RESUMO
Culex mosquitoes transmit bancroftian filariasis and arboviruses as West Nile Virus in the Middle East including Saudi Arabia. However, the prevalent Culex species in Al-Madinah region have not been reported and their role in disease transmission remains to be clarified. This work aimed to investigate the role of Culex in transmission of Wuchereria bancrofti, West Nile virus, Saint Louis encephalitis and Eastern Equine encephalitis in Al-Madinah, Saudi Arabia. Also, it was done to document the prevalent Culex species and to shed light on their bionomics and habits. Culex mosquitoes were collected using spray sheets and CDC light traps with CO2 release from July 2007 till June 2008. Also, Culex larvae were collected for 8 months during that period. Culex seasonal distribution and bionomics were documented and taxonomical identification was done. Females were dissected and microscopically examined for filarial stages. In addition, they were screened by the Vec-Test for West Nile virus, Saint Louis encephalitis and Eastern Equine encephalitis. A total of 3.6% human rooms and 4.7% of animal sheds were positive for Culex; more in the period of January-June 2008, compared to July-December 2007. Seven Culex species were found, two of which were recorded for the first time in the region; C. duttoni and C. decens. C. pipiens and C. quinquefasciatus were the most abundant; 59.3% of collected adults were C. pipiens, while C. quinquefasciatus constituted 22.1%. As for collected larvae, C. pipiens constituted 60% of them, whereas C. quinquefasciatus totalled 20%. Only C. pipie/Is was found to harbor West Nile Virus. In contrast, no other viruses or W bancrfoti stages were detected in the examined mosquitoes. There is a potential danger of the transmission of West Nile Virus in Al-Madinah especially by C. pipiens. Also, the possibility of future transmission of W. bancrofti, and the establishment of new endemic foci of bancroftian filariasis in the region, couldn't be overruled