Investigation of mosquito (diptera: culicidae)-borne viruses circulating in some selected areas of Lusaka district, Zambia.

Mosquito-borne viruses are RNA viruses cutting across different virus families and genera of emerging and re-emerging viruses that account for millions of disease incidences annually worldwide. Since the circulation of viruses in vectors heralds an outbreak of diseases, this present cross-sectional study was undertaken from February to April 2022 to investigate the presence of mosquito-borne viruses in captured mosquitoes from six selected residential areas of Lusaka. The Mosquitoes were collected using CDC light traps both indoors and outdoors supplemented with CO2 from yeast fermentation. The mosquitoes were morphologically identified and some were confirmed using mitochondrial cytochrome c oxidase subunit 1 DNA Barcoding. Female (2074) mosquitoes were pooled according to their genera and sampling locations. A total of 71 pools containing a maximum of 40 mosquitoes each were screened using a pan-flavivirus, pan-alphavirus, and pan-phlebovirus RT-PCR assay to detect the respective virus genera genome in total RNA extracted from the mosquito lysates. Phylogenetic analysis based on RNA-dependent RNA polymerase (RdRp) amino acid sequences was used to characterize the detected viruses. Three mosquito genera capable of transmitting arboviruses were identified in this study namely Aedes, Anopheles, and Culex mosquitoes. Aedes aegypti, Anopheles rufipes, and Culex quinquefasciatus were confirmed by DNA Barcoding. Three of the 71 pools tested positive for Phlebovirus and none of the pools was positive for either flavivirus or alphavirus. Only one positive sample was successfully sequenced and detected in a pool of Culex quinquefasciatus collected in Kanyama. The blast result from the NCBI website showed an 85.69% and 97.45% identity with Culex bunyavirus 2 for nucleotide (blastn) and protein (blastp) respectively. The detected virus showed the virus is closely related and clusters with Culex bunyavirus 2 and Culex bunya-like virus which are unclassified bunyaviruses forming a separate clade from other classified bunyaviruses. This study provides the first evidence of the circulation of Culex bunyavirus 2 among mosquitoes in the selected parts of Lusaka District. Further studies should be conducted to determine the potential of the detected virus in causing disease in humans or animals. In addition, similar studies should be conducted in other parts of Zambia to determine the presence of the virus