Trichinella britovi in Domestic Pig – a Case Report

Trichinellosis is a widespread parasitic disease caused by different genotypes of Trichinella. It is common in animals and can spread from its reservoir in wild animals to synanthropic animals, domestic animals and people. Different transmission patterns have been documented (Campbell 1988). They range from those in which humans do not play any role to those in which improper human behaviour is the only cause of transmission (Pozio 1998, Casulli et al. 2001). The infection pressure of the parasite biomass present in sylvatic animals and human malpractice in animal husbandry together can easily favour the transmission of Trichinella from the wild to the domestic habitat (Pozio 2001). The growing importance of sylvatic species in the persistence and re-emergence of trichinellosis in many regions was emphasized at the 10th International Conference on Trichinellosis (Dupouy-Camet et al. 2001). Few cases of finding of Trichinella britovi in domestic pigs are known (Serrano et al. 1998). This study deals with a case of pig trichinellosis in Estonia due to Trichinella britovi and makes an attempt to elucidate the transmission patterns in the actual case. At the end of 1994 routine meat inspection diagnosed trichinellosis in 3 hogs of 8-15 months of age from the Lõpe co-operative on the island of Hiiumaa. At the beginning of 1995 trichinellosis was diagnosed in one sow of the age of one year and 8 months on the same farm. Muscle samples from 2 of these 4 pigs (pig 19-month-old sow and pig 2-20-month-old sow) were submitted for thorough investigation at the department of parasitology of the Estonian Agricultural University. The other 2 positive pigs had been burned already. Samples (á 10 grams, except for 5 grams from tip of the tongue) were taken from 11 different muscles (see Table 1) and first investigated by the compressor method. Larvae were collected and counted after artificial digestion of muscle samples (Miller 1977). Muscle samples (diaphragm, masseter muscle, temporal muscle and eye muscles) of a cat from the same farm were taken and investigated as well. ReNa fur-animal farm is situated only about one kilometre from the Lõpe co-operative. 20 blue foxes (Alopex lagopus) aged 1-4 years and one mink (Mustela lutreola) were investigated with regard to Trichinella. Additionally 18 brown rats (Rattus norvegicus) caught in the feed preparation unit and adjacent rooms of the same farm were investigated for Trichinella. Samples (á 5 grams) were taken from diaphragm, thigh muscles, masseter muscle and temporal muscle. The above-mentioned artificial digestion method was used in case of all investigations. Because Trichinella infection of some farm furanimals was demonstrated, an investigation of Acta vet. scand. 2002, 43,131-134.