Genetic studies of pathologic conditions and susceptibility to infection in Biomphalaria glabrata.

During studies on the genetics of variation in susceptibility of B. galbrata to infection with S. mansoni, four types of proliferative amoebocytic accumulations have been observed. They occur in four different clonal stocks of B. glabrata, beginning as amoebocytic aggregations, namely, in the atrial cavity, pericardial cavity, periaortic space, and hemocoel between the stomach and intestine. Persistent amoebocytic accumulations involve the sinuses around the stomach, intestine, and hepatopancreas. In these snails, nests of undifferentiated cells occur in the anterior pericardial wall, which is considered to be a hemopoietic area. Crossing experiments indicate the involvement of genetic factors, possibly in combination with infectious agents.