Vet. Res. 35 (2004) 123-130
DOI: 10.1051/vetres:2003042

Tritrichomonas foetus: a scanning electron microscopy study of erythrocyte adhesion associated with hemolytic activity

Geraldo Attilio De Carli^a, Tiana Tasca^{a, b} and Fernanda Pires Borges<sup>a

a</sup>  Laboratório de Parasitologia Clínica, Faculdade de Farmácia, Pontifícia Universidade Católica do Rio Grande do Sul, Av. Ipiranga 6681, 90619-900 Porto Alegre, RS, Brazil
^b  Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600 - Anexo. 90035-003 Porto Alegre, RS, Brazil

(Received 3 July 2003; accepted 21 August 2003)

Abstract - The in vitro hemolytic activity of Tritrichomonas foetus was investigated. The parasite was tested against human erythrocytes of groups A, B, AB, and O, and against erythrocytes of nine adult animals of different species (the rabbit, rat, chicken, cat, dog, swine, horse, bovine, and sheep). The results showed that T. foetus strains (ATCC KV1, K, PAL, 5022, RJ, 90) did not present any hemolytic activity against any human erythrocyte group nor against rabbit, rat, chicken, cat, dog and swine erythrocytes. T. foetus strains, however, lysed horse, bovine, and sheep erythrocytes. No hemolysin released by the parasites could be identified. Hemolysis did not occur with trichomonad culture supernatants, with sonicated extracts of T. foetus, nor with killed organisms. Scanning electron microscopy (SEM) showed that human erythrocytes did not adhere to the trophozoites, in contrast horse erythrocytes adhered to the surface of the parasites and were phagocytosed for up to 90 min. The parasites are able to exert their cytopathic effects through: (a) physical contact established between the two cell surfaces, (b) toxins released from parasites into the interaction media, or (c) the association of both mechanisms. Further studies are necessary to clarify the importance of the hemolytic activity in the biology of T. foetus.

Key words: Tritrichomonas foetus / hemolytic activity / scanning electron microscopy / erythrophagocytosis / cytopathic effects

Corresponding author: Geraldo Attilio De Carli gdecarli@portoweb.com.br

© INRA, EDP Sciences 2004