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

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 (OR:2.33, CI 1.74, 3.14), cattle (OR:1.21, CI 0.87, 1.67), sheep (OR:1.12, 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 (OR:1.58, CI 1.25, 2.01) and between 2 and 5years old (OR:1.30, 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.

Abattoir based surveillance of cystic echinococcosis (CE) in the Sultanate of Oman during 2010-2013.

A passive surveillance was conducted in 8 selected abattoirs belonging to 8 governorates of Oman. Routine slaughtering of 282.020 animals was observed during 2010-2013 by duty veterinarians and suspected samples (n=1440) for cystic echinococcosis (CE) from camels (n=292), cattle (n=303), goats (n=682) and sheep (n=163) were collected. In total, 587 (40.8%) samples were found positive for CE and the highest percentage (64.2%) of positive samples belonged to Dhofar (Salalah) as compared to other governorates, p<0.01. The infection rate of CE was calculated as 5.3, 0.6, 0.07 and 0.03 in camel, cattle, sheep and goats respectively. Fertile cysts were found in 30.7% of positive samples and camels (52%) were found as major source of these followed by cattle (14.1%) and goats (9.7%). Percentage of positive to submitted samples was higher in females (67.9%) than males (29.8%). The fertility of cyst increased with age and the highest percentage of fertile cysts were collected from animals above 5 years of age (54.4%) followed by between 3 and 5 years (36.7%) and below 3 years of age (8.9%). For different breeds, 478 (62.7%) samples from local breeds of livestock were positive for CE as compared to 108 (15.9%) from imported animals (OR 8.92), p<0.01. The highest percent of positive samples was observed in cysts from lungs (54.4%) followed by those from liver (25.7%), liver and lungs (14.1%) and others (3.8%). Molecular investigations indicated that G1 and G6/7 were the two strains of CE circulating in camels and cattle while G1 was the only strain found in samples from small ruminants. Results indicated that CE is endemic in the livestock of Oman and further molecular epidemiological work in different host species is required for the conceptualization of a comprehensive control program.

Cystic hydatidosis in slaughtered goats from various municipal abattoirs in Oman.

A passive surveillance study was conducted from April 2012 to April 2013 to determine the incidence, the affect of age, sex and cyst location, fertility, and viability on the occurrence of cystic hydatidosis in slaughtered goats from six municipal abattoirs around Oman. Morphologic characterization of suspected visceral organs has shown that Echinococcos granulosus (E. granulosus) metacestodes were present in 9.2 % of the total samples (682). Incidence (per 10,000) varied from 1.4 to 1.5. There was a significant difference between abattoirs, with Salalah having the highest infection (63.2 %), followed by Nizwa (27.2 %), Al Buraimi (10.8 %), Bousher (7.2 %), and the lowest in Sohar (1.6 %). Infection was significantly higher in indigenous goats (22.1 %) compared with imported breeds (2.5 %) from Somalia. The visceral organs were found harboring one or more hydatid cysts. Greatest cyst infection was recorded in lungs (53.4 %), followed by heart (50 %), liver (6.2 %), and multiple organs (14 %). A significant difference was observed between females (25 %) and male goats (6 %). Furthermore, the fertility of the hydatid cysts was found higher in heart and lungs (100 %, 51.6 %) and the viability rate of protoscolices was high (64 %). The findings of this study demonstrated that cystic hydatidosis is common and widely distributed in local goats, and they might play an important role in the life cycle and transmission of this zoonosis in Oman.