Dataset Information

Blood Meal Sources of Anopheles spp. in Malaria Endemic Areas of Honduras.

ABSTRACT: Malaria remains a life-threatening disease in many tropical countries. Honduras has successfully reduced malaria transmission as different control methods have been applied, focusing mainly on indoor mosquitoes. The selective pressure exerted by the use of insecticides inside the households could modify the feeding behavior of the mosquitoes, forcing them to search for available animal hosts outside the houses. These animal hosts in the peridomicile could consequently become an important factor in maintaining vector populations in endemic areas. Herein, we investigated the blood meal sources and Plasmodium spp. infection on anophelines collected outdoors in endemic areas of Honduras. Individual PCR reactions with species-specific primers were used to detect five feeding sources on 181 visibly engorged mosquitoes. In addition, a subset of these mosquitoes was chosen for pathogen analysis by a nested PCR approach. Most mosquitoes fed on multiple hosts (2 to 4), and 24.9% of mosquitoes had fed on a single host, animal or human. Chicken and bovine were the most frequent blood meal sources (29.5% and 27.5%, respectively). The average human blood index (HBI) was 22.1%. None of the mosquitoes were found to be infected with Plasmodium spp. Our results show the opportunistic and zoophilic behavior of Anopheles mosquitoes in Honduras.

SUBMITTER: Escobar D

PROVIDER: S-EPMC7412045 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature

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Blood Meal Sources of <i>Anopheles</i> spp. in Malaria Endemic Areas of Honduras.

Escobar Denis D Ascencio Krisnaya K Ortiz Andrés A Palma Adalid A Sánchez Ana A Fontecha Gustavo G

Insects 20200716 7

Malaria remains a life-threatening disease in many tropical countries. Honduras has successfully reduced malaria transmission as different control methods have been applied, focusing mainly on indoor mosquitoes. The selective pressure exerted by the use of insecticides inside the households could modify the feeding behavior of the mosquitoes, forcing them to search for available animal hosts outside the houses. These animal hosts in the peridomicile could consequently become an important factor ...[more]

PMID: 32708582

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Project description:BackgroundAnopheles mosquitoes are the vectors of malaria, one of the most important infectious diseases in the tropics. More than 500 Anopheles species have been described worldwide, and more than 30 are considered a public health problem. In Honduras, information on the distribution of Anopheles spp. and its genetic diversity is scarce. This study aimed to describe the distribution and genetic diversity of Anopheles mosquitoes in Honduras.MethodsMosquitoes were captured in 8 locations in 5 malaria endemic departments during 2019. Two collection methods were used. Adult anophelines were captured outdoors using CDC light traps and by aspiration of mosquitoes at rest. Morphological identification was performed using taxonomic keys. Genetic analyses included the sequencing of a partial region of the cytochrome c oxidase 1 gene (cox1) and the ribosomal internal transcribed spacer 2 (ITS2).ResultsA total of 1320 anophelines were collected and identified through morphological keys. Seven Anopheles species were identified. Anopheles albimanus was the most widespread and abundant species (74.02%). To confirm the morphological identification of the specimens, 175 and 122 sequences were obtained for cox1 and ITS2, respectively. Both markers confirmed the morphological identification. cox1 showed a greater nucleotide diversity than ITS2 in all species. High genetic diversity was observed within the populations of An. albimanus while An. darlingi proved to be a highly homogeneous population. Phylogenetic analyses revealed clustering patterns in An. darlingi and An. neivai in relation to specimens from South America. New sequences for An. crucians, An. vestitipennis and An. neivai are reported in this study.ConclusionsHere we report the distribution and genetic diversity of Anopheles species in endemic areas of malaria transmission in Honduras. According to our results, both taxonomic and molecular approaches are useful tools in the identification of anopheline mosquitoes. However, both molecular markers differ in their ability to detect intraspecific genetic diversity. These results provide supporting data for a better understanding of the distribution of malaria vectors in Honduras.

Project description:Considering the diversity of feeding habits that females of some species of anophelines present, it is important to understand which vertebrates are part of blood food sources and how important is the role of each in the ecoepidemiology of malaria. There are many vector species for Plasmodium spp. in the State of Maranhão, Brazil. In São Luís Island, Anopheles aquasalis is the main vector for human malaria; this species is abundant in areas with primates that are positive for Plasmodium. Anopheles aquasalis has natural exophilic and zoophilic feeding behavior, but in cases of high density and absence of animals, presents quite varied behavior, and feeds on human blood. In this context, the objective of the present study was to identify Plasmodium spp. and the blood meal sources of anophelines in two environmental reserves on São Luís Island, state of Maranhão, using molecular methods.Between June and July 2013, female anophelines were collected in the Sítio Aguahy Private Reserve, in the municipality of São José de Ribamar, and in the Sítio Mangalho Reserve, located within the Maracanã Environmental Protection Area, in the municipality of São Luís. CDC-type light traps, Shannon traps and protected human bait were used during three consecutive hours in peridomestic and wooded areas. Pools of anophelines were formed using mosquitoes of the same species that had been caught at the same site on the same date. A genus-specific amplification protocol based on the 18S rRNA gene was used for qPCR and cPCR.A total of 416 anophelines were collected, of the following species: An. aquasalis (399), An. mediopunctatus (3), An. shannoni (1), An. nuneztovari (sensu lato) (1), An. goeldii (1), An. evansae (2) and An. (Nyssorhynchus) sp. (9), comprising 54 pools. Two pools were positive for Plasmodium (2/54) based on the 18S rRNA gene. In the phylogenetic analysis using the maximum likelihood method, based on a 240 bp fragment of the 18S rRNA gene, it was found that the sequences of Plasmodium sp. amplified from pools of An. aquasalis (pool 2) and An. nuneztovari (s.l.) (pool 10) were phylogenetically related to a clade of P. falciparum isolates from India, and to a clade of Plasmodium sp. isolates from psittacines in Brazil, respectively. Cat, dog and human DNA were identified in the blood meals of the anophelines sampled.The species An. aquasalis was the most abundant anopheline species in São Luís Island. Plasmodium spp. DNA was detected, thus confirming the importance of this species as the main vector on São Luís Island, Brazil. In addition, the presence of An. nuneztovari (s.l.) with DNA positive for Plasmodium spp. confirms its importance as a secondary vector.

Project description:BackgroundGenetic diversity is a key factor that enables adaptation and persistence of natural populations towards environmental conditions. It is influenced by the interaction of a natural population's dynamics and the environment it inhabits. Anopheles gambiae s.s. and Anopheles arabiensis are the two major and widespread malaria vectors in sub-Saharan Africa. Several studies have examined the ecology and population dynamics of these vectors. Ecological conditions along the Kilombero valley in Tanzania influence the distribution and population density of these two vector species. It remains unclear whether the ecological diversity within the Kilombero valley has affected the population structure of An. gambiae s.l. populations. The goal of this study was to characterise the genetic structure of sympatric An. gambiae s.s and An. arabiensis populations along the Kilombero valley.MethodologyMosquitoes were collected from seven locations in Tanzania: six from the Kilombero valley and one outside the valley (-700 km away) as an out-group. To archive a genome-wide coverage, 13 microsatellite markers from chromosomes X, 2 and 3 were used.ResultsHigh levels of genetic differentiation among An. arabiensis populations was observed, as opposed to An. gambiae s.s., which was genetically undifferentiated across the 6,650 km2 of the Kilombero valley landscape. It appears that genetic differentiation is not attributed to physical barriers or distance, but possibly by ecological diversification within the Kilombero valley. Genetic divergence among An. arabiensis populations (FST = 0.066) was higher than that of the well-known M and S forms of An. gambiae s. s. in West and Central Africa (FST = 0.035), suggesting that these populations are maintained by some level of reproductive isolation.ConclusionIt was hypothesized that ecological diversification across the valley may be a driving force for observed An. arabiensis genetic divergence. The impact of the observed An. arabiensis substructure to the prospects for new vector control approaches is discussed.

Project description:Chagas disease is a complex vector borne parasitic disease involving blood feeding Triatominae (Hemiptera: Reduviidae) insects, also known as kissing bugs, and the vertebrates they feed on. This disease has tremendous impacts on millions of people and is a global health problem. The etiological agent of Chagas disease, Trypanosoma cruzi (Kinetoplastea: Trypanosomatida: Trypanosomatidae), is deposited on the mammalian host in the insect's feces during a blood meal, and enters the host's blood stream through mucous membranes or a break in the skin. Identifying the blood meal sources of triatomine vectors is critical in understanding Chagas disease transmission dynamics, can lead to identification of other vertebrates important in the transmission cycle, and aids management decisions. The latter is particularly important as there is little in the way of effective therapeutics for Chagas disease. Several techniques, mostly DNA-based, are available for blood meal identification. However, further methods are needed, particularly when sample conditions lead to low-quality DNA or to assess the risk of human cross-contamination. We demonstrate a proteomics-based approach, using liquid chromatography tandem mass spectrometry (LC-MS/MS) to identify host-specific hemoglobin peptides for blood meal identification in mouse blood control samples and apply LC-MS/MS for the first time to Triatoma dimidiata insect vectors, tracing blood sources to species. In contrast to most proteins, hemoglobin, stabilized by iron, is incredibly stable even being preserved through geologic time. We compared blood stored with and without an anticoagulant and examined field-collected insect specimens stored in suboptimal conditions such as at room temperature for long periods of time. To our knowledge, this is the first study using LC-MS/MS on field-collected arthropod disease vectors to identify blood meal composition, and where blood meal identification was confirmed with more traditional DNA-based methods. We also demonstrate the potential of synthetic peptide standards to estimate relative amounts of hemoglobin acquired when insects feed on multiple blood sources. These LC-MS/MS methods can contribute to developing Ecohealth control strategies for Chagas disease transmission and can be applied to other arthropod disease vectors.

Dataset Information

Blood Meal Sources of Anopheles spp. in Malaria Endemic Areas of Honduras.

Publications

Blood Meal Sources of <i>Anopheles</i> spp. in Malaria Endemic Areas of Honduras.

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