English Abstract In 1987, 1626 sera were collected from free-range pigs,
involving 8 different farms spread all over the country. All sera were
examined for the presence of antibodies against T. spiralis and T. gondii
using ELISA techniques. Although the seroprevalence of both infections was
above the expected value of a parasite-free population, no high extinction
values were found. Since it isn't confirmed by further investigations that
the animals, seropositive for T. spiralis were actually infected, it is
recommended that free-range pigs participate in the regular T. spiralis
surveillance program on finishing pigs, both to generate permanent
information about the seroprevalence of T. spiralis of free-range pigs, as
well as to further investigate possible sources of infection. The
seroprevalence of T. gondii was only slightly higher than found in
comparable investigations on Dutch finishing pigs. However, no regular
information on the seroprevalence of T. gondii is available, since
investigations only take place occasionally. It is therefore recommended to
carry out periodic epizootilogical surveys in order to observe possible
trends in the seroprevalence of the infection.
