du Docteur Roux, 75724, Paris Cedex 15, France. .,Centre National de la Recherche Scientifique, URA3012, 28 rue du Docteur Roux, 75724, Paris Cedex 15, France.
| | - Abdoulaye Djimdé
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Odonto-Stomatology, Malaria Research and Training Center, USTTB, BP 1805, Bamako, Mali.
| | - Boubacar Maiga
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Odonto-Stomatology, Malaria Research and Training Center, USTTB, BP 1805, Bamako, Mali.
| | - Ousmane Touré
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Odonto-Stomatology, Malaria Research and Training Center, USTTB, BP 1805, Bamako, Mali.
| | - Ogobara K Doumbo
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Odonto-Stomatology, Malaria Research and Training Center, USTTB, BP 1805, Bamako, Mali.
| | - Amagana Dolo
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Odonto-Stomatology, Malaria Research and Training Center, USTTB, BP 1805, Bamako, Mali.
| | - Marita Troye-Blomberg
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20B, 106 91, Stockholm, Sweden.
| | - Valentina D Mangano
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
| | - Frederica Verra
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
| | - David Modiano
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
| | - Edith Bougouma
- Centre de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso.
| | - Sodiomon B Sirima
- Centre de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso.
| | - Muntaser Ibrahim
- Institute of Endemic Diseases, University of Khartoum, Medical Sciences Campus, Qasser Street, Khartoum, Sudan.
| | - Ayman Hussain
- Institute of Endemic Diseases, University of Khartoum, Medical Sciences Campus, Qasser Street, Khartoum, Sudan.
| | - Nahid Eid
- Institute of Endemic Diseases, University of Khartoum, Medical Sciences Campus, Qasser Street, Khartoum, Sudan.
| | - Abier Elzein
- Institute of Endemic Diseases, University of Khartoum, Medical Sciences Campus, Qasser Street, Khartoum, Sudan.
| | - Hiba Mohammed
- Institute of Endemic Diseases, University of Khartoum, Medical Sciences Campus, Qasser Street, Khartoum, Sudan.
| | - Ahmed Elhassan
- Institute of Endemic Diseases, University of Khartoum, Medical Sciences Campus, Qasser Street, Khartoum, Sudan.
| | - Ibrahim Elhassan
- Institute of Endemic Diseases, University of Khartoum, Medical Sciences Campus, Qasser Street, Khartoum, Sudan.
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, CGMRC, PO Box 230-80108, Kilifi, Kenya. .,Department of Medicine, Imperial College, St Mary's Campus, Norfolk Place, London, W2 1PG, UK.
| | - Carolyne Ndila
- KEMRI-Wellcome Trust Research Programme, CGMRC, PO Box 230-80108, Kilifi, Kenya.
| | - Alexander Macharia
- KEMRI-Wellcome Trust Research Programme, CGMRC, PO Box 230-80108, Kilifi, Kenya.
| | - Kevin Marsh
- KEMRI-Wellcome Trust Research Programme, CGMRC, PO Box 230-80108, Kilifi, Kenya.
| | - Alphaxard Manjurano
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK. .,Kilimanjaro Christian Medical College, Tumaini University, Moshi, Tanzania.
| | - Hugh Reyburn
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK. .,Kilimanjaro Christian Medical College, Tumaini University, Moshi, Tanzania.
| | - Martha Lemnge
- National Institute for Medical Research, Ocean Road, Dar es Salaam, Tanzania.
| | - Deus Ishengoma
- National Institute for Medical Research, Ocean Road, Dar es Salaam, Tanzania.
| | - Richard Carter
- Division of Biological Sciences, Ashworth Laboratories, University of Edinburgh, West Mains Rd., Edinburgh, EH9 3JT, UK.
| | - Nadira Karunaweera
- Department of Parasitology, Faculty of Medicine, University of Colombo, Kynsey Road, Colombo, Sri Lanka.
| | - Deepika Fernando
- Department of Parasitology, Faculty of Medicine, University of Colombo, Kynsey Road, Colombo, Sri Lanka.
| | - Rajika Dewasurendra
- Department of Parasitology, Faculty of Medicine, University of Colombo, Kynsey Road, Colombo, Sri Lanka.
| | - Christopher J Drakeley
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK. .,Kilimanjaro Christian Medical College, Tumaini University, Moshi, Tanzania.
| | - Eleanor M Riley
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK. .,Kilimanjaro Christian Medical College, Tumaini University, Moshi, Tanzania.
| | - Dominic P Kwiatkowski
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK. .,Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.
| | - Kirk A Rockett
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK. .,Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.
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20
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Stresman GH, Baidjoe AY, Stevenson J, Grignard L, Odongo W, Owaga C, Osoti V, Makori E, Shagari S, Marube E, Cox J, Drakeley C, Bousema T. Focal Screening to Identify the Subpatent Parasite Reservoir in an Area of Low and Heterogeneous Transmission in the Kenya Highlands. J Infect Dis 2015; 212:1768-77. [PMID: 26019285 DOI: 10.1093/infdis/jiv302] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 05/14/2015] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Mass screening and treatment currently fails to identify a considerable fraction of low parasite density infections, while mass treatment exposes many uninfected individuals to antimalarial drugs. Here we test a hybrid approach to screen a sentinel population to identify clusters of subpatent infections in the Kenya highlands with low, heterogeneous malaria transmission. METHODS Two thousand eighty-two inhabitants were screened for parasitemia by nested polymerase chain reaction (nPCR). Children aged ≤ 15 years and febrile adults were also tested for malaria by rapid diagnostic test (RDT) and served as sentinel members to identify subpatent infections within the household. All parasitemic individuals were assessed for multiplicity of infections by nPCR and gametocyte carriage by nucleic acid sequence-based amplification. RESULTS Households with RDT-positive individuals in the sentinel population were more likely to have nPCR-positive individuals (odds ratio: 1.71, 95% confidence interval, 1.60-1.84). The sentinel population identified 64.5% (locality range: 31.6%-81.2%) of nPCR-positive households and 77.3% (locality range: 24.2%-91.0%) of nPCR-positive individuals. The sensitivity of the sentinel screening approach was positively associated with transmission intensity (P = .037). CONCLUSIONS In this low endemic area, a focal screening approach with RDTs prior to the high transmission season was able to identify the majority of the subpatent parasite reservoirs.
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Affiliation(s)
- Gillian H Stresman
- Department of Immunology and Infection; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | | | - Jennifer Stevenson
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Lynn Grignard
- Department of Immunology and Infection; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Wycliffe Odongo
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu
| | - Chrispin Owaga
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu
| | - Victor Osoti
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu
| | - Euniah Makori
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu
| | - Shehu Shagari
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu
| | - Elisabeth Marube
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu
| | - Jonathan Cox
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Chris Drakeley
- Department of Immunology and Infection; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Teun Bousema
- Department of Immunology and Infection; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom Radboud University Nijmegen Medical Centre, The Netherlands
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21
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Thanh PV, Van Hong N, Van Van N, Van Malderen C, Obsomer V, Rosanas-Urgell A, Grietens KP, Xa NX, Bancone G, Chowwiwat N, Duong TT, D'Alessandro U, Speybroeck N, Erhart A. Epidemiology of forest malaria in Central Vietnam: the hidden parasite reservoir. Malar J 2015; 14:86. [PMID: 25880664 PMCID: PMC4342195 DOI: 10.1186/s12936-015-0601-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 02/01/2015] [Indexed: 11/17/2022] Open
Abstract
Background After successfully reducing the malaria burden to pre-elimination levels over the past two decades, the national malaria programme in Vietnam has recently switched from control to elimination. However, in forested areas of Central Vietnam malaria elimination is likely to be jeopardized by the high occurrence of asymptomatic and submicroscopic infections as shown by previous reports. This paper presents the results of a malaria survey carried out in a remote forested area of Central Vietnam where we evaluated malaria prevalence and risk factors for infection. Methods After a full census (four study villages = 1,810 inhabitants), the study population was screened for malaria infections by standard microscopy and, if needed, treated according to national guidelines. An additional blood sample on filter paper was also taken in a random sample of the population for later polymerase chain reaction (PCR) and more accurate estimation of the actual burden of malaria infections. The risk factor analysis for malaria infections was done using survey multivariate logistic regression as well as the classification and regression tree method (CART). Results A total of 1,450 individuals were screened. Malaria prevalence by microscopy was 7.8% (ranging from 3.9 to 10.9% across villages) mostly Plasmodium falciparum (81.4%) or Plasmodium vivax (17.7%) mono-infections; a large majority (69.9%) was asymptomatic. By PCR, the prevalence was estimated at 22.6% (ranging from 16.4 to 42.5%) with a higher proportion of P. vivax mono-infections (43.2%). The proportion of sub-patent infections increased with increasing age and with decreasing prevalence across villages. The main risk factors were young age, village, house structure, and absence of bed net. Conclusion This study confirmed that in Central Vietnam a substantial part of the human malaria reservoir is hidden. Additional studies are urgently needed to assess the contribution of this hidden reservoir to the maintenance of malaria transmission. Such evidence will be crucial for guiding elimination strategies.
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Affiliation(s)
- Pham Vinh Thanh
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.
| | - Nguyen Van Hong
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.
| | - Nguyen Van Van
- Provincial Malaria Station, Tam Ky City, Quang Nam Province, Vietnam.
| | | | - Valérie Obsomer
- Université Ccatholique de Louvain (UCL), Louvain-la-Neuve, Belgium.
| | | | | | - Nguyen Xuan Xa
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.
| | - Germana Bancone
- Shoklo Malaria Research Unit, Mae Sot, Tak Province, Thailand.
| | | | - Tran Thanh Duong
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.
| | - Umberto D'Alessandro
- Institute of Tropical Medicine Prince Leopold (ITM), Antwerp, Belgium. .,Medical Research Council Unit (MRC Unit), Fajara, The Gambia.
| | | | - Annette Erhart
- Institute of Tropical Medicine Prince Leopold (ITM), Antwerp, Belgium.
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22
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Stresman GH, Stevenson JC, Ngwu N, Marube E, Owaga C, Drakeley C, Bousema T, Cox J. High levels of asymptomatic and subpatent Plasmodium falciparum parasite carriage at health facilities in an area of heterogeneous malaria transmission intensity in the Kenyan highlands. Am J Trop Med Hyg 2014; 91:1101-8. [PMID: 25331807 DOI: 10.4269/ajtmh.14-0355] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In endemic settings, health facility surveys provide a convenient approach to estimating malaria transmission intensity. Typically, testing for malaria at facilities is performed on symptomatic attendees, but asymptomatic infections comprise a considerable proportion of the parasite reservoir. We sampled individuals attending five health facilities in the western Kenyan highlands. Malaria prevalence by rapid diagnostic test (RDT) was 8.6-32.9% in the health facilities. Of all polymerase chain reaction-positive participants, 46.4% (95% confidence interval [95% CI] = 42.6-50.2%) of participants had infections that were RDT-negative and asymptomatic, and 55.9% of those infections consisted of multiple parasite clones as assessed by merozoite surface protein-2 genotyping. Subpatent infections were more common in individuals reporting the use of non-artemisinin-based antimalarials in the 2 weeks preceding the survey (odds ratio = 2.49, 95% CI = 1.04-5.92) compared with individuals not reporting previous use of antimalarials. We observed a large and genetically complex pool of subpatent parasitemia in the Kenya highlands that must be considered in malaria interventions.
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Affiliation(s)
- Gillian H Stresman
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Jennifer C Stevenson
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Nnenna Ngwu
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Elizabeth Marube
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Chrispin Owaga
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Chris Drakeley
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Teun Bousema
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Jonathan Cox
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
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23
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Gryseels C, Uk S, Erhart A, Gerrets R, Sluydts V, Durnez L, Muela Ribera J, Hausmann Muela S, Menard D, Heng S, Sochantha T, D’Alessandro U, Coosemans M, Peeters Grietens K. Injections, cocktails and diviners: therapeutic flexibility in the context of malaria elimination and drug resistance in Northeast Cambodia. PLoS One 2013; 8:e80343. [PMID: 24244678 PMCID: PMC3823656 DOI: 10.1371/journal.pone.0080343] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 10/01/2013] [Indexed: 11/18/2022] Open
Abstract
Background Adherence to effective malaria medication is extremely important in the context of Cambodia’s elimination targets and drug resistance containment. Although the public sector health facilities are accessible to the local ethnic minorities of Ratanakiri province (Northeast Cambodia), their illness itineraries often lead them to private pharmacies selling “cocktails” and artemether injections, or to local diviners prescribing animal sacrifices to appease the spirits. Methods The research design consisted of a mixed methods study, combining qualitative (in-depth interviews and participant observation) and quantitative methods (household and cross-sectional survey). Results Three broad options for malaria treatment were identified: i) the public sector; ii) the private sector; iii) traditional treatment based on divination and ceremonial sacrifice. Treatment choice was influenced by the availability of treatment and provider, perceived side effects and efficacy of treatments, perceived etiology of symptoms, and patient-health provider encounters. Moreover, treatment paths proved to be highly flexible, changing mostly in relation to the perceived efficacy of a chosen treatment. Conclusions Despite good availability of anti-malarial treatment in the public health sector, attendance remained low due to both structural and human behavioral factors. The common use and under-dosage of anti-malaria monotherapy in the private sector (single-dose injections, single-day drug cocktails) represents a threat not only for individual case management, but also for the regional plan of drug resistance containment and malaria elimination.
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Affiliation(s)
| | - Sambunny Uk
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | - René Gerrets
- The Amsterdam Institute for Social Science Research, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Lies Durnez
- Institute of Tropical Medicine, Antwerp, Belgium
| | - Joan Muela Ribera
- Partners for Applied Social Sciences (PASS) International, Tessenderlo, Belgium
| | | | | | - Somony Heng
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Tho Sochantha
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | - Marc Coosemans
- Institute of Tropical Medicine, Antwerp, Belgium
- University of Antwerp, Antwerp, Belgium
| | - Koen Peeters Grietens
- Institute of Tropical Medicine, Antwerp, Belgium
- Partners for Applied Social Sciences (PASS) International, Tessenderlo, Belgium
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24
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Van Hong N, van den Eede P, Van Overmeir C, Vythilingham I, Rosanas-Urgell A, Vinh Thanh P, Thang ND, Hung NM, Hung LX, D'Alessandro U, Erhart A. A modified semi-nested multiplex malaria PCR (SnM-PCR) for the identification of the five human Plasmodium species occurring in Southeast Asia. Am J Trop Med Hyg 2013; 89:721-723. [PMID: 23980132 PMCID: PMC3795103 DOI: 10.4269/ajtmh.13-0027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
We have modified an existing semi-nested multiplex polymerase chain reaction (PCR) by adding one Plasmodium knowlesi-specific nested PCR, and validated the latter against laboratory and clinical samples. This new method has the advantage of being relatively affordable in low resource settings while identifying the five human Plasmodium species with a three-step PCR.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Annette Erhart
- *Address correspondence to Annette Erhart, Malariology Unit, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium. E-mail:
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