1
|
Noviyanti R, Miotto O, Barry A, Marfurt J, Siegel S, Thuy-Nhien N, Quang HH, Anggraeni ND, Laihad F, Liu Y, Sumiwi ME, Trimarsanto H, Coutrier F, Fadila N, Ghanchi N, Johora FT, Puspitasari AM, Tavul L, Trianty L, Utami RAS, Wang D, Wangchuck K, Price RN, Auburn S. Implementing parasite genotyping into national surveillance frameworks: feedback from control programmes and researchers in the Asia-Pacific region. Malar J 2020; 19:271. [PMID: 32718342 PMCID: PMC7385952 DOI: 10.1186/s12936-020-03330-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/09/2020] [Indexed: 01/13/2023] Open
Abstract
The Asia-Pacific region faces formidable challenges in achieving malaria elimination by the proposed target in 2030. Molecular surveillance of Plasmodium parasites can provide important information on malaria transmission and adaptation, which can inform national malaria control programmes (NMCPs) in decision-making processes. In November 2019 a parasite genotyping workshop was held in Jakarta, Indonesia, to review molecular approaches for parasite surveillance and explore ways in which these tools can be integrated into public health systems and inform policy. The meeting was attended by 70 participants from 8 malaria-endemic countries and partners of the Asia Pacific Malaria Elimination Network. The participants acknowledged the utility of multiple use cases for parasite genotyping including: quantifying the prevalence of drug resistant parasites, predicting risks of treatment failure, identifying major routes and reservoirs of infection, monitoring imported malaria and its contribution to local transmission, characterizing the origins and dynamics of malaria outbreaks, and estimating the frequency of Plasmodium vivax relapses. However, the priority of each use case varies with different endemic settings. Although a one-size-fits-all approach to molecular surveillance is unlikely to be applicable across the Asia-Pacific region, consensus on the spectrum of added-value activities will help support data sharing across national boundaries. Knowledge exchange is needed to establish local expertise in different laboratory-based methodologies and bioinformatics processes. Collaborative research involving local and international teams will help maximize the impact of analytical outputs on the operational needs of NMCPs. Research is also needed to explore the cost-effectiveness of genetic epidemiology for different use cases to help to leverage funding for wide-scale implementation. Engagement between NMCPs and local researchers will be critical throughout this process.
Collapse
Affiliation(s)
| | - Olivo Miotto
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Wellcome Sanger Institute, Hinxton, Cambridge, UK
- Centre for Genomics and Global Health, Big Data Institute, University of Oxford, Oxford, UK
| | - Alyssa Barry
- School of Medicine, Deakin University, Geelong, VIC, Australia
- Burnet Institute, Melbourne, VIC, Australia
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Jutta Marfurt
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, NT, Australia
| | - Sasha Siegel
- Wellcome Sanger Institute, Hinxton, Cambridge, UK
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, NT, Australia
| | - Nguyen Thuy-Nhien
- Centre for Tropical Medicine, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Huynh Hong Quang
- Institute of Malariology, Parasitology and Entomology, Quy Nhon, Vietnam
| | | | | | - Yaobao Liu
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, Jiangsu Province, China
| | | | | | - Farah Coutrier
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Nadia Fadila
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Najia Ghanchi
- Pathology, Aga Khan University Hospital, Karachi, Pakistan
| | - Fatema Tuj Johora
- Infectious Diseases Division, International Centre for Diarrheal Diseases Research, Bangladesh Mohakhali, Dhaka, Bangladesh
| | | | - Livingstone Tavul
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Leily Trianty
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | | | - Duoquan Wang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Kesang Wangchuck
- Royal Center for Disease Control, Department of Public Health, Ministry of Health, Thimphu, Bhutan
| | - Ric N Price
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, NT, Australia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Sarah Auburn
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand.
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, NT, Australia.
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| |
Collapse
|
2
|
Goryacheva II, Baranova AM, Lukashev AN, Gordeev MI, Usenbaev NT, Shaikevich EV. Genetic characterization of Plasmodium vivax in the Kyrgyz Republic. INFECTION GENETICS AND EVOLUTION 2018; 66:262-268. [PMID: 30339983 DOI: 10.1016/j.meegid.2018.10.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 10/14/2018] [Accepted: 10/15/2018] [Indexed: 10/28/2022]
Abstract
At the end of 2016, Kyrgyz Republic was certified by the World Health Organization as a malaria-free country, while only a decade ago this disease posed a serious health threat. The progress achieved by Kyrgyz Republic provides a unique example of tertian (Plasmodium vivax) malaria elimination. This success was based on an integrated approach, including measures for the treatment of infected people and disease prevention, vector control and the development of an effective national epidemiological surveillance system. Lower P. vivax msp-1, msp-3α, csp and dbpII genes polymorphism was revealed in Kyrgyz Republic in compare with that in Tajikistan. Molecular characterization of the causative agent found that P. vivax populations in Kyrgyz Republic was comprised by several lineages, highly divergent in the south-western and genetically homogeneous in the northern regions of Kyrgyz Republic, d. Such profile in the northern regions was compatible with several recent introductions rather than a long-term endemic circulation of the parasite. A low level of genetic variability suggested that the parasitic systems of tertian malaria, were not adapted, which, along with other factors, largely determined the possibility of malaria elimination in northern Kyrgyz Republic. Other determinants included environmental, social, and epidemiological factors that limited the spread of malaria. South-western Kyrgyz Republic, a region with a high level of interstate migration, requires considerable attention to prevent the spread of malaria.
Collapse
Affiliation(s)
- I I Goryacheva
- Vavilov Institute of General Genetics, Moscow 119991, Russia
| | | | | | - M I Gordeev
- Moscow Region State University, Moscow 105005, Russia
| | - N T Usenbaev
- Sanitary-Epidemiological Department of Kyrgyz Republic MOH, Bishkek, Kyrgyzstan
| | - E V Shaikevich
- Vavilov Institute of General Genetics, Moscow 119991, Russia.
| |
Collapse
|
3
|
Bourgard C, Albrecht L, Kayano ACAV, Sunnerhagen P, Costa FTM. Plasmodium vivax Biology: Insights Provided by Genomics, Transcriptomics and Proteomics. Front Cell Infect Microbiol 2018; 8:34. [PMID: 29473024 PMCID: PMC5809496 DOI: 10.3389/fcimb.2018.00034] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 01/25/2018] [Indexed: 12/17/2022] Open
Abstract
During the last decade, the vast omics field has revolutionized biological research, especially the genomics, transcriptomics and proteomics branches, as technological tools become available to the field researcher and allow difficult question-driven studies to be addressed. Parasitology has greatly benefited from next generation sequencing (NGS) projects, which have resulted in a broadened comprehension of basic parasite molecular biology, ecology and epidemiology. Malariology is one example where application of this technology has greatly contributed to a better understanding of Plasmodium spp. biology and host-parasite interactions. Among the several parasite species that cause human malaria, the neglected Plasmodium vivax presents great research challenges, as in vitro culturing is not yet feasible and functional assays are heavily limited. Therefore, there are gaps in our P. vivax biology knowledge that affect decisions for control policies aiming to eradicate vivax malaria in the near future. In this review, we provide a snapshot of key discoveries already achieved in P. vivax sequencing projects, focusing on developments, hurdles, and limitations currently faced by the research community, as well as perspectives on future vivax malaria research.
Collapse
Affiliation(s)
- Catarina Bourgard
- Laboratory of Tropical Diseases, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas - UNICAMP, Campinas, Brazil
| | - Letusa Albrecht
- Laboratory of Tropical Diseases, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas - UNICAMP, Campinas, Brazil.,Laboratory of Regulation of Gene Expression, Instituto Carlos Chagas, Curitiba, Brazil
| | - Ana C A V Kayano
- Laboratory of Tropical Diseases, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas - UNICAMP, Campinas, Brazil
| | - Per Sunnerhagen
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Fabio T M Costa
- Laboratory of Tropical Diseases, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas - UNICAMP, Campinas, Brazil
| |
Collapse
|
4
|
Barry AE, Waltmann A, Koepfli C, Barnadas C, Mueller I. Uncovering the transmission dynamics of Plasmodium vivax using population genetics. Pathog Glob Health 2015; 109:142-52. [PMID: 25891915 DOI: 10.1179/2047773215y.0000000012] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Population genetic analysis of malaria parasites has the power to reveal key insights into malaria epidemiology and transmission dynamics with the potential to deliver tools to support control and elimination efforts. Analyses of parasite genetic diversity have suggested that Plasmodium vivax populations are more genetically diverse and less structured than those of Plasmodium falciparum indicating that P. vivax may be a more ancient parasite of humans and/or less susceptible to population bottlenecks, as well as more efficient at disseminating its genes. These population genetic insights into P. vivax transmission dynamics provide an explanation for its relative resilience to control efforts. Here, we describe current knowledge on P. vivax population genetic structure, its relevance to understanding transmission patterns and relapse and how this information can inform malaria control and elimination programmes.
Collapse
Key Words
- Control,
- Elimination
- Genetic diversity,
- Genetics,
- Genomics,
- Linkage disequilibrium,
- Malaria,
- Microsatellites,
- Mitochondrial DNA,
- Plasmodium vivax,
- Population structure,
- Relapse,
- Single nucleotide polymorphisms,
- Transmission,
Collapse
|
5
|
Cornejo OE, Fisher D, Escalante AA. Genome-wide patterns of genetic polymorphism and signatures of selection in Plasmodium vivax. Genome Biol Evol 2014; 7:106-19. [PMID: 25523904 PMCID: PMC4316620 DOI: 10.1093/gbe/evu267] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Plasmodium vivax is the most prevalent human malaria parasite outside of Africa. Yet, studies aimed to identify genes with signatures consistent with natural selection are rare. Here, we present a comparative analysis of the pattern of genetic variation of five sequenced isolates of P. vivax and its divergence with two closely related species, Plasmodium cynomolgi and Plasmodium knowlesi, using a set of orthologous genes. In contrast to Plasmodium falciparum, the parasite that causes the most lethal form of human malaria, we did not find significant constraints on the evolution of synonymous sites genome wide in P. vivax. The comparative analysis of polymorphism and divergence across loci allowed us to identify 87 genes with patterns consistent with positive selection, including genes involved in the “exportome” of P. vivax, which are potentially involved in evasion of the host immune system. Nevertheless, we have found a pattern of polymorphism genome wide that is consistent with a significant amount of constraint on the replacement changes and prevalent negative selection. Our analyses also show that silent polymorphism tends to be larger toward the ends of the chromosomes, where many genes involved in antigenicity are located, suggesting that natural selection acts not only by shaping the patterns of variation within the genes but it also affects genome organization.
Collapse
Affiliation(s)
- Omar E Cornejo
- School of Biological Sciences, Washington State University
| | - David Fisher
- Center for Evolutionary Medicine and Informatics, the Biodesign Institute, Arizona State University
| | - Ananias A Escalante
- Center for Evolutionary Medicine and Informatics, the Biodesign Institute, Arizona State University School of Life Sciences, Arizona State University Present address: Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA.
| |
Collapse
|
6
|
Plasmodium vivax malaria: a re-emerging threat for temperate climate zones? Travel Med Infect Dis 2013; 11:51-9. [PMID: 23498971 DOI: 10.1016/j.tmaid.2013.01.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 01/23/2013] [Accepted: 01/23/2013] [Indexed: 11/20/2022]
Abstract
Plasmodium vivax was endemic in temperate areas in historic times up to the middle of last century. Temperate climate P. vivax has a long incubation time of up to 8-10 months, which partly explain how it can be endemic in temperate areas with a could winter. P. vivax disappeared from Europe within the last 40-60 years, and this change was not related to climatic changes. The surge of P. vivax in Northern Europe after the second world war was related to displacement of refugees and large movement of military personnel exposed to malaria. Lately P. vivax has been seen along the demilitarized zone in South Korea replication a high endemicity in North Korea. The potential of transmission of P. vivax still exist in temperate zones, but reintroduction in a larger scale of P. vivax to areas without present transmission require large population movements of P. vivax infected people. The highest threat at present is refugees from P. vivax endemic North Korea entering China and South Korea in large numbers.
Collapse
|
7
|
Castellanos ME, Bardají A, Menegon M, Mayor A, Desai M, Severini C, Menéndez C, Padilla N. Plasmodium vivax congenital malaria in an area of very low endemicity in Guatemala: implications for clinical and epidemiological surveillance in a malaria elimination context. Malar J 2012; 11:411. [PMID: 23217209 PMCID: PMC3541160 DOI: 10.1186/1475-2875-11-411] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 12/03/2012] [Indexed: 11/10/2022] Open
Abstract
This is a report of the first Plasmodium vivax congenital malaria case in Guatemala and the first case in Latin America with genotypical, histological and clinical characterization. The findings show that maternal P. vivax infection still occurs in areas that are in the pathway towards malaria elimination, and can be associated with detrimental health effects for the neonate. It also highlights the need in very low transmission areas of not only maintaining, but increasing awareness of the problem and developing surveillance strategies, based on population risk, to detect the infection especially in this vulnerable group of the population.
Collapse
Affiliation(s)
- María Eugenia Castellanos
- Centro de Estudios en Salud, Universidad del Valle de Guatemala, 18 avenida 11-95 zona 15 Vista Hermosa 3, Guatemala, Guatemala
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Arnott A, Barry AE, Reeder JC. Understanding the population genetics of Plasmodium vivax is essential for malaria control and elimination. Malar J 2012; 11:14. [PMID: 22233585 PMCID: PMC3298510 DOI: 10.1186/1475-2875-11-14] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 01/10/2012] [Indexed: 11/22/2022] Open
Abstract
Traditionally, infection with Plasmodium vivax was thought to be benign and self-limiting, however, recent evidence has demonstrated that infection with P. vivax can also result in severe illness and death. Research into P. vivax has been relatively neglected and much remains unknown regarding the biology, pathogenesis and epidemiology of this parasite. One of the fundamental factors governing transmission and immunity is parasite diversity. An understanding of parasite population genetic structure is necessary to understand the epidemiology, diversity, distribution and dynamics of natural P. vivax populations. In addition, studying the population structure of genes under immune selection also enables investigation of the dynamic interplay between transmission and immunity, which is crucial for vaccine development. A lack of knowledge regarding the transmission and spread of P. vivax has been particularly highlighted in areas where malaria control and elimination programmes have made progress in reducing the burden of Plasmodium falciparum, yet P. vivax remains as a substantial obstacle. With malaria elimination back on the global agenda, mapping of global and local P. vivax population structure is essential prior to establishing goals for elimination and the roll-out of interventions. A detailed knowledge of the spatial distribution, transmission and clinical burden of P. vivax is required to act as a benchmark against which control targets can be set and measured. This paper presents an overview of what is known and what is yet to be fully understood regarding P. vivax population genetics, as well as the importance and application of P. vivax population genetics studies.
Collapse
Affiliation(s)
- Alicia Arnott
- Centre for Population Health, Burnet Institute, Melbourne, Australia
| | | | | |
Collapse
|
9
|
Oshaghi M, Vatandoost H, Gorouhi A, Abai M, Madjidpour A, Arshi S, Sadeghi H, Nazari M, Mehravaran A. Anopheline species composition in borderline of Iran-Azerbaijan. Acta Trop 2011; 119:44-9. [PMID: 21513694 DOI: 10.1016/j.actatropica.2011.04.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 03/25/2011] [Accepted: 04/05/2011] [Indexed: 11/24/2022]
Abstract
Malaria is still one of the most important health-problems in the world and is endemic in Iran. Since 1994, after collapse of former Soviet Union, a new threat of malaria importation emerged from those countries into the northern Iran. This work was carried out to provide further evidence on the status of anopheline species composition, the malaria parasite species, and natural infectivity of mosquitoes distributed in Pars-Abad district, on the borderline of Azerbaijan in northwestern Iran. Mosquitoes were collected from May to December 2008 in anopheline seasonal activity and were identified at the species level. The genus- and species-specific primers against Plasmodium ssrDNA gene were used for specific amplification on female mosquito head+thorax. Members of the Anoheles maculipennis complex were identified by sequence analysis of the ribosomal internal transcribed spacer II (ITS2-rDNA). Morphological character-based identification showed that out of 1455 anopheline female specimens, 1121 (77%) were of A. maculipennis s.l. and 334 (23%) were of Anoheles hyrcanus. Molecular analysis of the species complex indicated the presence of Anoheles sacharovi 984 (67.6%) and A. maculipennis 137 (9.4%) in the region. None of themosquito's head-thorax was found to be naturally infected by malaria parasite. Results of this study, particularly high dominance of A. sacharovi, suggest a potential risk of malaria epidemic in the region, and the need for a continuous epidemiological surveillance.
Collapse
|
10
|
Rezanezhad H, Menegon M, Sarkari B, Hatam GR, Severini C. Characterization of the metacaspase 1 gene in Plasmodium vivax field isolates from southern Iran and Italian imported cases. Acta Trop 2011; 119:57-60. [PMID: 21524640 DOI: 10.1016/j.actatropica.2011.03.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 03/18/2011] [Accepted: 03/23/2011] [Indexed: 12/29/2022]
Abstract
Plasmodium vivax is still the more prevalent human Plasmodium outside Africa and despite this fact, there is still a deep lack of knowledge on its biology. Metacaspases are cysteine proteases related to metazoan caspases, involved in programmed cell death. Here, we have characterized the P. vivax metacaspase 1 gene in a total of 63 vivax isolates, 32 isolates collected in southern Iran and 31 Italian imported isolates originating from 12 different endemic countries. We have firstly identified DNA size polymorphism in P. vivax metacaspase 1 gene. A total of four different allelic sizes were found, resulting from the insertion of 1 to 4 tandem repeat units located within the intronic region of the P. vivax metacaspase 1. Similarly, we also have identified four distinct allelic types by using vivax merozoite surface protein-1 size polymorphism analysis.
Collapse
Affiliation(s)
- H Rezanezhad
- School of Pharmacy, University of Camerino, Camerino, Italy
| | | | | | | | | |
Collapse
|
11
|
Malaria vector control: from past to future. Parasitol Res 2011; 108:757-79. [PMID: 21229263 DOI: 10.1007/s00436-010-2232-0] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Accepted: 10/06/2010] [Indexed: 01/17/2023]
Abstract
Malaria is one of the most common vector-borne diseases widespread in the tropical and subtropical regions. Despite considerable success of malaria control programs in the past, malaria still continues as a major public health problem in several countries. Vector control is an essential part for reducing malaria transmission and became less effective in recent years, due to many technical and administrative reasons, including poor or no adoption of alternative tools. Of the different strategies available for vector control, the most successful are indoor residual spraying and insecticide-treated nets (ITNs), including long-lasting ITNs and materials. Earlier DDT spray has shown spectacular success in decimating disease vectors but resulted in development of insecticide resistance, and to control the resistant mosquitoes, organophosphates, carbamates, and synthetic pyrethroids were introduced in indoor residual spraying with needed success but subsequently resulted in the development of widespread multiple insecticide resistance in vectors. Vector control in many countries still use insecticides in the absence of viable alternatives. Few developments for vector control, using ovitraps, space spray, biological control agents, etc., were encouraging when used in limited scale. Likewise, recent introduction of safer vector control agents, such as insect growth regulators, biocontrol agents, and natural plant products have yet to gain the needed scale of utility for vector control. Bacterial pesticides are promising and are effective in many countries. Environmental management has shown sufficient promise for vector control and disease management but still needs advocacy for inter-sectoral coordination and sometimes are very work-intensive. The more recent genetic manipulation and sterile insect techniques are under development and consideration for use in routine vector control and for these, standardized procedures and methods are available but need thorough understanding of biology, ethical considerations, and sufficiently trained manpower for implementation being technically intensive methods. All the methods mentioned in the review that are being implemented or proposed for implementation needs effective inter-sectoral coordination and community participation. The latest strategy is evolution-proof insecticides that include fungal biopesticides, Wolbachia, and Denso virus that essentially manipulate the life cycle of the mosquitoes were found effective but needs more research. However, for effective vector control, integrated vector management methods, involving use of combination of effective tools, is needed and is also suggested by Global Malaria Control Strategy. This review article raises issues associated with the present-day vector control strategies and state opportunities with a focus on ongoing research and recent advances to enable to sustain the gains achieved so far.
Collapse
|
12
|
Zeyrek FY, Tachibana SI, Yuksel F, Doni N, Palacpac N, Arisue N, Horii T, Coban C, Tanabe K. Limited polymorphism of the Plasmodium vivax merozoite surface protein 1 gene in isolates from Turkey. Am J Trop Med Hyg 2011; 83:1230-7. [PMID: 21118926 DOI: 10.4269/ajtmh.2010.10-0353] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The 200-kD merozoite surface protein of Plasmodium vivax (PvMSP-1) is one of the leading vaccine candidates against P. vivax malaria. However, the gene encoding PvMSP-1 (pvmsp1) is highly polymorphic and is a major obstacle to effective vaccine development. To further understand polymorphism in pvmsp1, we obtained 30 full-length pvmsp1 sequences from southeastern Turkey. Comparative analysis of sequences from Turkey and other areas showed substantially limited polymorphism. Substitutions were found at 280 and 162 amino acid sites in samples from other regions and those from Turkey, respectively. Eight substitutions were unique to Turkey. In one of them, D/E at position 1706 in the C-terminal 19-kD region, the K/E change at 1709 was the only polymorphism previously known. Limited diversity was also observed in microsatellites. Data suggest a recent population bottleneck in Turkey that may have obscured a signature for balancing selection in the C-terminal 42-kD region, which was otherwise detectable in other areas.
Collapse
Affiliation(s)
- Fadile Yildiz Zeyrek
- Department of Microbiology, Harran University Medical Faculty, Sanliurfa, Turkey.
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Sinka ME, Bangs MJ, Manguin S, Coetzee M, Mbogo CM, Hemingway J, Patil AP, Temperley WH, Gething PW, Kabaria CW, Okara RM, Van Boeckel T, Godfray HCJ, Harbach RE, Hay SI. The dominant Anopheles vectors of human malaria in Africa, Europe and the Middle East: occurrence data, distribution maps and bionomic précis. Parasit Vectors 2010; 3:117. [PMID: 21129198 PMCID: PMC3016360 DOI: 10.1186/1756-3305-3-117] [Citation(s) in RCA: 411] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 12/03/2010] [Indexed: 11/10/2022] Open
Abstract
Background This is the second in a series of three articles documenting the geographical distribution of 41 dominant vector species (DVS) of human malaria. The first paper addressed the DVS of the Americas and the third will consider those of the Asian Pacific Region. Here, the DVS of Africa, Europe and the Middle East are discussed. The continent of Africa experiences the bulk of the global malaria burden due in part to the presence of the An. gambiae complex. Anopheles gambiae is one of four DVS within the An. gambiae complex, the others being An. arabiensis and the coastal An. merus and An. melas. There are a further three, highly anthropophilic DVS in Africa, An. funestus, An. moucheti and An. nili. Conversely, across Europe and the Middle East, malaria transmission is low and frequently absent, despite the presence of six DVS. To help control malaria in Africa and the Middle East, or to identify the risk of its re-emergence in Europe, the contemporary distribution and bionomics of the relevant DVS are needed. Results A contemporary database of occurrence data, compiled from the formal literature and other relevant resources, resulted in the collation of information for seven DVS from 44 countries in Africa containing 4234 geo-referenced, independent sites. In Europe and the Middle East, six DVS were identified from 2784 geo-referenced sites across 49 countries. These occurrence data were combined with expert opinion ranges and a suite of environmental and climatic variables of relevance to anopheline ecology to produce predictive distribution maps using the Boosted Regression Tree (BRT) method. Conclusions The predicted geographic extent for the following DVS (or species/suspected species complex*) is provided for Africa: Anopheles (Cellia) arabiensis, An. (Cel.) funestus*, An. (Cel.) gambiae, An. (Cel.) melas, An. (Cel.) merus, An. (Cel.) moucheti and An. (Cel.) nili*, and in the European and Middle Eastern Region: An. (Anopheles) atroparvus, An. (Ano.) labranchiae, An. (Ano.) messeae, An. (Ano.) sacharovi, An. (Cel.) sergentii and An. (Cel.) superpictus*. These maps are presented alongside a bionomics summary for each species relevant to its control.
Collapse
Affiliation(s)
- Marianne E Sinka
- Spatial Ecology and Epidemiology Group, Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Gunawardena S, Karunaweera ND, Ferreira MU, Phone-Kyaw M, Pollack RJ, Alifrangis M, Rajakaruna RS, Konradsen F, Amerasinghe PH, Schousboe ML, Galappaththy GNL, Abeyasinghe RR, Hartl DL, Wirth DF. Geographic structure of Plasmodium vivax: microsatellite analysis of parasite populations from Sri Lanka, Myanmar, and Ethiopia. Am J Trop Med Hyg 2010; 82:235-42. [PMID: 20133999 DOI: 10.4269/ajtmh.2010.09-0588] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Genetic diversity and population structure of Plasmodium vivax parasites can predict the origin and spread of novel variants within a population enabling population specific malaria control measures. We analyzed the genetic diversity and population structure of 425 P. vivax isolates from Sri Lanka, Myanmar, and Ethiopia using 12 trinucleotide and tetranucleotide microsatellite markers. All three parasite populations were highly polymorphic with 3-44 alleles per locus. Approximately 65% were multiple-clone infections. Mean genetic diversity (H(E)) was 0.7517 in Ethiopia, 0.8450 in Myanmar, and 0.8610 in Sri Lanka. Significant linkage disequilibrium was maintained. Population structure showed two clusters (Asian and African) according to geography and ancestry. Strong clustering of outbreak isolates from Sri Lanka and Ethiopia was observed. Predictive power of ancestry using two-thirds of the isolates as a model identified 78.2% of isolates accurately as being African or Asian. Microsatellite analysis is a useful tool for mapping short-term outbreaks of malaria and for predicting ancestry.
Collapse
Affiliation(s)
- Sharmini Gunawardena
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Abstract
The prospect of malaria eradication has been raised recently by the Bill and Melinda Gates Foundation with support from the international community. There are significant lessons to be learned from the major successes and failures of the eradication campaign of the 1960s, but cessation of transmission in the malaria heartlands of Africa will depend on a vaccine and better drugs and insecticides. Insect control is an essential part of reducing transmission. To date, two operational scale interventions, indoor residual spraying and deployment of long-lasting insecticide-treated nets (LLINs), are effective at reducing transmission. Our ability to monitor and evaluate these interventions needs to be improved so that scarce resources can be sensibly deployed, and new interventions that reduce transmission in a cost-effective and efficient manner need to be developed. New interventions could include using transgenic mosquitoes, larviciding in urban areas, or utilizing cost-effective consumer products. Alongside this innovative development agenda, the potential negative impact of insecticide resistance, particularly on LLINs, for which only pyrethroids are available, needs to be monitored.
Collapse
Affiliation(s)
- A Enayati
- School of Public Health and Environmental Health Research Centre, Mazandaran University of Medical Sciences, Sari, Iran.
| | | |
Collapse
|
16
|
Zakeri S, Safi N, Afsharpad M, Butt W, Ghasemi F, Mehrizi AA, Atta H, Zamani G, Djadid ND. Genetic structure of Plasmodium vivax isolates from two malaria endemic areas in Afghanistan. Acta Trop 2010; 113:12-9. [PMID: 19716798 DOI: 10.1016/j.actatropica.2009.08.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 08/18/2009] [Accepted: 08/21/2009] [Indexed: 11/17/2022]
Abstract
In this study, the nature and extent of genetic diversity of Plasmodium vivax populations circulating in Afghanistan have been investigated by analyzing three genetic markers: csp, msp-1, and msp-3 alpha. Blood samples (n=202) were collected from patients presenting with vivax malaria from south-western (Herat) and south-eastern (Nangarhar) parts of Afghanistan, and analysed using nested-PCR/RFLP and sequencing methods. Genotyping pvmsp-1 revealed type 1, type 2 and recombinant type 3 allelic variants, with type 1 predominant in parasites in both study areas. The sequence analysis of 57 P. vivax isolates identified a total of 26 distinct alleles. Genotyping pvcsp gene showed that VK210 type (86.6%) is predominant in Afghanistan. Moreover, three major types of the pvmsp-3 alpha locus: type A, type B and type C were distinguished among Afghani isolates. The predominant fragments among Nangarhar and Herat parasites were type A (70.8% and 67.9%, respectively). PCR/RFLP products with Hha I and Alu I were detected 52 and 38 distinct variants among Nangarhar and Herat isolates, respectively. These results strongly indicate that the P. vivax populations in Afghanistan are highly diverse.
Collapse
Affiliation(s)
- Sedigheh Zakeri
- Malaria and Vector Research Group, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
IgG subclasses pattern and high-avidity antibody to the C-terminal region of merozoite surface protein 1 of Plasmodium vivax in an unstable hypoendemic region in Iran. Acta Trop 2009; 112:1-7. [PMID: 19481997 DOI: 10.1016/j.actatropica.2009.05.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 05/03/2009] [Accepted: 05/22/2009] [Indexed: 11/22/2022]
Abstract
The C-terminal region of Plasmodium vivax merozoite surface protein 1 (PvMSP-1(19)) is a leading vaccine candidate for inclusion in a polyvalent malaria vaccine. In the present study, the IgG subclasses profile and the avidity of IgG to PvMSP-1(19) were evaluated in individuals (n=94) naturally exposed to P. vivax parasite in malaria endemic areas in Chabahar districts, Iran. In individuals with patent P. vivax malaria, 86.1% was sero-positive to PvMSP-1(19) and IgG1 (81.9%) was the predominant subclass. In addition, to determine the persistence of specific IgG, IgG1 and IgG3 antibodies to PvMSP-1(19), the frequency of antibodies was determined in the infected subjects (n=74) after treatment with standard chloroquine and it was detected that the frequency of responders was significantly reduced to 51.3%, 51% and 16.2%, respectively. The antigen-binding avidity of IgG antibodies to PvMSP-1(19) was measured in sero-positive sera and the high-avidity of IgG, IgG1 and IgG3 was found in 66.6%, 61% and 47% of the infected subjects with P. vivax, respectively. The present result shows that individuals who exposed to vivax malaria in the endemic region in Iran develop antibodies with high-avidity to PvMSP-1(19). These results could help to understand the interactions between the host and P. vivax parasite in development of MSP-1(19)-based vaccine.
Collapse
|
18
|
Matthys B, Sherkanov T, Karimov SS, Khabirov Z, Mostowlansky T, Utzinger J, Wyss K. History of malaria control in Tajikistan and rapid malaria appraisal in an agro-ecological setting. Malar J 2008; 7:217. [PMID: 18950536 PMCID: PMC2584067 DOI: 10.1186/1475-2875-7-217] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Accepted: 10/26/2008] [Indexed: 11/20/2022] Open
Abstract
Background Reported malaria cases in rice growing areas in western Tajikistan were at the root of a rapid appraisal of the local malaria situation in a selected agro-ecological setting where only scarce information was available. The rapid appraisal was complemented by a review of the epidemiology and control of malaria in Tajikistan and Central Asia from 1920 until today. Following a resurgence in the 1990s, malaria transmission has been reduced considerably in Tajikistan as a result of concerted efforts by the government and international agencies. The goal for 2015 is transmission interruption, with control interventions and surveillance currently concentrated in the South, where foci of Plasmodium vivax and Plasmodium falciparum persist. Methods The rapid malaria appraisal was carried out in six communities of irrigated rice cultivation during the peak of malaria transmission (August/September 2007) in western Tajikistan. In a cross-sectional survey, blood samples were taken from 363 schoolchildren and examined for Plasmodium under a light microscope. A total of 56 farmers were interviewed about agricultural activities and malaria. Potential Anopheles breeding sites were characterized using standardized procedures. A literature review on the epidemiology and control of malaria in Tajikistan was conducted. Results One case of P. vivax was detected among the 363 schoolchildren examined (0.28%). The interviewees reported to protect themselves against mosquito bites and used their own concepts on fever conditions, which do not distinguish between malaria and other diseases. Three potential malaria vectors were identified, i.e. Anopheles superpictus, Anopheles pulcherrimus and Anopheles hyrcanus in 58 of the 73 breeding sites examined (79.5%). Rice paddies, natural creeks and man-made ponds were the most important Anopheles habitats. Conclusion The presence of malaria vectors and parasite reservoirs, low awareness of, and protection against malaria in the face of population movements and inadequate surveillance may render local communities vulnerable to potential epidemics. To attain malaria transmission interruption in Tajikistan by 2015, there is a need for rigorous surveillance along with strengthening of primary health care facilities for effective case management, and possibly a more differentiated vector control strategy based on additional local evidence.
Collapse
Affiliation(s)
- Barbara Matthys
- Swiss Centre for International Health, Swiss Tropical Institute, P,O, Box, CH-4002 Basel, Switzerland.
| | | | | | | | | | | | | |
Collapse
|
19
|
Karunaweera ND, Ferreira MU, Munasinghe A, Barnwell JW, Collins WE, King CL, Kawamoto F, Hartl DL, Wirth DF. Extensive microsatellite diversity in the human malaria parasite Plasmodium vivax. Gene 2008; 410:105-12. [DOI: 10.1016/j.gene.2007.11.022] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Revised: 11/30/2007] [Accepted: 11/30/2007] [Indexed: 10/22/2022]
|
20
|
Bastos MS, da Silva-Nunes M, Malafronte RS, Hoffmann EHE, Wunderlich G, Moraes SL, Ferreira MU. Antigenic polymorphism and naturally acquired antibodies to Plasmodium vivax merozoite surface protein 1 in rural Amazonians. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2007; 14:1249-59. [PMID: 17699838 PMCID: PMC2168105 DOI: 10.1128/cvi.00243-07] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Merozoite surface protein 1 of Plasmodium vivax (PvMSP-1), a major target for malaria vaccine development, contains six highly polymorphic domains interspersed with conserved sequences. Although there is evidence that the sequence divergence in PvMSP-1 has been maintained over 5 million years by balanced selection exerted by the host's acquired immunity, the variant specificity of naturally acquired antibodies to PvMSP-1 remains poorly investigated. Here, we show that 15 recombinant proteins corresponding to PvMSP-1 variants commonly found in local parasites were poorly recognized by 376 noninfected subjects aged 5 to 90 years exposed to malaria in rural Amazonia; less than one-third of them had detectable immunoglobulin G (IgG) antibodies to at least one variant of blocks 2, 6, and 10 that were expressed, although 54.3% recognized the invariant 19-kDa C-terminal domain PvMSP-1(19). Although the proportion of responders to PvMSP-1 variants increased substantially during subsequent acute P. vivax infections, the specificity of IgG antibodies did not necessarily match the PvMSP-1 variant(s) found in infecting parasites. We discuss the relative contribution of antigenic polymorphism, poor immunogenicity, and original antigenic sin (the skew in the specificity of antibodies elicited by exposure to new antigenic variants due to preexisting variant-specific responses) to the observed patterns of antibody recognition of PvMSP-1. We suggest that antibody responses to the repertoire of variable domains of PvMSP-1 to which subjects are continuously exposed are elicited only after several repeated infections and may require frequent boosting, with clear implications for the development of PvMSP-1-based subunit vaccines.
Collapse
MESH Headings
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- Amino Acid Sequence
- Animals
- Antibodies, Protozoan/biosynthesis
- Antibodies, Protozoan/blood
- Antigenic Variation/genetics
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- Brazil
- Child
- Child, Preschool
- Cohort Studies
- Female
- Genetic Variation
- Humans
- Immunity, Innate/genetics
- Infant
- Infant, Newborn
- Male
- Merozoite Surface Protein 1/genetics
- Merozoite Surface Protein 1/immunology
- Middle Aged
- Molecular Sequence Data
- Plasmodium vivax/genetics
- Plasmodium vivax/immunology
- Polymorphism, Genetic
- Protein Structure, Tertiary/genetics
- Rural Population
Collapse
Affiliation(s)
- Melissa S Bastos
- Laboratories of Immunoepidemology, Institute of Tropical Medicine of São Paulo, University of São Paulo, 05403-000 São Paulo, Brazil
| | | | | | | | | | | | | |
Collapse
|
21
|
Oshaghi MA, Shemshad K, Yaghobi-Ershadi MR, Pedram M, Vatandoost H, Abaie MR, Akbarzadeh K, Mohtarami F. Genetic structure of the malaria vector Anopheles superpictus in Iran using mitochondrial cytochrome oxidase (COI and COII) and morphologic markers: a new species complex? Acta Trop 2007; 101:241-8. [PMID: 17367742 DOI: 10.1016/j.actatropica.2007.02.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2006] [Revised: 01/13/2007] [Accepted: 02/12/2007] [Indexed: 11/19/2022]
Abstract
Anopheles superpictus has been implicated as the most widespread malaria vector in Iran. We collected adult specimens from eight provinces across the country and subjected them to a morphological investigation as well as molecular analysis of mitochondrial DNA COI-COII region, using PCR-RFLP and analysis of DNA sequence alignment for 708bp of the COI locus. Two distinct morphological forms (A and B) of the species were found sympatric in all areas of study. PCR-RFLP using AluI separated the specimens into at least three genotypes (X, Y, and Z), and alignment of DNA sequences revealed a 12.3% variation in the COI region between the genotypes. However, the sequence variation does not correspond to the morphological forms. Our observations suggest that A. superpictus in Iran is likely a group species. However, further ecological, molecular, cytological, and epidemiological studies are necessary to clear the status of the taxon and the potential role of each putative species in the transmission of malaria.
Collapse
Affiliation(s)
- M A Oshaghi
- Department of Medical Entomology, School of Public Health & Institute of Health Research, Medical Sciences/University of Tehran, Tehran, Islamic Republic of Iran.
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Cornejo OE, Escalante AA. The origin and age of Plasmodium vivax. Trends Parasitol 2006; 22:558-63. [PMID: 17035086 PMCID: PMC1855252 DOI: 10.1016/j.pt.2006.09.007] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Revised: 08/11/2006] [Accepted: 09/25/2006] [Indexed: 11/21/2022]
Abstract
The evolutionary history of Plasmodium vivax has recently been addressed in terms of its origin as a parasite of humans and the age of extant populations. The consensus is that P. vivax originated as a result of a host switch from a non-human primate to hominids and that the extant populations did not originate as recently as previously proposed. Here, we show that, in a comparison of parasite isolates from across the world, Asian populations of P. vivax are the oldest. We discuss how this result, together with the phylogenetic evidence that P. vivax derived from Plasmodium found in Southeast Asian macaques, is most simply explained by assuming an Asian origin of this parasite. Nevertheless, the available data show only the tip of the iceberg. We discuss how sampling might affect time estimates to the most recent common ancestor for P. vivax populations and suggest that spatially explicit estimates are needed to understand the demographic history of this parasite better.
Collapse
Affiliation(s)
- Omar E Cornejo
- Emory University, Program in Population Biology, Ecology and Evolution, Atlanta, GA 20322, USA
| | | |
Collapse
|
23
|
Picot S. [Is Plasmodium vivax still a paradigm for uncomplicated malaria?]. Med Mal Infect 2006; 36:406-13. [PMID: 16842954 DOI: 10.1016/j.medmal.2006.06.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2006] [Accepted: 05/15/2006] [Indexed: 11/25/2022]
Abstract
P. vivax is supposed to be involved in benign tertian fever, responsible for a non-complicated disease that could be easily treated by standard antimalarial drug regimen. This could be considered as a long-standing paradigm of a non-virulent malaria parasite. When a patient exhibits severe malaria with the vivax parasite, the issue is often to find falciparum. However, with the implementation of molecular diagnosis, it has becoming more evident that vivax parasites could be involved in severe disease with probably a different pathogenesis. Mixed infections are frequent in various parts of Southeast Asian endemic areas and it was speculated that drugs used to treat falciparum could be involved in the development of vivax drug resistance. How should primaquine be used today for the treatment and prophylaxis of vivax malaria? Considering the re-emergence of vivax malaria in several areas, improving the treatment for this disease is certainly an important issue to avoid late episodes and transmission potential.
Collapse
Affiliation(s)
- S Picot
- EA 37-32, virulence et résistance de plasmodium, faculté de médecine de Lyon, université Claude-Bernard, 69373 Lyon, France.
| |
Collapse
|
24
|
Alam MT, Das MK, Dev V, Ansari MA, Sharma YD. PCR-RFLP method for the identification of four members of the Anopheles annularis group of mosquitoes (Diptera: Culicidae). Trans R Soc Trop Med Hyg 2006; 101:239-44. [PMID: 16806334 DOI: 10.1016/j.trstmh.2006.03.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Accepted: 03/21/2006] [Indexed: 11/25/2022] Open
Abstract
The Anopheles annularis group of mosquitoes is widely distributed in Southeast Asia and may be locally important as malaria vectors. Members of this group are morphologically very similar and often difficult to distinguish, particularly A. nivipes and A. philippinensis. We report the sequence analysis of the rDNA internal transcribed spacer 2 (ITS2) and Domain-3 (D3) regions of the four members of the A. annularis group -A. nivipes, A. philippinensis, A. annularis and A. pallidus - and a method for their molecular identification. No intraspecies sequence variation was detected among the specimens, while interspecific sequence differences were greater for ITS2 than the D3 regions. Comparison of the D3 sequences of the four species revealed two SmaI restriction sites in A. nivipes, but only one site in A. philippinensis, A. annularis and A. pallidus. The ApaI site was present in both A. philippinensis and A. pallidus, while an NcoI site was present in A. pallidus only. Restriction digestion of the PCR products of D3 fragment individually with SmaI, ApaI and NcoI produced a distinctive pattern for all the four species. We present, for the first time, a PCR-RFLP method to distinguish the four members of the A. annularis group of mosquitoes.
Collapse
Affiliation(s)
- Mohammad Tauqeer Alam
- Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
| | | | | | | | | |
Collapse
|