EXPERIMENTAL STUDIES ON MIXED INFECTION WITH PARAGONIMUS MIYAZAKII KAMO ET AL.,1961 AND OTHER SPECIES OF PARAGONIMUS IN AN ANIMAL
The mixed infection with Paragonimus miyazakii and P. ohirai and/or P. westermani to an experimental animal was designed to study the mutual relationship on the subjects of the susceptibility and the biological affinity as well as the host adaptation between different species of Paragonimus. The experimental animals of 3 cats, an albino rat and 13 dogs were fed on the metacercariae of these 2 or 3 species of Paragonimus simultaneously or at intervals of 5 to 20 days. The cohabitation of two species (P. miyazakii and P. ohirai) in a worm cyst was revealed in 5 animals of 2 cats, an albino rat and 2 dogs, whereas that of the other cohabitation with P. miyazakii and P. westermani was revealed only with one dog in spite of experiment on 9 animals. The cohabitation with P. ohirai and P. westermani was also shown, though only in one trial. The worm cyst revealing the cohabitation of two species amounted to 1 or 2 in number regardless of the number of metacercariae given in each experimental animal. No delay in development and maturity was recognized in 2 worms of different species or 3 worms of the same species of P. miyazakii and P. ohirai cohabiting in a cyst of each animal. In the case of 3 worms of different species cohabitation in a cyst the size of a worm belonging to one species was somewhat smaller than that of the other two worms belonging to the other species. The solitary worm of P. miyazakii, P. ohirai or P. westermani in a cyst also developed and matured as full as the cohabitants.