Crimean-Congo haemorrhagic fever: a seroepidemiological and tick survey inthe Sultanate of Oman

In 1995 and 1996, 4 persons from the Sultanate of Oman were confirmed with clinical Crimean-Congo haemorrhagic fever (CCHF). To assess the prevalence of CCHF virus infection in Omen, a convenience sample of imported and domes tic animals from farms, abattoirs and livestock markets was examined by enz yme-linked immunosorbent assay (ELISA) for immunoglobulin G (IgG) antibodie s to CCHF virus. Ticks were collected from selected animals, identified, po oled by species, host and location and tested for evidence of infection wit h CCHF virus by antigen-capture ELISA. Serum samples from individuals worki ng in animal and nonanimal contact-related jobs were also tested for CCHF a ntibodies. Serological evidence of infection was noted in 108 (22%) of 489 animals. Most of the ticks collected (618 of 912) from all species of sampl ed livestock were Hyalomma anatolicum anatolicum, a competent-vector and re servoir of CCHF virus. 243 tick pools were tested for CCHF antigen, and 19 pools were positive. Of the individuals working in animal contact-related j obs, 73 (30.3 %) of 241 non-Omani citizens and only 1 (2.4%) of 41 Omani ci tizens were CCHF antibody-positive. Butchers were more likely to have CCHF antibody than persons in other job categories. The presence of clinical dis ease and the serological results for animals and humans and infected Hyalom ma ticks provide ample evidence of the presence of CCHF virus in yet anothe r country in the Arabian Peninsula.