Lymphoid organ alterations enhanced by sub-lethal doses of coronaviruses in experimentally induced Trypanosoma cruzi infection in mice

The effect of sub-lethal doses of coronaviruses on the course of disease in CBA mice experimentally infected with a mildly pathogenic strain of Trypan osoma cruzi was investigated. Mice were inoculated with either T. cruzi, 0. 1 median lethal dose (LD50) of coronavirus (mouse hepatitis virus [MHV-3] o r virus X), or both pathogens. Levels of parasitemia, mortality, and the ex tent of pathologic alterations in lymphoid organs were determined. Mice ino culated with T. cruzi had mild alterations in their lymphoid organs and sur vived infection. In contrast, mice inoculated with both pathogens died, and had significantly higher levels of parasitemia and profound alterations in lymphoid organs. These results indicate that the pathologic profile of T. cruzi infection can be profoundly altered by subclinical infection with cor onaviruses.