Larval ecology and bionomics of Anopheles funestus in highland and lowland sites in western Kenya

Background An. funestus is a major Afrotropical vector of human malaria. This study sought to investigate the larval ecology, sporozoite infection rates and blood meal sources of An. funestus in western Kenya. Methods Larval surveys were carried out in Bungoma (Highland) and Kombewa (lowland) of western Kenya. Aquatic habitats were identified, characterized, georeferenced and carefully examined for mosquito larvae and predators. Indoor resting mosquitoes were sampled using pyrethrum spray catches. Adults and larvae were morphologically and molecularly identified to species. Sporozoite infections and blood meal sources were detected using real-time PCR and ELISA respectively. Results Of the 151 aquatic habitats assessed, 62/80 (78%) in Bungoma and 58/71(82%) in Kombewa were positive for mosquito larvae. Of the 3,193 larvae sampled, An. funestus larvae constitute 38% (1224/3193). Bungoma recorded a higher number of An. funestus larvae (85%, 95%, CI, 8.722–17.15) than Kombewa (15%, 95%, CI, 1.33–3.91). Molecular identification of larvae showed that 89% (n = 80) were An. funestus. Approximately 59%, 35% and 5% of An. funestus larvae co-existed with An. gambiae s.l, Culex spp and An. coustani in the same habitats respectively. Of 1,221 An. funestus s.l adults sampled, molecular identifications revealed that An. funestus constituted 87% (n = 201) and 88% (n = 179) in Bungoma and Kombewa, respectively. The Plasmodium falciparum sporozoite rate of An. funestus in Bungoma and Kombewa was 2% (3/174) and 1% (2/157), respectively, and the human blood index of An. funestus was 84% (48/57) and 89% (39/44) and for Bungoma and Kombewa, respectively. Conclusion Man-made ponds had the highest abundance of An. funestus larvae. Multiple regression and principal component analyses identified the distance to the nearest house as the key environmental factor associated with the abundance of An. funestus larvae in aquatic habitats. This study serves as a guide for the control of An. funestus and other mosquito species to complement existing vector control strategies.

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Larval ecology and bionomics of Anopheles funestus in highland and lowland sites in western Kenya

10.1101/2021.08.04.455104 ◽

2021 ◽

Author(s):

Isaiah Debrah ◽

Yaw A Afrane ◽

Linda E. Amoah ◽

Kevin O. Ochwedo ◽

Wolfgang R. Mukabana ◽

...

Keyword(s):

Blood Meal ◽

Control Strategies ◽

Mosquito Species ◽

Anopheles Funestus ◽

Principal Component ◽

Mosquito Larvae ◽

Aquatic Habitats ◽

Larval Ecology ◽

Western Kenya ◽

Falciparum Sporozoite

Background An. funestus is a major Afrotropical vector of human malaria. This study sought to investigate the larval ecology, sporozoite infection rates and blood meal sources of An. funestus in western Kenya. Methods Larval surveys were carried out in Bungoma (Highland) and Kombewa (lowland) of western Kenya. Aquatic habitats were identified, characterized, georeferenced and carefully examined for mosquito larvae and predators. Indoor resting mosquitoes were sampled using pyrethrum spray catches. Adults and larvae were morphologically and molecularly identified to species. Sporozoite infections and blood meal sources were detected using real-time PCR and ELISA respectively. Results Of the 151 aquatic habitats assessed, 62/80 (78%) in Bungoma and 58/71(82%) in Kombewa were positive for mosquito larvae. Of the 3,193 larvae sampled, An. funestus larvae constitute 38% (1224/3193). Bungoma recorded a higher number of An. funestus larvae (85%, 95%, CI, 8.722- 17.15) than Kombewa (15%, 95%, CI, 1.33- 3.91). Molecular identification of larvae showed that 89% (n=80) were An. funestus . Approximately 59%, 35% and 5% of An. funestus larvae co-existed with An. gambiae s.l , Culex spp and An. coustani in the same habitats respectively. Of 1,221 An. funestus s.l adults sampled, molecular identifications revealed that An. funestus constituted 87% (n=201) and 88% (n=179) in Bungoma and Kombewa, respectively. The Plasmodium falciparum sporozoite rate of An. funestus in Bungoma and Kombewa was 2% (3/174) and 1% (2/157), respectively, and the human blood index of An. funestus was 84% (48/57) and 89% (39/44) and for Bungoma and Kombewa, respectively. Conclusion Man-made ponds had the highest abundance of An. funestus larvae. Multiple regression and principal component analyses identified the distance to the nearest house as the key environmental factor associated with the abundance of An. funestus larvae in aquatic habitats . This study serves as a guide for the control of An. funestus and other mosquito species to complement existing vector control strategies.

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Aquatic habitats of the malaria vector, Anopheles funestus in rural south-eastern Tanzania

10.21203/rs.3.rs-20420/v1 ◽

2020 ◽

Author(s):

Ismail Hassani Nambunga ◽

Halfan S. Ngowo ◽

Salum A. Mapua ◽

Emmanuel E. Hape ◽

Betwel J. Msugupakulya ◽

...

Keyword(s):

Control Strategies ◽

Mosquito Species ◽

Anopheles Funestus ◽

Survival Strategies ◽

Aquatic Habitats ◽

Rural South ◽

South Eastern ◽

Ecological Requirements ◽

In The Wild ◽

Slow Moving

Abstract Background In rural south-eastern Tanzania, Anopheles funestus now dominates malaria transmission, mediating nearly nine in every ten new malaria infections. However, little is known about the ecological requirements and survival strategies of this mosquito species in the wild. Methods Potential mosquito aquatic habitats were systematically searched along 1000 m transects radiating from the centers of six villages in south-eastern Tanzania. All water bodies were geo-referenced, characterized and examined for presence of Anopheles larvae using standard 350mls dippers or 10L buckets. Larvae were collected for rearing, and the emergent adults identified to generic or species level, to confirm habitats containing An. funestus . Results One hundred and eleven (111) habitats were identified and assessed from the first five villages (all <300m altitude). Of these, 36 (32.4%) had An. funestus larvae co-occurring with other mosquito species. Another 47 (42.3%) had other Anopheles species and/or culicines but not An. funestus , and 28 (25.2%) had no mosquitoes. There were three main habitat types occupied by An. funestus, namely: a) small spring-fed pools with well-defined perimeters (36.1%), b) medium-sized natural ponds retaining water most of the year (16.7%), and c) slow-moving waters along river tributaries (47.2%). The habitats generally had clear waters with emergent surface vegetation, depths > 0.5m and distances < 100m from human dwellings. They were permanent or semi-permanent, retaining water most of the year. Water temperatures ranged from 25.2 to 28.8°C, pH from 6.5 to 6.7, turbidity from 26.6 to 54.8 NTU and total dissolved solids from 60.5 to 80.3 mg/L. In the sixth village (altitude >400m), very high densities of An. funestus were found along rivers with slow-moving clear waters and emergent vegetation. Conclusion This study has documented the diversity and key characteristics of aquatic habitats of An. funestus in south-eastern Tanzania, and will form an important basis for further ecological studies towards improved control strategies. Given the observed characteristics, An. funestus habitats in the area can indeed be described as fixed, few and findable. Future studies should therefore investigate potential of targeting these habitats with larviciding or larval source management to complement malaria control efforts in areas dominated by this vector.

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Aquatic habitats of the malaria vector, Anopheles funestus in rural south-eastern Tanzania

10.21203/rs.3.rs-20420/v2 ◽

2020 ◽

Author(s):

Ismail Hassani Nambunga ◽

Halfan S. Ngowo ◽

Salum A. Mapua ◽

Emmanuel E. Hape ◽

Betwel J. Msugupakulya ◽

...

Keyword(s):

Malaria Vector ◽

Control Strategies ◽

Mosquito Species ◽

Anopheles Funestus ◽

Survival Strategies ◽

Aquatic Habitats ◽

Rural South ◽

South Eastern ◽

Ecological Requirements ◽

Slow Moving

Abstract Background: In rural south-eastern Tanzania, Anopheles funestus are a major malaria vector, and have been implicated in nearly 90% of infective bites. However, little is known about the natural ecological requirements and survival strategies of this mosquito species.Methods: Potential mosquito aquatic habitats were systematically searched along 1000 m transects radiating from the centres of six villages in south-eastern Tanzania. All water bodies were geo-referenced, characterized and examined for presence of Anopheles larvae using standard 350mls dippers or 10L buckets. Larvae were collected for rearing, and the emergent adults identified to generic or species level, to confirm habitats containing An. funestus. Results: One hundred and eleven (111) habitats were identified and assessed from the first five villages (all <300m altitude). Of these, 36 (32.4%) had An. funestus larvae co-occurring with other mosquito species. Another 47 (42.3%) had other Anopheles species and/or culicines but not An. funestus, and 28 (25.2%) had no mosquitoes. There were three main habitat types occupied by An. funestus, namely: a) small spring-fed pools with well-defined perimeters (36.1%), b) medium-sized natural ponds retaining water most of the year (16.7%), and c) slow-moving waters along river tributaries (47.2%). The habitats generally had clear waters with emergent surface vegetation, depths > 0.5m and distances < 100m from human dwellings. They were permanent or semi-permanent, retaining water most of the year. Water temperatures ranged from 25.2 to 28.8°C, pH from 6.5 to 6.7, turbidity from 26.6 to 54.8 NTU and total dissolved solids from 60.5 to 80.3 mg/L. In the sixth village (altitude >400m), very high densities of An. funestus were found along rivers with slow-moving clear waters and emergent vegetation.Conclusion: This study has documented the diversity and key characteristics of aquatic habitats of An. funestus in south-eastern Tanzania, and will form an important basis for further ecological studies towards improved control strategies. Given the observed characteristics, An. funestus habitats in the area can indeed be described as fixed, few and findable. Future studies should therefore investigate potential of targeting these habitats with larviciding or larval source management to complement malaria control efforts in areas dominated by this vector.

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Aquatic habitats of the malaria vector, Anopheles funestus in rural south-eastern Tanzania

10.21203/rs.3.rs-20420/v3 ◽

2020 ◽

Author(s):

Ismail Hassani Nambunga ◽

Halfan S. Ngowo ◽

Salum A. Mapua ◽

Emmanuel E. Hape ◽

Betwel J. Msugupakulya ◽

...

Keyword(s):

Malaria Vector ◽

Malaria Control ◽

Mosquito Species ◽

Anopheles Funestus ◽

Survival Strategies ◽

Aquatic Habitats ◽

Rural South ◽

South Eastern ◽

Ecological Requirements ◽

Slow Moving

Abstract Background In rural south-eastern Tanzania, Anopheles funestus is a major malaria vector, and has been implicated in nearly 90% of all infective bites. Unfortunately, little is known about the natural ecological requirements and survival strategies of this mosquito species.Methods Potential mosquito aquatic habitats were systematically searched along 1000 m transects from the centres of six villages in south-eastern Tanzania. All water bodies were geo-referenced, characterized and examined for presence of Anopheles larvae using standard 350mls dippers or 10L buckets. Larvae were collected for rearing, and the emergent adults identified to confirm habitats containing An. funestus.Results One hundred and eleven (111) habitats were identified and assessed from the first five villages (all <300m altitude). Of these, 36 (32.4%) had An. funestus co-occurring with other mosquito species. Another 47 (42.3%) had other Anopheles species and/or culicines, but not An. funestus, and 28 (25.2%) had no mosquitoes. There were three main habitat types occupied by An. funestus, namely: a) small spring-fed pools with well-defined perimeters (36.1%), b) medium-sized natural ponds retaining water most of the year (16.7%), and c) slow-moving waters along river tributaries (47.2%). The habitats generally had clear waters with emergent surface vegetation, depths > 0.5m and distances < 100m from human dwellings. They were permanent or semi-permanent, retaining water most of the year. Water temperatures ranged from 25.2 to 28.8°C, pH from 6.5 to 6.7, turbidity from 26.6 to 54.8 NTU and total dissolved solids from 60.5 to 80.3 mg/L. In the sixth village (altitude >400m), very high densities of An. funestus were found along rivers with slow-moving clear waters and emergent vegetation.Conclusion This study has documented the diversity and key characteristics of aquatic habitats of An. funestus across villages in south-eastern Tanzania, and will form an important basis for further studies to improve malaria control. The observations suggest that An. funestus habitats in the area can indeed be described as fixed, few and findable based on their unique characteristics. Future studies should investigate the potential of targeting these habitats with larviciding or larval source management to complement malaria control efforts in areas dominated by this vector species.

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Empidomermis cozii n.gen., n.sp. (Mermithidae: Nematoda) a parasite of Anopheles funestus (Culicidae: Diptera) in West Africa

Canadian Journal of Zoology ◽

10.1139/z77-191 ◽

1977 ◽

Vol 55 (9) ◽

pp. 1475-1479 ◽

Cited By ~ 6

Author(s):

George O. Poinar Jr.

Keyword(s):

Blood Meal ◽

New Genus ◽

Adult Stage ◽

Anopheles Funestus ◽

Mosquito Larvae ◽

New Genus And Species ◽

Body Width ◽

Adult Females ◽

Mermithid Nematode ◽

Upper Volta

A new genus and species of mermithid nematode parasitizing adult females of Anopheles funestus (Giles) in Upper Volta is described. The new genus Empidomermis is characterized by having six head papillae, eight hypodermal cords, cuticle without noticeable cross fibers, two short slightly curved spicules (equal to or less than body width at cloaca), a relatively short S-shaped vagina, small amphids, and postparasitic juveniles with a well-developed tail appendage.The nematodes could only be successfully reared to maturity if the hosts were held on glucose 3–4 days after the blood meal. Postparasitic juvenile mermithids molted to the adult stage about 17 days after leaving their mosquito hosts and mating and oviposition occurred immediately afterwards. The eggs hatched about 54 days after oviposition when mosquito larvae were added to the container. Parasitized adult female A. funestus were sterilized and died soon after the nematodes emerged.

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Detection of Plasmodium sporozoites in Anopheles coustani s.l; a hindrance to malaria control strategies in highlands of western Kenya

10.1101/2021.02.10.430589 ◽

2021 ◽

Author(s):

Ayuya Stephen ◽

Kitungulu Nicholas ◽

Annette O. Busula ◽

Mark Kilongosi Webale ◽

Elizabeth Omukunda

Keyword(s):

Malaria Transmission ◽

Control Strategies ◽

Mosquito Species ◽

Cross Sectional Study ◽

Light Traps ◽

Chain Reaction ◽

Cross Sectional ◽

Western Kenya ◽

Polymerase Chain ◽

Sub Saharan

AbstractRe-emerging of high malaria incidences in highlands of western Kenya pose a challenge to malaria eradication efforts. Anopheles coustani is a sub-Saharan mosquito species implicated in transmission of malaria in many parts of Africa as a secondary vector. It is a zoo-anthropophilic species that has been assumed to be of negligible importance. A cross sectional study was carried out in April to June, 2020 in Eluche location, Mumias East sub-County, Kakamega County, Kenya to establish the contribution of Anopheles coustani in malaria transmission. Pyrethrum spray collections (PSC) and Centers for Disease Control (CDC) and prevention light traps were used for sampling mosquitoes. Mosquitoes were collected from both indoors; between 0700h and 1100h using PSC and outdoors between 1800h and 0700h using CDC light traps. All mosquitoes were identified morphologically and female Anopheles’ heads and thorax were analyzed further using Polymerase Chain Reaction (PCR) for Plasmodium sporozoite. A total of 188 female Anopheles mosquitoes were collected from both PSC and CDC light traps. This constituted of; 80(42.55%) An. coustani, 52(27.66%) An. funestus, 47(25.00%) An. maculipulpis, 8(4.26%) An. arabiensis and 1(0.53%) An. gambiae. Malaria sporozoite detection was done to all the Anopheles female mosquitoes but only two An. coustani tested positive for Plasmodium falciparum. In conclusion, Anopheles coustani plays a major role in outdoor malaria transmission in Mumias East Sub-County of Kakamega County in Western Kenya.

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Microbiota identified from preserved Anopheles

Malaria Journal ◽

10.1186/s12936-021-03754-7 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Bianca E Silva ◽

Zvifadzo Matsena Zingoni ◽

Lizette L. Koekemoer ◽

Yael L. Dahan-Moss

Keyword(s):

Microbial Diversity ◽

Vector Competence ◽

Mosquito Species ◽

Anopheles Funestus ◽

Cost Effective ◽

Diversity Indices ◽

Malaria Vectors ◽

Microbial Composition ◽

Culture Independent ◽

Culture Dependent

Abstract Background Mosquito species from the Anopheles gambiae complex and the Anopheles funestus group are dominant African malaria vectors. Mosquito microbiota play vital roles in physiology and vector competence. Recent research has focused on investigating the mosquito microbiota, especially in wild populations. Wild mosquitoes are preserved and transported to a laboratory for analyses. Thus far, microbial characterization post-preservation has been investigated in only Aedes vexans and Culex pipiens. Investigating the efficacy of cost-effective preservatives has also been limited to AllProtect reagent, ethanol and nucleic acid preservation buffer. This study characterized the microbiota of African Anopheles vectors: Anopheles arabiensis (member of the An. gambiae complex) and An. funestus (member of the An. funestus group), preserved on silica desiccant and RNAlater® solution. Methods Microbial composition and diversity were characterized using culture-dependent (midgut dissections, culturomics, MALDI-TOF MS) and culture-independent techniques (abdominal dissections, DNA extraction, next-generation sequencing) from laboratory (colonized) and field-collected mosquitoes. Colonized mosquitoes were either fresh (non-preserved) or preserved for 4 and 12 weeks on silica or in RNAlater®. Microbiota were also characterized from field-collected An. arabiensis preserved on silica for 8, 12 and 16 weeks. Results Elizabethkingia anophelis and Serratia oryzae were common between both vector species, while Enterobacter cloacae and Staphylococcus epidermidis were specific to females and males, respectively. Microbial diversity was not influenced by sex, condition (fresh or preserved), preservative, or preservation time-period; however, the type of bacterial identification technique affected all microbial diversity indices. Conclusions This study broadly characterized the microbiota of An. arabiensis and An. funestus. Silica- and RNAlater®-preservation were appropriate when paired with culture-dependent and culture-independent techniques, respectively. These results broaden the selection of cost-effective methods available for handling vector samples for downstream microbial analyses.

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Assessing Diversity, Plasmodium Infection and Blood Meal Sources in Mosquitoes (Diptera: Culicidae) from a Brazilian Zoological Park with Avian Malaria Transmission

Insects ◽

10.3390/insects12030215 ◽

2021 ◽

Vol 12 (3) ◽

pp. 215

Author(s):

Lilian de Oliveira Guimarães ◽

Roseli França Simões ◽

Carolina Romeiro Fernandes Chagas ◽

Regiane Maria Tironi de Menezes ◽

Fabiana Santos Silva ◽

...

Keyword(s):

Blood Meal ◽

Avian Malaria ◽

Mosquito Species ◽

Plasmodium Species ◽

Sao Paulo ◽

São Paulo ◽

Malaria Parasites ◽

Ecological Relationships ◽

Lack Of Information ◽

Avian Malaria Parasites

Avian malaria parasites are widespread parasites transmitted by Culicidae insects belonging to different genera. Even though several studies have been conducted recently, there is still a lack of information about potential vectors of Plasmodium parasites, especially in Neotropical regions. Former studies with free-living and captive animals in São Paulo Zoo showed the presence of several Plasmodium and Haemoproteus species. In 2015, a pilot study was conducted at the zoo to collect mosquitoes in order to find out (i) which species of Culicidae are present in the study area, (ii) what are their blood meal sources, and (iii) to which Plasmodium species might they be potential vectors. Mosquitoes were morphologically and molecularly identified. Blood meal source and haemosporidian DNA were identified using molecular protocols. A total of 25 Culicidae species were identified, and 6 of them were positive for Plasmodium/Haemoproteus DNA. Ten mosquito species had their source of blood meal identified, which were mainly birds, including some species that were positive for haemosporidian parasites in the former study mentioned. This study allowed us to expand the list of potential vectors of avian malaria parasites and to improve our knowledge of the evolutionary and ecological relationships between the highly diverse communities of birds, parasites, and vectors present at São Paulo Zoo.

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Mosquito Control Priorities in Florida—Survey Results from Florida Mosquito Control Districts

Pathogens ◽

10.3390/pathogens10080947 ◽

2021 ◽

Vol 10 (8) ◽

pp. 947

Author(s):

Rishi Kondapaneni ◽

Ashley N. Malcolm ◽

Brian M. Vazquez ◽

Eric Zeng ◽

Tse-Yu Chen ◽

...

Keyword(s):

State Government ◽

Mosquito Control ◽

Control Strategies ◽

Mosquito Species ◽

Research Priorities ◽

Current Control ◽

Control Programs ◽

Common Control ◽

Surveillance Programs ◽

Research Questions

Florida lies within a subtropical region where the climate allows diverse mosquito species including invasive species to thrive year-round. As of 2021, there are currently 66 state-approved Florida Mosquito Control Districts, which are major stakeholders for Florida public universities engaged in mosquito research. Florida is one of the few states with extensive organized mosquito control programs. The Florida State Government and Florida Mosquito Control Districts have long histories of collaboration with research institutions. During fall 2020, we carried out a survey to collect baseline data on the current control priorities from Florida Mosquito Control Districts relating to (1) priority control species, (2) common adult and larval control methods, and (3) major research questions to address that will improve their control and surveillance programs. The survey data showed that a total of 17 distinct mosquito species were considered to be priority control targets, with many of these species being understudied. The most common control approaches included truck-mounted ultra-low-volume adulticiding and biopesticide-based larviciding. The districts held interest in diverse research questions, with many prioritizing studies on basic science questions to help develop evidence-based control strategies. Our data highlight the fact that mosquito control approaches and priorities differ greatly between districts and provide an important point of comparison for other regions investing in mosquito control, particularly those with similar ecological settings, and great diversity of potential mosquito vectors, such as in Florida. Our findings highlight a need for greater alignment of research priorities between mosquito control and mosquito research. In particular, we note a need to prioritize filling knowledge gaps relating to understudied mosquito species that have been implicated in arbovirus transmission.

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Application of multivariable statistical techniques in plant-wide WWTP control strategies analysis

Water Science & Technology ◽

10.2166/wst.2007.586 ◽

2007 ◽

Vol 56 (6) ◽

pp. 75-83 ◽

Cited By ~ 3

Author(s):

X. Flores ◽

J. Comas ◽

I.R. Roda ◽

L. Jiménez ◽

K.V. Gernaey

Keyword(s):

Cluster Analysis ◽

Control Strategies ◽

Treatment Plant ◽

Principal Component ◽

Statistical Techniques ◽

Data Sets ◽

Data Set ◽

Casual Relation ◽

Evaluation Matrix ◽

Natural Groups

The main objective of this paper is to present the application of selected multivariable statistical techniques in plant-wide wastewater treatment plant (WWTP) control strategies analysis. In this study, cluster analysis (CA), principal component analysis/factor analysis (PCA/FA) and discriminant analysis (DA) are applied to the evaluation matrix data set obtained by simulation of several control strategies applied to the plant-wide IWA Benchmark Simulation Model No 2 (BSM2). These techniques allow i) to determine natural groups or clusters of control strategies with a similar behaviour, ii) to find and interpret hidden, complex and casual relation features in the data set and iii) to identify important discriminant variables within the groups found by the cluster analysis. This study illustrates the usefulness of multivariable statistical techniques for both analysis and interpretation of the complex multicriteria data sets and allows an improved use of information for effective evaluation of control strategies.

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