Human trichinellosis in Bulgaria--epidemiological situation and trends.

Human trichinellosis is a major food-borne zoonosis in Bulgaria with a high health, social, and economic impact. Every year outbreaks and sporadic cases are registered in the country. Epidemiological data based on standard protocols for epidemiological surveillance and control of human trichinellosis for each region in the country were collected and analysed at the National Centre of Infectious and Parasitic Diseases, and the main epidemiological trends during the past 17 years (1990-2006) were determined. Since 1991 human trichinellosis has become a re-emerging zoonosis in Bulgaria. A total number of 145 trichinellosis outbreaks and 238 sporadic cases were registered. Altogether, 7544 persons have consumed meat or meat products harbouring Trichinella larvae, and of these, 4108 individuals (54.45%) contracted trichinellosis (with 2 deaths). The annual incidence of human trichinellosis varied from 0.27 to 7.40 per 100,000 population. Fifty-seven of the outbreaks were sourced to wild boar meat consumption, 67 were due to consumption of pork products, and in 21 outbreaks the source of infection was unidentified (4 of them were associated with consumption of mixed meat--pork and wild boar meat products). The peaks of outbreaks (12 per year) were registered in 1994, 1998, 2002, and 2003. In recent years some decrease in the numbers of outbreaks was observed (2004: 6, 2005: 3, and 2006: 7).