Serosurvey in two rural areas evidences recent and previously undetected WNV and SLEV circulation in Costa Rica

West Nile virus (WNV) and Saint Louis encephalitis virus (SLEV) share similar virus transmission cycles that involve birds as amplifiers and mosquitoes as vectors. Mammals, including humans, are dead-end-hosts that may be asymptomatic or develop more severe symptoms. Costa Rica is a hyperendemic country for several flaviviruses such as Dengue (DENV) and Zika (ZIKV) and previous research showed limited and restricted SLEV and WNV circulation in horses, sloths, and monkeys. Nevertheless, actual seroprevalence and high transmission areas are not yet identified. To determine putative WNV and SLEV circulation, we sampled peri-domestic and domestic animals, humans, wild birds, and mosquitoes in rural households located in two DENV and ZIKV hyperendemic regions during the rainy and dry seasons of 2017-2018 and conducted PRNT assays for serology and RT-PCR for virus detection. At Cuajiniquil, serological evidence of WNV and SLEV was found in equines, humans, chickens, and wild birds. Also, 5 seroconversion events were recorded for WNV (2 equine), SLEV (1 human), and DENV-1 (2 humans). At Talamanca, a lack of WNV circulation was found, but evidence of SLEV circulation was recorded in equines, humans, and wild birds. No evidence of active viral infection was found in any mosquitoes or wild bird samples. This seroconversion evidence supports the active and recent circulation of SLEV and WNV in these two regions. This study provides clear-cut evidence of WNV and SLEV circulation and should be considered by the health and epidemiology authorities for future prevention and differential diagnostics.

Metagenomics of Mosquito-borne Flaviviruses in Various Geoclimatic Districts of Punjab, Pakistan

Mosquitoes are highly active vectors capable of transmitting various pathogenic and infectious diseases to humans and animals. The present study was designed to identify the major species of mosquitoes and mosquito-borne flaviviruses (Saint Louis Encephalitis, West Nile and Dengue Viruses) prevalent in three districts of Punjab representing the three agro-geoclimatic zones viz; Multan, Chakwal and Jhang. The collected mosquitoes were stereoscopically identified to confirm the species and sex of the mosquitoes. Stereoscopic identification confirmed that female mosquitoes were 4334 out of 10675 (40.6%), 2242 out of 7296 (30%) and 2040 out of 6450 (31.6%) from districts Chakwal, Jhang and Multan, respectively. It was concluded that Culex species were present in abundance (73.2%) as compared to Aedes species (26.7%) in the selected study districts. The results of multiplex RT-PCR depicted that Dengue, West Nile, Japanese encephalitis and Saint Louis encephalitis viruses were prevalent in the mosquitoes of all three selected districts. However, the prevalence of mosquito-borne viruses insignificantly varied (P>0.05) among the three districts. This study has provided a better understanding of the prevailing mosquito species and mosquito-borne viruses in the study districts that can help to devise appropriate control measures

Flavivirus Infection Associated with Cerebrovascular Events

Arthropod-borne viruses (arboviruses) of the genus Flavivirus are distributed globally and cause significant human disease and mortality annually. Flavivirus infections present a spectrum of clinical manifestations, ranging from asymptomatic to severe manifestations, including hemorrhage, encephalitis and death. Herein, we describe 3 case reports of cerebrovascular involvement in patients infected by dengue and Zika viruses in Sao Jose do Rio Preto, São Paulo State, Brazil, a hyperendemic area for arbovirus circulation, including dengue, yellow fever, chikungunya and Saint Louis encephalitis viruses. Our findings highlight the potential threat that unusual clinical manifestations may pose to arbovirus disease management and recovery.