Browsing by Author "Brenda, O.V."
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Item Attempts to Infect Some Small Laboratory Animals with Theileria parva(1961) Brocklesby, D.W.; Brenda, O.V.Research on East coast fever(T. parva infection) has been considerably hampered by the lack of a small laboratory host animal. All investigations have to be undertaken using as experimental animals, cattle, which are both cumbersome and expensive. This fact led some investigators to seek an alternative in tissue culture (Tsur, Neitz and Pols, 1957; Brocklesby and Hawking, 1958) but none of these attempts was very successful. It is generally assumed that all small laboratory animals are insusceptible to infection with T. parva, but a search of the literature failed to reveal reports of any extensive attempts to infect such animals. Jansen (1952) splenectomized 2 dassies (Procavia capensis) 16 and 21 days after infestation with infected Rhipicephalus appendiculatus nymphae, but no development of T. parva took place. Barnett and Bailey (1955) were not able to infect a small number of rabbits, guinea-pigs or hamsters. Barnett (1956), however, succeeded in maintaining a parasitaemia in goats by the repeated intravenous injection of infected bovine blood. Ticks which fed on one of the goats subsequently transmitted the disease to cattle. It is probable that other attempts remain unpublished.Item Cyclic Development and Longevity of Theileria parva in the Tick Rhipicephalus appendiculatus(1964) Martin, H.M.; Barnett, S.F.; Brenda, O.V.; East African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 In Vitro Growth of Tick Tissues (Rhipicephalus appendiculatus Neumann, 1901)(1962) Martin, H.M.; Brenda, O.V.The tissue culture of mammalian tissues is now a well-established procedure with many applications in numerous fields of biological research. The first successful attempt to grow insect tissues in vitro was made by Goldschmidt (1915) who recorded the growth of testicular follicle cells of Samia cecropia in hanging drop cultures of hemolymph. Since then many attempts to grow insect tissues have been made but little success was achieved until Trager (1935) succeeded in growing ovarian tissue of the silkworm (Bombyx mori) in hanging drop cultures. Trager obtained survival of such cultures for up to 2 weeks. Most other trials resulted in little. If any growth and even survival was for only short periods. However during the past 4 or 5 years much progress has been made in the culture of insect tissues. This, according to Grace (1958, 1959) and Day and Grace (1959) and others has been due in part to an increase in the knowledge of the chemical and physical composition of the hemolymph. This information has served as a guide for the development of media capable of supporting the growth of insect tissues for extended periods. However up to the time Trager (1959) reported initial outgrowths of several kinds of tissue from early pupae of Glossina palpalis in Vitro cellular outgrowths comparable to those seen earlier with vertebrate tissues were obtained with only one kind of insect tissueItem Some New Host Records for Hepatozoon Species in Kenya.(1963) Brocklesby, D.W.; Brenda, O.V.Sir,-We would like to record the discovery of Hepatozoon species in the lion (Panthem (Leo) leo), the leopard (Pal/them (Panthera) pardus) and the genet cat (Genetta tigrina).
