A study on intestinal lesions of experimentally reinfected dogs with Metagonimus yokogawai

ABSTRACT

The intestinal lesions were studied in dog metagonimiasis by reinfection. The metacercariae of M. yokogawai were collected from naturally infected sweetfish. A total of twenty dogs were divided into three groups; control, primary infection and reinfection groups. The 18 dogs were infected with 10,000 metacercariae; the 5 dogs in primary infection group were killed at the 5 days in 1 week, 4 weeks, 6 weeks after the infection. The remaining 13 dogs were kept for nine weeks, and challenged again with 5,000 metacercaricae. The reinfected dogs were killed at the 1 day, 3 days, 5 days and 1 week, 2 weeks, 4 weeks, 6 weeks, 8 weeks respectively. The chronologic changes of the intestinal lesions in both groups, the worm recovery rate, and distribution patten were examined by gross observation, light and scanning electron microscopies. From the results, it was inferred that the so-called spontaneous and/or self cure phenomena were of negligible importance in metagonimiasis in dogs. In the chronologic observations of pathologic process in intestine, it was also suggested that the host immunity tend to recover the intestinal integrity. And early invasion of young worm to the Lieberkuhn's crypt was considered as the primary cause of lesions of vill(Abstract is summarized again.)