Browsing by Author "Pierce, M.A."
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Item The Epizootiology of African swine fever in Africa(1969) Plowright, W.; Parker, J.; Pierce, M.A.; East African Veterinary Research Organisation, Muguga, Kabete, KenyaThe incidence of African swine fever virus in different body tissues in two populations of East African warthogs and the distribution of the virus in the tick population of Kenya, Tanzania and Uganda were studied. There was no evidence of transplacental infection or of excretion of the virus in the milk. In view of experimental evidence, infection by ingestion was improbable. Infected ticks were found in 40% of burrows in Kenya and Tanzania, but in none in Uganda. The highest rate of infection was in adult ticks, while no first-stage nymphs were infected. The virus recovered from ticks appeared to be similar to the typical field strain. Virus proliferation occurred in the ticks. Persistent infection with some strains of virus was acquired by laboratory ticks when fed on reacting pigs or infected blood in capillary tubes. The disease was transmitted by feeding for 18-34 weeks after the original infective feed. Trans-stadial transmission occurred regularly with the Uganda strain of virus but infrequently with the Tengani strain. Virus was excreted from the tick in the coxal fluid and probably also in the saliva. Relatively small doses of virus by the nasal and parenteral routes infected pigs regularly, while large doses by mouth failed to do so. Natural transfer of virus from wild to domestic pigs might take place when infected ticks are carried into piggeries. Although a large DNA virus, the African swine fever virus satisfied all the basic requirements for an arbovirus. -BMW.Item A Pathogenic Theilerial Syndrome Of Cattle In The Narok District Of kenya(1972) Irvin, A.D.; Brown, C.G.D.; Burridge, M.J.; Cunningham, M.P.; Musoke, A.J.; Pierce, M.A.; Radley, D.E.Two theilerial parasites, pathogenic for cattle, were isolated during a field trial conducted at Aitong in the Narok District of Kenya. In a series of laboratory experiments the first of these parasites was successfully transmitted to all of 18 cattle by syringe inoculation of piroplasm infected blood. Two lines were established which were passaged 5 and 3 times respectively_ The animals inoculated all underwent a haemolytic syndrome with anaemia and jaundice and 5 of them died. Macro- and microschizonts were seen in only one of these 18 animals, but piroplasms were present in large numbers. Animals which had recovered from infection and were challenged with Theileria parva all died and there was no evidence that previous infection had conferred any protection on them. This infection was not transmitted by ticks.
