Laboratory maintenance of Trypanosoma (Herpetosoma) rangeli Tejera, 1920

Two laboratory maintenance systems of Trypanosoma rangeli were compared. The maintenance by weekly subinoculations in Tobie's culture medium and the intrafemoral inoculation of Rhodnius prolixus with cultured flagellates, resulted in loss of infectivity of the metacyclic salivarian trypomastigotes for mice, ten months after maintenance in culture. With the system of cyclical passes through culture-Rhodnius-mouse-culture-Rhodnius, the infectivity of the metacyclic trypomastigotes for mice, was maintained during the three years of the experiment. The number and percentage of metacyclic trypomastigotes formed in the salivary glands of R. prolixus, previously inoculated intrafemorally or intracoelomically with culture forms of T. rangeli, did not show correlation with the inoculated dose, however the inoculated quantity demonstrated a direct relation with the mortality rate of the insects. The results indicate that T. rangeli requires an adequate maintenance system, so that under experimental condition the biological characteristics, normally expressed under natural conditions, are conserved.     

Opalinidae (Slopalinida) in South American Amphibia. Genus Zelleriella Metcalf, 1920 in Colombia

In September and October 1992, 97 Colombian amphibians collected at eight sites and comprising 25 species in eight families were checked for opalines in the cloaca. Zelleriella falcata Carini, 1933 was found in one Elachistocleis ovalis (Microhylidae); Z. microcarya Metcalf, 1923 in three of six Rana vaillanti (Ranidae); Z. stewarti n. sp. in four of seven Colostethus subpunctatus (Dendrobatidae); Z. dendrobatidis Metcalf, 1923 in one juvenile of C. palmatus; Z. antilliensis (Metcalf, 1914) in three of eight Bufo marinus (Bufonidae), one of 14 juveniles of Leptodactylus sp. (Leptodactylidae), four of five L. fuscus and one of three L. ventrimarmoratus; and Z. opisthocarya Metcalf, 1923 in one of eight B. marinus; Z. paludicolae Metcalf, 1923 in one of three L. ventrimarmoratus; Zelleriella sp. in one of six B. granulosus. Z. xyster is proposed as a new combination for Protoopalina xyster Metcalf, 1923. The occurrence, evolution and biogeography of Neotropical Zelleriella are discussed.     

Developmental stages of Trypanosoma cruzi-like flagellates in Cavernicola pilosa

The developmental stages of Trypanosoma cruzi ssp., found in the intestinal tract of Cavernicola pilosa, are described and measurements given for nine life stages. The frequencies of the various stages in foregut, midgut and hindgut of the triatomines are provided; parasites were rare in the foregut and metatrypomastigotes were seen only in the mid- and hindguts. All adult bugs examined harboured intestinal infections of T. cruzi-like flagellates, large clumps of amastigotes were frequently observed in the midgut. The faeces of C. pilosa, containing metacyclic trypomastigotes, did not produce patent parasitaemia when inoculated into mice. Inoculated mice were not protected against subsequent challenge infections with the highly virulent Tulahuen stock of T. c. cruzi. The blood of bats also failed to produce parasitaemia when inoculated into mice, nor were the mice protected against subsequent challenges with T. c. cruzi. Although the developmental stages described were very similar to those of T. c. cruzi it is presumed that they were stages of T. c. marinkellei because of their failure to infect mice and Rhodnius prolixus, and their failure to protect inoculated mice against challenge with T. c. cruzi.