Risk of transmission of viral haemorrhagic fevers and the insecticide susceptibility status of aedes aegypti (linnaeus) in some sites in Accra, Ghana

Abstract

Background: Dengue is one of the emerging diseases that can mostly only be controlled by vector control since there is no vaccine for the disease. Although, Dengue has not been reported in Ghana, movement of people from neighbouring countries where the disease has been reported can facilitate transmission of the disease. Objective: This study was carried on the University of Ghana campus to determine the risk of transmission of viral haemorrhagic fevers and the insecticide susceptibility status of Ae. aegypti in some sites in Accra, Ghana. Design: Larval surveys were carried to inspect containers within households and estimate larval indices and adult Aedes mosquitoes were collected using human landing collection technique. WHO tube assays was used to assess the insecticide susceptibility status of Aedes mosquitoes. Results: Ae. aegypti were the most prevalent species, 75.5% and followed by Ae. vittatus, 23.9 %. Ae. albopictus and Ae. granti were in smaller numbers. Household index (HI), Breteau index (BI), and container index were calculated as 8.2%, 11.2% and 10.3% respectively with man-vector contact rate of 0.67 bites/man-hour estimated for the area. The mortalities recorded for Ae. aegypti from WHO tube assays was 88%, 94%, 80% and 99% for DDT (4%), deltamethrin (0.05%), lambdacyhalothrin (0.05%) and permethrin (0.75%) respectively.Conclusion: The survey results indicated that the density of Aedes mosquitoes was considered to be sufficient to promote an outbreak of viral haemorrhagic fevers on Legon Campus. Aedes mosquitoes were found to be resistant to DDT, deltamethrin and lamdacyhalothrin, but susceptible to permethrin. Funding: This study was supported in part by Japan Initiative for Global Research Network on Infectious Diseases(J-Grid).Keywords: Mosquitoes, Aedes aegypti, insecticide, risk, VHF transmission, Ghana

Transmission risk assessment of Aedes-borne arboviral diseases in Accra, Ghana

“…Adults and larvae were identified and pooled for detection of DENV, ZIKV and CHIKV. All pools analysed were found negative for the viruses of interest, is in line with other studies that have been conducted in other sites in Ghana (13,22). Some studies have suggested that Aedes aegypti mosquitoes originating from the African continent may be less competent vectors of these flaviviruses (34,35) because the ability of these mosquitoes to serve as competent vectors is influenced by several biotic and abiotic factors.…”

“…One key finding in this study was the detection of Aedes albopictus in Madina. The presence of this vector has been documented before in Ghana, but this is the first time it has been recorded in such relatively high numbers (26). In a previous study, very few mosquitoes were identified as Aedes albopictus (Suzuki et al, 2016) whilst relatively higher numbers of the species were identified in this study.…”

“…The presence of Aedes mosquitoes have been well documented in Ghana and have been implicated for the transmission of yellow fever (13,22). Studies have detected the presence of antibodies and viral RNA of DENV in different localities in Ghana (16,17).…”

Species composition and risk of transmission of some Aedes-borne arboviruses in some sites in Northern Ghana

“…Albopictus in the samples collected. However, a survey [20] in southern Ghana detected the species in samples collected although in relatively low numbers. This may be due to the proximity of the southern site to a landing port which has been found to be the main route of importation of the species in many countries.…”

“…aegypti in the Damongo area [19]. However, the southern part of Ghana has been found to be a low-risk area [20]. The Damongo and Mole Game Reserve area have been a hotspot for Yellow fever outbreaks in recent times.…”