Trypanosoma congolense. 3. Serological responses of experimentally infected cattle.
Abstract A complement fixation (CF) test for the diagnosis of Trypanosome congolense infection in cattle was developed and compared with the indirect fluorescent antibody (IFA) test. Serological investigations were made with cattle immunized with irradiated T. congolense and challenged with untreated T. congolense. Trypanosomal antibodies were demonstrated by the CF test. The results indicated good specificity and sensitivity between the CF method and the IFA test. The CF test also afforded easier reading of results than the IFA test; however, antigen preparation was more difficult in the former. The serological responses detected by the IFA and CF test appeared to be influenced by early variations of parasitemia, although no correlation appeared to exist between titer and parasitemia at later stages of the infection. Antibodies were detected in animals which received injections of irradiated T. congolense prior to challenge with viable organisms.
Diurnal Variation in the Concentration of Trypanosoma congolense in the Blood-Vessels of the Ox's Ear
Summary (1) It can be shown that the normal distribution of T. congolense within the blood vessels of its mammalian host is most uneven, the concentration being much higher in capillaries than in arteries and veins. (2) In the ear the average concentration of trypanosomes throughout the vessels is inversely proportional to the amount of blood passing through in unit time, i.e., to the temperature. (3) This is reflected in blood-smears made from the ear veins, there being usually many more trypanosomes in the early morning than at midday. (4) Advantage of this knowledge should be taken in routine diagnostic procedures, and also when using blood-smears to measure the trypanocidal action of drugs.
Trypanosoma congolense. II. Histopathologic findings in experimentally infected cattle.
Abstract Heart, kidney, lung, liver, brain, spleen, lymph nodes, tongue, and diaphragm of 9 cattle experimentally infected with the Trans Mara I strain of Trypanosoma congolense, were examined histologically. A haemosiderosis, infiltrations in the kidney, changes in the vascular wall mainly of the arteries of the lung, scattered local perivascular, and meningeal infiltrations, and small juxtavascular glial nodules in the CNS were found.