Factors Associated with Seropositive Antibodies to Brucella melitensis in the Nakhon Nayok, Thailand
Chatchai Ekpanyaskul MD, MSc*, Somchai Santiwattanakul PhD**, Worapot Tantisiriwat MD, MPH*, Wanchai Buppanharun MD, MPH*
Affiliation : * Department of Preventive and Social Medicine, Faculty of Medicine, Srinakharinwirot University, Nakhon Nayok, Thailand ** Department of Pathology, Faculty of Medicine, Srinakharinwirot University, Nakhon Nayok, Thailand
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.
Keywords : Brucella melitensis, Seroprevalence, Zoonosis
