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.
Immunobiology of African trypanosomiasis.
African trypanosomes are flagellated Protozoa that include the causative agents of important human and animal diseases (Table I) and are fascinating biologically.
Prevalence of lice on dairy cattle in England and the bordering counties of Wales
A postal questionnaire was used to collect information on the prevalence of lice on cattle on a random sample of dairy farms in England and the bordering counties of Wales. Replies were received from 1040 (52.8 per cent) of the 1970 farms which were mailed. Fifty per cent of farmers reported having ever seen or suspected lice in their herds and 29 per cent reported possible infestations in the winter of 1996/97. Visits were made to 24 farms in the south west of England during February 1998. Twelve of the farmers said that they had seen or suspected lice in their herd since October 1997, and that lice were more frequently observed on the adult cattle. However, examination revealed lice on 18 of the 24 farms, and adult cattle were the least likely group to be infested.