02527naa a2200193 a 450000100080000000500110000800800410001910000230006024500750008326000090015852019630016765000130213065000230214370000160216670000210218270000220220370000190222577300890224417916361997-09-11       1995    bl uuuu     u00u1 u    #d1 aSILVA, R. A. M. S.  aInfection in wistar rats after oral inoculation of Trypanosoma evansi.  c1995  aTrypanosomosis due to Trypanosoma evansi represent one of the most important uncontrolled disease in the tropics and other parts of the world. These condition in specially prevalent in many developing countries and is a significant constrain to livestock production. T. evansi is the causative agent of "Mal de caderas" in the subtropical area of Argentina and Pantanal, Brazil. It is a salivarian trypanosome belonging to subgenus Trypanozoon and has no true intermediate hosts but it is transmitted directly or mechanically. In a similar manner that is observed in the stercorarian section, T. evansi demonstrated in this study a capacity to infect rats through oral route. Oral and intra-peritoneal (ip) inoculations of blood trypomastigotes as well as rats fed on infected carcasses resulted in 100% and 60% of rat infections respectivelly. The prepatent period of the parasitemia in animals inoculated orally with infected blood was eight days and nine days in rats fed on infected carcasses longer than those inoculated ip. All oral and i.p. infected animals died due to progressive infection. Three of five rats fed with infected carcasses also died. At necropsy, a striking feature was splenomegaly. The spleen was dark brown in colour, intensively congested and enlarged. The spleen of rats infected with blood enlarged twice from its normal size and eight times its normal weight. The spleen of rats fed on carcasses increased five times from its weight and aproximatelly two times its length. The spleen of rats inoculated i.p. increased two and half times its weight and only aproximatelly once and half its length. The liver and lungs were intensively hyperemic and the kidneys were congested in all infected animals. Similar alterations has been reported in T. brucei infection in mice and rats and by T. evansi in dogs. The high infectivity of T. evansi to rats through oral route could means that the oral important route in a sylvatic cycle.  aPantanal  aTrypanosoma evansi1 aRAMIREZ, L.1 aDAVILA, A. M. R.1 aPEREIRA, M. E. B.1 aHERRERA, H. M.  tMemorias do Instituto Oswaldo Cruz, Rio de Janeirogv.90, p.298, 1995. Suplemento I.