Infection of Rodent Myeloma Y3-Ag 1.2.3 Cells by Trypanosoma cruzi Metacyclic Trypomastigotes

Abstract

trapped in a hilly area close to the town of Sanare (9?45'N, 69?36'W, and 1,250 m altitude). The rodent carcass was brought to the parasitology lab for identification of some whitish bags attached to the rabbit pericardium. Two cysts were removed, with diameters of 2.8 cm and 2.2 cm, respectively. Hydatid fluid was extracted using a syringe. The fluid was observed microscopically, and a high number of protoscolices were seen (Fig. 1). Case two: A second rabbit was trapped in a dry low land, close to San Francisco village (10?17'N, 70?19'W, and 460 m altitude), Torres County, Lara State, and a few hydatid cysts found adhering to the left kidney and the thigh musculature. These cysts were only 1.5 to 2.0 cm in diameter; protoscolices were also removed from the hydatid fluid. In order to identify the larval stages, the brood capsules (n = 20), the protoscolices (n = 70), and the rostellar large hooks (n = 100) were measured; the results are presented in Am. Brood capsules had a thin membrane and measured 515-540 Am (mean: 526). Fully developed protoscolices were 120-157 long by 90-122 in diameter (mean: 136 by 108), and the large rostellar hooks ranged between 31.3-34.8 (mean: 32.6). On the basis of a comparison of the present data with the data published by Rausch et al. apped in a hilly area close t the town of Sanare (loc. cit.), we conclude that these cysts belong to the larval stage of E. oligarthrus. It should be pointed out that after carrying out a survey of over 4,000 mammals in Colombia, D'Alessandro et al., 1981 (loc. cit.) found no lagomorpha (Sylvilagusfloridanus) infected with Echinococcus cysts. Furthermore, we found no prior reference of rabbits involved in the life cycle of E. oligarthrus, and E. vogeli in Venezuela. Consequently, wild rabbits may be included as an alternate intermediate host for E. oligarthrus, at least in this Westcentral region of Venezuela, where pacas and agouti are rarely seen. One of us (MSY) has necropsied 12 pacas in the last 3 years with negative results for E. oligarthrus cysts. Finally, it should be recalled that in the taxonomy of cestode, the morphological characters are not now final criteria for differentiating species, and as stated by other authors (Smyth, 1979. In British Society for Parasitology Symposia, A. E. R. Taylor and R. Muller (eds.). Blackwell, Oxford, Vol. 17, pp. 75-101; Thompson and Kumaratilake, 1982, Trans. Roy. Soc. trop. Med. Hyg. 76: 13-16), other methods like ecological and immunological differences, in vitro cultivation, and protein separative techniques should be used for the identification of cestodes such as Echinococcus and other helminths.