These investigations were carried out in some of the villages around Taveta Town, Coast Province, Kenya, during the dry seasons of 1974, 1975 and 1976. The authors examined 83 wild rodents from villages where there is a high infection rate of S. mansoni and/or S. haematobium. The number and species of the rodents collected were as follows : 41

No abstract

The release of Schistosoma japonicum cercariae from Leytean Oncomelania quadrasi snails was observed under laboratory conditions. Two patterns of emergence were noted. The initial, nonperiodic emergence occurred immediately after submerging the snails in water and was followed by a periodic, diurnal emergence which peaked in the afternoon. The daily cercarial output of the periodic emergence appeared to be affected by exogenous light intensity. Furthermore, there was a cessation or reduction in cercarial output every 3rd or 4th day.

The rate of transmammary transmission of Stronglyloides ratti was examined in albino rats in terms of the route of subcutaneous (s.c.) migration from the infection site (the skin) to the cranium. Inoculation sites nearer the cranium resulted in less frequent transmammary infection. The maximum number of adult worms was recovered from the sucklings when the mother was inoculated in her hindquarter and sucklings were allowed to feed for 30-36 h after inoculation (AI). Few worms were recovered from sucklings when they were allowed to nurse during periods of less than 24 h AI or greater than 42 h AI. In lactating mothers, larval infection of the mammary glands was commonly observed, and these larvae showed an increased esophagus length. In nonlactating mothers, most larvae completed their migration to the cranium within 36 h AI.

The long-term maintenance of Schistosoma mansoni in intermediate snail hosts is described. Snails were infected with one or five miracidia to obtain the initial parasitized liver tissue. The serial implantations were conducted. When the materials for serial implantation were obtained 20 to 60 days after the hosts had begun to release cercariae, the proportion of snails becoming infected was higher than when materials obtained earlier were used. It made no difference whether the initial infection was with one or five miracidia. Our findings suggest the possibility of cloning of unisexual infections in experimental infections.