The characterization of four Trypanosoma vivax isolates from Colombia in South America showed that although minor phenotypic differences existed between them, these parasites are antigenically related and belong to a single serodeme. Characterization by isoenzyme assay, karyotyping and DNA probe analysis, showed the Colombian isolates to be more similar to the West African than to Kenyan T. vivax. There was, however, little serological cross-reactivity between South American and African groups of T. vivax. Although the T. vivax isolates from Colombia were pathogenic for dairy calves which showed the typical sign of progressive emaciation, these parasites failed to infect mice or tsetseand could not be cultivated as bloodstream forms in vitro.This study represents initial attempts to establish the phenotypic and serological diversity amongst T. vivax isolates from South America.

Murine monoclonal and polyclonal antibodies to antigens of Bonamia ostreae were assessed for serological comparison of parasites associated with different geographical origins of flat oysters, Ostrea edulis, and with Tiostrea lutaria. All Bonamia isolates from O. edulis reacted similary with polyclonal and monoclonal antibodies. The parasite associated with Tiostrea lutaria which lacks reactivity with 20 B2 MAB must be considered as a serologically distinct form of B. ostreae.