Trypanosoma cruzi in the opossum Didelphis marsupialis: Parasitological and serological follow-up of the acute infection

Histopathological study of experimental and natural infections by Trypanosoma cruzi in Didelphis marsupialis

“…It was also reported by Jansen et al (1991) that the G-49 strain caused higher levels of immunoglobulins and parasitemia compared to G-327, both being of sylvatic origin and isolated from naturally infected opossums. The Y strain, on the other hand, is known to present low levels of infection and immunoglobulins in the opossums (Jansen et al 1985), and in some cases the animals rid themselves of the parasites (Thomaz et al 1984).…”

“…Although the opossums acquire immunological maturity from the 80th day of age on (Block 1964), younger animals (45 days old), were able to control the infection by T. cruzi (Deane et al 1984c), suggesting that other mechanisms, probably nonspecific, are involved in the efficient control of the infection as also suggested by Jansen et al (1991), at least in animals at this age. Indeed, when 2 pouch young opossums (≅80 days) were inoculated subcutaneously with 2 x 10 3 blood forms of Y strain per gram of body weight, and killed at 8 month after infection, parasites and tis- sue lesions were not detected.…”

“…Jansen et al (1991), have shown that T. cruzi may or may not reach the opossums' scent glands depending on the levels of parasitemia induced by the size of the inoculum. This fact can explain why our naturally infected opossums did not present anal scent glands infection, though some isolates when obtained from the glands and inoculated in others (Jansen et al1991), were capable of further glandular colonization.…”

“…Parasitological studies (Deane et al1984a, Jansen et al 1985, Jansen et al 1991 of opossums experimentally infected with T. cruzi showed that since very young, opossums resist to experimental infections with high inocula and that two types of infection could occur: (1) apparently self-cured, where the results of sub-inoculation (in mice), xenodiagnosis and hemoculture became negative within a few weeks after inoculation, and the immunofluorescent antibody test (IFAT) was always positive at low titers and no invasion of the scent glands could be observed; (2) infection where the parasites were often intermittently recovered through xenodiagnosis and/or hemoculture, after many months; IFAT was persistently positive at high titers and most of the animals presented para-sites in the scent glands. These differences were considered by Deane et al (1984a,b) as related to the T. cruzi-strain, since: Y strain inoculations resulted in the first and F or sylvan-isolates inoculations resulted in the second pattern of infection.…”

Trypanosoma cruzi in the anal glands of urban opossums: I- isolation and experimental infections

“…Experimental infections -Six juvenile opussums (mean wt 350 g) were inoculated intraperitoneally (i/p) or s/c with 200 metacyclics/g (Jansen et al 1991), quantified according to Brener (1962) from the glandular content of a naturally infected opossum. These animals were obtained from the pouches of females which, together with their litters, had been found negative for T. cruzi by both blood examination and xenodiagnosis.…”