[Natural infection of Calomys musculinus (Rodentia, Cricetidae) by Trypanosoma cruzi].

In the rural area of Las Higueras, Río Cuarto, Córdoba, Argentina, a trypanosoma was isolated from a wild rodent (C. musculinus). The trypanosome was classified as Trypanosoma cruzi because of the following characteristics: morphology as described by Hoare for the Schizotrypanum sub-genus: thin shaped, pointed back end, nucleus placed approximately in the middle of the body, prominent and subterminal kinetoplast and short free flagellum. The size measurements were as follows: total lengh 22.02 +/- 0.40 micron, flagellum lengh 5.93 +/- 0.29 mu, Nuclear mean index (NP/NA) 1,21 +/- 0.07 (Table 1). For some authors, this last value is very important for diagnosis of the parasite. BALB/c albino mice were infected with blood of the captured animal; those mice showed a mild parasitemia and amastigotes nests in cardiac fiber (Fig 2 a y b). The xenodiagnosis performed with nimphs of Triatoma infestans on the laboratory mice was positive. The trypanosome grew very well in blood-agar medium. According with these findings along with the wide geographic distribution and density of C. musculinus in Argentina, one should wonder whether or not this rodent is infested withT. cruzi on its whole distribution range. Passages through T. infestans and laboratory mice produced a virulence enhancement of this strain. With these findings, the question is if this situation should take place in nature, affecting domestic animals in any way. The stated questions and findings should estimulate further research on the role of the wild fauna in the epidemiclogy of Chagas' disease in Argintina.