Studies of the relationship betweenSchistosomaand their intermediate hosts. III. The genusBiomphalariaandSchistosoma mansonifrom Egypt, Kenya, Sudan, Uganda, West Indies (St. Lucia) and Zaire (two different strains: Katanga and Kinshasa)

Abstract

ABSTRACTThe compatibility between strains ofSchistosoma mansonifrom Egypt, Kenya, Sudan, Uganda, the West Indies, and Zaire (two strains which came from Katanga and from Kinshasa), and various species and strains ofBiomphalaria, i.e.,Biomphalaria pfeifferi, B. alexandrina, B. glabrataandB. camerunensiswas investigated. Data as mortality, rate of infection of the surviving snails, duration of infection, cercarial production per day per positive snail, etc., were observed. The main emphasis was placed on determining the total cercarial production per 100 exposed snails for each snail population.It was possible to infect all the tested populations ofB. pfeifferiwith the various strains ofS. mansoni, but the observation as e.g. TCP/100 exposed snails varied greatly according to the population of snail and the strain ofS. mansoni. The results for the remaining species ofBiomphalariavaried greatly, depending on the combination, e.g.B. alexandrinawas only susceptible to the localS. mansonifrom Egypt.The highest TCP/100 exposed snails was more than 1 million for the strains ofS. mansonifrom Egypt, Kenya and the West Indies inB. alexandrina, B. pfeifferiandB. glabrata, respectively. The next group, with a TCP/100 exposed snails on 7 – 800 000 consists ofS. mansonifrom Sudan, Uganda and Zaire (Katanga) all inB. pfeifferi. The last tested strain ofS. mansoni, Zaire (Kinshasa) yielded a cercarial production on 500 000 per 100 exposed snails inB. pfeifferiandB. camerunensis.The shortest prepatent period, 19 days, was observed forS. mansonifrom Kinshasa, Zaire, inB. camerunensis, and the longest prepatent period, 25 days, was found for strains from Egypt and from the West Indies inB. alexandrinaandB. glabrata, respectively.In general, a very long duration of infection, lasting up to 200 days, was observed.