Reinvestigated life history of Moniliformis dubius Meyer, 1933 in Chiang Mai, Thailand.

The lite cycle of Moniliformis dubius Meyer, 1933 was investigated by using rats (Rattus norvegicus) as the definitive host and American cockroach (Periplaneta americana) as an intermediate host. At room temperature (22-26 degrees C), the shelled acanthor hatched in mid-gut of P. americana 3 days postinfection. released to be the acanthor and then penetrated the gut wall into the hemocoel 5 days postinfection. It further developed into acanthella with proboscis primordium 16 days postinfection. The cystacanth stage recovered 45-52 days postinfection. Rats were fed with the cystacanth, their intestine and feces were examined daily. Shelled acanthor was found in feces on the 31st day of the infection. From the above results, the life cycle of M. dubius was completed within 76-83 days. Observation of the mature adult by scanning electron microscope, both sexes were similar in morphology.

Experimental host of Stellantchasmus falcatus.

The purpose of this research was to determine the incidence and intensity of infection in experimental host of minute intestinal trematode, Stellantchasmus falcatus (family Heterophyidae). Experimental hosts consisting of uninfected mice (Mus musculus) and one-day-old chicks (Gallus gallus domesticus) were orally force fed with a hundred metacercariae of S. falcatus obtained from the body cavity of the freshwater fish Dermogenys pusillus. The worms, then, were checked from 24 hours to 30 days post-infection. The heterophyid flukes were distributed in the ileum and jejunum of the chicks and small intestine of mice with 70% (21/30) and 80% (24/30) of incidence and intensity of infection range from 1-44 (24.6) and 1-67 (7.8), respectively. The body size of S. falcatus at 24 hours; was 0.1-0.15 (0.13) x 0.29-0.39 (0.33) mm in chicks and 0.14-0.17 (0.15) x 0.29-0.32 (0.3) mm in mice. The maximum length and width of the worms were found within 5 days post-infection, of 0.2-0.25 (0.22) x 0.49-0.62 (0.55) in chicks and 0.19-0.22 (0.2) x 0.38-0.52 (0.44) mm in mice. Developing egg was found in the second day after infection and the number of egg increase with the age of the parasite. Embryonated eggs were recovered in the feces of mice 9 day post-infection. S. falcatus infection in the other experimental host was done in rat (Rattus norvegicus), but rats were fed with whole number of metacercariae which found in a body cavity of fish, D. pusillus. The results appear to be the same as in the chicks and mice.