Browsing by Author "Ashenafi, Hagos (PhD)"

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    Study on Concurrent T. Congolense and H. Contortus Experimental Infection in Goats: Interaction and Pathogenic Effects
    (AAU, 2006-06) Tadesse Wazza, Abebayehu; Ashenafi, Hagos (PhD)
    Study on concurrent Trypanosoma cOllgo/ellse and Haemonchus COllrortliS infections to assess the interaction and pathogenic effect of single and mixed experimentally induced infection were conducted in goals. A total of 25 goats of approximately one year old were divided into five groups and each group was infected either with H. COlltorWs one week after a preceding infection with T. congo/elise or with primary H. conlOrlus infection one week prior to T. cOllgo/ellse or infection with either the nematode or trypanosome alone, and the fifth group was served as non infected control. For experimental purpose each experimental animals were infected with T. congo/elise. derived from the donor goat after one passage in mice with total intravenous inoculation of 5x I 4 T. congo/elIse. The tOlal infective dose of H. cOl/torll/S, which was given orally to each animals was, 10,000 3rd stage larvae. Parasitological observations such as prepatent period, faecal egg count, woml burden and trypanosome parasitaemia; and hematological parameters like packed cell volume, haemoglobin concentration. mean corpuscular volume (MCV), mean corpuscular haemoglobin concentration (MCHC), red blood cell counts, white blood cell coul1ls. differential leukocyte counts (eosinophil, lymphocyte and neutrophils), total protein and also clinical parameters including body weight change, mortality rates among various treatment groups were made in mixed infected groups and in animals singly infected with ei ther parasites. It was revealed that the order of infection in the preceding or subsequent infection was very important in which the most hannful combination was a primary T. cOllgo/eflse infection one week prior to Ii. COllforllls super Infection. that resulted in progressive and sever anaemia accompanied by leucopenia, hypoprOleinemia, loss of weight and short prepatem period of H. COlftorlllS. Except animals mono infected with H. COnforms, which have shown macrocytic hypochromic anaemia, all other treatmem groups have revealed nomlocytic nonnochromic anaemia throughout the whole observation period. The result also showed that animals with concurrent T. cOllgo/ellse and Ii. COI/lortus run high risk of succumbing during the infection period. Higher rate of mortality and more pronounced pathological effects were observed in combined infections than single ones. It was concluded that the increased I/. cOlllortus egg excretion observed in animals infected with both parasites might signi fi cantly increase the risk of nematode infections. The interaction between these two highly potent anaemia causing pathogens should be considered whenever attempts are made to control these two diseases.