A retrospective serological survey of humans in India for Wanowrie virus

Wanowrie virus (WAN) is an ungrouped arbovirus having morphogenetic characters in common with Bunyavirus. It was isolated for the first time from ticks, Hyalomma marginatum isacci (6700 strain) and subsequently from a human case (68923 strain). In the absence of any reports on the prevalence of this virus amongst humans in India, 600 human sera were tested in the Complement Fixation (CF) test against both the strains of WAN virus. One hundred human sera were randomly selected from six different states, viz Jammu and Kashmir, Rajasthan, Orissa, Maharashtra, Karnataka and Tamil Nadu. CF antibodies were detected in 77 sera (12.8%) against the 6700 antigen while 91 sera (15.1%) possessed antibodies against the 68923 antigen; 60 sera were found to be reactive against both the antigens, with almost identical titres. There was no statistical difference in the distribution of CF reactive sera with respect to age, gender and geographic locations. All the CF reactive sera were found to be negative when tested in the neutralization test against the respective virus strains. The CF antibodies detected in these sera may have been produced during exposure to an antigenically closely related virus yet to be identified.