Echinococcosis in Libya. II. Prevalence of hydatidosis (Echinococcus granulosus) in sheep.

The incidence and geographical distribution of hydatidosis was examined in sheep from ten localities in Libya. A total of 402 cases of hydatid disease (7.85%) were confirmed in a total of 5118 sheep examined; 12.74% of adult sheep were infected, but only 0.29% of lambs. The liver was the organ most commonly infected (97.26% of all infections), followed by the lungs (58.70%), kidneys (1.76%), spleen (0.74%) and heart, mesentery and muscles (0.24% each). The intensity of infection varied from one to more than ten fertile or sterile cysts. Infections were light in 43.73% of livers and 47.03% of lungs, medium in 33.24% of livers and 42.79% of lungs, heavy in 13.55% of livers and 7.62% of lungs, and very heavy in 9.96% of livers and 2.54% of lungs. A total of 73.13% of the infections were found to be fertile, 18.90% sterile and 7.96% both sterile and partly calcified. Lung hydatids tended to be more fertile than liver cysts.