If the parasitic infections described previously have shown the tendency of declining prevalence in all three countries, then the situation has been contrary with trichinellosis. In Estonia, there have been the lowest number of cases through out the period reviewed. In the 1920s four cases were reported between 1924 and 1926. Beginning from 1945, when monitoring of T. spiralis was started, the first episode of four cases was reported in 1969. From 1985 to 1994, there have been 3 years when no trichinellosis was reported. The highest number of individuals infected (43) was in 1993. The only source of infection identified so far has been the meat of wild boars ( Jogiste and Barotov 1993). In domestic pigs, for the last years only one case has been reported on the island of Hiiumaa (Dago) and the carcass was not used for food.
Since 1967, the first three cases of human infection were reported in Latvia in 1973. Beginning from
1991, the number of cases has been rising every year with 81 cases (two lethal) in 1996. Beginning from 1994, the role of domestic pigs as the source of infection is rising: more than half of the patients being infected from the meat of domestic pigs.
The trichinellosis has been stated the most serious parasitic disease in Lithuania (Rockiene 1994). The epidemiology of trichinellosis in Lithuania has been thoroughly reviewed previously (Rockiene 1994). The foci of trichinellosis began to spread from the beginning of the 1970s from the southeast of Lithuania, and are now registered all over the country. The highest number of foci (101) was identified in 1994 with 718 people infected. The highest number of cases was in 1992 (819) from 76 foci. Since 1982, there have been 11 lethal cases of infection in Lithuania.
The ways of infection in all three countries are similar, several people being infected from the meat of one animal that had not gone through adequate veterinary control. With wild boars, it is often the case of poaching. Since 1990, licences on boar hunting have been abolished in Lithuania so that people could check the meat in veterinary laboratories without legal consequences. This has resulted in significant decrease in the numbers of infection due to consuming meat of wild boars (Rockiene 1994). The situation with domestic pigs can be associated with the decentralization process of animal breeding because of the reforms in the agricultural sector. It seems that the veterinary control measures have not kept in touch with all the changes, at least where trichinellosis is concerned. There are also case reports when farmers have sold meat without veterinary licence.
In Latvia and Lithuania, the main source of infection has changed during the 1990s: if in the 1970s and the 1980s people were infected mainly from wild boars, then in the last years domestic pigs have become the predominant source of infection.
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