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Ali R, Gebhardt ME, Lupiya JS, Muleba M, Norris DE. The first complete mitochondrional genome of Anopheles gibbinsi using a skimming sequencing approach. F1000Res 2024; 13:553. [PMID: 39036652 PMCID: PMC11258543 DOI: 10.12688/f1000research.148473.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/03/2024] [Indexed: 07/23/2024] Open
Abstract
Mosquitoes belonging to the genus Anopheles are the only vectors of human malaria. Anopheles gibbinsi has been linked to malaria transmission in Kenya, with recent collections in Zambia reporting the mosquito species exhibiting zoophilic and exophilic behavioral patterns with occasional contact with humans. Given the paucity of genetic data, and challenges to identification and molecular taxonomy of the mosquitoes belonging to the Anopheles genus; we report the first complete mitochondrial genome of An. gibbinsi using a genome skimming approach. An Illumina Novaseq 6000 platform was used for sequencing, the length of the mitochondrial genome was 15401 bp, with 78.5% AT content comprised of 37 genes. Phylogenetic analysis by maximum likelihood using concatenation of the 13 protein coding genes demonstrated that An. marshallii was the closest relative based on existing sequence data. This study demonstrates that the skimming approach is an inexpensive and efficient approach for mosquito species identification and concurrent taxonomic rectification, which may be a useful alternative for generating reference sequence data for evolutionary studies among the Culicidae.
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Affiliation(s)
- Renee Ali
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Mary E. Gebhardt
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | | | | | - Douglas E. Norris
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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2
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Máquina M, Opiyo MA, Cuamba N, Marrenjo D, Rodrigues M, Armando S, Nhate S, Luis F, Saúte F, Candrinho B, Lobo NF, Paaijmans KP. Multiple Anopheles species complicate downstream analysis and decision-making in a malaria pre-elimination area in southern Mozambique. Malar J 2024; 23:23. [PMID: 38238774 PMCID: PMC10797956 DOI: 10.1186/s12936-024-04842-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 01/05/2024] [Indexed: 01/22/2024] Open
Abstract
BACKGROUND Different anopheline species (even within a species group/complex) can differ in their feeding and resting behaviours, which impact both malaria transmission patterns as well as the efficacy of vector control interventions. While morphological identification of sampled specimens is an important first step towards understanding species diversity and abundance, misidentification can result in the implementation of less effective vector control measures, and consequently smaller reductions in the number of local malaria cases. Focusing on southern Mozambique, a malaria pre-elimination area where malaria remains persistent, the aims of this preliminary study were to use molecular identification (CO1 and ITS2 barcoding) to (1) validate the results from the morphological identification (with a particular focus on Anopheles pharoensis and Anopheles squamosus), and (2) have a closer look at the Anopheles coustani group (which includes Anopheles tenebrosus and Anopheles ziemanni). METHODS Female anopheline mosquitoes (n = 81) were identified morphologically and subsequently sequenced at the ribosomal DNA internal transcribed spacer region 2 (ITS2) and/or cytochrome oxidase subunit 1 (CO1) loci towards species determination. RESULTS Out of the 62 specimens that were identified morphologically to species, 4 (6.5%) were misidentified. Regarding the An. coustani group, morphological identification showed that several members are present in southern Mozambique, including An. coustani sensu lato (s.l.), An. ziemanni and An. tenebrosus. However, based on both ITS2 and CO1 sequences, the exact species remains unknown for the latter two members until voucher sequences are available for comparison. CONCLUSION The reason(s) for morphological misidentification of anopheline mosquitoes need to be mitigated. This is usually related to both the capacity (i.e. training) of the microscopist to identify anopheline species, and the information provided in the dichotomous identification key. As the An. coustani complex contributes to (residual) malaria transmission in sub-Saharan Africa, it may play a role in the observed persistent malaria in southern Mozambique. A better baseline characterizing of the local anophelines species diversity and behaviours will allow us to improve entomological surveillance strategies, better understand the impact of vector control on each local vector species, and identify new approaches to target those vector species.
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Affiliation(s)
- Mara Máquina
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Manhica, Mozambique
| | - Mercy A Opiyo
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Manhica, Mozambique
- ISGlobal, Barcelona, Spain
- Malaria Elimination Initiative, University of California San Francisco, San Francisco, CA, USA
| | - Nelson Cuamba
- Programa Nacional de Controlo da Malária, Ministério da Saúde, Maputo, Mozambique
- PMI VectorLink Project, Abt Associates Inc., Maputo, Mozambique
| | - Dulcisária Marrenjo
- Programa Nacional de Controlo da Malária, Ministério da Saúde, Maputo, Mozambique
| | | | | | - Sheila Nhate
- Maputo Provincial Health Service, Matola, Mozambique
| | - Fabião Luis
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Manhica, Mozambique
| | - Francisco Saúte
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Manhica, Mozambique
| | - Baltazar Candrinho
- Programa Nacional de Controlo da Malária, Ministério da Saúde, Maputo, Mozambique
| | - Neil F Lobo
- Malaria Elimination Initiative, University of California San Francisco, San Francisco, CA, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Krijn P Paaijmans
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Manhica, Mozambique.
- ISGlobal, Barcelona, Spain.
- Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ, USA.
- Simon A. Levin Mathematical, Computational and Modeling Sciences Center, Arizona State University, Tempe, AZ, USA.
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3
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Katowa B, Hamapumbu H, Thuma PE, Bérubé S, Wesolowski A, Moss WJ, Kobayashi T. Declining Age-Specific Seroprevalence and Seroconversion Rates in Plasmodium falciparum from 2009 to 2018 Documents Progress toward Malaria Elimination in Southern Zambia. Am J Trop Med Hyg 2023; 109:134-137. [PMID: 37127270 PMCID: PMC10324002 DOI: 10.4269/ajtmh.22-0401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 02/15/2023] [Indexed: 05/03/2023] Open
Abstract
Obtaining accurate malaria surveillance data is challenging in low-transmission settings because large sample sizes are required to estimate incidence and prevalence precisely. Serology is an additional tool to document progress toward malaria elimination. An enzyme immunoassay to Plasmodium falciparum lysate was used to estimate age-specific seroprevalence among residents of southern Zambia, where malaria transmission has declined to pre-elimination levels during the past two decades. Plasma was eluted from 3,362 dried blood spots collected during five cross-sectional surveys conducted between 2009 and 2012, and again in 2018. Annual seroconversion rates (SCRs), an estimate of the force of infection, were calculated using a reversible catalytic model. The SCR decreased by two thirds from a level of approximately 0.15/year in 2009 and 2010 to approximately 0.05/year in 2011 and 2012, and then decreased 5-fold to 0.01/year by 2018, demonstrating the utility of serology in documenting progress toward elimination.
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Affiliation(s)
| | | | | | - Sophie Bérubé
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Amy Wesolowski
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - William J. Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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4
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Nguyen VT, Collier TC, Seok S, Wang X, Mburu MM, Simubali L, Gebhardt ME, Norris DE, Lee Y. The first genome sequence of Anopheles squamous from Macha, Zambia. F1000Res 2023; 12:330. [PMID: 37842340 PMCID: PMC10568211 DOI: 10.12688/f1000research.130734.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/10/2023] [Indexed: 10/17/2023] Open
Abstract
Despite efforts to minimize the impacts of malaria and reduce the number of primary vectors, malaria has yet to be eliminated in Zambia. Understudied vector species may perpetuate malaria transmission in pre-elimination settings. Anopheles squamosus is one of the most abundantly caught mosquito species in southern Zambia and has previously been found with Plasmodium falciparum sporozoites, a causal agent of human malaria. This species may be a critical vector of malaria transmission, however, there is a lack of genetic information available for An. squamosus. We report the first genome data and the first complete mitogenome (Mt) sequence of An. squamosus. The sequence was extracted from one individual mosquito from the Chidakwa area in Macha, Zambia. The raw reads were obtained using Illumina Novaseq 6000 and assembled through NOVOplasty alignment with related species. The length of the An. squamosus Mt was 15,351 bp, with 77.9 % AT content. The closest match to the whole mitochondrial genome in the phylogenetic tree is the African malaria mosquito, Anopheles gambiae. Its genome data is available through National Center for Biotechnology Information (NCBI) Sequencing Reads Archive (SRA) with accession number SRR22114392. The mitochondrial genome was deposited in NCBI GenBank with the accession number OP776919. The ITS2 containing contig sequence was deposited in GenBank with the accession number OQ241725. Mitogenome annotation and a phylogenetic tree with related Anopheles mosquito species are provided.
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Affiliation(s)
- Valerie T. Nguyen
- Florida Medical Entomology Laboratory, Department of Entomology and Nematology, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, 32962, USA
| | | | - Sangwoo Seok
- Florida Medical Entomology Laboratory, Department of Entomology and Nematology, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, 32962, USA
| | - Xiaodi Wang
- Florida Medical Entomology Laboratory, Department of Entomology and Nematology, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, 32962, USA
| | | | | | - Mary E. Gebhardt
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, 21205, USA
| | - Douglas E. Norris
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, 21205, USA
| | - Yoosook Lee
- Florida Medical Entomology Laboratory, Department of Entomology and Nematology, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, 32962, USA
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5
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Saili K, de Jager C, Sangoro OP, Nkya TE, Masaninga F, Mwenya M, Sinyolo A, Hamainza B, Chanda E, Fillinger U, Mutero CM. Anopheles rufipes implicated in malaria transmission both indoors and outdoors alongside Anopheles funestus and Anopheles arabiensis in rural south-east Zambia. Malar J 2023; 22:95. [PMID: 36927373 PMCID: PMC10018844 DOI: 10.1186/s12936-023-04489-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 02/12/2023] [Indexed: 03/18/2023] Open
Abstract
BACKGROUND The primary malaria vector-control interventions, indoor residual spraying and long-lasting insecticidal nets, are effective against indoor biting and resting mosquito species. Consequently, outdoor biting and resting malaria vectors might elude the primary interventions and sustain malaria transmission. Varied vector biting and resting behaviour calls for robust entomological surveillance. This study investigated the bionomics of malaria vectors in rural south-east Zambia, focusing on species composition, their resting and host-seeking behaviour and sporozoite infection rates. METHODS The study was conducted in Nyimba District, Zambia. Randomly selected households served as sentinel houses for monthly collection of mosquitoes indoors using CDC-light traps (CDC-LTs) and pyrethrum spray catches (PSC), and outdoors using only CDC-LTs for 12 months. Mosquitoes were identified using morphological taxonomic keys. Specimens belonging to the Anopheles gambiae complex and Anopheles funestus group were further identified using molecular techniques. Plasmodium falciparum sporozoite infection was determined using sandwich enzyme-linked immunosorbent assays. RESULTS From 304 indoor and 257 outdoor light trap-nights and 420 resting collection, 1409 female Anopheles species mosquitoes were collected and identified morphologically; An. funestus (n = 613; 43.5%), An. gambiae sensu lato (s.l.)(n = 293; 20.8%), Anopheles pretoriensis (n = 282; 20.0%), Anopheles maculipalpis (n = 130; 9.2%), Anopheles rufipes (n = 55; 3.9%), Anopheles coustani s.l. (n = 33; 2.3%), and Anopheles squamosus (n = 3, 0.2%). Anopheles funestus sensu stricto (s.s.) (n = 144; 91.1%) and Anopheles arabiensis (n = 77; 77.0%) were the dominant species within the An. funestus group and An. gambiae complex, respectively. Overall, outdoor CDC-LTs captured more Anopheles mosquitoes (mean = 2.25, 95% CI 1.22-3,28) than indoor CDC-LTs (mean = 2.13, 95% CI 1.54-2.73). Fewer resting mosquitoes were collected with PSC (mean = 0.44, 95% CI 0.24-0.63). Sporozoite infectivity rates for An. funestus, An. arabiensis and An. rufipes were 2.5%, 0.57% and 9.1%, respectively. Indoor entomological inoculation rates (EIRs) for An. funestus s.s, An. arabiensis and An. rufipes were estimated at 4.44, 1.15 and 1.20 infectious bites/person/year respectively. Outdoor EIRs for An. funestus s.s. and An. rufipes at 7.19 and 4.31 infectious bites/person/year, respectively. CONCLUSION The findings of this study suggest that An. rufipes may play an important role in malaria transmission alongside An. funestus s.s. and An. arabiensis in the study location.
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Affiliation(s)
- Kochelani Saili
- International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772-00100, Nairobi, Kenya. .,University of Pretoria Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa.
| | - Christiaan de Jager
- University of Pretoria Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - Onyango P Sangoro
- International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Theresia E Nkya
- International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772-00100, Nairobi, Kenya.,Mbeya College of Health and Allied Sciences, University of Dar es Salaam, Mbeya, Tanzania
| | | | | | - Andy Sinyolo
- National Malaria Elimination Centre, Lusaka, Zambia
| | | | - Emmanuel Chanda
- World Health Organization, Regional Office for Africa, Brazzaville, Congo
| | - Ulrike Fillinger
- International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Clifford M Mutero
- International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772-00100, Nairobi, Kenya.,University of Pretoria Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
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6
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Salomé G, Riddin M, Braack L. Species Composition, Seasonal Abundance, and Biting Behavior of Malaria Vectors in Rural Conhane Village, Southern Mozambique. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:3597. [PMID: 36834293 PMCID: PMC9966379 DOI: 10.3390/ijerph20043597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/08/2023] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
Malaria vector surveillance provides important data to inform the effective planning of vector control interventions at a local level. The aim of this study was to determine the species diversity and abundance, biting activity, and Plasmodium infectivity of Anopheles mosquitoes from a rural village in southern Mozambique. Human landing catches were performed monthly between December 2020 and August 2021. All collected Anopheles were identified to the species level and tested for the presence of malaria parasites. Eight Anopheles species were identified among the 1802 collected anophelines. Anopheles gambiae sensu lato (s.l.) were the most abundant (51.9%) and were represented by Anopheles quadriannulatus and Anopheles arabiensis. Anopheles funestus s.l. represented 4.5%. The biting activity of An. arabiensis was more pronounced early in the evening and outdoors, whereas that of An. funestus sensu stricto (s.s.) was more intense late in the night, with no significant differences in location. One An. funestus s.s. and one An. arabiensis, both collected outdoors, were infected with Plasmodium falciparum. The overall entomologic inoculation rate was estimated at 0.015 infective bites per person per night. The significant outdoor and early evening biting activity of An. arabiensis and An. funestus found in this village may negatively impact the effectiveness of current vector control interventions. Additional vector control tools that can target these mosquitoes are needed.
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Affiliation(s)
- Graça Salomé
- UP Institute for Sustainable Malaria Control, School of Health Systems and Public Health, Faculty of Health Sciences, University of Pretoria, Pretoria 0028, South Africa
- Department of Physiological Sciences, Faculty of Medicine, Eduardo Mondlane University, 702 Salvador Allende Ave., Maputo P.O. Box 257, Mozambique
| | - Megan Riddin
- UP Institute for Sustainable Malaria Control, School of Health Systems and Public Health, Faculty of Health Sciences, University of Pretoria, Pretoria 0028, South Africa
| | - Leo Braack
- UP Institute for Sustainable Malaria Control, School of Health Systems and Public Health, Faculty of Health Sciences, University of Pretoria, Pretoria 0028, South Africa
- Malaria Consortium, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajavithi Rd, Ratchathewi, Bangkok 10400, Thailand
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7
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Koh C, Frangeul L, Blanc H, Ngoagouni C, Boyer S, Dussart P, Grau N, Girod R, Duchemin JB, Saleh MC. Ribosomal RNA (rRNA) sequences from 33 globally distributed mosquito species for improved metagenomics and species identification. eLife 2023; 12:82762. [PMID: 36688360 PMCID: PMC10014081 DOI: 10.7554/elife.82762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 01/19/2023] [Indexed: 01/24/2023] Open
Abstract
Total RNA sequencing (RNA-seq) is an important tool in the study of mosquitoes and the RNA viruses they vector as it allows assessment of both host and viral RNA in specimens. However, there are two main constraints. First, as with many other species, abundant mosquito ribosomal RNA (rRNA) serves as the predominant template from which sequences are generated, meaning that the desired host and viral templates are sequenced far less. Second, mosquito specimens captured in the field must be correctly identified, in some cases to the sub-species level. Here, we generate mosquito rRNA datasets which will substantially mitigate both of these problems. We describe a strategy to assemble novel rRNA sequences from mosquito specimens and produce an unprecedented dataset of 234 full-length 28S and 18S rRNA sequences of 33 medically important species from countries with known histories of mosquito-borne virus circulation (Cambodia, the Central African Republic, Madagascar, and French Guiana). These sequences will allow both physical and computational removal of rRNA from specimens during RNA-seq protocols. We also assess the utility of rRNA sequences for molecular taxonomy and compare phylogenies constructed using rRNA sequences versus those created using the gold standard for molecular species identification of specimens-the mitochondrial cytochrome c oxidase I (COI) gene. We find that rRNA- and COI-derived phylogenetic trees are incongruent and that 28S and concatenated 28S+18S rRNA phylogenies reflect evolutionary relationships that are more aligned with contemporary mosquito systematics. This significant expansion to the current rRNA reference library for mosquitoes will improve mosquito RNA-seq metagenomics by permitting the optimization of species-specific rRNA depletion protocols for a broader range of species and streamlining species identification by rRNA sequence and phylogenetics.
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Affiliation(s)
- Cassandra Koh
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Viruses and RNA Interference Unit, F-75015ParisFrance
| | - Lionel Frangeul
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Viruses and RNA Interference Unit, F-75015ParisFrance
| | - Hervé Blanc
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Viruses and RNA Interference Unit, F-75015ParisFrance
| | - Carine Ngoagouni
- Institut Pasteur de Bangui, Medical Entomology LaboratoryBanguiCentral African Republic
| | - Sébastien Boyer
- Institut Pasteur du Cambodge, Medical and Veterinary Entomology UnitPhnom PenhCambodia
| | | | - Nina Grau
- Institut Pasteur de Madagascar, Medical Entomology UnitAntananarivoMadagascar
| | - Romain Girod
- Institut Pasteur de Madagascar, Medical Entomology UnitAntananarivoMadagascar
| | - Jean-Bernard Duchemin
- Institut Pasteur de la Guyane, Vectopôle Amazonien Emile AbonnencCayenneFrench Guiana
| | - Maria-Carla Saleh
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Viruses and RNA Interference Unit, F-75015ParisFrance
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8
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Wesolowski A, Ippolito MM, Gebhardt ME, Ferriss E, Schue JL, Kobayashi T, Chaponda M, Kabuya JB, Muleba M, Mburu M, Matoba J, Musonda M, Katowa B, Lubinda M, Hamapumbu H, Simubali L, Mudenda T, Shields TM, Hackman A, Shiff C, Coetzee M, Koekemoer LL, Munyati S, Gwanzura L, Mutambu S, Stevenson JC, Thuma PE, Norris DE, Bailey JA, Juliano JJ, Chongwe G, Mulenga M, Simulundu E, Mharakurwa S, Agre P, Moss WJ. Policy Implications of the Southern and Central Africa International Center of Excellence for Malaria Research: Ten Years of Malaria Control Impact Assessments in Hypo-, Meso-, and Holoendemic Transmission Zones in Zambia and Zimbabwe. Am J Trop Med Hyg 2022; 107:68-74. [PMID: 36228913 PMCID: PMC9662215 DOI: 10.4269/ajtmh.21-1288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 05/28/2022] [Indexed: 11/07/2022] Open
Abstract
The International Centers of Excellence for Malaria Research (ICEMR) were established by the National Institute of Allergy and Infectious Diseases more than a decade ago to provide multidisciplinary research support to malaria control programs worldwide, operating in endemic areas and contributing technology, expertise, and ultimately policy guidance for malaria control and elimination. The Southern and Central Africa ICEMR has conducted research across three main sites in Zambia and Zimbabwe that differ in ecology, entomology, transmission intensity, and control strategies. Scientific findings led to new policies and action by the national malaria control programs and their partners in the selection of methods, materials, timing, and locations of case management and vector control. Malaria risk maps and predictive models of case detection furnished by the ICEMR informed malaria elimination programming in southern Zambia, and time series analyses of entomological and parasitological data motivated several major changes to indoor residual spray campaigns in northern Zambia. Along the Zimbabwe-Mozambique border, temporal and geospatial data are currently informing investigations into a recent resurgence of malaria. Other ICEMR findings pertaining to parasite and mosquito genetics, human behavior, and clinical epidemiology have similarly yielded immediate and long-term policy implications at each of the sites, often with generalizable conclusions. The ICEMR programs thereby provide rigorous scientific investigations and analyses to national control and elimination programs, without which the impediments to malaria control and their potential solutions would remain understudied.
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Affiliation(s)
- Amy Wesolowski
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Matthew M. Ippolito
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Mary E. Gebhardt
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Ellen Ferriss
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Jessica L. Schue
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Tamaki Kobayashi
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | | | | | | | | | | | | | | | | | | | | | | | - Andre Hackman
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Clive Shiff
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Maureen Coetzee
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand and National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Lizette L. Koekemoer
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand and National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Shungu Munyati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Lovemore Gwanzura
- Biomedical Research and Training Institute, Harare, Zimbabwe
- University of Zimbabwe Faculty of Medicine and Health Sciences, Harare, Zimbabwe
| | | | - Jennifer C. Stevenson
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Macha Research Trust, Choma, Zambia
| | - Philip E. Thuma
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Macha Research Trust, Choma, Zambia
| | - Douglas E. Norris
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | - Jonathan J. Juliano
- University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | | | - Modest Mulenga
- Directorate of Research and Postgraduate Studies, Lusaka Apex Medical University, Lusaka, Zambia
| | | | - Sungano Mharakurwa
- Biomedical Research and Training Institute, Harare, Zimbabwe
- Africa University, Mutare, Zimbabwe
| | - Peter Agre
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - William J. Moss
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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9
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Ippolito MM, Gebhardt ME, Ferriss E, Schue JL, Kobayashi T, Chaponda M, Kabuya JB, Muleba M, Mburu M, Matoba J, Musonda M, Katowa B, Lubinda M, Hamapumbu H, Simubali L, Mudenda T, Wesolowski A, Shields TM, Hackman A, Shiff C, Coetzee M, Koekemoer LL, Munyati S, Gwanzura L, Mutambu S, Stevenson JC, Thuma PE, Norris DE, Bailey JA, Juliano JJ, Chongwe G, Mulenga M, Simulundu E, Mharakurwa S, Agre PC, Moss WJ. Scientific Findings of the Southern and Central Africa International Center of Excellence for Malaria Research: Ten Years of Malaria Control Impact Assessments in Hypo-, Meso-, and Holoendemic Transmission Zones in Zambia and Zimbabwe. Am J Trop Med Hyg 2022; 107:55-67. [PMID: 36228903 PMCID: PMC9662223 DOI: 10.4269/ajtmh.21-1287] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 04/08/2022] [Indexed: 11/07/2022] Open
Abstract
For a decade, the Southern and Central Africa International Center of Excellence for Malaria Research has operated with local partners across study sites in Zambia and Zimbabwe that range from hypo- to holoendemic and vary ecologically and entomologically. The burden of malaria and the impact of control measures were assessed in longitudinal cohorts, cross-sectional surveys, passive and reactive case detection, and other observational designs that incorporated multidisciplinary scientific approaches: classical epidemiology, geospatial science, serosurveillance, parasite and mosquito genetics, and vector bionomics. Findings to date have helped elaborate the patterns and possible causes of sustained low-to-moderate transmission in southern Zambia and eastern Zimbabwe and recalcitrant high transmission and fatality in northern Zambia. Cryptic and novel mosquito vectors, asymptomatic parasite reservoirs in older children, residual parasitemia and gametocytemia after treatment, indoor residual spraying timed dyssynchronously to vector abundance, and stockouts of essential malaria commodities, all in the context of intractable rural poverty, appear to explain the persistent malaria burden despite current interventions. Ongoing studies of high-resolution transmission chains, parasite population structures, long-term malaria periodicity, and molecular entomology are further helping to lay new avenues for malaria control in southern and central Africa and similar settings.
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Affiliation(s)
- Matthew M. Ippolito
- Johns Hopkins University School of Medicine, Baltimore, Maryland
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Mary E. Gebhardt
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Ellen Ferriss
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Jessica L. Schue
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Tamaki Kobayashi
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | | | | | | | | | | | | | | | | | | | | | - Amy Wesolowski
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | - Andre Hackman
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Clive Shiff
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Maureen Coetzee
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand and National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Lizette L. Koekemoer
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand and National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Shungu Munyati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Lovemore Gwanzura
- Biomedical Research and Training Institute, Harare, Zimbabwe
- University of Zimbabwe Faculty of Medicine and Health Sciences, Harare, Zimbabwe
| | | | - Jennifer C. Stevenson
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Macha Research Trust, Choma, Zambia
| | | | - Douglas E. Norris
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | - Jonathan J. Juliano
- University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | | | - Modest Mulenga
- Directorate of Research and Postgraduate Studies, Lusaka Apex Medical University, Lusaka, Zambia
| | | | - Sungano Mharakurwa
- Biomedical Research and Training Institute, Harare, Zimbabwe
- Africa University, Mutare, Zimbabwe
| | - Peter C. Agre
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - William J. Moss
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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10
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Nkya TE, Fillinger U, Sangoro OP, Marubu R, Chanda E, Mutero CM. Six decades of malaria vector control in southern Africa: a review of the entomological evidence-base. Malar J 2022; 21:279. [PMID: 36184603 PMCID: PMC9526912 DOI: 10.1186/s12936-022-04292-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 09/05/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Countries in the southern Africa region have set targets for malaria elimination between 2020 and 2030. Malaria vector control is among the key strategies being implemented to achieve this goal. This paper critically reviews published entomological research over the past six decades in three frontline malaria elimination countries namely, Botswana Eswatini and Namibia, and three second-line malaria elimination countries including Mozambique, Zambia, and Zimbabwe. The objective of the review is to assess the current knowledge and highlight gaps that need further research attention to strengthen evidence-based decision-making toward malaria elimination. METHODS Publications were searched on the PubMed engine using search terms: "(malaria vector control OR vector control OR malaria vector*) AND (Botswana OR Swaziland OR Eswatini OR Zambia OR Zimbabwe OR Mozambique)". Opinions, perspectives, reports, commentaries, retrospective analysis on secondary data protocols, policy briefs, and reviews were excluded. RESULTS The search resulted in 718 publications with 145 eligible and included in this review for the six countries generated over six decades. The majority (139) were from three countries, namely Zambia (59) and Mozambique (48), and Zimbabwe (32) whilst scientific publications were relatively scanty from front-line malaria elimination countries, such as Namibia (2), Botswana (10) and Eswatini (4). Most of the research reported in the publications focused on vector bionomics generated mostly from Mozambique and Zambia, while information on insecticide resistance was mostly available from Mozambique. Extreme gaps were identified in reporting the impact of vector control interventions, both on vectors and disease outcomes. The literature is particularly scanty on important issues such as change of vector ecology over time and space, intervention costs, and uptake of control interventions as well as insecticide resistance. CONCLUSIONS The review reveals a dearth of information about malaria vectors and their control, most noticeable among the frontline elimination countries: Namibia, Eswatini and Botswana. It is of paramount importance that malaria vector research capacity and routine entomological monitoring and evaluation are strengthened to enhance decision-making, considering changing vector bionomics and insecticide resistance, among other determinants of malaria vector control.
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Affiliation(s)
- Theresia Estomih Nkya
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- University of Dar es Salaam, Mbeya College of Health and Allied Sciences, Mbeya, Tanzania
| | - Ulrike Fillinger
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | | | - Rose Marubu
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Emmanuel Chanda
- World Health Organization-Regional Office for Africa, Brazzaville, Republic of Congo
| | - Clifford Maina Mutero
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
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11
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Fernández Montoya L, Martí-Soler H, Máquina M, Comiche K, Cuamba I, Alafo C, Koekemoer LL, Sherrard-Smith E, Bassat Q, Galatas B, Aide P, Cuamba N, Jotamo D, Saúte F, Paaijmans KP. The mosquito vectors that sustained malaria transmission during the Magude project despite the combined deployment of indoor residual spraying, insecticide-treated nets and mass-drug administration. PLoS One 2022; 17:e0271427. [PMID: 36084031 PMCID: PMC9462736 DOI: 10.1371/journal.pone.0271427] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/23/2022] [Indexed: 11/18/2022] Open
Abstract
The "Magude project" aimed but failed to interrupt local malaria transmission in Magude district, southern Mozambique, by using a comprehensive package of interventions, including indoor residual spraying (IRS), pyrethroid-only long-lasting insecticide treated nets (LLINs) and mass-drug administration (MDA). Here we present detailed information on the vector species that sustained malaria transmission, their association with malaria incidence and behaviors, and their amenability to the implemented control interventions. Mosquitoes were collected monthly between May 2015 and October 2017 in six sentinel sites in Magude district, using CDC light traps both indoors and outdoors. Anopheles arabiensis was the main vector during the project, while An. funestus s.s., An. merus, An. parensis and An. squamosus likely played a secondary role. The latter two species have never previously been found positive for Plasmodium falciparum in southern Mozambique. The intervention package successfully reduced vector sporozoite rates in all species throughout the project. IRS was effective in controlling An. funestus s.s. and An. parensis, which virtually disappeared after its first implementation, but less effective at controlling An. arabiensis. Despite suboptimal use, LLINs likely provided significant protection against An. arabiensis and An. merus that sought their host largely indoors when people where in bed. Adding IRS on top of LLINs and MDA likely added value to the control of malaria vectors during the Magude project. Future malaria elimination attempts in the area could benefit from i) increasing the use of LLINs, ii) using longer-lasting IRS products to counteract the increase in vector densities observed towards the end of the high transmission season, and iii) a higher coverage with MDA to reduce the likelihood of human infection. However, additional interventions targeting vectors that survive IRS and LLINs by biting outdoors or indoors before people go to bed, will be likely needed to achieve local malaria elimination.
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Affiliation(s)
- Lucía Fernández Montoya
- ISGlobal, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
| | | | - Mara Máquina
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
| | - Kiba Comiche
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
| | - Inocencia Cuamba
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
| | - Celso Alafo
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
| | - Lizette L. Koekemoer
- Faculty of Health Sciences, WITS Research Institute for Malaria, University of the Witswatersrand and the Natitonal Institute for Communicable Diseases, Johannesburg, South Africa
| | - Ellie Sherrard-Smith
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, United Kingdom
| | - Quique Bassat
- ISGlobal, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
- ICREA, Barcelona, Spain
- Pediatrics Department, Hospital Sant Joan de Déu, Universitat de Barcelona, Esplugues, Barcelona, Spain
- Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Beatriz Galatas
- ISGlobal, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
| | - Pedro Aide
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
- Instituto Nacional da Saúde, Ministério da Saúde, Maputo, Mozambique
| | - Nelson Cuamba
- Programa Nacional de Controlo da Malária, Ministério da Saúde, Maputo, Mozambique
- PMI VectorLink Project, Abt Associates Inc., Maputo, Mozambique
| | - Dulcisaria Jotamo
- Programa Nacional de Controlo da Malária, Ministério da Saúde, Maputo, Mozambique
| | - Francisco Saúte
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
| | - Krijn P. Paaijmans
- ISGlobal, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
- Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ, United States of America
- The Biodesign Center for Immunotherapy, Vaccines and Virotherapy, Arizona State University, Tempe, AZ, United States of America
- Simon A. Levin Mathematical, Computational and Modeling Sciences Center, Arizona State University, Tempe, AZ, United States of America
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12
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Gebhardt ME, Krizek RS, Coetzee M, Koekemoer LL, Dahan-Moss Y, Mbewe D, Lupiya JS, Muleba M, Stevenson JC, Moss WJ, Norris DE. Expanded geographic distribution and host preference of Anopheles gibbinsi (Anopheles species 6) in northern Zambia. Malar J 2022; 21:211. [PMID: 35780113 PMCID: PMC9250713 DOI: 10.1186/s12936-022-04231-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 06/15/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Nchelenge District in northern Zambia suffers from holoendemic malaria transmission despite a decade of yearly indoor residual spraying (IRS) and insecticide-treated net (ITN) distributions. One hypothesis for this lack of impact is that some vectors in the area may forage in the early evening or outdoors. Anopheles gibbinsi specimens were identified in early evening mosquito collections performed in this study area, and further insight was gleaned into this taxon, including characterizing its genetic identity, feeding preferences, and potential role as a malaria vector. METHODS Mosquitoes were collected in July and August 2019 by CDC light traps in Nchelenge District in indoor sitting rooms, outdoor gathering spaces, and animal pens from 16:00-22:00. Host detection by PCR, COI and ITS2 PCR, and circumsporozoite (CSP) ELISA were performed on all samples morphologically identified as An. gibbinsi, and a subset of specimens were selected for COI and ITS2 sequencing. To determine risk factors for increased abundance of An. gibbinsi, a negative binomial generalized linear mixed-effects model was performed with household-level variables of interest. RESULTS Comparison of COI and ITS2 An. gibbinsi reference sequences to the NCBI database revealed > 99% identity to "Anopheles sp. 6" from Kenya. More than 97% of specimens were morphologically and molecularly consistent with An. gibbinsi. Specimens were primarily collected in animal pen traps (59.2%), followed by traps outdoors near where humans gather (24.3%), and traps set indoors (16.5%). Host DNA detection revealed a high propensity for goats, but 5% of specimens with detected host DNA had fed on humans. No specimens were positive for Plasmodium falciparum sporozoites. Animal pens and inland households > 3 km from Lake Mweru were both associated with increased An. gibbinsi abundance. CONCLUSIONS This is the first report of An. gibbinsi in Nchelenge District, Zambia. This study provided a species identity for unknown "An. sp. 6" in the NCBI database, which has been implicated in malaria transmission in Kenya. Composite data suggest that this species is largely zoophilic and exophilic, but comes into contact with humans and the malaria parasites they carry. This species should continue to be monitored in Zambia and neighbouring countries as a potential malaria vector.
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Affiliation(s)
- Mary E Gebhardt
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | - Rachel S Krizek
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Maureen Coetzee
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, and the Centre for Emerging Zoonotic & Parasitic Diseases, Vector Control Reference Laboratory, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
| | - Lizette L Koekemoer
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, and the Centre for Emerging Zoonotic & Parasitic Diseases, Vector Control Reference Laboratory, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
| | - Yael Dahan-Moss
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, and the Centre for Emerging Zoonotic & Parasitic Diseases, Vector Control Reference Laboratory, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
| | - David Mbewe
- Tropical Diseases Research Centre, Ndola, Zambia
| | | | | | - Jennifer C Stevenson
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Macha Research Trust, Choma, Zambia
| | - William J Moss
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Douglas E Norris
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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13
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Gebhardt ME, Searle KM, Kobayashi T, Shields TM, Hamapumbu H, Simubali L, Mudenda T, Thuma PE, Stevenson JC, Moss WJ, Norris DE. Understudied Anophelines Contribute to Malaria Transmission in a Low-Transmission Setting in the Choma District, Southern Province, Zambia. Am J Trop Med Hyg 2022; 106:tpmd210989. [PMID: 35344932 PMCID: PMC9128685 DOI: 10.4269/ajtmh.21-0989] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/29/2021] [Indexed: 11/11/2022] Open
Abstract
Malaria transmission has declined substantially in Southern Province, Zambia, which is considered a low-transmission setting. The Zambian government introduced a reactive test-and-treat strategy to identify active zones of transmission and treat parasitemic residents. This study was conducted in the Choma District, Southern Province, Zambia, concurrently with an evaluation of this strategy to identify vectors responsible for sustaining transmission, and to identify entomological, spatial, and ecological risk factors associated with increased densities of mosquitoes. Anophelines were collected with CDC light traps indoors and near animal pens in index cases and neighboring households. Outdoor collections captured significantly more anophelines than indoor traps, and 10 different anopheline species were identified. Four species (Anopheles arabiensis, An. rufipes, An. squamosus, and An. coustani) were positive for Plasmodium falciparum circumsporozoite protein by ELISA, and 61% of these 26 anophelines were captured outdoors. Bloodmeal assays confirm plasticity in An. arabiensis foraging, feeding both on humans and animals, whereas An. rufipes, An. squamosus, and An. coustani were largely zoophilic and exophilic. Linear regression of count data for indoor traps revealed that households with at least one parasitemic resident by polymerase chain reaction testing was associated with higher female anopheline counts. This suggests that targeting households with parasitemic individuals for vector interventions may reduce indoor anopheline populations. However, many vectors species responsible for transmission may not be affected by indoor interventions because they are primarily exophilic and forage opportunistically. These data underscore the necessity for further evaluation of vector surveillance and control tools that are effective outdoors, in conjunction with current indoor-based interventions.
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Affiliation(s)
- Mary E. Gebhardt
- Johns Hopkins Malaria Research Institute, The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Kelly M. Searle
- Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, Minnesota
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Timothy M. Shields
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | | | | | | | - Jennifer C. Stevenson
- Johns Hopkins Malaria Research Institute, The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Macha Research Trust, Choma, Zambia
| | - William J. Moss
- Johns Hopkins Malaria Research Institute, The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Douglas E. Norris
- Johns Hopkins Malaria Research Institute, The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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14
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Jones CM, Ciubotariu II, Muleba M, Lupiya J, Mbewe D, Simubali L, Mudenda T, Gebhardt ME, Carpi G, Malcolm AN, Kosinski KJ, Romero-Weaver AL, Stevenson JC, Lee Y, Norris DE. Multiple Novel Clades of Anopheline Mosquitoes Caught Outdoors in Northern Zambia. FRONTIERS IN TROPICAL DISEASES 2021; 2. [PMID: 35983564 PMCID: PMC9384971 DOI: 10.3389/fitd.2021.780664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Residual vector populations that do not come in contact with the most frequently utilized indoor-directed interventions present major challenges to global malaria eradication. Many of these residual populations are mosquito species about which little is known. As part of a study to assess the threat of outdoor exposure to malaria mosquitoes within the Southern and Central Africa International Centers of Excellence for Malaria Research, foraging female anophelines were collected outside households in Nchelenge District, northern Zambia. These anophelines proved to be more diverse than had previously been reported in the area. In order to further characterize the anopheline species, sequencing and phylogenetic approaches were utilized. Anopheline mosquitoes were collected from outdoor light traps, morphologically identified, and sent to Johns Hopkins Bloomberg School of Public Health for sequencing. Sanger sequencing from 115 field-derived samples yielded mitochondrial COI sequences, which were aligned with a homologous 488 bp gene segment from known anophelines (n = 140) retrieved from NCBI. Nuclear ITS2 sequences (n = 57) for at least one individual from each unique COI clade were generated and compared against NCBI’s nucleotide BLAST database to provide additional evidence for taxonomical identity and structure. Molecular and morphological data were combined for assignment of species or higher taxonomy. Twelve phylogenetic groups were characterized from the COI and ITS2 sequence data, including the primary vector species Anopheles funestus s.s. and An. gambiae s.s. An unexpectedly large proportion of the field collections were identified as An. coustani and An. sp. 6. Six phylogenetic groups remain unidentified to species-level. Outdoor collections of anopheline mosquitoes in areas frequented by people in Nchelenge, northern Zambia, proved to be extremely diverse. Morphological misidentification and underrepresentation of some anopheline species in sequence databases confound efforts to confirm identity of potential malaria vector species. The large number of unidentified anophelines could compromise the malaria vector surveillance and malaria control efforts not only in northern Zambia but other places where surveillance and control are focused on indoor-foraging and resting anophelines. Therefore, it is critical to continue development of methodologies that allow better identification of these populations and revisiting and cleaning current genomic databases.
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Affiliation(s)
- Christine M. Jones
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Ilinca I. Ciubotariu
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
- Department of Biological Sciences, Purdue University, West Lafayette, IN, United States
| | | | - James Lupiya
- Tropical Diseases Research Centre, Ndola, Zambia
| | - David Mbewe
- Tropical Diseases Research Centre, Ndola, Zambia
| | | | | | - Mary E. Gebhardt
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Giovanna Carpi
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
- Department of Biological Sciences, Purdue University, West Lafayette, IN, United States
| | - Ashley N. Malcolm
- Florida Medical Entomology Laboratory, Department of Entomology and Nematology, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, FL, United States
| | - Kyle J. Kosinski
- Florida Medical Entomology Laboratory, Department of Entomology and Nematology, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, FL, United States
| | - Ana L. Romero-Weaver
- Florida Medical Entomology Laboratory, Department of Entomology and Nematology, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, FL, United States
| | - Jennifer C. Stevenson
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Yoosook Lee
- Florida Medical Entomology Laboratory, Department of Entomology and Nematology, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, FL, United States
- Correspondence: Yoosook Lee, ; Douglas E. Norris,
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15
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Sangoro OP, Fillinger U, Saili K, Nkya TE, Marubu R, Masaninga F, Trigo SC, Tarumbwa C, Hamainza B, Baltazar C, Mberikunashe J, Chisanga B, Menale K, Chanda E, Mutero CM. Evaluating the efficacy, impact, and feasibility of community-based house screening as a complementary malaria control intervention in southern Africa: a study protocol for a household randomized trial. Trials 2021; 22:883. [PMID: 34872600 PMCID: PMC8646012 DOI: 10.1186/s13063-021-05768-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 10/27/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Concerted effort to control malaria has had a substantial impact on the transmission of the disease in the past two decades. In areas where reduced malaria transmission is being sustained through insecticide-based vector control interventions, primarily long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), non-insecticidal complementary tools will likely be needed to push towards malaria elimination. Once interruption in local disease transmission is achieved, insecticide-based measures can be scaled down gradually and eventually phased out, saving on costs of sustaining control programs and mitigating any unintended negative health and environmental impacts posed by insecticides. These non-insecticidal methods could eventually replace insecticidal methods of vector control. House screening, a non-insecticidal method, has a long history in malaria control, but is still not widely adopted in sub-Saharan Africa. This study aims to add to the evidence base for this intervention in low transmission settings by assessing the efficacy, impact, and feasibility of house screening in areas where LLINs are conventionally used for malaria control. METHODS A two-armed, household randomized clinical trial will be conducted in Mozambique, Zambia, and Zimbabwe to evaluate whether combined the use of house screens and LLINs affords better protection against clinical malaria in children between 6 months and 13 years compared to the sole use of LLINs. Eight hundred households will be enrolled in each study area, where 400 households will be randomly assigned the intervention, house screening, and LLINs while the control households will be provided with LLINs only. Clinical malaria incidence will be estimated by actively following up one child from each household for 6 months over the malaria transmission season. Cross-sectional parasite prevalence will be estimated by testing all participating children for malaria parasites at the beginning and end of each transmission season using rapid diagnostic tests. CDC light traps and pyrethrum spray catches (PSC) will be used to sample adult mosquitoes and evaluate the impact of house screening on indoor mosquito density, species distribution, and sporozoite rates. DISCUSSION This study will contribute epidemiological data on the impact of house screening on malaria transmission and assess the feasibility of its implementation on a programmatic scale. TRIAL REGISTRATION ClinicalTrials.gov PACTR202008524310568 . Registered on August 11, 2020.
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Affiliation(s)
- Onyango P Sangoro
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya.
| | - Ulrike Fillinger
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Kochelani Saili
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- School of Health Systems & Public Health, University of Pretoria, Pretoria, South Africa
| | | | - Rose Marubu
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | | | | | | | | | | | | | - Brian Chisanga
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- Department of Social Sciences, Wageningen University and Research, Wageningen, Netherlands
| | - Kassie Menale
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Emmanuel Chanda
- World Health Organization, Regional Office for Africa, Brazzaville, Congo
| | - Clifford Maina Mutero
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- School of Health Systems & Public Health, University of Pretoria, Pretoria, South Africa
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16
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Hoffman JE, Ciubotariu II, Simubali L, Mudenda T, Moss WJ, Carpi G, Norris DE, Stevenson JC. Phylogenetic Complexity of Morphologically Identified Anopheles squamosus in Southern Zambia. INSECTS 2021; 12:146. [PMID: 33567609 PMCID: PMC7915044 DOI: 10.3390/insects12020146] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 11/16/2022]
Abstract
Despite dramatic reductions in malaria cases in the catchment area of Macha Hospital, Choma District, Southern Province in Zambia, prevalence has remained near 1-2% by RDT for the past several years. To investigate residual malaria transmission in the area, this study focuses on the relative abundance, foraging behavior, and phylogenetic relationships of Anopheles squamosus specimens. In 2011, higher than expected rates of anthropophily were observed among "zoophilic" An. squamosus, a species that had sporadically been found to contain Plasmodium falciparum sporozoites. The importance of An. squamosus in the region was reaffirmed in 2016 when P. falciparum sporozoites were detected in numerous An. squamosus specimens. This study analyzed Centers for Disease Control (CDC) light trap collections of adult mosquitoes from two collection schemes: one performed as part of a reactive-test-and-treat program and the second performed along a geographical transect. Morphological identification, molecular verification of anopheline species, and blood meal source were determined on individual samples. Data from these collections supported earlier studies demonstrating An. squamosus to be primarily exophagic and zoophilic, allowing them to evade current control measures. The phylogenetic relationships generated from the specimens in this study illustrate the existence of well supported clade structure among An. squamosus specimens, which further emphasizes the importance of molecular identification of vectors. The primarily exophagic behavior of An. squamosus in these collections also highlights that indoor vector control strategies will not be sufficient for elimination of malaria in southern Zambia.
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Affiliation(s)
- Jordan E. Hoffman
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA;
| | - Ilinca I. Ciubotariu
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA; (I.I.C.); (G.C.)
| | | | - Twig Mudenda
- Macha Research Trust, Choma, Zambia; (L.S.); (T.M.); (J.C.S.)
| | - William J. Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA;
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Giovanna Carpi
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA; (I.I.C.); (G.C.)
| | - Douglas E. Norris
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Jennifer C. Stevenson
- Macha Research Trust, Choma, Zambia; (L.S.); (T.M.); (J.C.S.)
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
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17
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Finney M, McKenzie BA, Rabaovola B, Sutcliffe A, Dotson E, Zohdy S. Widespread zoophagy and detection of Plasmodium spp. in Anopheles mosquitoes in southeastern Madagascar. Malar J 2021; 20:25. [PMID: 33413398 PMCID: PMC7791646 DOI: 10.1186/s12936-020-03539-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 12/07/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria is a top cause of mortality on the island nation of Madagascar, where many rural communities rely on subsistence agriculture and livestock production. Understanding feeding behaviours of Anopheles in this landscape is crucial for optimizing malaria control and prevention strategies. Previous studies in southeastern Madagascar have shown that Anopheles mosquitoes are more frequently captured within 50 m of livestock. However, it remains unknown whether these mosquitoes preferentially feed on livestock. Here, mosquito blood meal sources and Plasmodium sporozoite rates were determined to evaluate patterns of feeding behaviour in Anopheles spp. and malaria transmission in southeastern Madagascar. METHODS Across a habitat gradient in southeastern Madagascar 7762 female Anopheles spp. mosquitoes were collected. Of the captured mosquitoes, 492 were visibly blood fed and morphologically identifiable, and a direct enzyme-linked immunosorbent assay (ELISA) was used to test for swine, cattle, chicken, human, and dog blood among these specimens. Host species identification was confirmed for multiple blood meals using PCR along with Sanger sequencing. Additionally, 1,607 Anopheles spp. were screened for the presence of Plasmodium falciparum, P. vivax-210, and P. vivax 247 circumsporozoites (cs) by ELISA. RESULTS Cattle and swine accounted, respectively, for 51% and 41% of all blood meals, with the remaining 8% split between domesticated animals and humans. Of the 1,607 Anopheles spp. screened for Plasmodium falciparum, Plasmodium vivax 210, and Plasmodium vivax 247 cs-protein, 45 tested positive, the most prevalent being P. vivax 247, followed by P. vivax 210 and P. falciparum. Both variants of P. vivax were observed in secondary vectors, including Anopheles squamosus/cydippis, Anopheles coustani, and unknown Anopheles spp. Furthermore, evidence of coinfection of P. falciparum and P. vivax 210 in Anopheles gambiae sensu lato (s.l.) was found. CONCLUSIONS Here, feeding behaviour of Anopheles spp. mosquitoes in southeastern Madagascar was evaluated, in a livestock rich landscape. These findings suggest largely zoophagic feeding behaviors of Anopheles spp., including An. gambiae s.l. and presence of both P. vivax and P. falciparum sporozoites in Anopheles spp. A discordance between P. vivax reports in mosquitoes and humans exists, suggesting high prevalence of P. vivax circulating in vectors in the ecosystem despite low reports of clinical vivax malaria in humans in Madagascar. Vector surveillance of P. vivax may be relevant to malaria control and elimination efforts in Madagascar. At present, the high proportion of livestock blood meals in Madagascar may play a role in buffering (zooprophylaxis) or amplifying (zoopotentiation) the impacts of malaria. With malaria vector control efforts focused on indoor feeding behaviours, complementary approaches, such as endectocide-aided vector control in livestock may be an effective strategy for malaria reduction in Madagascar.
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Affiliation(s)
- Micaela Finney
- College of Science and Mathematics, Auburn University, Auburn, AL, USA
| | - Benjamin A McKenzie
- School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL, USA
| | | | - Alice Sutcliffe
- Division of Parasitic Diseases and Malaria, Entomology Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Ellen Dotson
- Division of Parasitic Diseases and Malaria, Entomology Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Sarah Zohdy
- School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL, USA. .,College of Veterinary Medicine, Auburn University, Auburn, AL, USA.
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18
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Host feeding patterns of Nyssorhynchus darlingi (Diptera: Culicidae) in the Brazilian Amazon. Acta Trop 2021; 213:105751. [PMID: 33166514 DOI: 10.1016/j.actatropica.2020.105751] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 10/31/2020] [Indexed: 12/12/2022]
Abstract
Nyssorhynchus darlingi (Root) is the dominant malaria vector in the Brazilian Amazon River basin, with additional Anophelinae Grassi species involved in local and regional transmission. Mosquito blood-feeding behavior is an essential component to define the mosquito-human contact rate and shape the transmission cycle of vector-borne diseases. However, there is little information on the host preferences and blood-feeding behavior of Anophelinae vectors in rural Amazonian landscapes. The barrier screen sampling (BSS) method was employed to sample females from 34 peridomestic habitats in 27 rural communities from 11 municipalities in the Brazilian Amazon states of Acre, Amazonas, Pará and Rondônia, from August 2015 to November 2017. Nyssorhynchus darlingi comprised 97.94% of the females collected resting on barrier screens, and DNA sequence comparison detected 9 vertebrate hosts species. The HBI index ranged from 0.03-1.00. Results revealed the plasticity of Ny. darlingi in blood-feeding on a wide range of mainly mammalian hosts. In addition, the identification of blood meal sources using silica-dried females is appropriate for studies of human malaria vectors in remote locations.
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19
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Ciubotariu II, Jones CM, Kobayashi T, Bobanga T, Muleba M, Pringle JC, Stevenson JC, Carpi G, Norris DE. Genetic Diversity of Anopheles coustani (Diptera: Culicidae) in Malaria Transmission Foci in Southern and Central Africa. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:1782-1792. [PMID: 32614047 PMCID: PMC7899271 DOI: 10.1093/jme/tjaa132] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Indexed: 05/04/2023]
Abstract
Despite ongoing malaria control efforts implemented throughout sub-Saharan Africa, malaria remains an enormous public health concern. Current interventions such as indoor residual spraying with insecticides and use of insecticide-treated bed nets are aimed at targeting the key malaria vectors that are primarily endophagic and endophilic. Anopheles coustani s.l., an understudied vector of malaria, is a species previously thought to exhibit mostly zoophilic behavior. Like many of these understudied species, An. coustani has greater anthropophilic tendencies than previously appreciated, is often both endophagic and exophagic, and carries Plasmodium falciparum sporozoites. The aim of this study was to explore genetic variation of An. coustani mosquitoes and the potential of this species to contribute to malaria parasite transmission in high transmission settings in Zambia and the Democratic Republic of the Congo (DRC). Morphologically identified An. coustani specimens that were trapped outdoors in these study sites were analyzed by PCR and sequencing for species identification and bloodmeal sources, and malaria parasite infection was determined by ELISA and qPCR. Fifty An. coustani s.s. specimens were confirmed by analysis of mitochondrial DNA cytochrome c oxidase subunit I (COI) and ribosomal internal transcribed spacer region 2 (ITS2). Maximum likelihood phylogenetic analysis of COI and ITS2 sequences revealed two distinct phylogenetic groups within this relatively small regional collection. Our findings indicate that both An. coustani groups have anthropophilic and exophagic habits and come into frequent contact with P. falciparum, suggesting that this potential alternative malaria vector might elude current vector control measures in northern Zambia and southern DRC.
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Affiliation(s)
- Ilinca I Ciubotariu
- The Department of Biological Sciences, Purdue University, West Lafayette, IN
| | - Christine M Jones
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Tamaki Kobayashi
- The Department of Epidemiology, Division of Infectious Disease Epidemiology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Thierry Bobanga
- The Department of Family Medicine, School of Medicine, Université Protestante au Congo, Kinshasa, Democratic Republic of Congo
- The Department of Tropical Medicine, School of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | | | - Julia C Pringle
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Jennifer C Stevenson
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
- Macha Research Trust, Choma, Zambia
| | - Giovanna Carpi
- The Department of Biological Sciences, Purdue University, West Lafayette, IN
| | - Douglas E Norris
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
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20
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Bango ZA, Tawe L, Muthoga CW, Paganotti GM. Past and current biological factors affecting malaria in the low transmission setting of Botswana: A review. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2020; 85:104458. [PMID: 32668367 PMCID: PMC7354381 DOI: 10.1016/j.meegid.2020.104458] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 07/06/2020] [Accepted: 07/08/2020] [Indexed: 11/29/2022]
Abstract
Malaria continues to be one of the top infectious agents contributing to morbidity and mortality in sub-Saharan Africa. Annually, Botswana accounts only for a small proportion of cases (<<1%). Despite significantly reduced incidence rate, the country still experiences sporadic outbreaks that hamper the goal of malaria elimination. This review evaluated previous and current biological factors that impact malaria in Botswana, specifically focussing on the vectors, the parasite and the host. This was accomplished via a literature review evaluating these variables in Botswana. Current literature suggests that Anopheles arabiensis is the main malaria vector in the country. Several other potential vectors have been found widely distributed throughout Botswana in high numbers, yet remain largely unstudied with regards to their contribution to the country's malaria burden. We also report the most up to date list of all Anopheles species that have been found in Botswana. Plasmodium falciparum is responsible for the vast majority of symptomatic malaria in the country and some drug resistance markers have been documented for this species. Plasmodium vivax has been reported in asymptomatic subjects, even though a large proportion of the Botswana population appears to be Duffy antigen negative. Very little is known about the true distribution of P. vivax and no point of care testing infrastructure for this species exists in Botswana, making it difficult to tailor treatment to address possible recrudescence or relapse. Due to a genetically diverse population with a substantial Khoisan contribution into the Bantu genetic background, several phenotypes that potentially impact prevalence and severity of malaria exist within the country. These include sickle cell trait, Glucose-6-Phosphate Dehydrogenase deficiency, and Duffy negativity. This review highlights the information that currently exists on malaria in Botswana. It also postulates that a comprehensive understanding of these aforementioned biological factors may help to explain malaria persistence in Botswana.
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Affiliation(s)
| | - Leabaneng Tawe
- Botswana-University of Pennsylvania Partnership, Gaborone, Botswana; Department of Medical Laboratory Sciences, Faculty of Health Sciences, University of Botswana, Gaborone, Botswana
| | | | - Giacomo Maria Paganotti
- Botswana-University of Pennsylvania Partnership, Gaborone, Botswana; Division of Infectious Diseases, Perelman School of Medicine, University of Pennsylvania, PA, USA; Department of Biomedical Sciences, University of Botswana, Gaborone, Botswana.
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21
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Hamid-Adiamoh M, Amambua-Ngwa A, Nwakanma D, D'Alessandro U, Awandare GA, Afrane YA. Insecticide resistance in indoor and outdoor-resting Anopheles gambiae in Northern Ghana. Malar J 2020; 19:314. [PMID: 32867769 PMCID: PMC7460795 DOI: 10.1186/s12936-020-03388-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 08/25/2020] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Selection pressure from continued exposure to insecticides drives development of insecticide resistance and changes in resting behaviour of malaria vectors. There is need to understand how resistance drives changes in resting behaviour within vector species. The association between insecticide resistance and resting behaviour of Anopheles gambiae sensu lato (s.l.) in Northern Ghana was examined. METHODS F1 progenies from adult mosquitoes collected indoors and outdoors were exposed to DDT, deltamethrin, malathion and bendiocarb using WHO insecticide susceptibility tests. Insecticide resistance markers including voltage-gated sodium channel (Vgsc)-1014F, Vgsc-1014S, Vgsc-1575Y, glutathione-S-transferase epsilon 2 (GSTe2)-114T and acetylcholinesterase (Ace1)-119S, as well as blood meal sources were investigated using PCR methods. Activities of metabolic enzymes, acetylcholine esterase (AChE), non-specific β-esterases, glutathione-S-transferase (GST) and monooxygenases were measured from unexposed F1 progenies using microplate assays. RESULTS Susceptibility of Anopheles coluzzii to deltamethrin 24 h post-exposure was significantly higher in indoor (mortality = 5%) than outdoor (mortality = 2.5%) populations (P = 0.02). Mosquitoes were fully susceptible to malathion (mortality: indoor = 98%, outdoor = 100%). Susceptibility to DDT was significantly higher in outdoor (mortality = 9%) than indoor (mortality = 0%) mosquitoes (P = 0.006). Mosquitoes were also found with suspected resistance to bendiocarb but mortality was not statistically different (mortality: indoor = 90%, outdoor = 95%. P = 0.30). Frequencies of all resistance alleles were higher in F1 outdoor (0.11-0.85) than indoor (0.04-0.65) mosquito populations, while Vgsc-1014F in F0 An. gambiae sensu stricto (s.s) was significantly associated with outdoor-resting behaviour (P = 0.01). Activities of non-specific β-esterase enzymes were significantly higher in outdoor than indoor mosquitoes (Mean enzyme activity: Outdoor = : 1.70/mg protein; Indoor = 1.35/mg protein. P < 0.0001). AChE activity was also more elevated in outdoor (0.62/mg protein) than indoor (0.57/mg protein) mosquitoes but this was not significant (P = 0.08). Human blood index (HBI) was predominantly detected in indoor (18%) than outdoor mosquito populations (3%). CONCLUSIONS The overall results did not establish that there was a significant preference of resistant malaria vectors to solely rest indoors or outdoors, but varied depending on the resistant alleles present. Phenotypic resistance was higher in indoor than outdoor-resting mosquitoes, but genotypic and metabolic resistance levels were higher in outdoor than the indoor populations. Continued monitoring of changes in resting behaviour within An. gambiae s.l. populations is recommended.
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Affiliation(s)
- Majidah Hamid-Adiamoh
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP) and Department of Biochemistry, Cell and Molecular, University of Ghana, Legon, Ghana
- Medical Research Council Unit, The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Alfred Amambua-Ngwa
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP) and Department of Biochemistry, Cell and Molecular, University of Ghana, Legon, Ghana
- Medical Research Council Unit, The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Davis Nwakanma
- Medical Research Council Unit, The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Umberto D'Alessandro
- Medical Research Council Unit, The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP) and Department of Biochemistry, Cell and Molecular, University of Ghana, Legon, Ghana
| | - Yaw A Afrane
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP) and Department of Biochemistry, Cell and Molecular, University of Ghana, Legon, Ghana.
- Department of Medical Microbiology, College of Health Sciences, University of Ghana, Legon, Accra, Ghana.
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22
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Goupeyou-Youmsi J, Rakotondranaivo T, Puchot N, Peterson I, Girod R, Vigan-Womas I, Paul R, Ndiath MO, Bourgouin C. Differential contribution of Anopheles coustani and Anopheles arabiensis to the transmission of Plasmodium falciparum and Plasmodium vivax in two neighbouring villages of Madagascar. Parasit Vectors 2020; 13:430. [PMID: 32843082 PMCID: PMC7447585 DOI: 10.1186/s13071-020-04282-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 08/03/2020] [Indexed: 02/01/2023] Open
Abstract
Background Malaria is still a heavy public health concern in Madagascar. Few studies combining parasitology and entomology have been conducted despite the need for accurate information to design effective vector control measures. In a Malagasy region of moderate to intense transmission of both Plasmodium falciparum and P. vivax, parasitology and entomology have been combined to survey malaria transmission in two nearby villages. Methods Community-based surveys were conducted in the villages of Ambohitromby and Miarinarivo at three time points (T1, T2 and T3) during a single malaria transmission season. Human malaria prevalence was determined by rapid diagnostic tests (RDTs), microscopy and real-time PCR. Mosquitoes were collected by human landing catches and pyrethrum spray catches and the presence of Plasmodium sporozoites was assessed by TaqMan assay. Results Malaria prevalence was not significantly different between villages, with an average of 8.0% by RDT, 4.8% by microscopy and 11.9% by PCR. This was mainly due to P. falciparum and to a lesser extent to P. vivax. However, there was a significantly higher prevalence rate as determined by PCR at T2 (\documentclass[12pt]{minimal}
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\begin{document}$$\chi_{2}^{2}$$\end{document}χ22 = 7.46, P = 0.025). Likewise, mosquitoes were significantly more abundant at T2 (\documentclass[12pt]{minimal}
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\begin{document}$$\chi_{2}^{2}$$\end{document}χ22 = 64.8, P < 0.001), especially in Ambohitromby. At T1 and T3 mosquito abundance was higher in Miarinarivo than in Ambohitromby (\documentclass[12pt]{minimal}
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\begin{document}$$\chi_{2}^{2}$$\end{document}χ22 = 14.92, P < 0.001). Of 1550 Anopheles mosquitoes tested, 28 (1.8%) were found carrying Plasmodium sporozoites. The entomological inoculation rate revealed that Anopheles coustani played a major contribution in malaria transmission in Miarinarivo, being responsible of 61.2 infective bites per human (ib/h) during the whole six months of the survey, whereas, it was An. arabiensis, with 36 ib/h, that played that role in Ambohitromby. Conclusions Despite a similar malaria prevalence in two nearby villages, the entomological survey showed a different contribution of An. coustani and An. arabiensis to malaria transmission in each village. Importantly, the suspected secondary malaria vector An. coustani, was found playing the major role in malaria transmission in one village. This highlights the importance of combining parasitology and entomology surveys for better targeting local malaria vectors. Such study should contribute to the malaria pre-elimination goal established under the 2018–2022 National Malaria Strategic Plan. ![]()
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Affiliation(s)
- Jessy Goupeyou-Youmsi
- Immunology of Infectious Diseases Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar. .,Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France. .,Doctoral School "Complexité du Vivant", Sorbonne University, Paris, France.
| | - Tsiriniaina Rakotondranaivo
- G4 Malaria Group, Institut Pasteur de Madagascar, Antananarivo, Madagascar.,Doctoral School "Génie du vivant et modélisation" Mahajanga University, Mahajanga, Madagascar
| | - Nicolas Puchot
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique UMR2000, Institut Pasteur, Paris, France
| | - Ingrid Peterson
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Romain Girod
- Medical Entomology Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Inès Vigan-Womas
- Immunology of Infectious Diseases Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Richard Paul
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique UMR2000, Institut Pasteur, Paris, France
| | | | - Catherine Bourgouin
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France. .,Centre National de la Recherche Scientifique UMR2000, Institut Pasteur, Paris, France.
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23
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Goupeyou-Youmsi J, Rakotondranaivo T, Puchot N, Peterson I, Girod R, Vigan-Womas I, Paul R, Ndiath MO, Bourgouin C. Differential contribution of Anopheles coustani and Anopheles arabiensis to the transmission of Plasmodium falciparum and Plasmodium vivax in two neighbouring villages of Madagascar. Parasit Vectors 2020; 13:430. [PMID: 32843082 DOI: 10.1101/787432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 08/03/2020] [Indexed: 05/21/2023] Open
Abstract
BACKGROUND Malaria is still a heavy public health concern in Madagascar. Few studies combining parasitology and entomology have been conducted despite the need for accurate information to design effective vector control measures. In a Malagasy region of moderate to intense transmission of both Plasmodium falciparum and P. vivax, parasitology and entomology have been combined to survey malaria transmission in two nearby villages. METHODS Community-based surveys were conducted in the villages of Ambohitromby and Miarinarivo at three time points (T1, T2 and T3) during a single malaria transmission season. Human malaria prevalence was determined by rapid diagnostic tests (RDTs), microscopy and real-time PCR. Mosquitoes were collected by human landing catches and pyrethrum spray catches and the presence of Plasmodium sporozoites was assessed by TaqMan assay. RESULTS Malaria prevalence was not significantly different between villages, with an average of 8.0% by RDT, 4.8% by microscopy and 11.9% by PCR. This was mainly due to P. falciparum and to a lesser extent to P. vivax. However, there was a significantly higher prevalence rate as determined by PCR at T2 ([Formula: see text] = 7.46, P = 0.025). Likewise, mosquitoes were significantly more abundant at T2 ([Formula: see text] = 64.8, P < 0.001), especially in Ambohitromby. At T1 and T3 mosquito abundance was higher in Miarinarivo than in Ambohitromby ([Formula: see text] = 14.92, P < 0.001). Of 1550 Anopheles mosquitoes tested, 28 (1.8%) were found carrying Plasmodium sporozoites. The entomological inoculation rate revealed that Anopheles coustani played a major contribution in malaria transmission in Miarinarivo, being responsible of 61.2 infective bites per human (ib/h) during the whole six months of the survey, whereas, it was An. arabiensis, with 36 ib/h, that played that role in Ambohitromby. CONCLUSIONS Despite a similar malaria prevalence in two nearby villages, the entomological survey showed a different contribution of An. coustani and An. arabiensis to malaria transmission in each village. Importantly, the suspected secondary malaria vector An. coustani, was found playing the major role in malaria transmission in one village. This highlights the importance of combining parasitology and entomology surveys for better targeting local malaria vectors. Such study should contribute to the malaria pre-elimination goal established under the 2018-2022 National Malaria Strategic Plan.
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Affiliation(s)
- Jessy Goupeyou-Youmsi
- Immunology of Infectious Diseases Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar.
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France.
- Doctoral School "Complexité du Vivant", Sorbonne University, Paris, France.
| | - Tsiriniaina Rakotondranaivo
- G4 Malaria Group, Institut Pasteur de Madagascar, Antananarivo, Madagascar
- Doctoral School "Génie du vivant et modélisation" Mahajanga University, Mahajanga, Madagascar
| | - Nicolas Puchot
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France
- Centre National de la Recherche Scientifique UMR2000, Institut Pasteur, Paris, France
| | - Ingrid Peterson
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Romain Girod
- Medical Entomology Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Inès Vigan-Womas
- Immunology of Infectious Diseases Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Richard Paul
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France
- Centre National de la Recherche Scientifique UMR2000, Institut Pasteur, Paris, France
| | | | - Catherine Bourgouin
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France.
- Centre National de la Recherche Scientifique UMR2000, Institut Pasteur, Paris, France.
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Tedrow RE, Rakotomanga T, Nepomichene T, Howes RE, Ratovonjato J, Ratsimbasoa AC, Svenson GJ, Zimmerman PA. Anopheles mosquito surveillance in Madagascar reveals multiple blood feeding behavior and Plasmodium infection. PLoS Negl Trop Dis 2019; 13:e0007176. [PMID: 31276491 PMCID: PMC6663035 DOI: 10.1371/journal.pntd.0007176] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 07/29/2019] [Accepted: 05/13/2019] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND The Madagascar National Strategic Plan for Malaria Control 2018 (NSP) outlines malaria control pre-elimination strategies that include detailed goals for mosquito control. Primary surveillance protocols and mosquito control interventions focus on indoor vectors of malaria, while many potential vectors feed and rest outdoors. Here we describe the application of tools that advance our understanding of diversity, host choice, and Plasmodium infection in the Anopheline mosquitoes of the Western Highland Fringe of Madagascar. METHODOLOGY/PRINCIPAL FINDINGS We employed a modified barrier screen trap, the QUadrant Enabled Screen Trap (QUEST), in conjunction with the recently developed multiplex BLOOdmeal Detection Assay for Regional Transmission (BLOODART). We captured a total of 1252 female Anopheles mosquitoes (10 species), all of which were subjected to BLOODART analysis. QUEST collection captured a heterogenous distribution of mosquito density, diversity, host choice, and Plasmodium infection. Concordance between Anopheles morphology and BLOODART species identifications ranged from 93-99%. Mosquito feeding behavior in this collection frequently exhibited multiple blood meal hosts (single host = 53.6%, two hosts = 42.1%, three hosts = 4.3%). The overall percentage of human positive bloodmeals increased between the December 2017 and the April 2018 timepoints (27% to 44%). Plasmodium positivity was frequently observed in the abdomens of vectors considered to be of secondary importance, with an overall prevalence of 6%. CONCLUSIONS/SIGNIFICANCE The QUEST was an efficient tool for sampling exophilic Anopheline mosquitoes. Vectors considered to be of secondary importance were commonly found with Plasmodium DNA in their abdomens, indicating a need to account for these species in routine surveillance efforts. Mosquitoes exhibited multiple blood feeding behavior within a gonotrophic cycle, with predominantly non-human hosts in the bloodmeal. Taken together, this complex feeding behavior could enhance the role of multiple Anopheline species in malaria transmission, possibly tempered by zoophilic feeding tendencies.
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Affiliation(s)
- Riley E. Tedrow
- The Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Tovonahary Rakotomanga
- Direction de Lutte contre le Paludisme/National Malaria Control Program Madagascar, Ministry of Health, Antananarivo, Madagascar
| | - Thiery Nepomichene
- Unité d’Entomologie Médicale, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Rosalind E. Howes
- The Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Jocelyn Ratovonjato
- Direction de Lutte contre le Paludisme/National Malaria Control Program Madagascar, Ministry of Health, Antananarivo, Madagascar
| | - Arséne C. Ratsimbasoa
- Direction de Lutte contre le Paludisme/National Malaria Control Program Madagascar, Ministry of Health, Antananarivo, Madagascar
- Faculty of Medicine & Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar
| | - Gavin J. Svenson
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Invertebrate Zoology, Cleveland Museum of Natural History, Cleveland, Ohio, United States of America
| | - Peter A. Zimmerman
- The Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
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25
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Stevenson JC, Simubali L, Mudenda T, Cardol E, Bernier UR, Vazquez AA, Thuma PE, Norris DE, Perry M, Kline DL, Cohnstaedt LW, Gurman P, D'hers S, Elman NM. Controlled release spatial repellent devices (CRDs) as novel tools against malaria transmission: a semi-field study in Macha, Zambia. Malar J 2018; 17:437. [PMID: 30477502 PMCID: PMC6258499 DOI: 10.1186/s12936-018-2558-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 10/30/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The emergence of mosquitoes that can avoid indoor-deployed interventions, such as treated bed nets and indoor residual spraying, threatens the mainstay of malaria control in Zambia. Furthermore, the requirement for high coverage of these tools poses operational challenges. Spatial repellents are being assessed to supplement these vector control tools, but limitations exist in the residual effect of the repellent and the need for external power or heat for diffusion of the volatiles. METHODS A semi-field evaluation of a novel controlled release spatial repellent device (CRD) was conducted in Macha, Zambia. These devices emanate metofluthrin with no need for external power. Devices were deployed in huts within the semi-field system (SFS). Female Anopheles gambiae sensu stricto released within the SFS were trapped overnight by light traps and collected by aspiration the next morning inside and outside of huts to determine the extent of mosquito repellency and the impact on host-seeking and survival. Experiments studied the impact of number of devices as well as the presence of hut occupants. The study was complemented with numerical methods based on computational fluid dynamics to simulate spatial distribution of metofluthrin. RESULTS Presence of CRDs was associated with significant reductions in indoor counts of mosquitoes, regardless of whether huts were occupied or not. Repellency ranged from 15 to 60% compared to huts with no devices. Reducing the number of devices from 16 to 4 had little impact on repellency. When huts were occupied, indoor mosquito host-seeking was higher in the presence of CRDs, whilst survival was significantly reduced. CONCLUSIONS This study demonstrated that deployment of as few as four CRDs within a hut was associated with reduced indoor mosquito densities. As would be expected, presence of occupants within huts, resulted in greater indoor catches (both with and without devices). The increased indoor mosquito host-seeking and mortality in huts when devices were present may be explained by the excito-repellency activity of metofluthrin. These semi-field experiments provide preliminary data on the utility of CRD spatial repellents to reduce indoor densities of An. gambiae mosquitoes. Studies will further investigate the impact of CRDs on mosquito behaviour as well as epidemiological protective efficacy.
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Affiliation(s)
- Jennifer C Stevenson
- Macha Research Trust, P.O. Box 630166, Choma, Zambia. .,The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD, 21205, USA.
| | | | - Twig Mudenda
- Macha Research Trust, P.O. Box 630166, Choma, Zambia
| | - Esther Cardol
- Radboud University Nijmegen, Comeniuslaan 4, 6525 HP, Nijmegen, Netherlands
| | - Ulrich R Bernier
- United States Department of Agriculture-Agricultural Research Service, Center for Medical, Agricultural, and Veterinary Entomology, 1600 SW 23rd Drive, Gainesville, FL, 32608, USA
| | - Agustin Abad Vazquez
- Instituto Tecnológico de Buenos Aires (ITBA), Av. Madero 399, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Philip E Thuma
- Macha Research Trust, P.O. Box 630166, Choma, Zambia.,The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD, 21205, USA
| | - Douglas E Norris
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD, 21205, USA
| | - Melynda Perry
- Textile Materials Evaluation Team, The US Army Natick Soldier Research and Development Engineering Center (NSRDEC), Natick, MA, USA
| | - Daniel L Kline
- United States Department of Agriculture-Agricultural Research Service, Center for Medical, Agricultural, and Veterinary Entomology, 1600 SW 23rd Drive, Gainesville, FL, 32608, USA
| | - Lee W Cohnstaedt
- United States Department of Agriculture-Agricultural Research Service, The Arthropod-Borne, Animal Diseases Research Unit (ABADRU), Manhattan, KS, USA
| | - Pablo Gurman
- GearJump Technologies, LLC, P.O. Box 1600, Boston, MA, 02446, USA
| | - Sebastian D'hers
- Instituto Tecnológico de Buenos Aires (ITBA), Av. Madero 399, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Noel M Elman
- GearJump Technologies, LLC, P.O. Box 1600, Boston, MA, 02446, USA.
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26
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McCann RS, Gimnig JE, Bayoh MN, Ombok M, Walker ED. Microdam Impoundments Provide Suitable Habitat for Larvae of Malaria Vectors: An Observational Study in Western Kenya. JOURNAL OF MEDICAL ENTOMOLOGY 2018; 55:723-730. [PMID: 29462354 PMCID: PMC7296561 DOI: 10.1093/jme/tjy007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Indexed: 06/08/2023]
Abstract
Impoundments formed by microdams in rural areas of Africa are important sources of water for people, but they provide potential larval habitats for Anopheles (Diptera: Culicidae) mosquitoes that are vectors of malaria. To study this association, the perimeters of 31 microdam impoundments in western Kenya were sampled for Anopheles larvae in three zones (patches of floating and emergent vegetation, shorelines of open water, and aggregations of cattle hoofprints) across dry and rainy seasons. Of 3,169 larvae collected, most (86.8%) were collected in the rainy season. Of 2,403 larvae successfully reared to fourth instar or adult, nine species were identified; most (80.2%) were Anopheles arabiensis Patton, sampled from hoofprint zones in the rainy season. Other species collected were Anopheles coustani Laveran, Anopheles gambiae s.s. Giles, Anopheles funestus Giles, and Anopheles rivulorum Leeson, Anopheles pharoensis Theobald, Anopheles squamosus Theobald, Anopheles rufipes (Gough), and Anopheles ardensis (Theobald). Larvae of An. funestus were uncommon (1.5%) in both dry and rainy seasons and were confined to vegetated zones, suggesting that microdam impoundments are not primary habitats for this important vector species, although microdams may provide a dry season refuge habitat for malaria vectors, contributing to population persistence through the dry season. In this study, microdam impoundments clearly provided habitat for the malaria vector An. arabiensis in the rainy season, most of which was within the shallow apron side of the impoundments where people brought cattle for watering, resulting in compacted soil with aggregations of water-filled hoofprints. This observation suggests a potential conflict between public health concerns about malaria and people's need for stable and reliable sources of water.
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Affiliation(s)
- Robert S. McCann
- Department of Entomology, Michigan State University, East
Lansing, MI
- Current address: Laboratory of Entomology Wageningen,
University and Research Centre, PO Box 8031 6700 EH Wageningen, The
Netherlands
| | - John E. Gimnig
- Division of Parasitic Diseases and Malaria, Centers for
Disease Control and Prevention, Atlanta, Georgia
| | - M. Nabie Bayoh
- Centre for Global Health Research, Kenya Medical Research
Institute/Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Maurice Ombok
- Centre for Global Health Research, Kenya Medical Research
Institute/Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Edward D. Walker
- Department of Entomology, Michigan State University, East
Lansing, MI
- Department of Microbiology and Molecular Genetics, Michigan
State University, East Lansing, MI
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27
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Nashun B, You J, Ji M, Zhao S, Qin L, Chen X. Granuloma formation in the liver is relatively delayed, although sustained, in BCG‑infected mice co‑infected with Plasmodium. Mol Med Rep 2018; 17:7764-7768. [PMID: 29620231 DOI: 10.3892/mmr.2018.8836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 11/02/2017] [Indexed: 11/05/2022] Open
Abstract
The purpose of the present study was to examine the effects of Plasmodium on the process of granuloma formation in Bacille Calmette‑Guerin (BCG)‑infected mice. Female six‑week‑old BALB/c mice were co‑infected with BCG and Plasmodium. The liver index, pathological alterations and quantity of granulomas in the mice were observed when the mice were co‑injected with BCG and Plasmodium. The expression of inducible nitric oxide synthase (iNOS) was assessed by immunohistochemistry and reverse transcription‑polymerase chain reaction (RT‑PCR) analysis. In addition, the expression of interleukin (IL)‑10 in liver tissues was observed by RT‑PCR. Following co‑infection with BCG and Plasmodium, the swelling of the liver had been slowly restored to normal, and the time required to allow granulomas to subside had prolonged. In addition, the expression of iNOS increased, while the expression of IL‑10 gradually decreased in Plasmodium‑infected mice. It was concluded that the use of Plasmodium relatively delayed granuloma formation in livers of BCG‑infected mice. In addition, iNOS and IL‑10 are involved in this pathogenesis.
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Affiliation(s)
- Bayaer Nashun
- Laboratory Animal Center, Guangdong Medical University, Dongguan, Guangdong 523808, P.R. China
| | - Jianlan You
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong 510530, P.R. China
| | - Musi Ji
- Department of Internal Medicine, Liaobu Hospital, Dongguan, Guangdong 523400, P.R. China
| | - Siting Zhao
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong 510530, P.R. China
| | - Li Qin
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong 510530, P.R. China
| | - Xiaoping Chen
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong 510530, P.R. China
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28
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Erlank E, Koekemoer LL, Coetzee M. The importance of morphological identification of African anopheline mosquitoes (Diptera: Culicidae) for malaria control programmes. Malar J 2018; 17:43. [PMID: 29357873 PMCID: PMC5778787 DOI: 10.1186/s12936-018-2189-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 01/15/2018] [Indexed: 01/03/2023] Open
Abstract
Background The correct identification of disease vectors is the first step towards implementing an effective control programme. Traditionally, for malaria control, this was based on the morphological differences observed in the adults and larvae between different mosquito species. However, the discovery of species complexes meant that genetic tools were needed to separate the sibling species and today there are standard molecular techniques that are used to identify the two major malaria vector groups of mosquitoes. On the assumption that species-diagnostic DNA polymerase chain reaction (PCR) assays are highly species-specific, experiments were conducted to investigate what would happen if non-vector species were randomly included in the molecular assays. Methods Morphological keys for the Afrotropical Anophelinae were used to provide the a priori identifications. All mosquito specimens were then subjected to the standard PCR assays for members of the Anopheles gambiae complex and Anopheles funestus group. Results One hundred and fifty mosquitoes belonging to 11 morphological species were processed. Three species (Anopheles pretoriensis, Anopheles rufipes and Anopheles rhodesiensis) amplified members of the An. funestus group and four species (An. pretoriensis, An. rufipes, Anopheles listeri and Anopheles squamosus) amplified members of the An. gambiae complex. Conclusions Morphological identification of mosquitoes prior to PCR assays not only saves time and money in the laboratory, but also ensures that data received by malaria vector control programmes are useful for targeting the major vectors.
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Affiliation(s)
- Erica Erlank
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multidisciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Lizette L Koekemoer
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multidisciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Maureen Coetzee
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multidisciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. .,Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa.
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29
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Degefa T, Yewhalaw D, Zhou G, Lee MC, Atieli H, Githeko AK, Yan G. Indoor and outdoor malaria vector surveillance in western Kenya: implications for better understanding of residual transmission. Malar J 2017; 16:443. [PMID: 29110670 PMCID: PMC5674686 DOI: 10.1186/s12936-017-2098-z] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/28/2017] [Indexed: 11/10/2022] Open
Abstract
Background The widespread use of indoor-based malaria vector control interventions has been shown to alter the behaviour of vectors in Africa. There is an increasing concern that such changes could sustain residual transmission. This study was conducted to assess vector species composition, feeding behaviour and their contribution to indoor and outdoor malaria transmission in western Kenya. Methods Anopheles mosquito collections were carried out from September 2015 to April 2016 in Ahero and Iguhu sites, western Kenya using CDC light traps (indoor and outdoor), pyrethrum spray catches (PSCs) (indoor) and pit shelters (outdoor). Species within Anopheles gambiae s.l. and Anopheles funestus s.l. were identified using polymerase chain reaction (PCR). Enzyme-linked immunosorbent assay (ELISA) was used to determine mosquito blood meal sources and sporozoite infections. Results A total of 10,864 female Anopheles mosquitoes comprising An. gambiae s.l. (71.4%), An. funestus s.l. (12.3%), Anopheles coustani (9.2%) and Anopheles pharoensis (7.1%) were collected. The majority (61.8%) of the anopheline mosquitoes were collected outdoors. PCR result (n = 581) revealed that 98.9% An. arabiensis and 1.1% An. gambiae s.s. constituted An. gambiae s.l. in Ahero while this was 87% An. gambiae s.s. and 13% An. arabiensis in Iguhu. Of the 108 An. funestus s.l. analysed by PCR, 98.1% belonged to An. funestus s.s. and 1.9% to Anopheles leesoni. The human blood index (HBI) and bovine blood index (BBI) of An. arabiensis was 2.5 and 73.1%, respectively. Anopheles gambiae s.s. had HBI and BBI of 50 and 28%, respectively. The HBI and BBI of An. funestus was 60 and 22.3%, respectively. Forage ratio estimate revealed that An. arabiensis preferred to feed on cattle, An. gambiae s.s. showed preference for both human and cattle, while An. funestus preferred human over other hosts. In Ahero, the sporozoite rates for An. arabiensis and An. funestus were 0.16 and 1.8%, respectively, whereas in Iguhu, the sporozoite rates for An. gambiae s.s. and An. funestus were 2.3 and 2.4%, respectively. In Ahero, the estimated indoor and outdoor entomological inoculation rate (EIR) was 108.6 infective bites/person/year (79.0 from An. funestus and 29.6 from An. arabiensis) and 43.5 infective bites/person/year (27.9 from An. arabiensis and 15.6 from An. funestus), respectively. In Iguhu, the estimated indoor and outdoor EIR was 24.5 infective bites/person/year (18.8 from An. gambiae s.s. and 5.7 from An. funestus) and 5.5 infective bites/person/year (all from An. gambiae s.s.), respectively. Conclusion Anopheles gambiae s.s. showed an increasing tendency to feed on cattle. Anopheles arabiensis was highly zoophagic, whereas An. funestus showed anthropophagic behaviour. While the majority of malaria transmission occurred indoor, the magnitude of outdoor transmission was considerably high. Additional control tools that complement the existing interventions are required to control residual transmission.
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Affiliation(s)
- Teshome Degefa
- Department of Medical Laboratory Sciences, College of Health Sciences, Jimma University, Jimma, Ethiopia.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences, College of Health Sciences, Jimma University, Jimma, Ethiopia.,Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Ming-Chieh Lee
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Harrysone Atieli
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,School of Public Health, Maseno University, Kisumu, Kenya
| | - Andrew K Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA.
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30
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Kaindoa EW, Matowo NS, Ngowo HS, Mkandawile G, Mmbando A, Finda M, Okumu FO. Interventions that effectively target Anopheles funestus mosquitoes could significantly improve control of persistent malaria transmission in south-eastern Tanzania. PLoS One 2017; 12:e0177807. [PMID: 28542335 PMCID: PMC5436825 DOI: 10.1371/journal.pone.0177807] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 05/03/2017] [Indexed: 11/26/2022] Open
Abstract
Malaria is transmitted by many Anopheles species whose proportionate contributions vary across settings. We re-assessed the roles of Anopheles arabiensis and Anopheles funestus, and examined potential benefits of species-specific interventions in an area in south-eastern Tanzania, where malaria transmission persists, four years after mass distribution of long-lasting insecticide-treated nets (LLINs). Monthly mosquito sampling was done in randomly selected households in three villages using CDC light traps and back-pack aspirators, between January-2015 and January-2016, four years after the last mass distribution of LLINs in 2011. Multiplex polymerase chain reaction (PCR) was used to identify members of An. funestus and Anopheles gambiae complexes. Enzyme-linked immunosorbent assay (ELISA) was used to detect Plasmodium sporozoites in mosquito salivary glands, and to identify sources of mosquito blood meals. WHO susceptibility assays were done on wild caught female An. funestus s.l, and physiological ages approximated by examining mosquito ovaries for parity. A total of 20,135 An. arabiensis and 4,759 An. funestus were collected. The An. funestus group consisted of 76.6% An. funestus s.s, 2.9% An. rivulorum, 7.1% An. leesoni, and 13.4% unamplified samples. Of all mosquitoes positive for Plasmodium, 82.6% were An. funestus s.s, 14.0% were An. arabiensis and 3.4% were An. rivulorum. An. funestus and An. arabiensis contributed 86.21% and 13.79% respectively, of annual entomological inoculation rate (EIR). An. arabiensis fed on humans (73.4%), cattle (22.0%), dogs (3.1%) and chicken (1.5%), but An. funestus fed exclusively on humans. The An. funestus populations were 100% susceptible to organophosphates, pirimiphos methyl and malathion, but resistant to permethrin (10.5% mortality), deltamethrin (18.7%), lambda-cyhalothrin (18.7%) and DDT (26.2%), and had reduced susceptibility to bendiocarb (95%) and propoxur (90.1%). Parity rate was higher in An. funestus (65.8%) than An. arabiensis (44.1%). Though An. arabiensis is still the most abundant vector species here, the remaining malaria transmission is predominantly mediated by An. funestus, possibly due to high insecticide resistance and high survival probabilities. Interventions that effectively target An. funestus mosquitoes could therefore significantly improve control of persistent malaria transmission in south–eastern Tanzania.
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Affiliation(s)
- Emmanuel W. Kaindoa
- Ifakara Health Institute, Environmental Health and Ecological Sciences Thematic Group, Morogoro, Tanzania
- University of the Witwatersrand, School of Public Health, Faculty of Health Science, Johannesburg, South Africa
- * E-mail:
| | - Nancy S. Matowo
- Ifakara Health Institute, Environmental Health and Ecological Sciences Thematic Group, Morogoro, Tanzania
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Halfan S. Ngowo
- Ifakara Health Institute, Environmental Health and Ecological Sciences Thematic Group, Morogoro, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, G12 8QQ, University of Glasgow, Glasgow, United Kingdom
| | - Gustav Mkandawile
- Ifakara Health Institute, Environmental Health and Ecological Sciences Thematic Group, Morogoro, Tanzania
| | - Arnold Mmbando
- Ifakara Health Institute, Environmental Health and Ecological Sciences Thematic Group, Morogoro, Tanzania
- Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland
| | - Marcelina Finda
- Ifakara Health Institute, Environmental Health and Ecological Sciences Thematic Group, Morogoro, Tanzania
| | - Fredros O. Okumu
- Ifakara Health Institute, Environmental Health and Ecological Sciences Thematic Group, Morogoro, Tanzania
- University of the Witwatersrand, School of Public Health, Faculty of Health Science, Johannesburg, South Africa
- Institute of Biodiversity, Animal Health and Comparative Medicine, G12 8QQ, University of Glasgow, Glasgow, United Kingdom
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31
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Moreno M, Saavedra MP, Bickersmith SA, Prussing C, Michalski A, Tong Rios C, Vinetz JM, Conn JE. Intensive trapping of blood-fed Anopheles darlingi in Amazonian Peru reveals unexpectedly high proportions of avian blood-meals. PLoS Negl Trop Dis 2017; 11:e0005337. [PMID: 28231248 PMCID: PMC5322880 DOI: 10.1371/journal.pntd.0005337] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 01/18/2017] [Indexed: 11/25/2022] Open
Abstract
Anopheles darlingi, the main malaria vector in the Neotropics, has been considered to be highly anthropophilic. However, many behavioral aspects of this species remain unknown, such as the range of blood-meal sources. Barrier screens were used to collect resting Anopheles darlingi mosquitoes from 2013 to 2015 in three riverine localities (Lupuna, Cahuide and Santa Emilia) in Amazonian Peru. Overall, the Human Blood Index (HBI) ranged from 0.58-0.87, with no significant variation among years or sites. Blood-meal analysis revealed that humans are the most common blood source, followed by avian hosts (Galliformes-chickens and turkeys), and human/Galliforme mixed-meals. The Forage Ratio and Selection Index both show a strong preference for Galliformes over humans in blood-fed mosquitoes. Our data show that 30% of An. darlingi fed on more than one host, including combinations of dogs, pigs, goats and rats. There appears to be a pattern of host choice in An. darlingi, with varying proportions of mosquitoes feeding only on humans, only on Galliformes and some taking mixed-meals of blood (human plus Galliforme), which was detected in the three sites in different years, indicating that there could be a structure to these populations based on blood-feeding preferences. Mosquito age, estimated in two localities, Lupuna and Cahuide, ranged widely between sites and years. This variation may reflect the range of local environmental factors that influence longevity or possibly potential changes in the ability of the mosquito to transmit the parasite. Of 6,204 resting An. darlingi tested for Plasmodium infection, 0.42% were infected with P. vivax. This study provides evidence for the first time of the usefulness of barrier screens for the collection of blood-fed resting mosquitoes to calculate the Human Blood Index (HBI) and other blood-meal sources in a neotropical malaria endemic setting.
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Affiliation(s)
- Marta Moreno
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Marlon P. Saavedra
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigacion y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Sara A. Bickersmith
- Wadsworth Center, New York State Department of Health, Albany, NY, United States of America
| | - Catharine Prussing
- Department of Biomedical Sciences, School of Public Health, State University of New York-Albany, NY, United States of America
| | - Adrian Michalski
- Wadsworth Center, New York State Department of Health, Albany, NY, United States of America
| | - Carlos Tong Rios
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigacion y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Joseph M. Vinetz
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Jan E. Conn
- Wadsworth Center, New York State Department of Health, Albany, NY, United States of America
- Department of Biomedical Sciences, School of Public Health, State University of New York-Albany, NY, United States of America
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32
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Stevenson JC, Norris DE. Implicating Cryptic and Novel Anophelines as Malaria Vectors in Africa. INSECTS 2016; 8:E1. [PMID: 28025486 PMCID: PMC5371929 DOI: 10.3390/insects8010001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 12/09/2016] [Accepted: 12/12/2016] [Indexed: 11/24/2022]
Abstract
Entomological indices and bionomic descriptions of malaria vectors are essential to accurately describe and understand malaria transmission and for the design and evaluation of appropriate control interventions. In order to correctly assign spatio-temporal distributions, behaviors and responses to interventions to particular anopheline species, identification of mosquitoes must be accurately made. This paper reviews the current methods and their limitations in correctly identifying anopheline mosquitoes in sub-Saharan Africa, and highlights the importance of molecular methods to discriminate cryptic species and identify lesser known anophelines. The increasing number of reports of Plasmodium infections in assumed "minor", non-vector, and cryptic and novel species is reviewed. Their importance in terms of evading current control and elimination strategies and therefore maintaining malaria transmission is emphasized.
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Affiliation(s)
- Jennifer C Stevenson
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
- Macha Research Trust, Choma P.O. Box 630166, Southern Province, Zambia.
| | - Douglas E Norris
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
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