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Keven JB, Vinit R, Katusele M, Reimer LJ, Zimmerman PA, Karl S, Walker ED. Genetic differentiation and bottleneck effects in the malaria vectors Anopheles farauti and Anopheles punctulatus after an LLIN-based vector control program in Papua New Guinea. Ecol Evol 2024; 14:e10917. [PMID: 38371856 PMCID: PMC10869881 DOI: 10.1002/ece3.10917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 01/09/2024] [Accepted: 01/15/2024] [Indexed: 02/20/2024] Open
Abstract
Implementation of long-lasting insecticide-treated net (LLIN) programs to control human malaria transmission leads to substantial reductions in the abundance of Anopheles mosquitoes, but the impact on the population genetic structure of the malaria vectors is poorly known, nor has it been investigated in Papua New Guinea, where malaria is highly endemic and where several species of Anopheles have vector roles. Here, we applied Wright's F-statistic, analysis of molecular variance, Bayesian structure analysis, and discriminant analysis of principle components to microsatellite genotype data to analyze the population genetic structure of Anopheles farauti between and within the northern and southern lowland plains and of Anopheles punctulatus within the northern plain of Papua New Guinea after such a program. Bottleneck effects in the two malaria vectors were analyzed using Luikart and Cornuet's tests of heterozygosity. A large, panmictic population of An. punctulatus pre-LLIN program diverged into two subregional populations corresponding to Madang and East Sepik provinces post-LLIN distribution and experienced a genetic bottleneck during this process. By contrast, the An. farauti population existed as two regional populations isolated by mountain ranges pre-LLIN, a genetic structure that persisted after the distribution of LLINs with no further geographic differentiation nor evidence of a genetic bottleneck. These findings show the differential response of populations of different vector species to interventions, which has implications for program sustainability and gene flow.
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Affiliation(s)
- John B. Keven
- Department of Population Health and Disease Prevention, Program in Public HealthUniversity of California‐IrvineIrvineCaliforniaUSA
- Department of EntomologyMichigan State UniversityEast LansingMichiganUSA
- Department of Microbiology and Molecular GeneticsMichigan State UniversityEast LansingMichiganUSA
- Vector‐borne Diseases UnitPapua New Guinea Institute of Medical ResearchMadangMadang ProvincePapua New Guinea
| | - Rebecca Vinit
- Vector‐borne Diseases UnitPapua New Guinea Institute of Medical ResearchMadangMadang ProvincePapua New Guinea
| | - Michelle Katusele
- Vector‐borne Diseases UnitPapua New Guinea Institute of Medical ResearchMadangMadang ProvincePapua New Guinea
| | - Lisa J. Reimer
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Peter A. Zimmerman
- Center for Global Health and Diseases, Pathology DepartmentCase Western Reserve UniversityClevelandOhioUSA
| | - Stephan Karl
- Vector‐borne Diseases UnitPapua New Guinea Institute of Medical ResearchMadangMadang ProvincePapua New Guinea
- Australian Institute of Tropical Health and MedicineJames Cook UniversityCairnsQueenslandAustralia
| | - Edward D. Walker
- Department of EntomologyMichigan State UniversityEast LansingMichiganUSA
- Department of Microbiology and Molecular GeneticsMichigan State UniversityEast LansingMichiganUSA
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2
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Gueye A, Ngom EHM, Diagne A, Ndoye BB, Dione ML, Sambe BS, Sokhna C, Diallo M, Niang M, Dia I. Host feeding preferences of malaria vectors in an area of low malaria transmission. Sci Rep 2023; 13:16410. [PMID: 37775717 PMCID: PMC10542387 DOI: 10.1038/s41598-023-43761-z] [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: 06/28/2023] [Accepted: 09/28/2023] [Indexed: 10/01/2023] Open
Abstract
Studying the behaviour and trophic preferences of mosquitoes is an important step in understanding the exposure of vertebrate hosts to vector-borne diseases. In the case of human malaria, transmission increases when mosquitoes feed more on humans than on other animals. Therefore, understanding the spatio-temporal dynamics of vectors and their feeding preferences is essential for improving vector control measures. In this study, we investigated the feeding behaviour of Anopheles mosquitoes at two sites in the Sudanian areas of Senegal where transmission is low following the implementation of vector control measures. Blood-fed mosquitoes were collected monthly from July to November 2022 by pyrethrum spray catches in sleeping rooms of almost all houses in Dielmo and Ndiop villages, and blood meals were identified as from human, bovine, ovine, equine and chicken by ELISA. Species from the An. gambiae complex were identified by PCR. The types and numbers of potential domestic animal hosts were recorded in each village. The Human Blood Index (HBI) and the Manly Selection Ratio (MSR) were calculated to determine whether hosts were selected in proportion to their abundance. Spatio-temporal variation in HBI was examined using the Moran's index. A total of 1251 endophilic Anopheles females were collected in 115 bedrooms, including 864 blood fed females of 6 species. An. arabiensis and An. funestus were predominant in Dielmo and Ndiop, respectively. Of the 864 blood meals tested, 853 gave a single host positive result mainly on bovine, equine, human, ovine and chicken in decreasing order in both villages. Overall, these hosts were not selected in proportion to their abundance. The human host was under-selected, highlighting a marked zoophily for the vectors. Over time and space, the HBI were low with no obvious trend, with higher and lower values observed in each of the five months at different points in each village. These results highlight the zoophilic and exophagic behaviour of malaria vectors. This behaviour is likely to be a consequence of the distribution and use of LLINs in both villages and may increase risk of residual outdoor transmission. This underlines the need to study the feeding host profile of outdoor resting populations and how domestic animals may influence malaria epidemiology in order to tailor effective malaria vector control strategies in the two villages.
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Affiliation(s)
- Assiyatou Gueye
- Pole de Zoologie Medicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - El Hadji Malick Ngom
- Pole de Zoologie Medicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Aissatou Diagne
- Pole Immunophysiopathologie et Maladies Infectieuses, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Baye Bado Ndoye
- Pole de Zoologie Medicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Mamadou Lamine Dione
- Pole de Zoologie Medicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Babacar Souleymane Sambe
- Pole Immunophysiopathologie et Maladies Infectieuses, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Cheikh Sokhna
- UMR Vecteurs Infections Tropicales et Mediterraneennes (VITROME), Campus International UCAD-IRD, Route des Peres Maristes, BP 1386, Dakar, Senegal
| | - Mawlouth Diallo
- Pole de Zoologie Medicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Makhtar Niang
- Pole Immunophysiopathologie et Maladies Infectieuses, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Ibrahima Dia
- Pole de Zoologie Medicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal.
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Katusele M, Lagur S, Endersby-Harshman N, Demok S, Goi J, Vincent N, Sakur M, Dau A, Kilepak L, Gideon S, Pombreaw C, Makita L, Hoffmann A, Robinson LJ, Laman M, Karl S. Insecticide resistance in malaria and arbovirus vectors in Papua New Guinea, 2017-2022. Parasit Vectors 2022; 15:426. [PMID: 36376932 PMCID: PMC9664807 DOI: 10.1186/s13071-022-05493-3] [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: 05/15/2022] [Accepted: 09/13/2022] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Insecticide resistance (IR) monitoring is essential for evidence-based control of mosquito-borne diseases. While widespread pyrethroid resistance in Anopheles and Aedes species has been described in many countries, data for Papua New Guinea (PNG) are limited. Available data indicate that the local Anopheles populations in PNG remain pyrethroid-susceptible, making regular IR monitoring even more important. In addition, Aedes aegypti pyrethroid resistance has been described in PNG. Here, Anopheles and Aedes IR monitoring data generated from across PNG between 2017 and 2022 are presented. METHODS Mosquito larvae were collected in larval habitat surveys and through ovitraps. Mosquitoes were reared to adults and tested using standard WHO susceptibility bioassays. DNA from a subset of Aedes mosquitoes was sequenced to analyse the voltage-sensitive sodium channel (Vssc) region for any resistance-related mutations. RESULTS Approximately 20,000 adult female mosquitoes from nine PNG provinces were tested. Anopheles punctulatus sensu lato mosquitoes were susceptible to pyrethroids but there were signs of reduced mortality in some areas. Some Anopheles populations were also resistant to DDT. Tests also showed that Aedes. aegypti in PNG are resistant to pyrethroids and DDT and that there was also likelihood of bendiocarb resistance. A range of Vssc resistance mutations were identified. Aedes albopictus were DDT resistant and were likely developing pyrethroid resistance, given a low frequency of Vssc mutations was observed. CONCLUSIONS Aedes aegypti is highly pyrethroid resistant and also shows signs of resistance against carbamates in PNG. Anopheles punctulatus s.l. and Ae. albopictus populations exhibit low levels of resistance against pyrethroids and DDT in some areas. Pyrethroid-only bed nets are currently the only programmatic vector control tool used in PNG. It is important to continue to monitor IR in PNG and develop proactive insecticide resistance management strategies in primary disease vectors to retain pyrethroid susceptibility especially in the malaria vectors for as long as possible.
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Affiliation(s)
- Michelle Katusele
- PNG Institute of Medical Research, Madang, Madang Province Papua New Guinea
| | - Solomon Lagur
- PNG Institute of Medical Research, Madang, Madang Province Papua New Guinea
| | - Nancy Endersby-Harshman
- School of BioSciences, Bio21 Institute, The University of Melbourne, Parkville, Victoria Australia
| | - Samuel Demok
- PNG Institute of Medical Research, Madang, Madang Province Papua New Guinea
| | - Joelyn Goi
- PNG Institute of Medical Research, Madang, Madang Province Papua New Guinea
| | - Naomi Vincent
- PNG Institute of Medical Research, Madang, Madang Province Papua New Guinea
- Burnet Institute of Medical Research, Melbourne, Victoria Australia
- Papua New Guinea National Department of Health, Port Moresby, National Capitol District Papua New Guinea
| | - Muker Sakur
- PNG Institute of Medical Research, Madang, Madang Province Papua New Guinea
| | - Absalom Dau
- PNG Institute of Medical Research, Madang, Madang Province Papua New Guinea
| | - Lemen Kilepak
- PNG Institute of Medical Research, Madang, Madang Province Papua New Guinea
| | - Stephen Gideon
- PNG Institute of Medical Research, Madang, Madang Province Papua New Guinea
- Papua New Guinea National Department of Health, Port Moresby, National Capitol District Papua New Guinea
| | - Christine Pombreaw
- PNG Institute of Medical Research, Madang, Madang Province Papua New Guinea
| | - Leo Makita
- Papua New Guinea National Department of Health, Port Moresby, National Capitol District Papua New Guinea
| | - Ary Hoffmann
- School of BioSciences, Bio21 Institute, The University of Melbourne, Parkville, Victoria Australia
| | - Leanne J. Robinson
- PNG Institute of Medical Research, Madang, Madang Province Papua New Guinea
- Burnet Institute of Medical Research, Melbourne, Victoria Australia
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria Australia
| | - Moses Laman
- PNG Institute of Medical Research, Madang, Madang Province Papua New Guinea
| | - Stephan Karl
- PNG Institute of Medical Research, Madang, Madang Province Papua New Guinea
- Australian Institute of Tropical Health and Medicine, James Cook University, Smithfield, Queensland Australia
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Mueller I, Vantaux A, Karl S, Laman M, Witkowski B, Pepey A, Vinit R, White M, Barry A, Beeson JG, Robinson LJ. Asia-Pacific ICEMR: Understanding Malaria Transmission to Accelerate Malaria Elimination in the Asia Pacific Region. Am J Trop Med Hyg 2022; 107:131-137. [PMID: 36228917 PMCID: PMC9662229 DOI: 10.4269/ajtmh.21-1336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 07/06/2022] [Indexed: 01/31/2023] Open
Abstract
Gaining an in-depth understanding of malaria transmission requires integrated, multifaceted research approaches. The Asia-Pacific International Center of Excellence in Malaria Research (ICEMR) is applying specifically developed molecular and immunological assays, in-depth entomological assessments, and advanced statistical and mathematical modeling approaches to a rich series of longitudinal cohort and cross-sectional studies in Papua New Guinea and Cambodia. This is revealing both the essential contribution of forest-based transmission and the particular challenges posed by Plasmodium vivax to malaria elimination in Cambodia. In Papua New Guinea, these studies document the complex host-vector-parasite interactions that are underlying both the stunning reductions in malaria burden from 2006 to 2014 and the significant resurgence in transmission in 2016 to 2018. Here we describe the novel analytical, surveillance, molecular, and immunological tools that are being applied in our ongoing Asia-Pacific ICEMR research program.
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Affiliation(s)
- Ivo Mueller
- Population Health & Immunity Division, Walter + Eliza Hall Institutes, Melbourne, Australia;,University of Melbourne, Melbourne, Australia;,Address correspondence to Ivo Mueller, Population Health & Immunity Division, Walter + Eliza Hall Institutes, 1G Royal Parade, Parkville, Victoria, Australia 3052. E-mail:
| | | | - Stephan Karl
- Australian Institute of Tropical Health & Medicine, James Cook University, Cairns, Australia;,PNG Institute of Medical Research, Madang, Papua New Guinea
| | - Moses Laman
- PNG Institute of Medical Research, Madang, Papua New Guinea
| | | | - Anais Pepey
- Institute Pasteur Cambodia, Phnom Penh, Cambodia
| | - Rebecca Vinit
- PNG Institute of Medical Research, Madang, Papua New Guinea
| | | | - Alyssa Barry
- Deakin University, Geelong, Australia;,Burnet Institute, Melbourne, Australia
| | - James G. Beeson
- University of Melbourne, Melbourne, Australia;,Burnet Institute, Melbourne, Australia;,Monash University, Victoria, Australia
| | - Leanne J. Robinson
- Population Health & Immunity Division, Walter + Eliza Hall Institutes, Melbourne, Australia;,PNG Institute of Medical Research, Madang, Papua New Guinea;,Burnet Institute, Melbourne, Australia;,Monash University, Victoria, Australia
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5
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Mbewe RB, Keven JB, Mzilahowa T, Mathanga D, Wilson M, Cohee L, Laufer MK, Walker ED. Blood-feeding patterns of Anopheles vectors of human malaria in Malawi: implications for malaria transmission and effectiveness of LLIN interventions. Malar J 2022; 21:67. [PMID: 35241083 PMCID: PMC8892392 DOI: 10.1186/s12936-022-04089-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 02/16/2022] [Indexed: 11/23/2022] Open
Abstract
Background Access to human hosts by Anopheles mosquitoes is a key determinant of vectorial capacity for malaria, but it can be limited by use of long-lasting insecticidal nets (LLINs). In Malawi, pyrethroid-treated LLINs with and without the synergist piperonyl butoxide (PBO) were distributed to control malaria. This study investigated the blood-feeding patterns of malaria vectors and whether LLINs containing pyrethroid and PBO led to a reduction of human blood feeding than those containing only pyrethroids. Methods Mosquitoes were sampled inside houses from May 2019 through April 2020 by aspiration, pyrethrum spray catch, and light trap methods in two sites. One site (Namanolo, Balaka district) had LLINs containing only pyrethroids whereas the other (Ntaja, Machinga district) had LLINs with both pyrethroids and PBO. Anopheles species, their blood-meal host, and infection with Plasmodium falciparum were determined using PCR methods. Results A total of 6585 female Anopheles were sampled in 203 houses. Of these, 633 (9.6%) were blood-fed mosquitoes comprising of 279 (44.1%) Anopheles arabiensis, 103 (16.3%) Anopheles gambiae 212 (33.5), Anopheles funestus, 2 (0.3%), Anopheles parensis and 37 (5.8%) were unidentified Anopheles spp. Blood meal hosts were successfully identified for 85.5% (n = 541) of the blood-fed mosquitoes, of which 436 (81.0%) were human blood meals, 28 (5.2%) were goats, 11 (2.0%) were dogs, 60 (11.1%) were mixed goat-human blood meals, 5 (0.9%) were dog–human, and 1 was a mixed dog-goat. Human blood index (fraction of blood meals that were humans) was significantly higher in Namanolo (0.96) than Ntaja (0.89). Even though human blood index was high, goats were over-selected than humans after accounting for relative abundance of both hosts. The number of infectious Anopheles bites per person-year was 44 in Namanolo and 22 in Ntaja. Conclusion Although LLINs with PBO PBO may have reduced human blood feeding, access to humans was extremely high despite high LLIN ownership and usage rates in both sites. This finding could explain persistently high rates of malaria infections in Malawi. However, this study had one village for each net type, thus the observed differences may have been a result of other factors present in each village. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04089-7.
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Affiliation(s)
- Rex B Mbewe
- Department of Physics and Biochemical Sciences, Polytechnic, University of Malawi, Blantyre, Malawi. .,Department of Entomology, Michigan State University, East Lansing, MI, 48824, USA.
| | - John B Keven
- Department of Entomology, Michigan State University, East Lansing, MI, 48824, USA.,Department of Public Health, University of California-Irvine, Irvine, CA, USA
| | - Themba Mzilahowa
- Malaria Alert Center, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Don Mathanga
- Malaria Alert Center, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Mark Wilson
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Lauren Cohee
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Miriam K Laufer
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Edward D Walker
- Department of Entomology, Michigan State University, East Lansing, MI, 48824, USA.,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
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6
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Keven JB, Katusele M, Vinit R, Rodríguez-Rodríguez D, Hetzel MW, Robinson LJ, Laman M, Karl S, Walker ED. Vector composition, abundance, biting patterns and malaria transmission intensity in Madang, Papua New Guinea: assessment after 7 years of an LLIN-based malaria control programme. Malar J 2022; 21:7. [PMID: 34983530 PMCID: PMC8729043 DOI: 10.1186/s12936-021-04030-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 12/17/2021] [Indexed: 11/18/2022] Open
Abstract
Background A malaria control programme based on distribution of long-lasting insecticidal bed nets (LLINs) and artemisinin combination therapy began in Papua New Guinea in 2009. After implementation of the programme, substantial reductions in vector abundance and malaria transmission intensity occurred. The research reported here investigated whether these reductions remained after seven years of sustained effort. Methods All-night (18:00 to 06:00) mosquito collections were conducted using human landing catches and barrier screen methods in four villages of Madang Province between September 2016 and March 2017. Anopheles species identification and sporozoite infection with Plasmodium vivax and Plasmodium falciparum were determined with molecular methods. Vector composition was expressed as the relative proportion of different species in villages, and vector abundance was quantified as the number of mosquitoes per barrier screen-night and per person-night. Transmission intensity was quantified as the number of sporozoite-infective vector bites per person-night. Results Five Anopheles species were present, but vector composition varied greatly among villages. Anopheles koliensis, a strongly anthropophilic species was the most prevalent in Bulal, Matukar and Wasab villages, constituting 63.7–73.8% of all Anopheles, but in Megiar Anopheles farauti was the most prevalent species (97.6%). Vector abundance varied among villages (ranging from 2.8 to 72.3 Anopheles per screen-night and 2.2–31.1 Anopheles per person-night), and spatially within villages. Malaria transmission intensity varied among the villages, with values ranging from 0.03 to 0.5 infective Anopheles bites per person-night. Most (54.1–75.1%) of the Anopheles bites occurred outdoors, with a substantial proportion (25.5–50.8%) occurring before 22:00. Conclusion The estimates of vector abundance and transmission intensity in the current study were comparable to or higher than estimates in the same villages in 2010–2012, indicating impeded programme effectiveness. Outdoor and early biting behaviours of vectors are some of the likely explanatory factors. Heterogeneity in vector composition, abundance and distribution among and within villages challenge malaria control programmes and must be considered when planning them. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-04030-4.
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Affiliation(s)
- John B Keven
- Department of Entomology, Michigan State University, East Lansing, MI, USA. .,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA. .,Papua New Guinea Institute of Medical Research, Vector-Borne Diseases Unit, Madang, Papua New Guinea.
| | - Michelle Katusele
- Papua New Guinea Institute of Medical Research, Vector-Borne Diseases Unit, Madang, Papua New Guinea
| | - Rebecca Vinit
- Papua New Guinea Institute of Medical Research, Vector-Borne Diseases Unit, Madang, Papua New Guinea
| | | | - Manuel W Hetzel
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Leanne J Robinson
- Papua New Guinea Institute of Medical Research, Vector-Borne Diseases Unit, Madang, Papua New Guinea.,Burnet Institute, Melbourne, VIC, Australia.,Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Moses Laman
- Papua New Guinea Institute of Medical Research, Vector-Borne Diseases Unit, Madang, Papua New Guinea
| | - Stephan Karl
- Papua New Guinea Institute of Medical Research, Vector-Borne Diseases Unit, Madang, Papua New Guinea.,Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Edward D Walker
- Department of Entomology, Michigan State University, East Lansing, MI, USA.,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
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7
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Keven JB, Katusele M, Vinit R, Rodríguez-Rodríguez D, Hetzel MW, Robinson LJ, Laman M, Karl S, Foran DR, Walker ED. Nonrandom Selection and Multiple Blood Feeding of Human Hosts by Anopheles Vectors: Implications for Malaria Transmission in Papua New Guinea. Am J Trop Med Hyg 2021; 105:1747-1758. [PMID: 34583342 PMCID: PMC8641310 DOI: 10.4269/ajtmh.21-0210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 07/21/2021] [Indexed: 11/07/2022] Open
Abstract
Nonrandom selection and multiple blood feeding of human hosts by Anopheles mosquitoes may exacerbate malaria transmission. Both patterns of blood feeding and their relationship to malaria epidemiology were investigated in Anopheles vectors in Papua New Guinea (PNG). Blood samples from humans and mosquito blood meals were collected in villages and human genetic profiles ("fingerprints") were analyzed by genotyping 23 microsatellites and a sex-specific marker. Frequency of blood meals acquired from different humans, identified by unique genetic profiles, was fitted to Poisson and negative binomial distributions to test for nonrandom patterns of host selection. Blood meals with more than one genetic profiles were classified as mosquitoes that fed on multiple humans. The age of a person bitten by a mosquito was determined by matching the blood-meal genetic profile to the villagers' genetic profiles. Malaria infection in humans was determined by PCR test of blood samples. The results show nonrandom distribution of blood feeding among humans, with biased selection toward males and individuals aged 15-30 years. Prevalence of Plasmodium falciparum infection was higher in this age group, suggesting males in this age range could be super-spreaders of malaria parasites. The proportion of mosquitoes that fed on multiple humans ranged from 6% to 13% among villages. The patterns of host utilization observed here can amplify transmission and contribute to the persistence of malaria in PNG despite efforts to suppress it with insecticidal bed nets. Excessive feeding on males aged 15-30 years underscores the importance of targeted interventions focusing on this demographic group.
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Affiliation(s)
- John B. Keven
- Department of Microbiology and Molecular Genetics, and Department of Entomology, Michigan State University, East Lansing, Michigan
- Vector-borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Michelle Katusele
- Vector-borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Rebecca Vinit
- Vector-borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Daniela Rodríguez-Rodríguez
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- Department of Epidemiology and Public Health, University of Basel, Basel, Switzerland
| | - Manuel W. Hetzel
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- Department of Epidemiology and Public Health, University of Basel, Basel, Switzerland
| | - Leanne J. Robinson
- Vector-borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
- Vector-Borne Diseases and Tropical Public Health Group, Burnet Institute, Melbourne, Victoria, Australia
- Division of Population Health and Immunity, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Moses Laman
- Vector-borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Stephan Karl
- Vector-borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - David R. Foran
- School of Criminal Justice and Department of Integrative Biology, Michigan State University, Michigan
| | - Edward D. Walker
- Department of Microbiology and Molecular Genetics, and Department of Entomology, Michigan State University, East Lansing, Michigan
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8
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Fikrig K, Harrington LC. Understanding and interpreting mosquito blood feeding studies: the case of Aedes albopictus. Trends Parasitol 2021; 37:959-975. [PMID: 34497032 DOI: 10.1016/j.pt.2021.07.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 07/23/2021] [Accepted: 07/23/2021] [Indexed: 12/31/2022]
Abstract
Blood feeding is a fundamental mosquito behavior with consequences for pathogen transmission and control. Feeding behavior can be studied through two lenses - patterns and preference. Feeding patterns are assessed via blood meal analyses, reflecting mosquito-host associations influenced by environmental and biological parameters. Bias can profoundly impact results, and we provide recommendations for mitigating these effects. We also outline design choices for host preference research, which can take many forms, and highlight their respective (dis)advantages for preference measurement. Finally, Aedes albopictus serves as a case study for how to apply these lessons to interpret data and understand feeding biology. We illustrate how assumptions and incomplete evidence can lead to inconsistent interpretations by reviewing Ae. albopictus feeding studies alongside prevalent narratives about perceived behavior.
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Affiliation(s)
- Kara Fikrig
- Department of Entomology, Cornell University, Ithaca, NY, USA.
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Ambrose L, Ortiz‐Barrientos D, Cooper RD, Lobo NF, Burkot TR, Russell TL, Beebe NW. Gene flow between island populations of the malaria mosquito, Anopheles hinesorum, may have contributed to the spread of divergent host preference phenotypes. Evol Appl 2021; 14:2244-2257. [PMID: 34603496 PMCID: PMC8477600 DOI: 10.1111/eva.13288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 06/23/2021] [Accepted: 07/13/2021] [Indexed: 12/04/2022] Open
Abstract
Anopheles hinesorum is a mosquito species with variable host preference. Throughout New Guinea and northern Australia, An. hinesorum feeds on humans (it is opportunistically anthropophagic) while in the south-west Pacific's Solomon Archipelago, the species is abundant but has rarely been found biting humans (it is exclusively zoophagic in most populations). There are at least two divergent zoophagic (nonhuman biting) mitochondrial lineages of An. hinesorum in the Solomon Archipelago representing two independent dispersals. Since zoophagy is a derived (nonancestral) trait in this species, this leads to the question: has zoophagy evolved independently in these two populations? Or conversely: has nuclear gene flow or connectivity resulted in the transfer of zoophagy? Although we cannot conclusively answer this, we find close nuclear relationships between Solomon Archipelago populations indicating that recent nuclear gene flow has occurred between zoophagic populations from the divergent mitochondrial lineages. Recent work on isolated islands of the Western Province (Solomon Archipelago) has also revealed an anomalous, anthropophagic island population of An. hinesorum. We find a common shared mitochondrial haplotype between this Solomon Island population and another anthropophagic population from New Guinea. This finding suggests that there has been recent migration from New Guinea into the only known anthropophagic population from the Solomon Islands. Although currently localized to a few islands in the Western Province of the Solomon Archipelago, if anthropophagy presents a selective advantage, we may see An. hinesorum emerge as a new malaria vector in a region that is now working on malaria elimination.
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Affiliation(s)
- Luke Ambrose
- School of Biological SciencesUniversity of QueenslandBrisbaneQldAustralia
| | | | - Robert D. Cooper
- Australian Defence Force, Malaria and Infectious Disease InstituteBrisbaneQldAustralia
| | | | | | | | - Nigel W. Beebe
- School of Biological SciencesUniversity of QueenslandBrisbaneQldAustralia
- CSIROBrisbaneQldAustralia
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10
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Hii J, Hustedt J, Bangs MJ. Residual Malaria Transmission in Select Countries of Asia-Pacific Region: Old Wine in a New Barrel. J Infect Dis 2021; 223:S111-S142. [PMID: 33906222 PMCID: PMC8079134 DOI: 10.1093/infdis/jiab004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Background Despite substantial reductions in malaria burden and improvement in case management, malaria remains a major public health challenge in the Asia-Pacific region. Residual malaria transmission (RMT) is the fraction of total transmission that persists after achievement of full operational coverage with effective insecticide-treated bed nets (ITNs)/long-lasting insecticidal nets (LLINs) and/or indoor residual spray interventions. There is a critical need to standardize and share best practices for entomological, anthropological, and product development investigative protocols to meet the challenges of RMT and elimination goals. Methods A systematic review was conducted to describe when and where RMT is occurring, while specifically targeting ownership and usage of ITN/LLINs, indoor residual spray application, insecticide susceptibility of vectors, and human and vector biting behavior, with a focus on nighttime activities. Results Sixty-six publications from 1995 to present met the inclusion criteria for closer review. Associations between local vector control coverage and use with behaviors of human and mosquito vectors varied by locality and circumstance. Consequently, the magnitude of RMT is insufficiently studied and analyzed with sparse estimates of individual exposure in communities, insufficient or incomplete observations of ITN/LLIN use, and the local human population movement into and from high-risk areas. Conclusions This review identified significant gaps or deficiencies that require urgent attention, namely, developing standardized procedures and methods to estimate risk exposure beyond the peridomestic setting, analytical approaches to measure key human-vector interactions, and seasonal location-specific agricultural or forest use calendars, and establishing the collection of longitudinal human and vector data close in time and location.
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Affiliation(s)
- Jeffrey Hii
- Malaria Consortium Asia, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia
| | | | - Michael J Bangs
- Public Health and Malaria Control Department, PT Freeport Indonesia, International SOS, Jl. Kertajasa, Kuala Kencana, Papua, Indonesia.,Department of Entomology, Faculty of Agriculture, Kasertart University, Bangkok, Thailand
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11
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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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12
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Hernández-Valencia JC, Rincón DS, Marín A, Naranjo-Díaz N, Correa MM. Effect of land cover and landscape fragmentation on anopheline mosquito abundance and diversity in an important Colombian malaria endemic region. PLoS One 2020; 15:e0240207. [PMID: 33057442 PMCID: PMC7561141 DOI: 10.1371/journal.pone.0240207] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 09/23/2020] [Indexed: 11/25/2022] Open
Abstract
Landscape structure influences the distribution and abundance of anopheline mosquitoes and has an indirect impact on malaria transmission. This work aimed to determine the effect of land cover and landscape fragmentation on anopheline mosquito abundance and diversity in an important Colombian malaria endemic area, the Bajo Cauca region. Diversity indices were calculated for Anopheles mosquitoes collected in various localities of the region. Land cover types were characterized using orthorectified aerial photographs to estimate landscape metrics. The relationship between landscape fragmentation and species diversity was evaluated by regression analysis. The correlation between species abundance and land cover types was determined using canonical correspondence analyses. Results showed a statistically significant tendency for a lower diversity of the Anopheles community in landscapes with higher patch number, patch density and effective mesh size. For most species, there was evidence of a significant relationship between species abundance and land covers modified by anthropic activities which generate forest loss. These results indicate that activities that modify the landscape structure and land cover composition generate changes that affect the spatial distribution and composition of epidemiologically-important Anopheles species, which may impact malaria distribution in a region. This information is useful to guide control interventions that promote unfavorable landscapes for malaria vector propagation.
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Affiliation(s)
- Juan C. Hernández-Valencia
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia
| | - Daniel S. Rincón
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia
| | - Alba Marín
- Universidad de Antioquia, Medellín, Colombia
| | - Nelson Naranjo-Díaz
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia
| | - Margarita M. Correa
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia
- * E-mail: ,
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13
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Decreased bioefficacy of long-lasting insecticidal nets and the resurgence of malaria in Papua New Guinea. Nat Commun 2020; 11:3646. [PMID: 32686679 PMCID: PMC7371689 DOI: 10.1038/s41467-020-17456-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 06/30/2020] [Indexed: 11/17/2022] Open
Abstract
Papua New Guinea (PNG) has the highest malaria transmission outside of Africa. Long-lasting insecticidal nets (LLINs) are believed to have helped to reduce average malaria prevalence in PNG from 16% in 2008 to 1% in 2014. Since 2015 malaria in PNG has resurged significantly. Here, we present observations documenting decreased bioefficacy of unused LLINs with manufacturing dates between 2013 and 2019 collected from villages and LLIN distributors in PNG. Specifically, we show that of n = 167 tested LLINs manufactured after 2013, only 17% are fulfilling the required World Health Organisation bioefficacy standards of ≥ 80% 24 h mortality or ≥ 95% 60 min knockdown in bioassays with pyrethroid susceptible Anopheles farauti mosquitoes. In contrast, all (100%, n = 25) LLINs with manufacturing dates prior to 2013 are meeting these bioefficacy standards. These results suggest that decreased bioefficacy of LLINs is contributing to the malaria resurgence in PNG and increased scrutiny of LLIN quality is warranted. Malaria prevalence in Papua New Guinea has risen in recent years after almost a decade of decline. In this study, the authors demonstrate that long-lasting insecticidal nets used in the country that were manufactured since 2013 have significantly reduced bioefficacy.
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14
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Keven JB, Artzberger G, Gillies ML, Mbewe RB, Walker ED. Probe-based multiplex qPCR identifies blood-meal hosts in Anopheles mosquitoes from Papua New Guinea. Parasit Vectors 2020; 13:111. [PMID: 32111232 PMCID: PMC7048118 DOI: 10.1186/s13071-020-3986-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 02/21/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Determination of blood-meal hosts in blood-fed female Anopheles mosquitoes is important for evaluating vectorial capacity of vector populations and assessing effectiveness of vector control measures. Sensitive molecular methods are needed to detect traces of host blood in mosquito samples, to differentiate hosts, and to detect mixed host blood meals. This paper describes a molecular probe-based quantitative PCR for identifying blood-meal hosts in Anopheles malaria vectors from Papua New Guinea. METHODS TaqMan oligonucleotide probes targeting specific regions of mitochondrial or nuclear DNA of the three primary Anopheles blood-meal hosts, humans, pigs and dogs, were incorporated into a multiplex, quantitative PCR which was optimized for sensitivity and specificity. RESULTS Amplification of serially diluted DNA showed that the quantitative PCR detected as low as 10-5 ng/μl of host DNA. Application to field-collected, blood-fed Anopheles showed that the quantitative PCR identified the vertebrate hosts for 89% (335/375) of mosquitoes whereas only 55% (104/188) of blood-meal samples tested in a conventional PCR were identified. Of the 104 blood-fed Anopheles that were positive in both PCR methods, 16 (15.4%) were identified as mixed blood meals by the quantitative PCR whereas only 3 (2.9%) were mixed blood meals by the conventional PCR. CONCLUSIONS The multiplex quantitative PCR described here is sensitive at detecting low DNA concentration and mixed host DNA in samples and useful for blood-meal analysis of field mosquitoes, in particular mixed-host blood meals.
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Affiliation(s)
- John B Keven
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA. .,Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Georgia Artzberger
- Department of Biomedical Laboratory Diagnostics, Michigan State University, East Lansing, MI, USA
| | - Mary L Gillies
- Department of Biomedical Laboratory Diagnostics, Michigan State University, East Lansing, MI, USA
| | - Rex B Mbewe
- Department of Entomology, Michigan State University, East Lansing, MI, USA.,Department of Physics and Biochemical Sciences, University of Malawi, The Polytechnic, Blantyre, Malawi
| | - Edward D Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA.,Department of Entomology, Michigan State University, East Lansing, MI, USA
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15
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Tedrow RE, Ratovonjato J, Walker ED, Ratsimbasoa AC, Zimmerman PA. A Novel Assay for Simultaneous Assessment of Mammalian Host Blood, Mosquito Species, and Plasmodium spp. in the Medically Important Anopheles Mosquitoes of Madagascar. Am J Trop Med Hyg 2020; 100:544-551. [PMID: 30675844 DOI: 10.4269/ajtmh.18-0782] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Anopheles mosquitoes vary in habitat preference, feeding pattern, and susceptibility to various measures of vector control. Consequently, it is important that we identify reservoirs of disease, identify vectors, and characterize feeding patterns to effectively implement targeted control measures. Using 467 anopheline mosquito abdomen squashes captured in Madagascar, we designed a novel ligase detection reaction and fluorescent microsphere assay, dubbed Bloodmeal Detection Assay for Regional Transmission (BLOODART), to query the bloodmeal content, identify five Anopheles mosquito species, and detect Plasmodium infection. Validation of mammalian bloodspots was achieved by preparation and analysis of known hosts (singular and mixed), sensitivity to degradation and storage method were assessed through mosquito feeding experiments, and quantification was explored by altering ratios of two mammal hosts. BLOODART identifications were validated by comparison with mosquito samples identified by sequenced portions of the internal transcribed spacer 2. BLOODART identification of control mammal bloodspots was 100% concordant for singular and mixed mammalian blood. BLOODART was able to detect hosts up to 42 hours after digestion when mosquito samples were stored in ethanol. A mammalian host was identified in every field-collected, blood-fed female Anopheles mosquito by BLOODART. The predominant mosquito host was cow (n = 451), followed by pig (n = 26) and human (n = 25). Mixed species bloodmeals were commonly observed (n = 33). A BLOODART molecular identification was successful for 318/467 mosquitoes, with an overall concordance of 60% with all field-captured, morphologically identified Anopheles specimens. BLOODART enables characterization of large samples and simultaneous pathogen detection to monitor and incriminate disease vectors in Madagascar.
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Affiliation(s)
- Riley E Tedrow
- Department of Biology, Case Western Reserve University, Cleveland, Ohio.,The Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Jocelyn Ratovonjato
- Direction de Lutte contre le Paludisme/National Malaria Control Program Madagascar, Antananarivo, Madagascar
| | - Edward D Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan
| | - Arsene C Ratsimbasoa
- Faculty of Medicine and Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar.,Direction de Lutte contre le Paludisme/National Malaria Control Program Madagascar, Antananarivo, Madagascar
| | - Peter A Zimmerman
- The Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio.,Department of Biology, Case Western Reserve University, Cleveland, Ohio
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16
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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: 21] [Impact Index Per Article: 4.2] [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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17
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Keven JB, Walker ED, Venta PJ. A Microsatellite Multiplex Assay for Profiling Pig DNA in Mosquito Bloodmeals. JOURNAL OF MEDICAL ENTOMOLOGY 2019; 56:907-914. [PMID: 30768665 PMCID: PMC6595529 DOI: 10.1093/jme/tjz013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Indexed: 06/09/2023]
Abstract
Genetic profiling has been used to link mosquito bloodmeals to the individual humans, but this analysis has not been done for other mammalian bloodmeals. In this study, we describe a microsatellite-based method for identifying individual pigs in mosquito bloodmeals based on their unique multilocus genotypes. Eleven tetranucleotide microsatellites and a sex-specific marker were selected based on Smith-Waterman DNA sequence alignment scores from the reference genome and primers were designed with features that reduce primer dimers, promote complete adenylation, and enable fluorescent labeling of amplicons. A multiplex polymerase chain reaction (PCR) assay was optimized and validated by analyzing DNA of individual pigs from several nuclear families and breeds before it was used to analyze genomic DNA of pig-derived mosquito bloodmeals from villages of Papua New Guinea. Population analysis of the nuclear families showed high expected and observed heterozygosity. The probability of observing two unrelated or sibling individuals sharing the same genotype at a single microsatellite locus or a combination of loci was vanishingly low. Samples had unique genotypes and gender was accurately predicted. Analysis of 129 pig bloodmeals identified 19 unique genotypes, which varied greatly in frequency in the mosquito bloodmeal samples. The high allelic diversity of the microsatellite loci and low probability of false attribution of identity show that this genotyping method reliably distinguishes distantly and closely related pigs and can be used to identify individual pigs from genotyped mosquito bloodmeals.
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Affiliation(s)
- John B Keven
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Edward D Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI
| | - Patrick J Venta
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI
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18
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Keven JB, Katusele M, Vinit R, Koimbu G, Vincent N, Thomsen EK, Karl S, Reimer LJ, Walker ED. Species abundance, composition, and nocturnal activity of female Anopheles (Diptera: Culicidae) in malaria-endemic villages of Papua New Guinea: assessment with barrier screen sampling. Malar J 2019; 18:96. [PMID: 30909928 PMCID: PMC6434780 DOI: 10.1186/s12936-019-2742-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 03/21/2019] [Indexed: 11/18/2022] Open
Abstract
Background Community composition of Anopheles mosquitoes, and their host-seeking and peridomestic behaviour, are important factors affecting malaria transmission. In this study, barrier screen sampling was used to investigate species composition, abundance, and nocturnal activity of Anopheles populations in villages of Papua New Guinea. Methods Mosquitoes were sampled from 6 pm to 6 am in five villages from 2012 to 2016. The barrier screens were positioned between the village houses and the perimeter of villages where cultivated and wild vegetation (“the bush”) grew thickly. Female Anopheles that rested on either village or bush side of the barrier screens, as they commuted into and out of the villages, were captured. Similarity in species composition among villages was assessed. Mosquitoes captured on village and bush sides of the barrier screens were sorted by feeding status and by hour of collection, and their numbers were compared using negative binomial generalized linear models. Results Females of seven Anopheles species were present in the sample. Species richness ranged from four to six species per village, but relative abundance was highly uneven within and between villages, and community composition was similar for two pairs of villages and highly dissimilar in a fifth. For most Anopheles populations, more unfed than blood-fed mosquitoes were collected from the barrier screens. More blood-fed mosquitoes were found on the side of the barrier screens facing the village and relatively more unfed ones on the bush side, suggesting commuting behaviour of unfed host-seeking females into the villages from nearby bush and commuting of blood-fed females away from villages towards the bush. For most populations, the majority of host-seeking mosquitoes arrived in the village before midnight when people were active and unprotected from the mosquitoes by bed nets. Conclusion The uneven distribution of Anopheles species among villages, with each site dominated by different species, even among nearby villages, emphasizes the importance of vector heterogeneity in local malaria transmission and control. Yet, for most species, nocturnal activity patterns of village entry and host seeking predominantly occurred before midnight indicating common behaviours across species and populations relative to human risk of exposure to Anopheles bites. Electronic supplementary material The online version of this article (10.1186/s12936-019-2742-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- John B Keven
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea. .,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA.
| | - Michelle Katusele
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Rebecca Vinit
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Gussy Koimbu
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Naomi Vincent
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | | | - Stephan Karl
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.,Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, Melbourne University, Parkville, VIC, Australia
| | - Lisa J Reimer
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Edward D Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
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19
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Pasay CJ, Yakob L, Meredith HR, Stewart R, Mills PC, Dekkers MH, Ong O, Llewellyn S, Hugo RLE, McCarthy JS, Devine GJ. Treatment of pigs with endectocides as a complementary tool for combating malaria transmission by Anopheles farauti (s.s.) in Papua New Guinea. Parasit Vectors 2019; 12:124. [PMID: 30890165 PMCID: PMC6423892 DOI: 10.1186/s13071-019-3392-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 03/08/2019] [Indexed: 11/24/2022] Open
Abstract
Background Outdoor, early-biting, zoophagic behaviours by Anopheles farauti (s.s.) can compromise the effectiveness of bed nets for malaria control. In the Western Pacific region, pigs and dogs represent significant alternative blood sources for mosquitoes. Treating these animals with endectocides may impact mosquito survival and complement control measures. This hypothesis was explored using membrane feeding assays (MFAs), direct feeds on treated pigs, pharmacokinetic analyses and a transmission model. Results Ivermectin was 375-fold more mosquitocidal than moxidectin (24 h LC50 = 17.8 ng/ml vs 6.7 µg/ml) in MFAs, and reduced mosquito fecundity by > 50% at ≥ 5 ng/ml. Treatment of pigs with subcutaneous doses of 0.6 mg/kg ivermectin caused 100% mosquito mortality 8 days after administration. Lethal effects persisted for up to 15 days after administration (75% death within 10 days). Conclusion The application of these empirical data to a unique malaria transmission model that used a three-host system (humans, pigs and dogs) predicts that the application of ivermectin will cause a significant reduction in the entomological inoculation rate (EIR = 100 to 0.35). However, this is contingent on local malaria vectors sourcing a significant proportion of their blood meals from pigs. This provides significant insights on the benefits of deploying endectocides alongside long-lasting insecticide-treated nets (LLINs) to address residual malaria transmission. Electronic supplementary material The online version of this article (10.1186/s13071-019-3392-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Cielo J Pasay
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.
| | - Laith Yakob
- Department of Disease Control, School of Hygiene and Tropical Medicine, London, London, UK
| | - Hannah R Meredith
- Department of Disease Control, School of Hygiene and Tropical Medicine, London, London, UK
| | - Romal Stewart
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Paul C Mills
- School of Veterinary Science, University of Queensland, Gatton, QLD, Australia
| | - Milou H Dekkers
- Queensland Animal Science Precinct, University of Queensland, Gatton, QLD, Australia
| | - Oselyne Ong
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Stacey Llewellyn
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - R Leon E Hugo
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - James S McCarthy
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Gregor J Devine
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.
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Pollard EJM, Russell TL, Burkot TR. Maximising mosquito collections from barrier screens: the impacts of physical design and operation parameters. Parasit Vectors 2019; 12:31. [PMID: 30642379 PMCID: PMC6332603 DOI: 10.1186/s13071-019-3291-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 01/07/2019] [Indexed: 11/18/2022] Open
Abstract
Background Traditional methods for collecting outdoor resting mosquitoes are generally inefficient with relatively low numbers caught per unit effort. The barrier screen, designed to intercept mosquitoes as they fly between areas where blood meals are obtained and oviposition sites where eggs are laid, was developed in 2013 as a novel method of sampling outdoor mosquito populations. Barrier screens do not use an odorant lure and are thus a non-mechanical, simple, low maintenance and passive sampling method for use, even in isolated locations. Methods To maximise mosquito collections from barrier screens, multiple Latin square 3 × 3 experiments were conducted in Smithfield, Queensland, Australia. Parameters of barrier screens were varied including the effects of construction materials (net weight and colour), screen design and frequency of inspections. Results Significantly more mosquitoes were collected on simple dark coloured screens of 50% or 70% shading weight with collections every 30 min. Sixty percent of mosquitoes were found on barrier screens within 60 cm of the ground. Conclusions The barrier screen is a relatively new adaptable tool that can answer a number of behavioural, ecological and epidemiological questions relevant for the surveillance and basic understanding of the movement and resting habits of mosquitoes by sex or physiological status. This method has demonstrated robustness in collecting a wide range of mosquito species as well as flexibility in where barrier screens can be deployed to explore mosquito movements within rural and peri-domestic environments. Electronic supplementary material The online version of this article (10.1186/s13071-019-3291-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Edgar J M Pollard
- Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Cairns, 4870, Australia.
| | - Tanya L Russell
- Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Cairns, 4870, Australia
| | - Thomas R Burkot
- Australian Institute of Tropical Health and Medicine, James Cook University, QLD, Cairns, 4870, Australia
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