Factors associated with seropositive antibodies to Brucella melitensis in the Nakhon Nayok, Thailand

Abstract

Backgroud: Human brucellosis is a re-emerging disease in Thailand. In 2006, Her Royal Highness Princess Maha Chakri Sirindhorn Medical Center, Nakorn Nayok province had diagnosed three cases of brucellosis which have never been reported in this area. Objective: To conduct an epidemiologic study with the aim of evaluating the sero-prevalence and factors associated with seropositive antibodies to Brucella melitensis among residents who live in the same sub-district of the first index case. Material and Method: In 2007, a study was conducted in Chumpon sub-district, Ongkharak district, Nakhon Nayok province, Thailand where the outbreak took place in the previous year. The 86 subjects were selected from three villages in the present study area. Blood specimens were collected and tested for antibodies for Brucella melitensis using a serum agglutination test. A structural interview questionnaire was used to detect any possible risk factors. A binary logistic regression was utilized for analyzing the statistical data. Results: Of all participants in the present study, 45.35% (95% CI; 34.61-56.08%) had seropositive antibodies to Brucella melitensis. Multivariate analysis indicated that factors associated with seropositive titers were highly related to contact with labored or aborted goats, adjusted odds ratio = 27.16 (95% CI = 1.02-721.53) and the consumption of raw goat products, adjusted odds ratio = 6.27 (95% CI = 1.25-31.36). Conclusion: High seropositive prevalence of Brucella melitenis after the 2006 outbreak was found in the present study. The associated factors of infection are direct contact with infected animals and this is similar with the other outbreak areas in Thailand and the endemic countries. Therefore, local authorities should not only provide the communities with health education, but also conduct continued surveillance in order to help control and prevent the epidemic.