FIRST DETECTION OF WEST NILE VIRUS ANTIBODIES IN ANIMALS IN LIBYA

Abstract

Intro: West Nile virus (WNV) is a global important mosquito-borne flavivirus causing West Nile disease (WND) with morbidity and mortality in humans and animals. It is endemic in many North African countries, however, in Libya, WND was reported in humans by serology but never been reported in animals. Methods: A total of 578 and 63 serum samples from horses and dogs, respectively, were collected from healthy unvaccinated animals between 2016 - 2019. A commercially available competitive ELISA (c-ELISA) kit was initially used to test samples. Positive and doubtful sera for anti‐WNV IgG antibodies using the c-ELISA were confirmed and also screened for WNV and Usutu virus (USUV) antibodies using virus neutralization test (VNT). Findings: The results of anti‐WNV antibodies using c-ELISA showed that 13.1% (76 out of 578) of horses samples and 30.1% (19 out of 63) of dogs samples were positive. A confirmation of ELISA equine and canine positive and doubtful samples using VNT was done. VNT showed that 68.4% (52 out of 76) of serum horses samples were positive and had an overall titration from 1:10 to 1:80. Among the ELISA dogs positive and doubtful samples, VNT showed that 78.9% (15 out of 19) were positive and had an overall titration from 1:10 to 1:80. Discussion: There is lack of information from many African countries and the real burden of WNV infections in Africa is not well known, however, strong evidence on the circulation of WNV in the continent. Horse remains the most relevant species to monitor the circulation of WNV but seroprevalence studies carried out on different animals reported WNV infection in different African countries, however, their role in the transmission cycle is not well understood. Only few countries have reported WNV from dogs in Africa with very scarce information from North Africa. Conclusion: Future research on WND is urgently needed in Libya.