The histopathology of experimental disease produced in mice infected with Trypanosoma vivax.

An acute form of trypanosomiasis (course of disease 4 to 8 days) was produced in mice experimentally infected with a strain of T. vivax. The features of the disease were: a parasitemia which appeared to increase exponentially from 23.8 to 243.6 times 10(6) trypanosomes per ml within the last 24 hours of the disease; anaemia was not severe in the disease in mice; the basic histological lesion was generalized fibrin thrombus formation in the blood vessels of the heart, lung, spleen and brain; trypanosome enboli were present in the brain, spleen and liver of infected mice. The disease in mice could prove a useful model in studies of the pathogenesis of acute trypanosomiasis and also in studies in the mechanism of generalized intravascular coagulation.

Experimental Rift Valley fever in West African Dwarf sheep.

West African Dwarf sheep were challenged with a low mouse brain-passaged Rift Valley fever virus (Ib-AR 55172) isolated from Nigeria. Viraemia, mild febrile reaction and neutralising antibodies were demonstrated in inoculated animals.

Cellular changes in tissues of newborn mice infected with Mokola virus: ultrastructural and biochemical changes.

Cellular and biochemical changes which occurred in the tissues of newborn mice infected with Mokola virus, a rabies-related virus (rhabdovirus group), were described. The virus was transmitted along the peripheral nerves and appeared in various tissues of the body, but did not replicate in any except the nervous system, where it manifested its gross effects. While Mokola virus increased the synthesis of glycogen and total protein in infected brain, liver, lung, spleen and heart, it reduced the activity of monoamine oxidase in the brain. Virus multiplication occurred in the normal rough endoplasmic reticulum. During virus reproduction the membranes of the endoplasmic reticulum, Golgi complex and mitochondria were destroyed and replaced by a viral matrix. Virus maturation also occurred within the rough endoplasmic reticulum.

Serum proteins, blood and plasma volumes in experimental Trypanosoma vivax infections of sheep and goats.

Measurements of blood and plasma volumes using 131I-albumin, and of red cell volume using 51Cr in goats and sheep infected with Trypanosoma vivax for 1 to 2 months (at which time the anaemia was severe) showed statistically significant increases in blood volume (29 per cent and 57 per cent) and plasma volume (44 per cent and 59 per cent), and decreases in red cell volume per kilogram body weight (49 per cent and 50 per cent) in goats and sheep respectively. Total serum proteins and gamma globulins increased, while serum albumin decreased, in T. vivax infected sheep and goats. These findings indicate that the anaemia manifested, with mean packed cell volume decreased by 60 per cent and 47 per cent in goats and sheep respectively at the time of red cell volume measurements, is attributable partly to haemodilution and partly to an actual decrease in total volume oc circulating red blood cells.

Free plasma amino acid profiles of normal and Trypanosoma vivax infected sheep.

The free amino acids in the plasma of normal and Trypanosoma vivax infected sheep and also in the trypanosome organism per se were determined. Threonine, asparagine, methionine, tyrosine, citrulline, ornithine, histidine, arginine and urea were significantly decreased in the plasma of infected sheep. Alanine was significantly elevated in plasma of infected sheep. Valine, isoleucine, leucine values were also elevated in the plasma of infected sheep, although not at significant level. Taurine was present among the amino acid profile of T. vivax organisms and also in the plasma of normal and infected sheep. The significance of the amino acid changes in terms of host and T. vivax metabolism is discussed.

Experimantal Congo virus (Ib -AN 7620) infection in primates.

Three primates inoculated with Congo virus (CV) developed viremia. The animals showed neither any rise in rectal temperature, nor signs of overt disease; however, in one of them pruritus and rash were observed. Skin biopsy revealed vasculitis and hemorrhage. By complement fixation, neutralization and gel diffusion tests CV antibodies were demonstrated in the convalescent sera of the three animals.