Incidence of human brucellosis in a rural area in Western Greece after the implementation of a vaccination programme against animal brucellosis

BACKGROUND Brucellosis continues to be an important source of morbidity in several countries, particularly among agricultural and pastoral populations. The purpose of this study was to examine if there is an effect on the incidence of human brucellosis after the implementation of an animal brucellosis control programme. METHODS The study was conducted in the Municipality of Tritaia in the Prefecture of Achaia in Western Greece during the periods 1997-1998 and 2000-2002. Health education efforts were made during 1997-1998 to make the public take preventive measures. In the time period from January 1999 to August 2002 a vaccination programme against animal brucellosis was realised in the specific region. The vaccine used was the B. melitensis Rev-1 administered by the conjuctival route. Comparisons were performed between the incidence rates of the two studied periods. RESULTS There was a great fall in the incidence rate between 1997-1998 (10.3 per 1,000 population) and the period 2000-2002 after the vaccination (0.3 per 1,000 population). The considerable decrease of the human incidence rate is also observed in the period 2000-2002 among persons whose herds were not as yet vaccinated (1.4 vs. 10.3 per 1,000 population), indicating a possible role of health education in the decline of human brucellosis. CONCLUSION The study reveals a statistically significant decline in the incidence of human brucellosis after the vaccination programme and underlines the importance of an ongoing control of animal brucellosis in the prevention of human brucellosis. The reduction of human brucellosis can be best achieved by a combination of health education and mass animal vaccination.