Browsing by Author "Peirce, M.A."
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Item Blood Parasites of the Impala (Aepyceros Melampus) in the Serengeti National Park(1973) Irvin, A.D.; Omwoyo, P.; Purnell, R.E.; Peirce, M.A.; Schiemann, B.; East African Veterinary Research Organisation, Muguga, P.O. Kabete, Kenya. Serengeti Research Institute, Tanzania National Parks, P.O. Box 3144, Arusha, TanzaniaThe incidence of parasites was: Theileria 44.7%, Trypanozoon 5.8%, Haematoxenus 2.3% and Borrelia 1.2%. There was no evidence that these parasites were pathogenic to their hosts. Rhipicephalus evertsi ticks collected from these animals showed a salivary gland infection rate of 5.4%. Haematoxenus has not been described previously from impala.Item Carnivores as Vehicles for Ticks Carrying Disease Agents: A Possible Role of the Large-Spotted Genet, Genetta Tigrina, In the Epizootiology of East Coast Fever(1970) Purnell, R.E.; Peirce, M.A.; Musoke, A.; FAO Tick-borne Disease Project: East African Veterinary Research OrganizationCaptive genets were offered the ears of steers which had died of East Coast fever (E.c.F.), and on which nymphal Rhipicephalus appendiculatus were feeding. The genets fed on the ears and the ticks re-attached to the genets and completed their engorgement. After moulting, the resultant adult ticks were applied to a steer which had a typical fatal E.C.P. reaction.Item Ectoparasites from East African Vertebrates(1975) Peirce, M.A.; East African Veterinary Research Organization, Muguga, P.O. Kabete, Kenya.Records of ticks, mites and fleas found on 19 species of mammals and 4 of birds in Kenya, Uganda and Tanzania are presented. They include Xenopsylla brasiliensis (Baker) from Rattus rattus and Cricetomys gambianus, and also Haemaphysalis leachii (Aud.) from a potto (Perodicticus potto).Item Observations on the haematozoa found in birds from the Northern Frontier District of Kenya(1970) Peirce, M.A.Garnham (1950) emphasized the need for a more extensive study of the blood parasites of the East African vertebrates and recorded a number of parasitic blood infections, including those from avian species. More recently Oosthuizen and Markus (l967a, 1967b) have commenced a survey of birds in Southern Africa. and have recorded haematozoa from avian species which also occur in East Africa (Oosthuizen and Markus, 1969a, 1969b).Item The Possible Role of the Eland (Taurotragusoryx) in the Epidemiology of East Coast Fever and Other Bovine Theilerioses(1972) Irvin, A.D.; Peirce, M.A.; Purnell, R.E.; King, J.M.Rhipicephalus appendiculatus Neum. the normal vector of east coast fever (caused by Theileria parva) in cattle in Kenya is commonly found on eland (Taurotragus oryx), which are subject to theileriasis caused by Cytauxzoon taurotragi and possibly by a species of Theileria also. It is thought that eland may possibly act as a reservoir of T. parva, and an experiment was carried out to determine whether the theilerial piroplasms of eland could be transmitted to cattle. Nymphs of R. appendiculatus and R. simus Koch were fed on the ears of 7 parasitaemic eland, and after the moult to the adult stage, some were dissected and others fed on uninfected cattle. Of those dissected, 1 of 29 adults of R. simus and 8 of 64 of R. appendiculatus had parasites in the salivary glands that appeared indistinguishable from T. parva. The 5 cattle that the ticks fed on, however, did not become infected and were proved to be fully susceptible to T. parva, all dying of typical east coast fever 12-17 days after challenge with that parasite. Serological tests had also proved negativeItem Theileria Parva: Comparative Infection Rates of Adult and Nymphal Rhipicephalus Appendiculatus(1971) Purnell, R.E.; Boarer, C.D.H.; Peirce, M.A.; East African Veterinary Research Organization, Muguga, P.O. Kabete, KenyaThe tick Rhipicephalus appendiculatus is the usual vector of Theileria parva, the causative organism of East Coast fever (ECF) of cattle. When immature ticks engorge on parasitaemic cattle, they imbibe red cells containing T. parva piroplasms. The parasite subsequently undergoes a cycle of development in the body of the tick resulting in the production of a stage infective for cattle in the tick's next instar. It is generally accepted that adult ticks, which have engorged as nymphs on infected cattle, are largely responsible for the maintenance of the disease in the field (Theiler, 1905). However, Reichenow (1940) has suggested that if larval and nymphal ticks are fed on animals with the same level of infection, more parasite groups will be present in the salivary glands of the resultant nymphs than in those of the resultant adults. Reichenow also suggested that a group of nymphs, unlike a group of adult ticks, will begin to feed synchronously when applied to a host, and that the maturation of the parasite can be completed after 72 h feeding instead of 108 h as in adult female ticks.Item Theileria Parva: Variation in the Infection Rate of the Vector Tick, Rhipicephalus Appendiculatus(1974) Purnell, R.E.; Ledger, M.A.; Omwoyo, P.L.; Payne, R.C.; Peirce, M.A.; East African Veterinary Research Organization, P,O, Box 32, Kikuyu, KenyaThe variation in Theileria parva infection rates of experimental batches of adult Rhipicephalus appendiculatus ticks, used during the course of several years, was examined. It was found that considerable variation occurred, but that this could not always be correlated with the piroplasm parasitaemia in the cattle on which the ticks engorged as nymphs. Statistical analysis showed that the infection rate of ticks fed on cattle with a parasitaemia of 41–50 per cent was significantly higher than that of ticks fed on cattle with lower parasitaemias. A number of experiments were then carried out in which one or several factors of this aspect of the host-parasite relationship remained constant whilst others were altered. None of these factors was seen to play a major part in the variation. Finally, randomly selected groups of 10 ticks which had dropped engorged as nymphs from the same animal on the same day were examined. The variation observed even in these groups was so great that it was concluded that the infection rate could depend on a factor such as the juxtaposition of possibly-infected gut epithelial cells and developing salivary glands during the nymphal moult.Item Transovarial Infection with African Swine Fever Virus in the Argasid Tick, Ornithodoros Moubata Porcinus, Walton(1970) Perry, C.T.; Plowright, W.; Peirce, M.A.Adult ticks (Ornithodoros moubata porcinus) collected from warthog burrows were tested for infection by examining their excretions for African swine fever virus (ASFV). All of 3 infected females ticks from one burrow transmitted virus to their eggs and nymphal offspring and filial infection rates were high (55- 81%). Nymphae infected transovarially transmitted virus regularly by feeding on pigs. Four pools of unfed first-stage nymphal ticks, collected from warthog burrows, contained ASFV. Transovarial infection of the tick is one of the natural maintenances mechallisms for ASFVItem Two New Hosts for Clinostomum Phalacrocoracis Dubois, 1931 (Trematoda), from Uganda(1970) Peirce, M.A.; Din, N.A.; East African Veterinary Research Organization, Muguga, P.O. Kabete, Kenya.; Scientific Warden, Queen Elizabeth National Park, UgandaClinostomum phalacrocoracis is recorded for the first time from Pelecanus onocrotalus and P. rufescens in Uganda. The incidence and intensity of infection, higher in the former species, are related to the feeding habits of the hosts. Although both species feed on Tilapia nilotica[Oreochromis niloticus], P. onocrotalus feeds on larger specimens which presumably harbour greater numbers of metacercariae.
