Browsing by Author "Barnett, S.F."
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Item Cyclic Development and Longevity of Theileria parva in the Tick Rhipicephalus appendiculatus(1964) Martin, H.M.; Barnett, S.F.; Brenda, O.V.; East African Veterinary Research OrganizationFull details of the technical methods evolved in the study of Theileria parva in the tick Rhipicephalus appendiculatus are described. Stages of T. parva discovered in intestinal contents, gut epithelial cells, and the cells of the salivary glands are fully described. Only the stages of the parasite found in the salivary glands and ducts could definitely be said to be a part of the normal life cycle of T. parva. Multiplication occurred in this site by a process of multiple fission. No sexual stages were discovered. Salivary gland inclusions of T. lawrencei (South African strain) were similar to those of T. parva. The many sources of error that have confused earlier workers are fully discussed. Studies on the longevity of T. parva in its tick vector confirmed the fact that the contained parasites die before the tick. Ticks become noninfective within 34–40 weeks after molting but are capable of feeding up to 15 months. It was found that ticks infected with T. parva could transmit the parasite to cattle 24 hours after being placed on the host.Item Experiments to Discover a Suitable Fluid for Moats Around Tick-Proof Stalls(Comm. for Technical Cooperation in Africa South of the Sahara, Publ. Bureau, 1965) Barnett, S.F.; Brocklesby, D.W.; East African Veterinary Research OrganizationFor experimental work at the EAVRO animals infected with Theileria parva and other tick-borne parasites are housed in specially designed tick-proof stalls that are surrounded inside the building by a moat. This note records the results of some experiments that were performed to discover a suitable fluid to place in these moats. It was important that the fluid should be cheap and that it should not affect the ticks that would be feeding on the animals for experimental purposes. Water might act as a good mechanical barrier, but it was felt that some fluid with tick-killing properties would be preferable, particularly when exotic parasites such as Theileria annulata were being studied. Fluids commonly used as ixodicides containing B.H.C. or Toxaphene could not be employed because of the danger of their affecting ticks feeding on the experimental animals.Item The Isolation of “Theileria Lawrencei (Kenya)” from a Wild Buffalo (Syncerus Caffer) and its Serial Passage Through Captive Buffaloes.(1966) Brocklesby, D.W.; Barnett, S.F. ; East African Veterinary Research Organisation, MugugaThe isolation of a parasite referred to as “Theileria lawrencei (Kenya)” by the collection of engorged nymphae of Rhipicephalus appendiculatus from a wild African buffalo is described. The parasite was serially transmitted by ticks through four buffalo calves: one of them died and the others reacted and recovered. The wild buffalo was apparently a healthy carrier of the infection, but the recovered experimental buffaloes did not remain infectious to ticks. The infections in three of the buffaloes were transmissable to cattle.Item The Literature Concerning Theileridae of the African Buffalo (Syncerus Caffer)(1966) Barnett, S.F.; Brocklesby, D.W.The African Buffalo (Syncerus caifer) has for many years been suspected of being implicated in the epizootiology of East Coast Fever (E.C.F.) or a similar disease. Various investigators and field workers in different parts of Africa have made observations but only in South Africa and Kenya has it definitely been proved that the buffalo can act as a reservoir of an East Coast Fever-like disease.Item A Mild Form of East Coast Fever (Theileria Parva) With Persistence of Infection(1966) Brooklesby, D.W.; Barnett, S.F.; East African Veterinary Research OrganizationA parasite, isolated from some unknown wild animal, was transmitted through ten passages in high-grade cattle via Rhipicephalus appendiculatus and R. kochi. It proved to be a strain of Theileria parva of low virulence. Only 25 per cent of infected cattle died and the mortality rate was directly related to the number of ticks used to transmit the parasite. Some animals became carriers after recovery. It is suggested that the existence of such mild strains with persistent infectivity may account for some of the alleged successes of field treatments and possibly for sporadic cases of East Coast Fever that occur in areas with a long history of freedom from the disease.Item Notes on Animal Diseases XVI-Bovine Brucellosis (Contacious Abortion(1950) Barnett, S.F.Bovine brucellosis is a contagious disease caused by the bacillus Brucella abortus. This organism produces characteristic inflammatory and degenerative changes in the pregnant uterus leading to abortion, which is frequently followed by a temporary or permanent sterility. Bulls may sometimes become infected, when abscesses are formed in the testicle and epididymis. The disease is world-wide in distribution and is found in Kenya in both purebred and Zebu cattle.Item A Small Controlled Trial of the Anthelmintics Haloxon and Thiabendazole in Sheep(1963) Barnett, S.F.Both haloxon and thiabendazole were highly efficient anthelrnintics against the following nematodes in the abomasum and small intestine Haemonchus contortus, Ostertagia circumcincta, Trichostrongylus colubriformis, Trichostrongylus axei, Cooperia curticei, Bunostomum trigonocephalum. Haloxon had no effect on Oesophagostomum columbianuln, whereas thiabendazole was highly efficient.Item Studies on Macroschizonts of Theileria parva(Elsevier, 1961) Barnett, S.F.; Brocklesby, D.W.; Vidler, B.O.; East African Veterinary Research Organisation, MugugaA series of measurements was made of the schizonts of Theileria parva in the hope that these criteria might be used in the differential diagnosis of the theilerial species. Macroschizonts were found to have an average size of 4.8 μ, which was smaller than expected. They contained from 1 to 85 nuclei, with an average of 8. In autopsy smears there were from 4 to 760 schizonts per thousand lymphocytes, with an average of 264. The degree of parasitosis at death was not correlated with the duration of illness. A plea is made for the use of the terms ‘macroschizonts’ and ‘microschizonts’ in place of the more traditional ‘agamonts’ and ‘gamonts’.Item The Susceptibility of the African Buffalo (Syxcerus Caffer) to Infection with Theileria Parva (Theiler, 1904)(1966) Barnett, S.F.; Brocklesby, D.W.; East African Veterinary Research OrganizationSix African buffaloes were exposed to infection with Theileria parva. Two of them showed no evidence of infection. Two exhibited only lymph node enlargement with parasites detected in smears. One underwent a mild febrile reaction, but no parasites could be found. One animal had a slight fever and parasites were present: ticks collected from this buffalo transmitted typical East Coast Fever to cattle.
