Occurrence of West Nile Fever in equine, birds, human and mosquitoes in Beheira Province

ABSTRACT

A total of 257 serum samples including, equine [56], birds [95] and human [106] were collected from rural area in Behera Province during the period extended from the beginning of June to the end of October 2013 to be examined for presence of antibodies against West Nile virus by ELISA. In addition, a total of 943 mosquitoes [25 mosquitoes groups] were collected by CDC light trap from the same place and during the same period where homogenized tissue samples of mosquitoes were obtained to be examined for presence of viral RNA of WNV by real time RT-PCR. The serological examination of serum samples clarified that the prevalence of IgG antibodies against WNV was 100, 4.2 and 58.5% in equine, birds and human serum samples, respectively. Moreover, some epidemiological aspects of human samples were studied including gender, age and health status. Statistical analysis indicated significant differences in detection of IgG antibodies against WNFV in different genders where the higher detection rate was observed in females [42.30%], than in males [35%], in different age groups where the higher detection rate was observed in age group 40 - < 60 years [83.33%] followed by age group 20 - <40 years [42.85%], then the age group 60 - < 80 [37.50%] and the least detection rate of IgG was observed in age group 1 - < 20 years [16.66%] and in health status where the highest detection rate was recorded in meningitis patients [80.9%] followed by FUO patients [64.4%] and lastly apparent healthy individuals [40%]. On the other side, real time RT-PCR examination of samples of mosquitoes clarified no detection of the viral RNA of WNV in all examined samples. The obtained results confirmed the endimicity of WNV in equine in Egypt and the role played by birds in transmission of WNV to human. Although, examined mosquitoes were found to negative for presence of the viral RNA, their role in transmission of WNV could not denied