Seroprevalence of Cystic Hydatidosis in Small Ruminants (Sheep and Goats) Naturally Exposed to the Infection in the North Midland Region (Misrata and Sirt) of Libya

The aim of this serological work was to determine the occurrence of cystic hydatidosis in sheep and goats using ELISA together with antigen B derived from camel hydatid cyst fluid in the North Midland region of Libya including Misrata and Sirt districts. Cystic hydatid disease (CHD) is a zoonotic disease which causes serious public health and veterinary problems as a result of infection in North African countries including Libya. The sensitivity and accuracy of any serological test used for the detection of anti-hydatid antibodies in serum samples are found to depend on the composition, concentration and stability of the antigen in use. Thirteen rural villages of two districts, namely Misrata and Sirt, are located in the north midland of the country. Misrata is almost an agricultural area and about 200km east of Tripoli and Sirt which is almost a pasture area and about 500km also east of Tripoli, were included in the current study. Incidence of cystic hydatidosis was investigated serologically using serum samples collected randomly from 2651 animals of three groups; lambs under two years old (240), adult sheep over two years old (2082) and adult goats over two years old (329). Antigen B of camel hydatid cyst fluid was used together with ELISA for the detection of the presence of total IgG antibodies against hydatid disease in the collected serum samples. 1377/2651 serum samples from all animal groups of both districts gave an overall ELISA seropositivity of 52%. The overall ELISA seropositivity for each group of animals was 55/240 (23%), 1235/2082 (59%) and 87/329 (26%) for lambs, adult sheep and goats respectively. In the Sirt district, the overall seropositivity was 648/1408 (46%) and among the villages, it was 25% from El-Gbeba and 63% from El-Arbaien, while in the Misrata district, the overall seropositivity was 729/1243 (59%) and among the villages, it was 43% from Saso and 78% from Tawergha. Statistical analysis showed no significant differences in the rate of seropositivity between lambs and goats (23% and 26%), but there was a significant difference between these two groups and adult sheep (59%), in comparison, however, there was no significant difference in general between the two district areas which was 59% in Misrata and 46% in Sirt. The slight differences in the total rate of seropositivity between both districts in general and between villages of each district could be due to sharing the same environmental conditions, grazing methods, and human behaviour as both districts bordering each other. Also, statistical analysis showed significant differences in the rate of seropositivity between lambs (23%) and adult sheep (68%), and in the case of goats, there was no significant difference between the age groups, 24% for goats 2-<4 yrs old and 29% for goats 7+yrs old. Outlining control measures should include de-worming of shepherd dogs and elimination of stray dogs as well as public health education to ensure effective reduction of disease incidence in livestock.