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Benz U, Traore MM, Revay EE, Traore AS, Prozorov AM, Traoré I, Junnila A, Cui L, Saldaitis A, Kone AS, Yakovlev RV, Ziguime Y, Gergely P, Samake S, Keita A, Müller GC, Weitzel T, Rothe C. Effect of textile colour on vector mosquito host selection: a simulated field study in Mali, West Africa. J Travel Med 2024; 31:taae049. [PMID: 38498330 DOI: 10.1093/jtm/taae049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/11/2024] [Accepted: 03/14/2024] [Indexed: 03/20/2024]
Abstract
BACKGROUND The effect of clothing colour on the biting rates of different vector mosquito species is not well understood. Studies under tropical field conditions are lacking. This study aimed to determine the influence of clothing colours on mosquito biting rates in rural and suburban settings in West Africa. METHODS We performed a simulated field study in a suburban and a rural site in Mali using Mosquito-Magnet traps utilizing CO2 and other attractants, which were covered with black, white, and black/white striped textile sheets covers. These targets operated continuously for 10 consecutive days with bright nights (around full moon) and 10 consecutive days with dark nights (around new moon). Trapped mosquitoes were collected and catch rates counted hourly. Mosquitoes were morphologically identified to the species complex level (Anopheles gambiae s.l. and Culex pipiens s.l.) or species level (Aedes aegypti). A subset of Anopheles specimens were further identified by molecular methods. RESULTS Under bright-night conditions, An. gambiae s.l. was significantly more attracted to black targets than to white and striped targets; during dark nights, no target preference was noted. During bright nights, Cx. pipiens s.l. was significantly more attracted to black and striped targets than to white targets; a similar trend was noted during dark nights (not significant). For day-active Ae. aegypti, striped targets were more attractive than the other targets and black were more attractive than white targets. CONCLUSIONS The study firstly demonstrated that under field conditions in Mali, West Africa, mosquito catch rates were influenced by different clothing colours, depending on mosquito species and light conditions. Overall, light colours were least attractive to host-seeking mosquitoes. Using white or other light-coloured clothing can potentially reduce bite exposure and risk of disease transmission in endemic tropical regions.
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Affiliation(s)
- Ursula Benz
- Division of Infectious Diseases and Tropical Medicine, LMU University Hospital, Munich, Germany
| | - Mohamad M Traore
- Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technology of Bamako, Bamako, Mali
| | - Edita E Revay
- Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technology of Bamako, Bamako, Mali
| | - Amadou S Traore
- Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technology of Bamako, Bamako, Mali
| | - Alexey M Prozorov
- Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technology of Bamako, Bamako, Mali
| | - Issa Traoré
- Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technology of Bamako, Bamako, Mali
| | - Amy Junnila
- Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technology of Bamako, Bamako, Mali
| | - Liwang Cui
- Division of Infectious Diseases and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Aidas Saldaitis
- Department of Entomology, State Nature Research Centre, Institute of Ecology, Vilnius, Lithuania
| | - Aboubakr S Kone
- Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technology of Bamako, Bamako, Mali
| | - Roman V Yakovlev
- Department of Ecology, Altai State University, Barnaul, Russian Federation
| | - Younoussa Ziguime
- Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technology of Bamako, Bamako, Mali
| | - Petrányi Gergely
- Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technology of Bamako, Bamako, Mali
| | - Siriman Samake
- Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technology of Bamako, Bamako, Mali
| | - Alou Keita
- Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technology of Bamako, Bamako, Mali
| | - Günter C Müller
- Faculty of Medicine and Odonto-Stomatology, University of Sciences, Techniques and Technology of Bamako, Bamako, Mali
| | - Thomas Weitzel
- Travel Medicine Program, Clínica Alemana, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago, Chile
- Instituto de Ciencias e Innovación en Medicina (ICIM), Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago, Chile
| | - Camilla Rothe
- Division of Infectious Diseases and Tropical Medicine, LMU University Hospital, Munich, Germany
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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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3
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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: 9] [Impact Index Per Article: 4.5] [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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4
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Seidahmed O, Jamea S, Kurumop S, Timbi D, Makita L, Ahmed M, Freeman T, Pomat W, Hetzel MW. Stratification of malaria incidence in Papua New Guinea (2011-2019): Contribution towards a sub-national control policy. PLOS GLOBAL PUBLIC HEALTH 2022; 2:e0000747. [PMID: 36962582 PMCID: PMC10022348 DOI: 10.1371/journal.pgph.0000747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 10/20/2022] [Indexed: 11/22/2022]
Abstract
Malaria risk in Papua New Guinea (PNG) is highly heterogeneous, between and within geographical regions, which is operationally challenging for control. To enhance targeting of malaria interventions in PNG, we investigated risk factors and stratified malaria incidence at the level of health facility catchment areas. Catchment areas and populations of 808 health facilities were delineated using a travel-time accessibility approach and linked to reported malaria cases (2011-2019). Zonal statistics tools were used to calculate average altitude and air temperature in catchment areas before they were spatially joined with incidence rates. In addition, empirical Bayesian kriging (EBK) was employed to interpolate incidence risk strata across PNG. Malaria annual incidence rates are, on average, 186.3 per 1000 population in catchment areas up to 600 m, dropped to 98.8 at (800-1400) m, and to 24.1 cases above 1400 m altitude. In areas above the two altitudinal thresholds 600m and 1400m, the average annual temperature drops below 22°C and 17°C, respectively. EBK models show very low- to low-risk strata (<100 cases per 1000) in the Highlands, National Capital District and Bougainville. In contrast, patches of high-risk (>200 per 1000) strata are modelled mainly in Momase and Islands Regions. Besides, strata with moderate risk (100-200) predominate throughout the coastal areas. While 35.7% of the PNG population (estimated 3.33 million in 2019) lives in places at high or moderate risk of malaria, 52.2% (estimated 4.88 million) resides in very low-risk areas. In five provinces, relatively large proportions of populations (> 50%) inhabit high-risk areas: New Ireland, East and West New Britain, Sandaun and Milne Bay. Incidence maps show a contrast in malaria risk between coastal and inland areas influenced by altitude. However, the risk is highly variable in low-lying areas. Malaria interventions should be guided by sub-national risk levels in PNG.
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Affiliation(s)
- Osama Seidahmed
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
- University of Basel, Basel, Switzerland
| | - Sharon Jamea
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Serah Kurumop
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Diana Timbi
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Leo Makita
- National Department of Health, Port Moresby, Papua New Guinea
| | - Munir Ahmed
- Rotarians Against Malaria, Port Moresby, Papua New Guinea
| | - Tim Freeman
- Rotarians Against Malaria, Port Moresby, Papua New Guinea
| | - William Pomat
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Manuel W Hetzel
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
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5
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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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6
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Investigating differences in village-level heterogeneity of malaria infection and household risk factors in Papua New Guinea. Sci Rep 2021; 11:16540. [PMID: 34400687 PMCID: PMC8367982 DOI: 10.1038/s41598-021-95959-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/27/2021] [Indexed: 11/13/2022] Open
Abstract
Malaria risk is highly heterogeneous. Understanding village and household-level spatial heterogeneity of malaria risk can support a transition to spatially targeted interventions for malaria elimination. This analysis uses data from cross-sectional prevalence surveys conducted in 2014 and 2016 in two villages (Megiar and Mirap) in Papua New Guinea. Generalised additive modelling was used to characterise spatial heterogeneity of malaria risk and investigate the contribution of individual, household and environmental-level risk factors. Following a period of declining malaria prevalence, the prevalence of P. falciparum increased from 11.4 to 19.1% in Megiar and 12.3 to 28.3% in Mirap between 2014 and 2016, with focal hotspots observed in these villages in 2014 and expanding in 2016. Prevalence of P. vivax was similar in both years (20.6% and 18.3% in Megiar, 22.1% and 23.4% in Mirap) and spatial risk heterogeneity was less apparent compared to P. falciparum. Within-village hotspots varied by Plasmodium species across time and between villages. In Megiar, the adjusted odds ratio (AOR) of infection could be partially explained by household factors that increase risk of vector exposure, such as collecting outdoor surface water as a main source of water. In Mirap, increased AOR overlapped with proximity to densely vegetated areas of the village. The identification of household and environmental factors associated with increased spatial risk may serve as useful indicators of transmission hotspots and inform the development of tailored approaches for malaria control.
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7
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Rodríguez-Rodríguez D, Katusele M, Auwun A, Marem M, Robinson LJ, Laman M, Hetzel MW, Pulford J. Human Behavior, Livelihood, and Malaria Transmission in Two Sites of Papua New Guinea. J Infect Dis 2021; 223:S171-S186. [PMID: 33906224 PMCID: PMC8079136 DOI: 10.1093/infdis/jiaa402] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Background Malaria transmission is currently resurging in Papua New Guinea (PNG). In addition to intervention coverage, social and cultural factors influence changes in epidemiology of malaria in PNG. This study aimed to better understand the role of human behavior in relation to current malaria control efforts. Methods A mixed-method design was used in 2 sites in PNG. In-depth interviews, focus group discussions, cross-sectional malaria indicator survey, and population census were implemented. Results We identified 7 population groups based on demographics and behavioral patterns with potential relevance to Anopheles exposure. People spend a substantial amount of time outdoors or in semiopen structures. Between 4 pm and 8 am, all types of activities across all groups in both study sites may be exposing individuals to mosquito bites; sleeping under a long-lasting insecticidal net was the exception. The later in the night, the more outdoor presence was concentrated in adult men. Conclusions Our findings highlight the potential of outdoor exposure to hamper malaria control as people spend a remarkable amount of time outdoors without protection from mosquitoes. To prevent ongoing transmission, targeting of groups, places, and activities with complementary interventions should consider setting-specific human behaviors in addition to epidemiological and entomological data.
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Affiliation(s)
- Daniela Rodríguez-Rodríguez
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland.,Papua New Guinea Institute of Medical Research, Goroka and Madang, Papua New Guinea
| | - Michelle Katusele
- Papua New Guinea Institute of Medical Research, Goroka and Madang, Papua New Guinea
| | - Alma Auwun
- Papua New Guinea Institute of Medical Research, Goroka and Madang, Papua New Guinea
| | - Magdalene Marem
- Papua New Guinea Institute of Medical Research, Goroka and Madang, Papua New Guinea
| | - Leanne J Robinson
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.,Burnet Institute, Melbourne, Australia
| | - Moses Laman
- Papua New Guinea Institute of Medical Research, Goroka and Madang, Papua New Guinea
| | - Manuel W Hetzel
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Justin Pulford
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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8
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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: 29] [Impact Index Per Article: 7.3] [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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9
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Pollard EJM, Russell TL, Apairamo A, Burkot TR. Unique fine scale village spatial-temporal distributions of Anopheles farauti differ by physiological state and sex. Parasit Vectors 2019; 12:558. [PMID: 31771626 PMCID: PMC6878657 DOI: 10.1186/s13071-019-3815-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 11/19/2019] [Indexed: 12/05/2022] Open
Abstract
Background The ecology of many mosquitoes, including Anopheles farauti, the dominant malaria vector in the southwest Pacific including the Solomon Islands, remains inadequately understood. Studies to map fine scale vector distributions are biased when trapping techniques use lures that will influence the natural movements of mosquitoes by attracting them to traps. However, passive collection methods allow the detailed natural distributions of vector populations by sex and physiological states to be revealed. Methods The barrier screen, a passive mosquito collection method along with human landing catches were used to record An. farauti distributions over time and space in two Solomon Island villages from May 2016 to July 2017. Results Temporal and spatial distributions of over 15,000 mosquitoes, including males as well as unfed, host seeking, blood-fed, non-blood fed and gravid females were mapped. These spatial and temporal patterns varied by species, sex and physiological state. Sugar-fed An. farauti were mostly collected between 10–20 m away from houses with peak activity from 18:00 to 19:00 h. Male An. farauti were mostly collected greater than 20 m from houses with peak activity from 19:00 to 20:00 h. Conclusions Anopheles farauti subpopulations, as defined by physiological state and sex, are heterogeneously distributed in Solomon Island villages. Understanding the basis for these observed heterogeneities will lead to more accurate surveillance of mosquitoes and will enable spatial targeting of interventions for greater efficiency and effectiveness of vector control.![]()
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Affiliation(s)
- Edgar J M Pollard
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, 4870, Australia.
| | - Tanya L Russell
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, 4870, Australia
| | - Allan Apairamo
- National Vector Borne Disease Control Program, Honiara, Solomon Islands
| | - Thomas R Burkot
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, 4870, Australia
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