Impact of sugarcane irrigation on malaria vector Anopheles mosquito fauna, abundance and seasonality in Arjo-Didessa, Ethiopia

Abstract BackgroundDespite extensive irrigation development in Ethiopia, limited studies assessed the impact of irrigation on malaria vector mosquito composition, abundance and seasonality. This study aimed to evaluate the impact of sugarcane irrigation on species composition, abundance and seasonality of malaria vectors.MethodsAdult Anopheles mosquitoes were collected using CDC light traps from three irrigated and three non-irrigated clusters in and around Arjo-Didessa sugarcane irrigation scheme in southwestern Ethiopia. Mosquitoes were surveyed in four seasons: two wet and two dry, in 2018 and 2019. Mosquito species composition, abundance and seasonality were compared between irrigated and non-irrigated clusters. Anopheles mosquitoes were sorted out to species using morphological keys and molecular techniques. Chi-square was used to test the relationships between Anopheles species occurrence, and environmental and seasonal parameters.ResultsOverall, 2,108 female Anopheles mosquitoes comprising of six species were collected. Of these, 92.7% (n=1,954) were from irrigated clusters and 7.3% (n=154) from the non-irrigated. The Anopheles gambiae complex was the most abundant (67.3%) followed by Anopheles coustani complex (25.3 %) and Anopheles pharoensis (5.7%). PCR-based identification revealed that 74.7% (n=168) of the An. gambiae comlex were Anopheles arabiensis and 22.7% (n=51) Anopheles amharicus. The density of An. gambiae complex (both indoor and outdoor) was higher in irrigated than non-irrigated clusters. The overall anopheline mosquito abundance during the wet seasons (87.2%; n=1,837) was higher than the dry seasons (12.8%; n=271).ConclusionThe ongoing sugarcane irrigation activities in Arjo-Didessa created conditions suitable for malaria transmitting Anopheles species diversity and abundance. This could drive malaria transmission in Arjo-Didessa and its environs in both dry and wet seasons. Currently practiced malaria vector interventions need to be strengthened by including larval source management to reduce vector abundance in the irrigated areas.

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Impact of sugarcane irrigation on malaria vector Anopheles mosquito fauna, abundance and seasonality in Arjo-Didessa, Ethiopia

10.21203/rs.3.rs-37850/v3 ◽

2020 ◽

Author(s):

Assalif Demissew Shifera ◽

Dawit Hawaria ◽

Solomon Kibret ◽

Abebe Animut ◽

Arega Tsegaye ◽

...

Keyword(s):

Species Composition ◽

Malaria Vector ◽

Mosquito Species ◽

Malaria Vectors ◽

Anopheline Mosquito ◽

Chi Square ◽

Anopheles Species ◽

Mosquito Abundance ◽

Anopheles Mosquitoes ◽

The Impact

Abstract Background: Although irrigation activities are increasing in Ethiopia, limited studies evaluated their impact on malaria vector mosquito composition, abundance and seasonality. This study aimed at evaluating the impact of sugarcane irrigation on species composition, abundance and seasonality of malaria vectors. Methods : Adult Anopheles mosquitoes were collected using CDC light traps from three irrigated and three non-irrigated clusters in and around Arjo-Didessa sugarcane irrigation scheme in southwestern Ethiopia. Mosquito collections were conducted in four seasons: two wet and two dry, in 2018 and 2019. Mosquito species composition, abundance and seasonality were compared between irrigated and non-irrigated clusters. Anopheles mosquitoes were identified to species using morphological keys and An. gambiae s.l to sibling species using PCR. Chi-square was used to analyze the association between Anopheles species occurrence and environmental and seasonal parameters. Results: Overall, 2,108 female Anopheles mosquitoes comprising of six species were collected. Of these, 92.7% (n=1954) were from irrigated clusters and 7.3% (n=154) from the non-irrigated. An. gambiae s.l was the most abundant (67.3%) followed by An. coustani complex (25.3 %) and An. pharoensis (5.7%). PCR based identification revealed that 74.7% (n=168) of the An. gambiae s.l were An. arabiensis and 22.7% (n=51) An. amharicus . Density of An. gambiae s.l. (both indoor and outdoor) was higher in irrigated than non-irrigated clusters. The overall anopheline mosquito abundance during the wet seasons (87.2%; n=1837) was higher than the dry seasons (12.8%; n=271). Conclusion : The ongoing sugarcane irrigation activities in Arjo-Didessa created conditions suitable for increased malaria transmitting Anopheles species diversity and abundance. This in turn could drive malaria transmission in Arjo-Didessa and its environs in both dry and wet seasons. Thus, currently practiced malaria vector interventions need to be strengthened and consider larval source management to reduce vector abundance in the irrigated areas. Key Words: Malaria, Irrigation, Anopheles mosquitoes, vector density, An. amharicus , Ethiopia

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Impact of Sugarcane Irrigation on Malaria Vector Anopheles Mosquito Fauna, Abundance and Seasonality in Arjo-Didessa, Ethiopia

10.21203/rs.3.rs-37850/v1 ◽

2020 ◽

Author(s):

Assalif Demissew Shifera ◽

Dawit Hawaria ◽

Solomon Kibret ◽

Abebe Animut ◽

Arega Tsegaye ◽

...

Keyword(s):

Species Composition ◽

Malaria Vector ◽

Mosquito Species ◽

Malaria Vectors ◽

Anopheline Mosquito ◽

Chi Square ◽

Anopheles Species ◽

Mosquito Abundance ◽

Anopheles Mosquitoes ◽

The Impact

Abstract Background: Although irrigation activities are increasing in Ethiopia, limited studies evaluated their impact on malaria vector mosquito composition, abundance and seasonality. This study aimed at evaluating the impact of sugarcane irrigation on species composition, abundance and seasonality of malaria vectors. Methods: Adult Anopheles mosquitoes were collected using CDC light traps from three irrigated and three non-irrigated clusters in and around Arjo-Didessa sugarcane irrigation scheme in southwestern Ethiopia. Mosquito collections were conducted in four seasons: two wet and two dry, in 2018 and 2019. Mosquito species composition, abundance and seasonality were compared between irrigated and non-irrigated clusters. Anopheles mosquitoes were identified to species using morphological keys and An. gambiae s.l to sibling species using PCR. Chi-square was used to analyze the association between Anopheles species occurrence and environmental and seasonal parameters. Results: Overall, 2,108 female Anopheles mosquitoes comprising of six species were collected. Of these, 92.7% (n=1954) were from irrigated clusters and 7.3% (n=154) from the non-irrigated. An. gambiae s.l was the most abundant (67.3%) followed by An. coustani complex (25.3 %) and An. pharoensis (5.7%). PCR based identification revealed that 74.7% (n=168) of the An. gambiae s.l were An. arabiensis and 22.7% (n=51) An. amharicus. Density of An. gambiae s.l. (both indoor and outdoor) was higher in irrigated than non-irrigated clusters. The overall anopheline mosquito abundance during the wet seasons (87.2%; n=1837) was higher than the dry seasons (12.8%; n=271). Conclusion: The ongoing sugarcane irrigation activities in Arjo-Didessa created conditions suitable for increased malaria transmitting Anopheles species diversity and abundance. This in turn could drive malaria transmission in Arjo-Didessa and its environs in both dry and wet seasons. Thus, currently practiced malaria vector interventions need to be strengthened and consider larval source management to reduce vector abundance in the irrigated areas.

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Impact of sugarcane irrigation on malaria vector Anopheles mosquito fauna, abundance and seasonality in Arjo-Didessa, Ethiopia

Malaria Journal ◽

10.1186/s12936-020-03416-0 ◽

2020 ◽

Vol 19 (1) ◽

Author(s):

Assalif Demissew ◽

Dawit Hawaria ◽

Solomon Kibret ◽

Abebe Animut ◽

Arega Tsegaye ◽

...

Keyword(s):

Species Composition ◽

Malaria Vector ◽

Mosquito Species ◽

Molecular Techniques ◽

Malaria Vectors ◽

Anopheline Mosquito ◽

Chi Square ◽

Mosquito Abundance ◽

Southwestern Ethiopia ◽

The Impact

Abstract Background Despite extensive irrigation development in Ethiopia, limited studies assessed the impact of irrigation on malaria vector mosquito composition, abundance and seasonality. This study aimed to evaluate the impact of sugarcane irrigation on species composition, abundance and seasonality of malaria vectors. Methods Adult Anopheles mosquitoes were collected using CDC light traps from three irrigated and three non-irrigated clusters in and around Arjo-Didessa sugarcane irrigation scheme in southwestern Ethiopia. Mosquitoes were surveyed in four seasons: two wet and two dry, in 2018 and 2019. Mosquito species composition, abundance and seasonality were compared between irrigated and non-irrigated clusters. Anopheles mosquitoes were sorted out to species using morphological keys and molecular techniques. Chi square was used to test the relationships between Anopheles species occurrence, and environmental and seasonal parameters. Results Overall, 2108 female Anopheles mosquitoes comprising of six species were collected. Of these, 92.7% (n = 1954) were from irrigated clusters and 7.3% (n = 154) from the non-irrigated. The Anopheles gambiae complex was the most abundant (67.3%) followed by Anopheles coustani complex (25.3%) and Anopheles pharoensis (5.7%). PCR-based identification revealed that 74.7% (n = 168) of the An. gambiae complex were Anopheles arabiensis and 22.7% (n = 51) Anopheles amharicus. The density of An. gambiae complex (both indoor and outdoor) was higher in irrigated than non-irrigated clusters. The overall anopheline mosquito abundance during the wet seasons (87.2%; n = 1837) was higher than the dry seasons (12.8%; n = 271). Conclusion The ongoing sugarcane irrigation activities in Arjo-Didessa created conditions suitable for malaria transmitting Anopheles species diversity and abundance. This could drive malaria transmission in Arjo-Didessa and its environs in both dry and wet seasons. Currently practiced malaria vector interventions need to be strengthened by including larval source management to reduce vector abundance in the irrigated areas.

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Impact of sugarcane irrigation on malaria vector Anopheles mosquito fauna, abundance and seasonality in Arjo-Didessa, Ethiopia

10.21203/rs.3.rs-37850/v2 ◽

2020 ◽

Author(s):

Assalif Demissew Shifera ◽

Dawit Hawaria ◽

Solomon Kibret ◽

Abebe Animut ◽

Arega Tsegaye ◽

...

Keyword(s):

Species Composition ◽

Malaria Vector ◽

Mosquito Species ◽

Molecular Techniques ◽

Malaria Vectors ◽

Chi Square ◽

Mosquito Abundance ◽

Southwestern Ethiopia ◽

Four Seasons ◽

The Impact

Abstract Background: Despite extensive irrigation development in Ethiopia, limited studies assessed the impact of irrigation on malaria vector mosquito composition, abundance and seasonality. This study aimed at evaluating the impact of sugarcane irrigation on species composition, abundance and seasonality of malaria vectors. Methods: Adult Anopheles mosquitoes were collected using CDC light traps from three irrigated and three non-irrigated clusters in and around Arjo-Didessa sugarcane irrigation scheme in southwestern Ethiopia. Mosquitoes were surveyed in four seasons: two wet and two dry, in 2018 and 2019. Mosquito species composition, abundance and seasonality were compared between irrigated and non-irrigated clusters. Anopheles mosquitoes were sorted out to species using morphological keys and molecular techniques. Chi-square was used to test the relationships between Anopheles species occurrence, and environmental and seasonal parameters. Results: Overall, 2,108 female Anopheles mosquitoes comprising of six species were collected. Of these, 92.7% (n=1954) were from irrigated clusters and 7.3% (n=154) from the non-irrigated. An. gambiae s.l was the most abundant (67.3%) followed by An. coustani complex (25.3 %) and An. pharoensis (5.7%). PCR based identification revealed that 74.7% (n=168) of the An. gambiae s.l were An. arabiensis and 22.7% (n=51) An. amharicus. Density of An. gambiae s.l. (both indoor and outdoor) was higher in irrigated than non-irrigated clusters. The overall anopheline mosquito abundance during the wet seasons (87.2%; n=1837) was higher than the dry seasons (12.8%; n=271).Conclusion: The ongoing sugarcane irrigation activities in Arjo-Didessa created conditions suitable for malaria transmitting Anopheles species diversity and abundance. This could drive malaria transmission in Arjo-Didessa and its environs in both dry and wet seasons. Thus, currently practiced malaria vector interventions need to be strengthened by including larval source management to reduce vector abundance in the irrigated areas.

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Anopheline Mosquito Species Composition, Kdr Mutation Frequency, and Parasite Infectivity Status in Northern Tanzania

Journal of Medical Entomology ◽

10.1093/jme/tjz245 ◽

2020 ◽

Vol 57 (3) ◽

pp. 933-938 ◽

Cited By ~ 1

Author(s):

Eliningaya J Kweka ◽

Humphrey D Mazigo ◽

Lucile J Lyaruu ◽

Emmanuel A Mausa ◽

Nelius Venter ◽

...

Keyword(s):

Species Composition ◽

Malaria Transmission ◽

Malaria Vector ◽

Mosquito Species ◽

Malaria Prevalence ◽

Vector Species ◽

Anopheline Mosquito ◽

Larval Stages ◽

Northern Tanzania ◽

Homozygous Resistant

Abstract The scaling-up of malaria control interventions in northern Tanzania has resulted in a decline in malaria prevalence and vector species composition. Despite this achievement, residual malaria transmission remains a concern in the area. The main aim of this study was to investigate malaria vector species composition, parasite infectivity rates, and the presence of insecticide knockdown resistance (kdr) mutations in three sites that have experienced a significant decline in malaria in northern Tanzania. Adult mosquitoes were sampled using light traps in houses and hand-aspirators in cowsheds, whereas the standard dipping method was used for sampling mosquito larvae. Adult mosquitoes identified as Anopheles gambiae s.l. and An. funestus s.l. and larval stages III and IV of An. gambiae s.l. were stored in absolute ethanol for further laboratory molecular identification. The identified species in the An. gambiae complex were An. gambiae s.s., An. merus, An. quadriannulatus, and An. arabiensis, whereas the An. funestus group comprised An. funestus s.s., An. rivulorum, and An. leesoni. For An. gambiae s.s. analyzed from Zeneth, 47.6% were kdr-East homozygous susceptible, 35.7% kdr-East heterozygous resistant, 9.6% kdr-East homozygous resistant, and 7.1% undefined, whereas specimens from Kwakibuyu were 45.5% kdr-East homozygous susceptible, 32.7% kdr-East heterozygous resistant, 16.3% kdr-East homozygous resistant, and 5.5% undefined. There were no kdr-West alleles identified from any specimen. The overall malaria parasite infectivity rate was 0.75%. No infections were found in Moshi. The findings indicate that populations of the major malaria vector mosquitoes are still present in the study area, with An. funestus taking a lead in malaria transmission.

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Anopheles species composition and some climatic factors that influence their survival and population abundance in Anambra East LGA, Anambra State, Nigeria

Nigerian Journal of Parasitology ◽

10.4314/njpar.v41i2.17 ◽

2020 ◽

Vol 41 (2) ◽

Author(s):

C.M Egbuche ◽

A.E Onyido ◽

P.U Umeanaeto ◽

E.N Nwankwo ◽

I.F Omah ◽

...

Keyword(s):

Relative Humidity ◽

Species Composition ◽

Climatic Factors ◽

Seasonal Abundance ◽

Human Landing Catch ◽

Morphological Identification ◽

Climatic Data ◽

Anopheles Species ◽

Anambra State ◽

Anopheles Mosquitoes

Malaria parasites are transmitted in nature through the bites of female Anopheles mosquitoes. However, the vector distribution varies in time and space. This study aimed to determine the species composition, abundance and climatic factors influencing Anopheles mosquitoes in Anambra East Local Government Area of Anambra State, Nigeria from October 2016 to September 2017. Adult Anopheles mosquitoes were collected from indoor and outdoor locations using Pyrethrum Knockdown Collection (PKC) and Human Landing Catch (HLC) Methods respectively. Anopheles mosquito larvae were collected using dipping method. Morphological identification of Anopheles species was carried out using standard identification keys. Climatic data was obtained from Nigerian Meteorological Agency Office in Anambra State. A total of 8181 female Anopheles mosquitoes which comprised 4127 (50.4%) larvae and 4054 (49.6%) adults were collected (P > 0.05) in the study. Four Anopheles species: An. gambiae s. l (70.1%), An. funestus group (18.2%), An. moucheti (6.3%) and An. nili (5.4%) were identified (P < 0.05). In the study area, 2608 (31.9%), 3025 (37.0%) and 2548 (31.1%) Anopheles mosquitoes were collected from Aguleri, Igbariam and Nsugbe respectively; with 100% species overlap. In each selected selected town, the Simpson’s index of diversity was ~2 and Shannon-wiener diversity was ~1. Only An. gambiaes l showed varied seasonal abundance with wet season contributing 67.9% and dry season 32.1% of the overall An. gambiaes. l collection (P < 0.05). The correlation between rainfall and An. gambiae s. l. abundance was significantly strong (r = 0.66; P < 0.05). No significant correlation was found between Anopheles species abundance and temperature as well as relative humidity. The study revealed the preponderance of four Anopheles species: An. gambiae s. l., An. funestus, An. moucheti and An. nili; and rainfall is the only climatic factor that causes temporal change in the abundance of one of the species, An. gambiaes. l. in the study area. Keywords: Anopheles mosquitoes, abundance, temperature, rainfall, relative humidity

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Morphological Identification, Species Composition and Distribution of Mosquitoes in Kosti region, White Nile State, Central Sudan

Malaysian Journal of Medical and Biological Research ◽

10.18034/mjmbr.v6i1.463 ◽

2019 ◽

Vol 6 (1) ◽

pp. 7-18

Author(s):

Mai M. Nour ◽

Mariam Atta Elmannan Aboud ◽

Nahla Osman Mohamed Ali

Keyword(s):

Species Composition ◽

Morphological Identification ◽

Correct Identification ◽

Anopheles Species ◽

Mosquito Abundance ◽

Central Sudan ◽

Global Positioning ◽

White Nile ◽

Species Composition And Distribution ◽

Vector Control Strategy

Mosquitoes are a large diverse group of insects, with members being most important as vectors of diseases. The correct identification of mosquitoes is crucial to the control of the mosquito-borne diseases. This study was designed to provide baseline data on the species composition and distribution of members of the Anophelines and Culicines genera in ten selected localities in Kosti region, White Nile State, Central Sudan. Global Positioning System (GPS) was used to select collection sites. Adult mosquitoes were collected by pyrethrum spray catch (PSC) from randomly selected houses in Allia, Alnsr, Alskahdeed, Almrabie, Alshati, Althwrat, Alraba, Block 26, Block 32 and Khadugli in Kosti region during September 2014-August 2015. The Anophelines and Culicines mosquitoes were identified using standard morphological keys. Two Anopheles species and three Culex species were morphologically identified. These were An. gambiae s.s.; An. pharoensis; Cx. quinquefasciatus; Cx. univittatus and Cx. pipiens. This is the first report of An. pharoensis in the study area. The Highest mosquito abundance was observed in the September followed by October, while the lowest mosquito abundance was in July. An. gambiae s.s and Cx. quinquefasciatus were the predominant species which has importance as they indicate the presence of Malaria and arboviral infections in the study areas; respectively. These findings are of importance in the planning and implementation of vector control strategy in the Kosti region, White Nile state.

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Host-seeking behavior and hourly biting rhythm of vectors in malaria endemic district of Arba Minch area, Southwest Ethiopia

10.21203/rs.2.20364/v1 ◽

2020 ◽

Author(s):

Melkam Abiye Zeru ◽

Simon Shibru ◽

Fekadu Massebo

Keyword(s):

Malaria Vector ◽

Negative Binomial ◽

Malaria Vectors ◽

Malaria Vector Control ◽

Southwest Ethiopia ◽

Anopheles Mosquitoes ◽

Host Seeking ◽

Human Landing ◽

Seeking Behavior ◽

The Impact

Abstract Background The early and outdoor biting behaviors of malaria vectors are among the key challenges in malaria control. Hence, understanding the host-seeking behavior and the peak biting time of malaria vectors is important in malaria vector control programs. This study assessed the host-seeking behavior and hourly biting activity of malaria mosquitoes in Chano Mille village in Arba Minch district, southwest Ethiopia. Methods The first trial was done by keeping cattle together with human that collects the entered mosquitoes in tent, while the other was done by keeping cattle outside a 1 m distance from human collector inside a tent. In both trials, mosquito collation was done inside tents baited by cattle and human using human landing catches (HLC) techniques. Four human volunteers’ were recruited and trained to collect mosquitoes in the four tents from 18:00-24:00 for three months. Two tents were selected randomly for human alone and two for cattle baited collections in the first night and then rotated to minimize the variation due to location of tents and collectors skill. The tent trial was done close to the shore of the Lake Abaya to minimize the interference of other animals on mosquito movement. The peak biting hour of malaria vectors was assessed within a Chano village from 18:00-6:00. Mosquito collation was done both indoor and outdoor by HLC. Morphological speciation of Anopheles mosquitoes was done. The sporozoite infectivity status of Anopheles pharoensis was examined using enzyme-linked immuno-sorbent assay technique. The data was analyzed using a Generalized Estimating Equations with a negative binomial distribution. Results An. pharoensis, An. gambiae complex and An. tenebrosus were the three species documented during the trial. Keeping cattle together with human collector inside the tent attracted 42% ( P < 0.001) more An. pharoensis compared to human alone tent. Also, keeping cattle outside near to a tent with human at 1 m distance, attracted the entering An. pharoensis into the tent inside with human by 46% ( P = 0.002) than human in a tent with no cattle outside the same tent. The impact was not significant for An. gambiae complex and An. tenebrosus. Anopheles pharoensis and An. gambiae complex showed early night biting activity with peak biting from 19.00-20:00 which was significant for both An. gambiae complex ( P < 0.001) and An. pharoensis ( P = 0.015). Anopheles gambiae complex was mainly biting humans outdoor in the village. Conclusions Finally, keeping cattle within and close to human dwellings could increase malaria vectors bite exposure particularly to the zoophilic malaria vector An. pharoensis and, hence deployment of cattle far from human residence could be recommended to reduce the human exposure. The outdoor and early hours biting behavior of the An. gambiae complex could be a threat for success of current indoor based interventions and hence, tools could be designed to reduce this threat.

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Morphological and molecular characterization of endophilic Anopheles gambiae complex, in Itu Local Government Area, Akwa Ibom State, Nigeria

Nigerian Journal of Parasitology ◽

10.4314/njpar.v41i1.12 ◽

2020 ◽

Vol 41 (1) ◽

pp. 75-81

Author(s):

B.E. Bassey ◽

K.N. Opara ◽

L.P. Usip

Keyword(s):

Local Government ◽

Anopheles Gambiae ◽

Molecular Characterization ◽

Malaria Control ◽

Local Government Area ◽

Malaria Control Programme ◽

Anopheles Species ◽

Gambiae Complex ◽

Anopheles Mosquitoes ◽

Significant Difference

Malaria is still regarded as a major public health problem in sub-Saharan African countries. Anopheles mosquitoes have been implicated as the major malaria vectors. However, species abundance, composition and distribution vary between different ecological zones. This study investigated the composition and distribution of Anopheles gambiae mosquitoes in Itu Local Government Area, Akwa Ibom State, Nigeria. Adult Anopheles mosquitoes were sampled bi-weekly from 15 randomly selected houses each from three communities in the study area by pyrethroid spray capture (PSC) method. Adult Anopheles species were identified morphologically and sibling species were further subjected to species- specific polymerase chain reaction (PCR) typing. A total of 269 female Anopheles species were caught between July and December, 2015. The study indicated significant (p<0.05) abundance of Anopheles gambiae siblings, with An. gambiae s.s recording 219(81.41%) followed by An. arabiensis 32(11.90%). A proportion of the samples were unidentified 18(6.69%). There was a significant difference (p<0.05) in the distribution of A. gambiae complex over the period of the study with a peak in September 89(33.01%). Anopheles mosquitoes were more abundant in Itu Oma 120(44.66%) than West Itam 98(36.43%) and East Itam 51(18.96%). The study also recorded significantly (p<0.05) higher rate of blood engorged female Anopheles (54.05%). This finding showed that An. gambiae s.s was the predominant malaria vector in the area and also, the incidence of malaria been likely to increase during the wet season. Therefore, vector control must be carried out in these communities to reduce the number of these indoor biting mosquitoes. This study therefore, will be useful as baseline data to help design strategies for malaria control in Itu Local Government Area and also facilitate the success of the ongoing effort on the malaria control programme in the State. Keywords: Malaria; Anopheles, morphological; molecular; characterization; Akwa Ibom; Nigeria.

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Malaria vector species composition and relative abundance in Mutare and Mutasa districts, Zimbabwe

Journal of Entomological and Acarological Research ◽

10.4081/jear.2015.4955 ◽

2015 ◽

Vol 47 (3) ◽

pp. 79 ◽

Cited By ~ 7

Author(s):

S. Sande ◽

M. Zimba ◽

P. Chinwada ◽

H.T. Masendu ◽

A. Makuwaza

Keyword(s):

Species Composition ◽

Relative Abundance ◽

Malaria Vector ◽

Sibling Species ◽

Mosquito Species ◽

Sensu Stricto ◽

Malaria Vectors ◽

Morphological Identification ◽

Vector Species ◽

Vector Behaviour

Regular entomological monitoring is important to determine changes in mosquito species composition and relative densities of malaria vectors in relation to vector control interventions. A study to gain insights into malaria vector species composition and relative abundance was undertaken in Mutare and Mutasa districts, Zimbabwe. Two methods; indoor resting catches and larval sampling were used to collect indoor resting adults and larvae from May 2013 to April 2014. Mosquitoes collected as adults and reared from larvae that were identified morphologically as potential malaria vectors were further processed to sibling species by polymerase chain reaction (PCR). Morphological identification of anopheline mosquitoes showed presence of two complexes: An. funestus and An. gambiae. The total number of female members of the An. funestus group and An. gambiae complex collected by both methods from the two sites was 840 and 31 respectively. Malaria vector species of both complexes were more abundant in Mutare than in Mutasa. The PCR-based assays showed the presence of four sibling species: An. funestus sensu stricto (90.8%, 267/294) and An. leesoni (5.1%, 15/294), of An. funestus group; An. arabiensis (41.9%, 13/31) and An. quadriannulatus (48.4%, 15/31) of the An. gambiae complex. About 4% and 5% of specimens of An. gambiae complex and An. funestus group respectively did not amplify. Of the two identified malaria vector sibling species, An. funestus sensu stricto was more abundant (95.4%, 267/280) than An. arabiensis (4.6%, 13/280), suggesting the replacement to secondary vector of An. arabiensis, which was previously the predominant vector species. An. funestus sensu stricto and An. arabiensis, the most important vectors of human malaria were identified in this study, but their resting and biting habits as well as insecticide susceptibility are unclear. Further studies on vector behaviour are therefore recommended.

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