Studies on Haemonchus contortus Infection Desert Goats in South Darfur State, Sudan.

The present study comprises a 12 month abattoir survey on the prevalence of H. contortus in desert goats combined with experimental studies on the disease course as induced by different dose levels of infective larvae (150, 300 and 500 L/Kg bwt.). The results of the survey demonstrated the prevalence of the parasite with seasonal variation throughout the year. The highest percentage (100%) was recorded in July, September and October while the lowest percentage (32%) was recorded in March. The overall mean worm burden per animal was 369.6 ± 11.4 for total worm count, 118.2 ± 27.0 for adult worm and 306.2 ± 62 for immature larvae. The prevalence of the parasite and the mean worm burden were positively correlated with rainfall and relative humidity rather than with temperature. The results of the experimental infection demonstrated the susceptibility of desert goats to different levels of infective dose of 150 L/Kg bwt. and above. The clinical signs were manifested by dullness, weakness, inappetence, emaciation, constipation, pallor of visible mucous membranes and reduced body weight gain. Anaemia was further evident by the significant reduction in Hb. concentration and PCV. H. contortus eggs were detected in faeces 17 to 18 days post infection with a maximum shedding on day 23 or 24. Death occurred within 5 to 35 days in 50%, 83% and 100% of goats infected with 150, 300 and 500 L/Kg bwt. respectively. The pathological alterations of H. contortus infected animals were mainly confined to the abomasum which showed diffuse congestion, haemorrhages and multifocal erosions. Adult worms were present inside the abomasum or attached to the mucosa. The histopathological alterations were mainly dominated by oedema and congestion of the submucosa with moderate infiltration of inflammatory cells on the lamina propria. The mucosal surface was occasionally interrupted with scattered areas of superficial erosions and des squamation of the lining epithelium. The biochemical alterations of the disease course were characterized by significant reduction in total protein, albumin and iron concentration in the serum of infected goats