Observations on an isolate of Schistosoma bovis from Tanzania

The eggs of Schistosoma bovis isolated from Misungwi, Tanzania measure 211.1 micrometer +/- 18.4 long and 66.7 micrometer +/- 5.4 wide. The parasite is naturally transmitted by Bulinus africanus and is compatible in the laboratory with snails belonging to the B. truncatus. B. forskali, and B. reticulatus groups. The compatibility with B. africanus group snails is shared with isolates from Kenya and Sudan but not with S. bovis from more northern distributions. Enzyme analyses were carried out by isoelectric focusing. In adult worms, phosphoglucomutase (PGM), hexokinase (HK), malate dehydrogenase (MDH), and lactate dehydrogenase (LDH) proved to be monomorphic whereas two types of glucosephosphate isomerase (GPI), three types of glucose-6-phosphate dehydrogenase (G6PDH), and two types of acid phosphatase (AcP) were identified. Differences in the pI values of gPI and MDH of snail digestive glands and of larval parasites allowed the intramolluscan stages to be characterised. The GPI heterogeneity encountered was common both to the larval and adult parasites. The enzyme types identified in S. bovis are discussed both from an intra- and interspecific viewpoint.