الملخص الإنجليزي
Cystic echinococcosis (CE) is a silent cyclozoonotic disease caused by a larval stage of Echinococcus granulosus that can affect both human and domestic or wild animals. This study aimed to investigate the epidemiology of CE in human, intermediate livestock (camels, cattle, goats and sheep), human and final host (dogs), to identify the genotypes of Echinococcus granulosus and to analyze biochemical parameters of hydatid cystic fluids (HCF). The slaughterhouse-based study conducted as a passive surveillance during the period of 2009-2013. A routine slaughtering was monitoring in eight slaughterhouses belonging to seven governorates of Oman (Muscat, Al Bettina, Al Sharqiyah, Al Dakhiliyah, Al Dhahirah, Al Buraimi and Dhofar). In total, 288728 animals (5203 camels, 38294 cattle, 218026 goats and 5203 sheep) were slaughtered and out of these, 1440 (292 camels, 303 cattle, 682 goats and 163 sheep) suspected samples for CE were collected and analyzed. The highest percentage of positivity was recorded from camels (92.8%) followed by cattle (77.2%), sheep (12.3%) and goats (9.1%). When compared between different governorates, the highest percentage of positive samples was recorded in Dhofar (90%) followed by Al Dakhliyah (48.8%), Al Buraimi (42.3%), Muscat (11.9%), AI Dhahirah (11.8%) and Al Batinah (10%). The overall prevalence/1000 of CE against the total population of each animal species were calculated as 2.8%, 0.8%, 0.06% and 0.04% in camel, cattle, sheep and goat respectively. About 29.8% of the samples from male animals found positive for CE as compared to the female (67.9%) animals. The percentage of CE positivity was found to be increasing with age of animals, and the highest percentage was observed in the samples from the group of above 5 years of age (86.9%) followed by the group of between 3 to 5 years (36.1%) and the group which below 3 years of age (20.8%). About 478 (62.7%) of the samples from the local livestock breeds were found positive for CE as compared to 108 (15.9%) from the imported breeds of the livestock. In addition, the highest percentage of positive observed in cysts from multiple organs (87%) followed by those from lungs (81.1%), other organs (24.6%), livers
(23.1%) and fats (0.5%). To determine the sero-epidemiology of CE in human and livestock, a comprehensive cross-sectional serological survey study conducted. 2,802 of sera were randomly collected from camels (n=706), cattle (n=687), goats (n=701) and sheep (n=708) from all governorates of Oman. The samples been analyzed using EgAgB prepared from crude hydatid cystic fluid. The overall serological exposure to CE been recorded in 410 (14.6%) sera samples. However, the highest sero-positivity was observed in camels (22.4%) followed by cattle (12.9%), sheep (12.2%) and goats (10.9%). Female animals showed higher sero-positivity (15.4%) as compared to male (10.6%). Animals above 5 years of age (18.3%) showed higher sero-positivity followed by those up to 2 years of age (15.1%) and between 2 to 5 years (12.4%). 1,369 sera were collected randomly from male and female patients of different ages from three government hospitals (401 Sohar, 357 Salalah
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and 611 ROP Hospitals). GenWay human ELISA for the detection of E. granulosus antibodies used to analyzed the sera samples. The antibodies of E. granulosus been detected in four (0.29 %) samples and higher sero-positivity was recorded from SQH at Salalah (0.56%) and Sohar Hospital (0.5%) only. Sera from male group showed higher % of sero-positivity (0.44%) as compared female group (0.14%) and similar values, slightly higher in age group between 21-40 years (0.22%) than in older age group (41- 60 years) (0.15 %). Different techniques used for detection of E. granulosus eggs in the final host and the transmission patterns been compared in this study. A total of 128 faecal samples collected from dogs from eight governorates in Oman. However, eight (6.3%) were found suspected for E. granulosus by using copro-parasitlogical technique and of these five (3.9%) were confirmed through coproAg-ELISA and copro-PCR techniques. 17 stray dogs were shot, autopsied, and examined for the presence of E. granulosus adult worms. The adult worms of E. gramulosus were detected in three (17.6) stray dogs and they were used as a gold standard.
The molecular characterization of E granulosus by genotyping using a single tube multiplex PCR (MPCR) and sequence analysis of a mt NAD 1 471 bp gene has demonstrated the occurrence of two genotypes; E. granulosus senso stricto G1 or sheep strain and E. canadensis G6 or camel strain circulating in the livestock of Oman. In addition, both genotypes (G1 and G6) been reported to be the cause of human infection in various countries. The biochemical parameters of fertile and sterile hydatid cystic fluid (HCF) from livers and lungs of cattle, goats, and camel using Beckman coulter analyzer were determined. Quantitative variation in the mean of phosphate (mmol/l) concentration of HCF from the lungs and the mean of sodium (mmol/l) concentration in the HCF from the livers of camels and cattle isolates were found to be statistically significant (p<0.05). Quantitative variation in the mean of glucose (mg/dl), total protein (mg/dl), urea (mg/dl), triglyceride GPO (mg/dl) and iron (ug/dl) concentration from the fertile lungs of cattle and camels were statistically significant (p<0.05). In goats, only the mean of chloride (mmol/l) concentration from the HCF of lungs was found significantly different (p<0.05) compared HCF of livers. This result has indicated that, the quantity of biochemical parameters in HCF probably relates to the strains of E. granulosus, protoscolices presence, geographical location and to the cyst location.
In summary, this study indicated that CE is an important public health concern in Oman, and it existing in different levels according to the geographical locations, human traditional practices and other environmental factors. Further studies of human CE through hospital cases and sero-surveillance will provide valuable information for implementation of this disease prevention and management strategies in Oman.
