Browsing by Author "Morzaria, S.P."
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Item A Differential Diagnostic Criterion for Babesia Major and Babesia Bigemina Vermicules from Tick Haemolymph(1977) Morzaria, S.P.; Brocklesby, D.W.; Agricultural Research Council, Institute for Research on Animal Diseases, Compton, Nr. Newbury, Berks., U.K.Babesia major mature and immature vermicules in the haemolymph of Haemaphysalis punctata were measured and found to be significantly larger than vermicules of Babesia bigemina. Mature B. major vermicules had a mean length of 15.53 μm and mature B. bigemina vermicules had a mean length of 11.79 μm. This difference provides a new criterion for the differentiation of the two species.Item East Coast Fever the Significance of Host Ace in Infection or Immunization of Cattle with Theileria Parva(1979) Irvin, A.D.; Dobbelaere, D.A.E.; Morzaria, S.P.; Spooner, P.R.; Dolan, T.T.; Young, A.S.; Gettinby, G.; International Laboratory for Research on Animal Diseases, Nairobi, Kenya; Kenya Agricultural Research Institute, Muguga, Kenya; University of Strathclyde, Glasgow, UKT a number of tick-borne diseases of cattle, young animals show a significant resistance to infection which is independent of maternally transferred or acquired immunity. Such resistance has been detected in babesiosis (Riek 1968, Zwart and Brocklesby, 1979) an: lasmosis (Ristic, 1968; 1981) and heartwater (Uilenberg, 1983), but,10 evidence for an age-related innate resistance has been described in theileriosis apart from the rather equivocal data reported by Adler and Ellenbogen (1935) for calves infected with Theileria annulata.Item Further Studies on the Immunization of Cattle against Theileria La Wrencei by Infection and Chemoprophylaxis(Elsevier, 1979) Radley, D.E.; Young, A.S.; Grootenhuis, J.G.; Cunningham, M.P.; Dolan, T.T.; Morzaria, S.P.; Veterinary Research Department, Kenya Agricultural Research Institute, Muguga; Veterinary Laboratories, Kabete (Kenya); International Centre for Insect Physiology and Ecology, Kenya; MAFF Central Veterinary Laboratories, Great Britain.Three experiments were carried out to ascertain the feasibility of immunization of cattle against Theileria lawrencei using infection and chemoprophylaxis. In the first two experiments, cattle were immunized with a combination of three theilerial strains (‘cocktail’) and simultaneous treatment with an experimental formulation of oxytetracycline. When groups of these immunized cattle were challenged with stabilates of T. lawrencei isolated from African buffalo captured in Kenya and Tanzania, many of the immunized cattle had severe reactions and 3 out of 20 died, as did 18 of the 20 controls. A paddock containing carrier buffalo which maintained a population of Rhipicephalus appendiculatus continuously infected with T. lawrencei, was used in a second and third experiments. Cocktail immunized and control cattle were exposed to this tick challenge, and 55% of the immunized animals and 91% of the controls died. The protection provided by cocktail immunization was compared with immunization using different isolates of T. lawrencei from the buffalo paddock, but little difference in the degree of protection was detected. However, a high degree of immunity was observed when cocktail immunized cattle which had undergone a T. lawrencei stabilate challenge were exposed in the paddock. Only mild reactions were seen and no deaths occurred. Field immunization of cattle against T. lawrencei may be difficult due to immunovariants of this parasite emanating from the buffalo populations.Item Preliminary Studies on an Atypical Strain of Bovine Theileria Isolated in Kenya(1974) Burridge, M.J.; Brown, C.G.D.; Crawford, J.G.; Kirimi, I.M.; Morzaria, S.P.; Payne, R.C.; East African Veterinary Research Organization, PO Box 32, Kikuyu, Kenya FAO/UNDP Project KEN 22, Veterinary Research Laboratory, PO Kabete, KenyaA theilerial parasite infective for cattle, Theileria sp. (Githunguri), was isolated from the Kiambu District of Kenya through Rhipicephalus appendiculatus ticks. Eight cattle were experimentally infected with Theileria sp. (Githunguri); their reactions were characterized by the production of low numbers of macroschizonts, no microschizonts, few or no piroplasms, and a transient febrile response. All these cattle recovered from clinically mild reactions to infection, but were fully susceptible to subsequent Theileria parva (Muguga) challenge. A cell culture isolate of Theileria sp. (Githunguri) was made from injected lymphoid cells of a reacting animal and, from the resultant in vitro culture suspension, a schizont antigen of the parasite was prepared for the indirect fluorescent antibody test. Serological studies on Theileria sp. (Githunguri), using this test, indicated that it was antigenically distinct from T. parva, T. lawrencei and T. mutans, but had some antigens in common with T. parva and T. lawrencei.Item Ultrastructure of Babesia Major in the Tick Haemaphysalis Punctata(1976) Morzaria, S.P.; Bland, P.; Brocklesby, D.W.; Agricultural Research Council, Institute for Research on Animal Diseases, Compton, Newbury, BerkshireHaemaphysalis punctata ticks were infected with Babesia major by allowing them to feed on an infected splenectomised calf. Heavily infected ticks were dissected and the guts and the ovaries were processed to study the ultrastructure of B major in these organs. The morphology of the parasites in the gut and the ovary was identical. It was shown that the parasite contained a reduced form of an apical complex consisting of characteristic organelles such as the polar ring, rhoptries, micronemes and microtubules. A primitive conoid was situated at the anterior end of the parasite and consisted of delicate helical rings. The occurrence of these organelles confirmed the inclusion of this parasite in the subphylum Apicomplexa.
