Diversity and Abundance of Potential Vectors of Rift Valley Fever Virus in the North Region of Cameroon

Abstract

Rift Valley fever (RVF) is a major viral zoonosis transmitted by mosquitoes. The virus is endemic in most parts of sub-Saharan Africa and can affect humans, livestock, and wild ungulates. Knowledge of the biology of vectors of Rift Valley fever virus (RVFV) is essential for the establishment of effective control measures of the disease. The objective of this study was to determine the species diversity and relative abundance of potential RVFV vectors in the North Region of Cameroon. Adult mosquitoes were trapped during the wet and dry seasons from December 2017 to January 2019 with “EVS Light” traps with CO2 baits placed at selected sites. The captured mosquitoes were identified using dichotomous keys according to standard procedures. The abundance was calculated with regard to site, zone, and collection season. A total of 27,851 mosquitoes belonging to four genera (Aedes, Anopheles, Mansonia, and Culex) and comprising 31 species were caught (including 22 secondary vectors (98.05%) and nine primary vectors (1.94%). The total number of mosquitoes varied significantly depending on the locality (p-value < 0.001). The average number of mosquitoes collected per trap night was significantly higher in irrigated areas (p-value < 0.001), compared to urban and non-irrigated areas. The study revealed the presence of potential primary and secondary vectors of RVFV with varying abundance and diversity according to locality and ecological site in the North Region of Cameroon. The results showed that the genus Mansonia with the species Ma. uniformis and Ma. africana formed the dominant taxon (52.33%), followed by the genera Culex (45.04%) and Anopheles (2.61%). The need for molecular analysis (PCR) tests for RVFV RNA research and viral isolation methods on these vectors to determine their role in the epidemiology and control of RVF cannot be overemphasized.

Demographic and environmental factors associated with the distribution of Aedes albopictus in Cameroon

“…However, a study in 2018 identified Ae . albopictus at a higher latitude near the city of Garoua at 9.3° N for the first time (Rodrigue Simonet et al, 2020 ), which is in line with global distribution predictions (Kraemer et al, 2015 ).…”

“…albopictus to extend its range into Europe and North America (Hopperstad et al, 2021 ; Takumi et al, 2009 ). For instance, in contrast to other analysis delimitation (Tedjou et al, 2019 ), Rodrigue Simonet et al ( 2020 ) found for first time Ae . albopictus in latitudes above 6° N. Further studies and molecular analysis are needed to elucidate whether Ae .…”

“…Collection of vector data (immature stages or adults) was done using different methods, for instance, for adult mosquitoes the following methods were used: human landing catches (Akono Ntonga et al, 2017 ; Antonio‐Nkondjio et al, 2012 ; Nopowo et al, 2019 ), CDC light traps (Antonio‐Nkondjio et al, 2012 ), EVS lights (Rodrigue Simonet et al, 2020 ) and sweep nets (Mayi et al, 2020 ). Locations were not sampled over time and precision of the data points is uncertain (Akono Ntonga et al, 2017 ; Kamgang et al, 2017 ; Nopowo et al, 2019 ; Ntoumba et al, 2020 ; Rodrigue Simonet et al, 2020 ; Tedjou et al, 2020 ). The authors were able to conduct this analysis due to the advancement and availability of satellite data.…”

Mosquito-Borne Arboviruses Occurrence and Distribution in the Last Three Decades in Central Africa: A Systematic Literature Review

“… Species Virus Diagnosis References Ae. aegypti DENV V, V, V, P, V [ 190 , 191 , 197 , 198 , 199 ] CHIK V, V, V, P, V, V, P + V, V, V [ 190 , 191 , 197 , 198 , 199 , 200 , 201 , 202 , 203 ] ZIKV V, V, V, V, P, V [ 149 , 190 , 191 , 197 , 198 , 199 ] YFV V, V, V, P, V, V [ 190 , 191 , 197 , 198 , 199 , 204 ] RVFV V + P, V, V, V [ ...…”

Distribution and Molecular Identification of Culex pipiens and Culex tritaeniorhynchus as Potential Vectors of Rift Valley Fever Virus in Jazan, Saudi Arabia

“…Potential arthropod vector identification is important to understand which mosquitoes species may maintain the virus during inter-epidemic phases. It is also important to gain a clear understanding of the community composition and abundance of such mosquito species that may act as a vector for RVFV survival and transmission [9,10]. Survival of RVFV in a specific environment greatly depends on the availability of competent vectors abundance in addition to different factors such as population density of livestock, temperature conditions and rainfall.…”