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Ashine T, Ebstie YA, Ibrahim R, Epstein A, Bradley J, Nouredayem M, Michael MG, Sidiahmed A, Negash N, Kochora A, Sulieman JE, Reynolds AM, Alemayehu E, Zemene E, Eyasu A, Dagne A, Hailemeskel E, Jaiteh F, Geleta D, Lejore E, Weetman D, Hussien AM, Saad F, Assefa G, Solomon H, Bashir A, Massebo F, Peeters K, Yewhalaw D, Kafy HT, Donnelly MJ, Gadisa E, Malik EM, Wilson AL. Investigating the association between household exposure to Anopheles stephensi and malaria in Sudan and Ethiopia: A case-control study protocol. PLoS One 2024; 19:e0309058. [PMID: 39226299 DOI: 10.1371/journal.pone.0309058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 08/06/2024] [Indexed: 09/05/2024] Open
Abstract
BACKGROUND Endemic African malaria vectors are poorly adapted to typical urban ecologies. However, Anopheles stephensi, an urban malaria vector formerly confined to South Asia and the Persian Gulf, was recently detected in Africa and may change the epidemiology of malaria across the continent. Little is known about the public health implications of An. stephensi in Africa. This study is designed to assess the relative importance of household exposure to An. stephensi and endemic malaria vectors for malaria risk in urban Sudan and Ethiopia. METHODS Case-control studies will be conducted in 3 urban settings (2 in Sudan, 1 in Ethiopia) to assess the association between presence of An. stephensi in and around households and malaria. Cases, defined as individuals positive for Plasmodium falciparum and/or P. vivax by microscopy/rapid diagnostic test (RDT), and controls, defined as age-matched individuals negative for P. falciparum and/or P. vivax by microscopy/RDT, will be recruited from public health facilities. Both household surveys and entomological surveillance for adult and immature mosquitoes will be conducted at participant homes within 48 hours of enrolment. Adult and immature mosquitoes will be identified by polymerase chain reaction (PCR). Conditional logistic regression will be used to estimate the association between presence of An. stephensi and malaria status, adjusted for co-occurrence of other malaria vectors and participant gender. CONCLUSIONS Findings from this study will provide evidence of the relative importance of An. stephensi for malaria burden in urban African settings, shedding light on the need for future intervention planning and policy development.
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Affiliation(s)
- Temesgen Ashine
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
- Department of Biology, College of Natural and Computational Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Yehenew Asmamaw Ebstie
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Rayyan Ibrahim
- Department of Community Medicine, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Adrienne Epstein
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - John Bradley
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Mujahid Nouredayem
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Mikiyas G Michael
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Amani Sidiahmed
- Department of Community Medicine, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Nigatu Negash
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Abena Kochora
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Jihad Eltaher Sulieman
- Sennar Malaria Research and Training Centre (SMART Centre), Federal Ministry of Health, Khartoum, Sudan
| | - Alison M Reynolds
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Eba Alemayehu
- Tropical and Infectious Disease Research Centre, Jimma University, Jimma, Ethiopia
| | - Endalew Zemene
- Tropical and Infectious Disease Research Centre, Jimma University, Jimma, Ethiopia
| | - Adane Eyasu
- Tropical and Infectious Disease Research Centre, Jimma University, Jimma, Ethiopia
| | - Alemayehu Dagne
- Tropical and Infectious Disease Research Centre, Jimma University, Jimma, Ethiopia
| | - Elifaged Hailemeskel
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Fatou Jaiteh
- Unit of Socio-Ecological Health Research, Department of Public Health, Institute of Tropical Medicine, Antwerpen, Belgium
| | - Dereje Geleta
- School of Public Health, College of Medicine and Health Sciences, Hawassa University, Hawassa, Ethiopia
| | - Ephrem Lejore
- School of Public Health, College of Medicine and Health Sciences, Hawassa University, Hawassa, Ethiopia
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Ahmed Mahmoud Hussien
- Primary Health Care General Directorate, Federal Ministry of Health, Khartoum, Sudan
| | - Fadwa Saad
- Primary Health Care General Directorate, Federal Ministry of Health, Khartoum, Sudan
| | - Gudissa Assefa
- Disease Prevention and Control Directorate, Ethiopian Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Hiwot Solomon
- Disease Prevention and Control Directorate, Ethiopian Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Abdelgadir Bashir
- Department of Community Medicine, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Fekadu Massebo
- Department of Biology, College of Natural and Computational Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Koen Peeters
- Unit of Socio-Ecological Health Research, Department of Public Health, Institute of Tropical Medicine, Antwerpen, Belgium
| | - Delenasaw Yewhalaw
- Tropical and Infectious Disease Research Centre, Jimma University, Jimma, Ethiopia
| | - Hmooda Toto Kafy
- Directorate General of Global Health, Federal Ministry of Health, Khartoum, Sudan
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Endalamaw Gadisa
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Elfatih M Malik
- Department of Community Medicine, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Anne L Wilson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Ntabi JDM, Lissom A, Djontu JC, Nkemngo FN, Diafouka-Kietela S, Mayela J, Missontsa G, Djogbenou L, Ndo C, Wondji C, Adegnika AA, Lenga A, Borrmann S, Ntoumi F. Entomological indicators of Plasmodium species transmission in Goma Tsé-Tsé and Madibou districts, in the Republic of Congo. Malar J 2024; 23:21. [PMID: 38229020 DOI: 10.1186/s12936-023-04823-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 12/16/2023] [Indexed: 01/18/2024] Open
Abstract
BACKGROUND Malaria remains a major public health problem in the Republic of Congo, with Plasmodium falciparum being the deadliest species of Plasmodium in humans. Vector transmission of malaria is poorly studied in the country and no previous report compared rural and urban data. This study aimed to determine the Anopheles fauna and the entomological indices of malaria transmission in the rural and urban areas in the south of Brazzaville, and beyond. METHODS Indoor household mosquitoes capture using electric aspirator was performed in rural and urban areas during raining and dry seasons in 2021. The identification of Anopheles species was done using binocular magnifier and nested-PCR. TaqMan and nested-PCR were used to detect the Plasmodium species in the head/thorax and abdomens of Anopheles. Some entomological indices including the sporozoite infection rate, the entomological inoculation rate and the man biting rate were estimated. RESULTS A total of 699 Anopheles mosquitoes were collected: Anopheles gambiae sensu lato (s.l.) (90.7%), Anopheles funestus s.l. (6.9%), and Anopheles moucheti (2.4%). Three species of An. gambiae s.l. were identified including Anopheles gambiae sensu stricto (78.9%), Anopheles coluzzii (15.4%) and Anopheles arabiensis (5.7%). The overall sporozoite infection rate was 22.3% with a predominance of Plasmodium falciparum, followed by Plasmodium malariae and Plasmodium ovale. Anopheles aggressiveness rate was higher in households from rural area (1.1 bites/night) compared to that from urban area (0.8 ib/p/n). The overall entomological inoculation rate was 0.13 ib/p/n. This index was 0.17 ib/p/n and 0.092 ib/p/n in rural and in urban area, respectively, and was similar during the dry (0.18 ib/p/n) and rainy (0.14 ib/p/n) seasons. CONCLUSION These findings highlight that malaria transmission remains high in rural and urban area in the south of Republic of Congo despite the ongoing control efforts, thereby indicating the need for more robust interventions.
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Affiliation(s)
- Jacques Dollon Mbama Ntabi
- Fondation Congolaise Pour La Recherche Médicale, Brazzaville, Republic of the Congo.
- Faculté Des Sciences Et Techniques, Université Marien Ngouabi, Brazzaville, Republic of the Congo.
| | - Abel Lissom
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- Department of Biological Science, Faculty of Science, University of Bamenda, Bamenda, Cameroon
| | - Jean Claude Djontu
- Fondation Congolaise Pour La Recherche Médicale, Brazzaville, Republic of the Congo
| | - Francis N Nkemngo
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Centre Region, Yaounde, Cameroon
| | | | - Jolivet Mayela
- Fondation Congolaise Pour La Recherche Médicale, Brazzaville, Republic of the Congo
| | - Georges Missontsa
- Fondation Congolaise Pour La Recherche Médicale, Brazzaville, Republic of the Congo
| | - Luc Djogbenou
- Tropical Infectious Deseases Research Center (TIDRC), University of Abomey-Calavi, Cotonou, Benin
| | - Cyrille Ndo
- Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Centre Region, Yaounde, Cameroon
- Department of Parasitology and Microbiology, Center for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Charles Wondji
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroun
| | - Ayola Akim Adegnika
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- German Center of Infection Research (DZIF), Tübingen, Germany
| | - Arsène Lenga
- Faculté Des Sciences Et Techniques, Université Marien Ngouabi, Brazzaville, Republic of the Congo
| | - Steffen Borrmann
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center of Infection Research (DZIF), Tübingen, Germany
| | - Francine Ntoumi
- Fondation Congolaise Pour La Recherche Médicale, Brazzaville, Republic of the Congo.
- Faculté Des Sciences Et Techniques, Université Marien Ngouabi, Brazzaville, Republic of the Congo.
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.
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Allan R, Weetman D, Sauskojus H, Budge S, Hawail TB, Baheshm Y. Confirmation of the presence of Anopheles stephensi among internally displaced people's camps and host communities in Aden city, Yemen. Malar J 2023; 22:1. [PMID: 36593465 PMCID: PMC9806911 DOI: 10.1186/s12936-022-04427-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 12/23/2022] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Declines in global malaria cases and deaths since the millennium are currently challenged by multiple factors including funding limitations, limits of, and resistance to vector control tools, and also recent spread of the invasive vector species, Anopheles stephensi-especially into novel urban settings where malaria rates are typically low. Coupled with general increases in urbanization and escalations in the number of conflicts creating rapid and unplanned population displacement into temporary shelter camps within host urban areas, particularly in the Middle East and sub-Saharan Africa, increased urban malaria is a major threat to control and elimination. METHODS Entomological monitoring surveys (targeting Aedes aegypti) of water containers across urban areas hosting internally displaced people (IDP) communities in Aden city, Yemen, were performed by The MENTOR Initiative, a non-governmental organisation. As part of these surveys in 2021 23 larvae collected and raised to adults were morphologically identified as An. stephensi. Twelve of the samples were sent to Liverpool School of Tropical Medicine for independent morphological assessment and genetic analysis by sequencing the ribosomal ITS2 region and the mitochondrial COI gene. RESULTS All twelve samples were confirmed morphologically and by sequence comparison of the single ITS2 and COI haplotype detected to the NCBI BLAST database as An. stephensi. Phylogenetic analysis with comparable COI sequences indicated close relationship to haplotypes found in Djibouti and Ethiopia. CONCLUSION The study results confirm the presence of An. stephensi in Yemen. Confirmation of the species in multiple urban communities hosting thousands of IDPs living in temporary shelters with widescale dependency on open water containers is of particular concern due to the vulnerability of the population and abundance of favourable breeding sites for the vector. Proactive monitoring and targeted integrated vector management are required to limit impacts in this area of typically low malaria transmission, and to prevent further the spread of An. stephensi within the region.
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Affiliation(s)
- Richard Allan
- The MENTOR Initiative, Burns House, Harlands Road, Haywards Heath, RH16 1PG UK
| | - David Weetman
- grid.48004.380000 0004 1936 9764Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA UK
| | - Hendrik Sauskojus
- The MENTOR Initiative, Burns House, Harlands Road, Haywards Heath, RH16 1PG UK
| | - Sophie Budge
- The MENTOR Initiative, Burns House, Harlands Road, Haywards Heath, RH16 1PG UK
| | - Tarek Bin Hawail
- The MENTOR Initiative, Burns House, Harlands Road, Haywards Heath, RH16 1PG UK
| | - Yasser Baheshm
- Ministry of Health in Yemen, National Malaria Control Programme, Aden, Yemen
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Adelman ZN, Kojin BB. Malaria-Resistant Mosquitoes (Diptera: Culicidae); The Principle is Proven, But Will the Effectors Be Effective? JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:1997-2005. [PMID: 34018548 DOI: 10.1093/jme/tjab090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Indexed: 06/12/2023]
Abstract
Over the last few decades, a substantial number of anti-malarial effector genes have been evaluated for their ability to block parasite infection in the mosquito vector. While many of these approaches have yielded significant effects on either parasite intensity or prevalence of infection, just a few have been able to completely block transmission. Additionally, many approaches, while effective against the parasite, also disrupt or alter important aspects of mosquito physiology, leading to corresponding changes in lifespan, reproduction, and immunity. As the most promising approaches move towards field-based evaluation, questions of effector gene robustness and durability move to the forefront. In this forum piece, we critically evaluate past effector gene approaches with an eye towards developing a deeper pipeline to augment the current best candidates.
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Affiliation(s)
- Zach N Adelman
- Department of Entomology and AgriLife Research, Texas A&M University, College Station, TX, USA
| | - Bianca B Kojin
- Department of Entomology and AgriLife Research, Texas A&M University, College Station, TX, USA
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Sinka ME, Pironon S, Massey NC, Longbottom J, Hemingway J, Moyes CL, Willis KJ. A new malaria vector in Africa: Predicting the expansion range of Anopheles stephensi and identifying the urban populations at risk. Proc Natl Acad Sci U S A 2020; 117:24900-24908. [PMID: 32929020 PMCID: PMC7547157 DOI: 10.1073/pnas.2003976117] [Citation(s) in RCA: 145] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
In 2012, an unusual outbreak of urban malaria was reported from Djibouti City in the Horn of Africa and increasingly severe outbreaks have been reported annually ever since. Subsequent investigations discovered the presence of an Asian mosquito species; Anopheles stephensi, a species known to thrive in urban environments. Since that first report, An. stephensi has been identified in Ethiopia and Sudan, and this worrying development has prompted the World Health Organization (WHO) to publish a vector alert calling for active mosquito surveillance in the region. Using an up-to-date database of published locational records for An. stephensi across its full range (Asia, Arabian Peninsula, Horn of Africa) and a set of spatial models that identify the environmental conditions that characterize a species' preferred habitat, we provide evidence-based maps predicting the possible locations across Africa where An. stephensi could establish if allowed to spread unchecked. Unsurprisingly, due to this species' close association with man-made habitats, our maps predict a high probability of presence within many urban cities across Africa where our estimates suggest that over 126 million people reside. Our results strongly support the WHO's call for surveillance and targeted vector control and provide a basis for the prioritization of surveillance.
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Affiliation(s)
- M E Sinka
- Department of Zoology, University of Oxford, Oxford, United Kingdom, OX1 3SZ;
| | - S Pironon
- Biodiversity Informatics and Spatial Analysis Department, Royal Botanic Gardens Kew, Richmond, Surrey, United Kingdom, TW9 3DS
| | - N C Massey
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom, OX3 7LF
| | - J Longbottom
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom, L3 5QA
| | - J Hemingway
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom, L3 5QA
| | - C L Moyes
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom, OX3 7LF
| | - K J Willis
- Department of Zoology, University of Oxford, Oxford, United Kingdom, OX1 3SZ
- Biodiversity Informatics and Spatial Analysis Department, Royal Botanic Gardens Kew, Richmond, Surrey, United Kingdom, TW9 3DS
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Ararat-Sarria M, Prado CC, Camargo M, Ospina LT, Camargo PA, Curtidor H, Patarroyo MA. Sexual forms obtained in a continuous in vitro cultured Colombian strain of Plasmodium falciparum (FCB2). Malar J 2020; 19:57. [PMID: 32014000 PMCID: PMC6998264 DOI: 10.1186/s12936-020-3142-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 01/25/2020] [Indexed: 12/03/2022] Open
Abstract
Background The epidemiological control of malaria has been hampered by the appearance of parasite resistance to anti-malarial drugs and by the resistance of mosquito vectors to control measures. This has also been associated with weak transmission control, mostly due to poor control of asymptomatic patients associated with host-vector transmission. This highlights the importance of studying the parasite’s sexual forms (gametocytes) which are involved in this phase of the parasite’s life-cycle. Some African and Asian strains of Plasmodium falciparum have been fully characterized regarding sexual forms’ production; however, few Latin-American strains have been so characterized. This study was aimed at characterizing the Colombian FCB2 strain as a gametocyte producer able to infect mosquitoes. Methods Gametocyte production was induced in in vitro cultured P. falciparum FCB2 and 3D7 strains. Pfap2g and Pfs25 gene expression was detected in FCB2 strain gametocyte culture by RT-PCR. Comparative analysis of gametocytes obtained from both strains was made (counts and morphological changes). In vitro zygote formation from FCB2 gametocytes was induced by incubating a gametocyte culture sample at 27 °C for 20 min. A controlled Anopheles albimanus infection was made using an artificial feed system with cultured FCB2 gametocytes (14–15 days old). Mosquito midgut dissection was then carried out for analyzing oocysts. Results The FCB2 strain expressed Pfap2g, Pfs16, Pfg27/25 and Pfs25 sexual differentiation-related genes after in vitro sexual differentiation induction, producing gametocytes that conserved the expected morphological features. The amount of FCB2 gametocytes produced was similar to that from the 3D7 strain. FCB2 gametocytes were differentiated into zygotes and ookinetes after an in vitro low-temperature stimulus and infected An. albimanus mosquitoes, developing to oocyst stage. Conclusions Even with the history of long-term FCB2 strain in vitro culture maintenance, it has retained its sexual differentiation ability. The gametocytes produced here preserved these parasite forms’ usual characteristics and An. albimanus infection capability, thus enabling its use as a tool for studying sexual form biology, An. albimanus infection comparative analysis and anti-malarial drug and vaccine development.
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Affiliation(s)
- Monica Ararat-Sarria
- Receptor-Ligand Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia.,PhD Programme in Biomedical and Biological Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Cesar Camilo Prado
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
| | - Milena Camargo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
| | - Laura Tatiana Ospina
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
| | - Paola Andrea Camargo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
| | - Hernando Curtidor
- Receptor-Ligand Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia.,Animal Science Faculty, Universidad de Ciencias Aplicadas y Ambientales (U.D.C.A), Bogotá, Colombia
| | - Manuel Alfonso Patarroyo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia. .,School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia.
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Seyfarth M, Khaireh BA, Abdi AA, Bouh SM, Faulde MK. Five years following first detection of Anopheles stephensi (Diptera: Culicidae) in Djibouti, Horn of Africa: populations established-malaria emerging. Parasitol Res 2019; 118:725-732. [PMID: 30671729 DOI: 10.1007/s00436-019-06213-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/10/2019] [Indexed: 12/24/2022]
Abstract
The Asian malaria mosquito, Anopheles stephensi, is a well-known and important vector of Plasmodium falciparum and P. vivax. Until 2013, its geographical distribution was confined to central and southern Asia including the Arabian Peninsula. In the Horn of Africa (HoA) Region, An. stephensi was first recorded from Djibouti in 2012, when it was linked geographically and temporally with an unusual outbreak of urban P. falciparum malaria. In 2016, An. stephensi was detected in the neighbouring Somali Region of Ethiopia. In order to determine whether An. stephensi populations have become established in Djibouti and contributed to the unusual rise in local malaria cases there, we carried out continuous vector surveillance from January 2013 to December 2017, investigated seasonal changes in An. stephensi population densities and bionomics, analysed available literature describing malaria in Djibouti since 2013, and investigated whether An. stephensi may have contributed to local malaria transmission by detecting circumsporozoite antigen of P. falciparum and P. vivax in female anophelines. From 2013 to 2016, seasonal activity of An. stephensi in urban Djibouti City primarily occurred during the colder, wetter season between September and May, with either no or rare trap catches from June to August. Unlike past years, this species was detected year-round, including the extremely hot summer months of June to August 2017. This change in seasonal occurrence may indicate that An. stephensi populations are adapting to their new environment in sub-Saharan Africa, facilitating their spread within Djibouti City. Among the 96 female An. stephensi investigated for malaria infectivity, three (3.1%) were positive for P. falciparum circumsporozoite antigen, including one P. falciparum/P. vivax VK 210 double infection. Subsequent to the unusual resurgence of local malaria in 2013, with 1684 confirmed cased reported for that year, malaria case numbers increased continuously, peaking at 14,810 in 2017. Prior to 2016, only P. falciparum malaria cases had been reported, but in 2016, autochthonously acquired P. vivax malaria cases occurred for the first time at a rate of 16.7% among all malaria cases recorded that year. This number increased to 36.7% in 2017. Our data indicate that the dynamics of malaria species in Djibouti is currently changing rapidly, and that An. stephensi can be involved in the transmission of both P. falciparum and P. vivax, simultaneously. Considering the extremely high potential impact of urban malaria on public health, the timely deployment of optimal multinational vector surveillance and control programs against An. stephensi is strongly recommended, not only for the HoA Region, but for the entire African continent.
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Affiliation(s)
- Marco Seyfarth
- Bundeswehr Medical Office, Office of the Surgeon General, Koblenz, Germany
| | - Bouh A Khaireh
- Solidaris Health, Public Health and Development Research Center, 10 Boulevard de la République, BP 1000, Djibouti, Republic of Djibouti.,Department of Microbiology, Faculty of Medicine, University of Djibouti, BP 1906, 12 Rue de l'École de Médecine, Djibouti, Republic of Djibouti
| | - Abdoulilah A Abdi
- President Health Advisor, Cabinet of the President, Republic of Djibouti and Directorate, Djiboutian Armed Forces Health Service, Djibouti City, Republic of Djibouti
| | - Samatar M Bouh
- Director Health Information System, Ministry of Health, Djibouti City, Republic of Djibouti
| | - Michael K Faulde
- Department XXI B, Section Medical Entomology/Zoology, Bundeswehr Central Hospital, PO Box 7460, D-56064, Koblenz, Germany. .,Institute of Medical Microbiology, Immunology and Parasitology, University Clinics Bonn, 53105, Bonn, Germany.
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Eldering M, Bompard A, Miura K, Stone W, Morlais I, Cohuet A, van Gemert GJ, Brock PM, Rijpma SR, van de Vegte-Bolmer M, Graumans W, Siebelink-Stoter R, Da DF, Long CA, Morin MJ, Sauerwein RW, Churcher TS, Bousema T. Comparative assessment of An. gambiae and An. stephensi mosquitoes to determine transmission-reducing activity of antibodies against P. falciparum sexual stage antigens. Parasit Vectors 2017; 10:489. [PMID: 29041962 PMCID: PMC5646129 DOI: 10.1186/s13071-017-2414-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 10/01/2017] [Indexed: 01/08/2023] Open
Abstract
Background With the increasing interest in vaccines to interrupt malaria transmission, there is a demand for harmonization of current methods to assess Plasmodium transmission in laboratory settings. Potential vaccine candidates are currently tested in the standard membrane feeding assay (SMFA) that commonly relies on Anopheles stephensi mosquitoes. Other mosquito species including Anopheles gambiae are the dominant malaria vectors for Plasmodium falciparum in sub-Saharan Africa. Methods Using human serum and monoclonal pre-fertilization (anti-Pfs48/45) and post-fertilization (anti-Pfs25) antibodies known to effectively inhibit sporogony, we directly compared SMFA based estimates of transmission-reducing activity (TRA) for An. stephensi and An. gambiae mosquitoes. Results In the absence of transmission-reducing antibodies, average numbers of oocysts were similar between An. gambiae and An. stephensi. Antibody-mediated TRA was strongly correlated between both mosquito species, and absolute TRA estimates for pre-fertilisation monoclonal antibodies (mAb) showed no significant difference between the two species. TRA estimates for IgG of naturally exposed individuals and partially effective concentrations of anti-Pfs25 mAb were higher for An. stephensi than for An. gambiae. Conclusion Our findings support the use of An. stephensi in the SMFA for target prioritization. As a vaccine moves through product development, better estimates of TRA and transmission-blocking activity (TBA) may need to be obtained in epidemiologically relevant parasite-species combination. Electronic supplementary material The online version of this article (10.1186/s13071-017-2414-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maarten Eldering
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Anaïs Bompard
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Kazutoyo Miura
- National Institute of Allergy and Infectious Diseases, Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, MD, USA
| | - Will Stone
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Isabelle Morlais
- Institut de Recherche pour le Développement, UMR MIVEGEC UM-CNRS 5290-IRD 224, Montpellier, France
| | - Anna Cohuet
- Institut de Recherche pour le Développement, UMR MIVEGEC UM-CNRS 5290-IRD 224, Montpellier, France
| | - Geert-Jan van Gemert
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Patrick M Brock
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, UK.,Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Sanna R Rijpma
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Wouter Graumans
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rianne Siebelink-Stoter
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Dari F Da
- Institut de Recherche en Sciences de la Santé, Bobo Dioulasso, Burkina Faso
| | - Carole A Long
- National Institute of Allergy and Infectious Diseases, Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, MD, USA
| | | | - Robert W Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Thomas S Churcher
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands. .,Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK.
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9
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Molina-Cruz A, Zilversmit MM, Neafsey DE, Hartl DL, Barillas-Mury C. Mosquito Vectors and the Globalization of Plasmodium falciparum Malaria. Annu Rev Genet 2016; 50:447-465. [PMID: 27732796 DOI: 10.1146/annurev-genet-120215-035211] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Plasmodium falciparum malaria remains a devastating public health problem. Recent discoveries have shed light on the origin and evolution of Plasmodium parasites and their interactions with their vertebrate and mosquito hosts. P. falciparum malaria originated in Africa from a single horizontal transfer between an infected gorilla and a human, and became global as the result of human migration. Today, P. falciparum malaria is transmitted worldwide by more than 70 different anopheline mosquito species. Recent studies indicate that the mosquito immune system can be a barrier to malaria transmission and that the P. falciparum Pfs47 gene allows the parasite to evade mosquito immune detection. Here, we review the origin and globalization of P. falciparum and integrate this history with analysis of the biology, evolution, and dispersal of the main mosquito vectors. This new perspective broadens our understanding of P. falciparum population structure and the dispersal of important parasite genetic traits.
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Affiliation(s)
- Alvaro Molina-Cruz
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852;
| | - Martine M Zilversmit
- Richard Guilder Graduate School and Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024
| | - Daniel E Neafsey
- Genome Sequencing and Analysis Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142
| | - Daniel L Hartl
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Carolina Barillas-Mury
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852;
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10
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Ndo C, Kopya E, Menze-Djantio B, Toto JC, Awono-Ambene P, Lycett G, Wondji CS. High susceptibility of wild Anopheles funestus to infection with natural Plasmodium falciparum gametocytes using membrane feeding assays. Parasit Vectors 2016; 9:341. [PMID: 27301693 PMCID: PMC4908716 DOI: 10.1186/s13071-016-1626-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/07/2016] [Indexed: 01/15/2023] Open
Abstract
Background Anopheles funestus is a major vector of malaria in sub-Saharan Africa. However, because it is difficult to colonize, research on this mosquito species has lagged behind other vectors, particularly the understanding of its susceptibility and interactions with the Plasmodium parasite. The present study reports one of the first experimental infections of progeny from wild-caught An. funestus with the P. falciparum parasite providing a realistic avenue for the characterisation of immune responses associated with this infection. Methods Wild-fed resting An. funestus females were collected using electric aspirators and kept in cages for four days until they were fully gravid and ready to oviposit. The resulting eggs were reared to adults F1 mosquitoes under insectary conditions. Three to five day-old An. funestus F1 females were fed with infected blood taken from gametocyte carriers using an artificial glass-parafilm feeding system. Feeding rate was recorded and fed mosquitoes were dissected at day 7 to count oocysts in midguts. Parallel experiments were performed with the known Plasmodium-susceptible An. coluzzii Ngousso laboratory strain, to monitor our blood handling procedures and infectivity of gametocytes. Results The results revealed that An. funestus displays high and similar level of susceptibility to Plasmodium infection compared to An. coluzzii, and suggest that our methodology produces robust feeding and infection rates in wild An. funestus progeny. The prevalence of infection in An. funestus mosquitoes was 38.52 % (range 6.25–100 %) and the median oocyst number was 12.5 (range 1–139). In parallel, the prevalence in An. coluzzii was 39.92 % (range 6.85–97.5 %), while the median oocyst number was 32.1 (range 1–351). Conclusions Overall, our observations are in line with the fact that both species are readily infected with P. falciparum, the most common and dangerous malaria parasite in sub-Saharan Africa, and since An. funestus is widespread throughout Africa, malaria vector control research and implementation needs to seriously address this vector species too. Additionally, the present work indicates that it is feasible to generate large number of wild F1 infected An. funestus mosquitoes using membrane feeding assays, which can be used for comprehensive study of interactions with the Plasmodium parasite. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1626-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Cyrille Ndo
- Malaria Research Laboratory, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon. .,Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK. .,Faculty of Medicine and Pharmaceutical Sciences, University of Douala, P.O. Box 2701, Douala, Cameroon.
| | - Edmond Kopya
- Malaria Research Laboratory, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon.,Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Benjamin Menze-Djantio
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.,Research Unit Liverpool School of Tropical Medicine, OCEAC, P.O. Box 288, Yaoundé, Cameroon
| | - Jean Claude Toto
- Malaria Research Laboratory, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Parfait Awono-Ambene
- Malaria Research Laboratory, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Gareth Lycett
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Charles S Wondji
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.,Research Unit Liverpool School of Tropical Medicine, OCEAC, P.O. Box 288, Yaoundé, Cameroon
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11
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Plasmodium evasion of mosquito immunity and global malaria transmission: The lock-and-key theory. Proc Natl Acad Sci U S A 2015; 112:15178-83. [PMID: 26598665 DOI: 10.1073/pnas.1520426112] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Plasmodium falciparum malaria originated in Africa and became global as humans migrated to other continents. During this journey, parasites encountered new mosquito species, some of them evolutionarily distant from African vectors. We have previously shown that the Pfs47 protein allows the parasite to evade the mosquito immune system of Anopheles gambiae mosquitoes. Here, we investigated the role of Pfs47-mediated immune evasion in the adaptation of P. falciparum to evolutionarily distant mosquito species. We found that P. falciparum isolates from Africa, Asia, or the Americas have low compatibility to malaria vectors from a different continent, an effect that is mediated by the mosquito immune system. We identified 42 different haplotypes of Pfs47 that have a strong geographic population structure and much lower haplotype diversity outside Africa. Replacement of the Pfs47 haplotypes in a P. falciparum isolate is sufficient to make it compatible to a different mosquito species. Those parasites that express a Pfs47 haplotype compatible with a given vector evade antiplasmodial immunity and survive. We propose that Pfs47-mediated immune evasion has been critical for the globalization of P. falciparum malaria as parasites adapted to new vector species. Our findings predict that this ongoing selective force by the mosquito immune system could influence the dispersal of Plasmodium genetic traits and point to Pfs47 as a potential target to block malaria transmission. A new model, the "lock-and-key theory" of P. falciparum globalization, is proposed, and its implications are discussed.
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12
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Molina-Cruz A, Barillas-Mury C. The remarkable journey of adaptation of the Plasmodium falciparum malaria parasite to New World anopheline mosquitoes. Mem Inst Oswaldo Cruz 2015; 109:662-7. [PMID: 25185006 PMCID: PMC4156459 DOI: 10.1590/0074-0276130553] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 02/25/2014] [Indexed: 12/22/2022] Open
Abstract
Plasmodium falciparum originated in Africa, dispersed around the
world as a result of human migration and had to adapt to several different indigenous
anopheline mosquitoes. Anophelines from the New World are evolutionary distant form
African ones and this probably resulted in a more stringent selection of
Plasmodium as it adapted to these vectors. It is thought that
Plasmodium has been genetically selected by some anopheline species
through unknown mechanisms. The mosquito immune system can greatly limit infection
and P. falciparum evolved a strategy to evade these responses, at
least in part mediated by Pfs47, a highly polymorphic gene. We
propose that adaptation of P. falciparum to new vectors may require
evasion of their immune system. Parasites with a Pfs47 haplotype
compatible with the indigenous mosquito vector would be able to survive and be
transmitted. The mosquito antiplasmodial response could be an important determinant
of P. falciparum population structure and could affect malaria
transmission in the Americas.
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Affiliation(s)
- Alvaro Molina-Cruz
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Carolina Barillas-Mury
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
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13
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Pimenta PFP, Orfano AS, Bahia AC, Duarte APM, Ríos-Velásquez CM, Melo FF, Pessoa FAC, Oliveira GA, Campos KMM, Villegas LM, Rodrigues NB, Nacif-Pimenta R, Simões RC, Monteiro WM, Amino R, Traub-Cseko YM, Lima JBP, Barbosa MGV, Lacerda MVG, Tadei WP, Secundino NFC. An overview of malaria transmission from the perspective of Amazon Anopheles vectors. Mem Inst Oswaldo Cruz 2015; 110:23-47. [PMID: 25742262 PMCID: PMC4371216 DOI: 10.1590/0074-02760140266] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 12/18/2014] [Indexed: 02/07/2023] Open
Abstract
In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Anopheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence.
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Affiliation(s)
- Paulo FP Pimenta
- Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG,
Brasil
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, AM,
Brasil
| | | | - Ana C Bahia
- Instituto Oswaldo Cruz-Fiocruz, Rio de Janeiro, RJ, Brasil
| | - Ana PM Duarte
- Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG,
Brasil
| | | | - Fabrício F Melo
- Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG,
Brasil
| | | | | | - Keillen MM Campos
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, AM,
Brasil
| | | | | | | | - Rejane C Simões
- Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brasil
| | - Wuelton M Monteiro
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, AM,
Brasil
| | - Rogerio Amino
- Unité de Biologie et Génétique du Paludisme, Institut Pasteur, Paris,
France
| | | | - José BP Lima
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, AM,
Brasil
- Instituto Oswaldo Cruz-Fiocruz, Rio de Janeiro, RJ, Brasil
| | - Maria GV Barbosa
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, AM,
Brasil
| | - Marcus VG Lacerda
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, AM,
Brasil
- Instituto Leônidas e Maria Deane-Fiocruz, Manaus, AM, Brasil
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14
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Faulde MK, Rueda LM, Khaireh BA. First record of the Asian malaria vector Anopheles stephensi and its possible role in the resurgence of malaria in Djibouti, Horn of Africa. Acta Trop 2014; 139:39-43. [PMID: 25004439 DOI: 10.1016/j.actatropica.2014.06.016] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 06/20/2014] [Accepted: 06/29/2014] [Indexed: 11/26/2022]
Abstract
Anopheles stephensi is an important vector of urban malaria in India and the Persian Gulf area. Its previously known geographical range includes southern Asia and the Arab Peninsula. For the first time, we report A. stephensi from the African continent, based on collections made in Djibouti, on the Horn of Africa, where this species' occurrence was linked to an unusual urban outbreak of Plasmodium falciparum malaria, with 1228 cases reported from February to May 2013, and a second, more severe epidemic that emerged in November 2013 and resulted in 2017 reported malaria cases between January and February 2014. Anopheles stephensi was initially identified using morphological identification keys, followed by sequencing of the Barcode cytochrome c-oxidase I (COI) gene and the rDNA second internal transcribed spacer (ITS2). Positive tests for P. falciparum circumsporozoite antigen in two of six female A. stephensi trapped in homes of malaria patients in March 2013 are evidence that autochthonous urban malaria transmission by A. stephensi has occurred. Concurrent with the second malaria outbreak, P. falciparum-positive A. stephensi females were detected in Djibouti City starting in November 2013. In sub-Saharan Africa, newly present A. stephensi may pose a significant future health threat because of this species' high susceptibility to P. falciparum infection and its tolerance of urban habitats. This may lead to increased malaria outbreaks in African cities. Rapid interruption of the urban malaria transmission cycle, based on integrated vector surveillance and control programs aimed at the complete eradication of A. stephensi from the African continent, is strongly recommended.
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15
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Terheggen U, Drew DR, Hodder AN, Cross NJ, Mugyenyi CK, Barry AE, Anders RF, Dutta S, Osier FHA, Elliott SR, Senn N, Stanisic DI, Marsh K, Siba PM, Mueller I, Richards JS, Beeson JG. Limited antigenic diversity of Plasmodium falciparum apical membrane antigen 1 supports the development of effective multi-allele vaccines. BMC Med 2014; 12:183. [PMID: 25319190 PMCID: PMC4212128 DOI: 10.1186/s12916-014-0183-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 09/10/2014] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Polymorphism in antigens is a common mechanism for immune evasion used by many important pathogens, and presents major challenges in vaccine development. In malaria, many key immune targets and vaccine candidates show substantial polymorphism. However, knowledge on antigenic diversity of key antigens, the impact of polymorphism on potential vaccine escape, and how sequence polymorphism relates to antigenic differences is very limited, yet crucial for vaccine development. Plasmodium falciparum apical membrane antigen 1 (AMA1) is an important target of naturally-acquired antibodies in malaria immunity and a leading vaccine candidate. However, AMA1 has extensive allelic diversity with more than 60 polymorphic amino acid residues and more than 200 haplotypes in a single population. Therefore, AMA1 serves as an excellent model to assess antigenic diversity in malaria vaccine antigens and the feasibility of multi-allele vaccine approaches. While most previous research has focused on sequence diversity and antibody responses in laboratory animals, little has been done on the cross-reactivity of human antibodies. METHODS We aimed to determine the extent of antigenic diversity of AMA1, defined by reactivity with human antibodies, and to aid the identification of specific alleles for potential inclusion in a multi-allele vaccine. We developed an approach using a multiple-antigen-competition enzyme-linked immunosorbent assay (ELISA) to examine cross-reactivity of naturally-acquired antibodies in Papua New Guinea and Kenya, and related this to differences in AMA1 sequence. RESULTS We found that adults had greater cross-reactivity of antibodies than children, although the patterns of cross-reactivity to alleles were the same. Patterns of antibody cross-reactivity were very similar between populations (Papua New Guinea and Kenya), and over time. Further, our results show that antigenic diversity of AMA1 alleles is surprisingly restricted, despite extensive sequence polymorphism. Our findings suggest that a combination of three different alleles, if selected appropriately, may be sufficient to cover the majority of antigenic diversity in polymorphic AMA1 antigens. Antigenic properties were not strongly related to existing haplotype groupings based on sequence analysis. CONCLUSIONS Antigenic diversity of AMA1 is limited and a vaccine including a small number of alleles might be sufficient for coverage against naturally-circulating strains, supporting a multi-allele approach for developing polymorphic antigens as malaria vaccines.
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Affiliation(s)
- Ulrich Terheggen
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia. .,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia.
| | - Damien R Drew
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.
| | | | - Nadia J Cross
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.
| | - Cleopatra K Mugyenyi
- Centre for Geographic Medicine, Coast, Kenya Medical Research Institute, Kilifi, Kenya.
| | - Alyssa E Barry
- Walter and Eliza Hall Institute, Melbourne, Australia. .,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia.
| | | | | | - Faith H A Osier
- Centre for Geographic Medicine, Coast, Kenya Medical Research Institute, Kilifi, Kenya.
| | - Salenna R Elliott
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.
| | - Nicolas Senn
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea. .,Swiss Tropical and Public Health Institute, Basel, Switzerland.
| | - Danielle I Stanisic
- Walter and Eliza Hall Institute, Melbourne, Australia. .,Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Kevin Marsh
- Centre for Geographic Medicine, Coast, Kenya Medical Research Institute, Kilifi, Kenya.
| | - Peter M Siba
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Ivo Mueller
- Walter and Eliza Hall Institute, Melbourne, Australia. .,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia. .,Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Jack S Richards
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia. .,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia. .,Department of Microbiology, Monash University, Clayton, Victoria, Australia.
| | - James G Beeson
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia. .,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia. .,Department of Microbiology, Monash University, Clayton, Victoria, Australia.
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16
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Lalubin F, Delédevant A, Glaizot O, Christe P. Natural malaria infection reduces starvation resistance of nutritionally stressed mosquitoes. J Anim Ecol 2014; 83:850-7. [PMID: 24286465 DOI: 10.1111/1365-2656.12190] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 11/24/2013] [Indexed: 11/26/2022]
Abstract
In disease ecology, there is growing evidence that environmental quality interacts with parasite and host to determine host susceptibility to an infection. Most studies of malaria parasites have focused on the infection costs incurred by the hosts, and few have investigated the costs on mosquito vectors. The interplay between the environment, the vector and the parasite has therefore mostly been ignored and often relied on unnatural or allopatric Plasmodium/vector associations. Here, we investigated the effects of natural avian malaria infection on both fecundity and survival of field-caught female Culex pipiens mosquitoes, individually maintained in laboratory conditions. We manipulated environmental quality by providing mosquitoes with different concentrations of glucose-feeding solution prior to submitting them to a starvation challenge. We used molecular-based methods to assess mosquitoes' infection status. We found that mosquitoes infected with Plasmodium had lower starvation resistance than uninfected ones only under low nutritional conditions. The effect of nutritional stress varied with time, with the difference of starvation resistance between optimally and suboptimally fed mosquitoes increasing from spring to summer, as shown by a significant interaction between diet treatment and months of capture. Infected and uninfected mosquitoes had similar clutch size, indicating no effect of infection on fecundity. Overall, this study suggests that avian malaria vectors may suffer Plasmodium infection costs in their natural habitat, under certain environmental conditions. This may have major implications for disease transmission in the wild.
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Affiliation(s)
- Fabrice Lalubin
- Department of Ecology and Evolution, Le Biophore, University of Lausanne, CH-1015, Lausanne, Switzerland.,Museum of Zoology, Place de la Riponne 6, CH-1014, Lausanne, Switzerland
| | - Aline Delédevant
- Department of Ecology and Evolution, Le Biophore, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Olivier Glaizot
- Department of Ecology and Evolution, Le Biophore, University of Lausanne, CH-1015, Lausanne, Switzerland.,Museum of Zoology, Place de la Riponne 6, CH-1014, Lausanne, Switzerland
| | - Philippe Christe
- Department of Ecology and Evolution, Le Biophore, University of Lausanne, CH-1015, Lausanne, Switzerland
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17
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Basseri HR, Mohamadzadeh Hajipirloo H, Mohammadi Bavani M, Whitten MMA. Comparative susceptibility of different biological forms of Anopheles stephensi to Plasmodium berghei ANKA strain. PLoS One 2013; 8:e75413. [PMID: 24086525 PMCID: PMC3781038 DOI: 10.1371/journal.pone.0075413] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Accepted: 08/16/2013] [Indexed: 11/22/2022] Open
Abstract
Background There are varying degrees of compatibility between malaria parasite-mosquito species, and understanding this compatibility may be crucial for developing effective transmission-blocking vaccines. This study investigates the compatibility of different biological forms of a malaria vector, Anopheles stephensi, to Plasmodium berghei ANKA strain. Methods Several biologically different and allopatric forms of A. stephensi were studied. Three forms were isolated from different regions of southern Iran: the variety mysorensis, the intermediate form and the native type form, and an additional type form originated from India (Beech strain).The mosquitoes were experimentally infected with P. berghei to compare their susceptibility to parasitism. Anti-mosquito midgut antiserum was then raised in BALB/cs mice immunized against gut antigens from the most susceptible form of A. stephensi (Beech strain), and the efficacy of the antiserum was assessed in transmission-blocking assays conducted on the least susceptible mosquito biological form. Results The susceptibility of different biological forms of A. stephensi mosquito to P. berghei was specifically inter-type varied. The Beech strain and the intermediate form were both highly susceptible to infection, with higher oocyst and sporozoite infection rates than intermediate and mysorensis forms. The oocyst infection, and particularly sporozite infection, was lowest in the mysorensis strain. Antiserum raised against midgut proteins of the Indian Beech type form blocked infection in this mosquito population, but it was ineffective at blocking both oocyst and sporozoite development in the permissive but geographically distant intermediate form mosquitoes. This suggests that a strong degree of incompatibility exists between the mosquito strains in terms of midgut protein(s) acting as putative ookinete receptors. Conclusions The incompatibility in the midgut protein profiles between two biological forms of A. stephensi demonstrates a well-differentiated population structure according to geographical origin. Therefore, the design of potential transmission-blocking strategies should incorporate a more thorough understanding of intra-species variations in host-parasite interactions.
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Affiliation(s)
- Hamid R. Basseri
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Habib Mohamadzadeh Hajipirloo
- Department of Parasitology and Mycology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran
- * E-mail:
| | - Mulood Mohammadi Bavani
- Department of Parasitology and Mycology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Miranda M. A. Whitten
- Institute of Life Science, College of Medicine, Swansea University, Singleton Park, Swansea, United Kingdom
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18
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Shinzawa N, Ishino T, Tachibana M, Tsuboi T, Torii M. Phenotypic dissection of a Plasmodium-refractory strain of malaria vector Anopheles stephensi: the reduced susceptibility to P. berghei and P. yoelii. PLoS One 2013; 8:e63753. [PMID: 23717475 PMCID: PMC3662785 DOI: 10.1371/journal.pone.0063753] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 04/03/2013] [Indexed: 01/08/2023] Open
Abstract
Anopheline mosquitoes are the major vectors of human malaria. Parasite-mosquito interactions are a critical aspect of disease transmission and a potential target for malaria control. Current investigations into parasite-mosquito interactions frequently assume that genetically resistant and susceptible mosquitoes exist in nature. Therefore, comparisons between the Plasmodium susceptibility profiles of different mosquito species may contribute to a better understanding of vectorial capacity. Anopheles stephensi is an important malaria vector in central and southern Asia and is widely used as a laboratory model of parasite transmission due to its high susceptibility to Plasmodium infection. In the present study, we identified a rodent malaria-refractory strain of A. stephensi mysorensis (Ehime) by comparative study of infection susceptibility. A very low number of oocysts develop in Ehime mosquitoes infected with P. berghei and P. yoelii, as determined by evaluation of developed oocysts on the basal lamina. A stage-specific study revealed that this reduced susceptibility was due to the impaired formation of ookinetes of both Plasmodium species in the midgut lumen and incomplete crossing of the midgut epithelium. There were no apparent abnormalities in the exflagellation of male parasites in the ingested blood or the maturation of oocysts after the rounding up of the ookinetes. Overall, these results suggest that invasive-stage parasites are eliminated in both the midgut lumen and epithelium in Ehime mosquitoes by strain-specific factors that remain unknown. The refractory strain newly identified in this report would be an excellent study system for investigations into novel parasite-mosquito interactions in the mosquito midgut.
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Affiliation(s)
- Naoaki Shinzawa
- Department of Molecular Parasitology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan.
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19
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Sinden RE, Carter R, Drakeley C, Leroy D. The biology of sexual development of Plasmodium: the design and implementation of transmission-blocking strategies. Malar J 2012; 11:70. [PMID: 22424474 PMCID: PMC3315749 DOI: 10.1186/1475-2875-11-70] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 03/16/2012] [Indexed: 12/15/2022] Open
Abstract
A meeting to discuss the latest developments in the biology of sexual development of Plasmodium and transmission-control was held April 5-6, 2011, in Bethesda, MD. The meeting was sponsored by the Bill & Melinda Gates Foundation and the National Institutes of Health, National Institute of Allergy and Infectious Diseases (NIH/NIAID) in response to the challenge issued at the Malaria Forum in October 2007 that the malaria community should re-engage with the objective of global eradication. The consequent rebalancing of research priorities has brought to the forefront of the research agenda the essential need to reduce parasite transmission. A key component of any transmission reduction strategy must be methods to attack the parasite as it passes from man to the mosquito (and vice versa). Such methods must be rationally based on a secure understanding of transmission from the molecular-, cellular-, population- to the evolutionary-levels. The meeting represented a first attempt to draw together scientists with expertise in these multiple layers of understanding to discuss the scientific foundations and resources that will be required to provide secure progress toward the design and successful implementation of effective interventions.
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Affiliation(s)
- Robert E Sinden
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK.
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20
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Otranto D, Latrofa MS, Brianti E, Annoscia G, Parisi A, Dantas-Torres F, Bain O, Gasser RB. An assessment of genetic variability in the mitochondrial cytochrome c oxidase subunit 1 gene of Cercopithifilaria sp. (Spirurida, Onchocercidae) from dog and Rhipicephalus sanguineus populations. Mol Cell Probes 2011; 26:81-9. [PMID: 22227114 DOI: 10.1016/j.mcp.2011.12.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 12/17/2011] [Accepted: 12/18/2011] [Indexed: 11/27/2022]
Abstract
This study investigates sequence variation in mitochondrial cytochrome c oxidase subunit 1 gene within Cercopithifilaria sp. recorded recently in Italy. Fourteen sequence types (haplotypes) were characterized for 163 (7.7%) amplicons from 2111 Genomic DNA samples prepared from skin samples from dogs and from Rhipicephalus sanguineus (ticks) from different geographical areas of the Mediterranean basin (i.e., Italy, Spain and Greece). The most prevalent sequence types represented haplotypes I (70.5%) and X (16.0%), followed by haplotype VIII (4.9%) and other 11 haplotypes (8.6%). Three haplotypes (II, V and VI) were found exclusively in ticks. The overall intraspecific nucleotide variation among pcox1 haplotypes ranged from 0.4 to 3.5% (mean = 1.6%), whereas a mean interspecific difference of 9.5% was detected as compared with other onchocercids. Phylogenetic analysis of the nucleotide sequence data showed a clustering of Cercopithifilaria sp. with the other Cercopithifilaria species (with strong statistical support) to the exclusion of other onchocercids. The number of haplotypes identified here might be explained by complex ecology and transmission patterns as well as the high mutation rate of mitochondrial DNA and/or inbreeding associated with hosts and their vectors.
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Affiliation(s)
- Domenico Otranto
- Dipartimento di Sanità Pubblica e Zootecnia, Università degli Studi di Bari, Valenzano, Italy.
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Barry AE, Schultz L, Buckee CO, Reeder JC. Contrasting population structures of the genes encoding ten leading vaccine-candidate antigens of the human malaria parasite, Plasmodium falciparum. PLoS One 2009; 4:e8497. [PMID: 20041125 PMCID: PMC2795866 DOI: 10.1371/journal.pone.0008497] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 12/07/2009] [Indexed: 11/21/2022] Open
Abstract
The extensive diversity of Plasmodium falciparum antigens is a major obstacle to a broadly effective malaria vaccine but population genetics has rarely been used to guide vaccine design. We have completed a meta-population genetic analysis of the genes encoding ten leading P. falciparum vaccine antigens, including the pre-erythrocytic antigens csp, trap, lsa1 and glurp; the merozoite antigens eba175, ama1, msp's 1, 3 and 4, and the gametocyte antigen pfs48/45. A total of 4553 antigen sequences were assembled from published data and we estimated the range and distribution of diversity worldwide using traditional population genetics, Bayesian clustering and network analysis. Although a large number of distinct haplotypes were identified for each antigen, they were organized into a limited number of discrete subgroups. While the non-merozoite antigens showed geographically variable levels of diversity and geographic restriction of specific subgroups, the merozoite antigens had high levels of diversity globally, and a worldwide distribution of each subgroup. This shows that the diversity of the non-merozoite antigens is organized by physical or other location-specific barriers to gene flow and that of merozoite antigens by features intrinsic to all populations, one important possibility being the immune response of the human host. We also show that current malaria vaccine formulations are based upon low prevalence haplotypes from a single subgroup and thus may represent only a small proportion of the global parasite population. This study demonstrates significant contrasts in the population structure of P. falciparum vaccine candidates that are consistent with the merozoite antigens being under stronger balancing selection than non-merozoite antigens and suggesting that unique approaches to vaccine design will be required. The results of this study also provide a realistic framework for the diversity of these antigens to be incorporated into the design of next-generation malaria vaccines.
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Affiliation(s)
- Alyssa E Barry
- Centre for Population Health, Burnet Institute, Melbourne, Australia.
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22
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Ecological immunology of mosquito-malaria interactions: Of non-natural versus natural model systems and their inferences. Parasitology 2009; 136:1935-42. [PMID: 19490728 DOI: 10.1017/s0031182009006234] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
There has been a recent shift in the literature on mosquito/Plasmodium interactions with an increasingly large number of theoretical and experimental studies focusing on their population biology and evolutionary processes. Ecological immunology of mosquito-malaria interactions - the study of the mechanisms and function of mosquito immune responses to Plasmodium in their ecological and evolutionary context - is particularly important for our understanding of malaria transmission and how to control it. Indeed, describing the processes that create and maintain variation in mosquito immune responses and parasite virulence in natural populations may be as important to this endeavor as describing the immune responses themselves. For historical reasons, Ecological Immunology still largely relies on studies based on non-natural model systems. There are many reasons why current research should favour studies conducted closer to the field and more realistic experimental systems whenever possible. As a result, a number of researchers have raised concerns over the use of artificial host-parasite associations to generate inferences about population-level processes. Here I discuss and review several lines of evidence that, I believe, best illustrate and summarize the limitations of inferences generated using non-natural model systems.
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