Sero-epidemiology of cystic echinococcosis (Echinococcus granulosus) in the livestock of Oman.

ABSTRACT

A cross-sectional serological survey of cystic echinocossis was carried out on 2802 randomly collected sera of camels (n=706), cattle (n=687), goats (n=701) and sheep (n=708) from all governorates of Oman. The samples were analysed by in house indirect ELISA (iELISA) using Echinococcus granulosus antigen B (EgAgB) of naturally infected camels. The overall percentage of antibodies against EgAgB was found to be 14.6%. The highest percentage of positive was observed in sera from camels (22.4%) followed by cattle (12.9%), sheep (12.2%) and goats (10.9%). The highest percentage of seropositivity was observed in females (15.4%) as compared to male animals (10.6%). The imported livestock were found more seropositive (15.2%) as compared to local (14.7%) and crossbred livestock (14.1%). The highest exposure was observed in animals with the age group of above 5years (18.3%) followed by the age group of up to 2years (15.1%,) and those between 2 and 5years (12.4%). The univariate analysis has indicated that camels (OR2.33, CI 1.74, 3.14), cattle (OR1.21, CI 0.87, 1.67), sheep (OR1.12, CI 0.81, 1.55) were more likely to test positive than goats. Furthermore, females (OR 1.53, CI 1.11, 2.11) were more likely to test seropositive. Sera from animals above 5years of age (OR1.58, CI 1.25, 2.01) and between 2 and 5years old (OR1.30, CI 0.98, 1.71) were found more likely to test seropositive than those up to 2years of age. The multivariable analysis at individual level indicated that camels (OR 2.07, CI 1.66, 2.56, p<0.001) and female (OR 1.43, CI 1.04, 1.98, p=0.030) were more likely to acquire CE. At herd level, the final multivariable model indicated that herds located in Dofar and Musandam (OR 4.48, CI 2.69, 7.45, p<0.001), in areas receiving seasonal rains (OR 2.54, CI 1.09, 5.90, p<0.001) and practicing transhumance (OR 4.22, CI 1.84, 9.65, p<0.001) and sedentary (OR 2.07, CI 1.38, 3.12, p=0.001) farming system were more likely to acquire CE in Oman. The study documents the serological evidence of CE in livestock of Oman and a carefully planned control program should be devised after further epidemiological and molecular investigations in the intermediate and final hosts.