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Accueil du site → Doctorat → États-Unis → 1989 → Sheep fascioliasis in Morocco : Epidemiology and serodiagnosis

University of Minnesota (1989)

Sheep fascioliasis in Morocco : Epidemiology and serodiagnosis

Khallaayoune, Khalid

Titre : Sheep fascioliasis in Morocco : Epidemiology and serodiagnosis

Auteur : Khallaayoune, Khalid

Université de soutenance : University of Minnesota

Grade : Doctor of Philosophy (PhD) 1989

Résumé
Seasonal transmission of Fasciola hepatica in the Middle-Atlas over a three-year period was observed. Fluke burdens in sentinel sheep were correlated with the dynamics of the snail intermediate host. These findings revealed two primary periods of transmission, which occurred in the spring and in the fall of each year. Strategic anthelmintic treatment studies in lambs indicated that 3 treatments at three month-intervals, with albendazole or fenbendazole, resulted in 6.4 and 3.75 Kg advantage, respectively when compared with the untreated control group. In ewes, this treatment improved the fertility and reduced the mortality rates. Field surveys conducted throughout Morocco for snails that might be responsible for the transmission of Fasciola hepatica, indicated that Lymnaea truncatula and L. peregra were widely distributed within Morocco. Lymnaea palustris and L. stagnalis were limited to the Gharb and Chefchaouen respectively. Natural infection with F. hepatica was only detected in L. truncatula. Laboratory studies demonstrated that development of L. truncatula snail eggs can only occur within a temperature range of 10$\sp\circ$ to 30$\sp\circ$C. Exposure of eggs to high (37$\sp\circ$C) or low temperature (4$\sp\circ$C) caused a subsequent increase in the development period as well as a reduction in the rate of hatching. Cross-reaction of antigenic extract of F. hepatica with other helminth species was determined by both the precipitin test and the ELISA. Shared antigens were demonstrated between F. hepatica and Moniezia expansa, Cysticercus tenuicollis and hydatid cyst (Echinococcus granulosus), while no cross-reactivity was observed with either Oestrus ovis or Haemonchus contortus. Comparison of the somatic (adult extract), metabolic (excretory-secretory) and tegumental antigens of F. hepatica in the ELISA showed that accurate diagnosis of experimental fascioliasis might be realized utilizing the metabolic antigen. In naturally infected sheep, somatic and metabolic antigens were the most sensitive in detecting infection, while the tegumental antigen showed the least cross-reactivity (8%) in all the assays.

Mots clés : fascioliasis, Veterinary services, Biological sciences

Accès au document : Proquest Dissertations & Theses

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