Epidemiological measures of Crimean-Congo haemorrhagic fever infection in Sistan va Baluchestan province, Iran

Abstract number: 1134_02_347

Holakouie Naieni K., Izadi S., Chinikar S., Nadim A.

Objectives:

Since 1999, many cases of Crimean-Congo Hemorrhagic Fever have been reported from different parts of Iran. This study intends to define CCHF seroprevalence, incidence rates, and the most important risk in Sistan va Baluchestan province, Iran.

Methods:

Using cluster sampling with probability proportional to size, 310 subjects were selected from various Zahedan and Zabol districts in the northern part of the province. Blood samples were drawn from consenting subjects, once at the beginning of the study and then 6 months later. A total of 18 out of 285 subjects who consented to give blood samples were actually positive on IgM and IgG capture ELISA tests.

Results:

The calculated seroprevalence was 6.32% (95% CI: 3.24% to 9.40%). Of the subjects who were sampled for the second time (226 persons), only one had experienced seroconversion. The calculated incidence rate was 0.48 (95% CI: 0.00% to 1.44%).

14 out of the 18 subjects with definitely positive IgG or IgM were females. In multivariate analysis, age, education, and history of slaughtering livestock were significantly related to the risk of infection. History of travel to the rural areas was inversely related to the risk of infection. Only one of the seropositive subjects had a history of tick bite.

Conclusion:

This study shows the importance of subclinical infections in the epidemiology of this disease in Iran. It also seems that the risk of infection for housewives is high. Regardless of the high female to male ratio of seropositive subjects, it appears that the epidemiologic characteristics of the infection in this region are not so different compared to other parts of the world.

This investigation received financial support from the WHO's Eastern Mediterranean Regional Office (EMRO), Division of communicable Diseases (DCD) and the WHO Special Programme for Research and Training in Tropical Diseases (TDR): The EMRO DCD/TDR Small Grants Scheme for Operational Research in Tropical and Other Communicable Diseases.