Lesion Characterizations, Associated Risk Factors and Financial Implication of Zoonotic Hydatid Cyst of Dromedary Camels Slaughtered at Addis Ababa, Akaki Kality Municipal Abattoir, Ethiopia

Abstract

Hydatid cyst, is zoonotic helminthic parasites of Taeniid families having significant economic crisis in the world. A cross-sectional study was conducted from October 2021 to May 2022 to characterize hydatid cyst lesions, analysis of associated risk factors and estimate annual direct financial loss due to hydatid cyst infected organs condemnation during postmortem examination in dromedary camels slaughtered at Addis Ababa, Akaki Kality Municipal abattoir, Ethiopia. A total of 370 camels were purposively sampled and systemic meat inspection was employed to detect the presence of hydatid cyst. Out of 370 hydatid cysts like cases examined in different organs, 96 (25.9%) camels were found harboring hydatid cyst. The percentage of hydatid cyst in adult camels were 29.67%; OR= 1.54 while in young it was 18.55%. Likewise, the prevalence of hydatid cyst in poor, medium and good body condition score was 61.4%; OR= 10.79, 30.89%; OR= 3.30 and 12.11% respectively. Results indicated that age and body condition score had statically significant effect (P<0.05) on prevalence of hydatid cyst. The overall prevalence of hydatid cyst in male dromedary camel was (14.59%; OR=0.83;) found higher than female (11.35%). The overall prevalence of hydatid cyst in camels originated from Borana, East Hararge, Jigjiga, Karrayyu, Matahara, Minjar-shenkora and Wollo were 9.18%, 0.54%; OR= 2.12, 4.86%; OR= 2.06, 3.51%; OR= 1.18, 3.78%; OR= 0.94, 1.08%; OR= 0.78 and 2.97%; OR= 1.31, respectively. Result indicated, origin and sex didn’t have significant effect (P>0.05) on the overall prevalence of hydatid cyst. Out of 96 total infected camels, only 9 (9.38%) cases had hydatid cyst on both lung and liver while the remaining 87 (90.62%) cases had hydatid cysts only in single organs. Of 105 total infected organs, percentage of distribution of hydatid cyst in lungs, livers, spleen and heart were 87.61%, 10.47%, 0.95% and 0.95% respectively. Result showed that out of 105 examined organs of camels, 51 organs harboring less than three hydatid cysts number while 54 organs had greater than or equal to three hydatid cysts. Grossly, hydatid cyst of lung had a shape of cotton ball, implanted in lung parenchyma, filled with clear to slightly turbid fluid, soft and malleable to touch and inside white germinal layer while hydatid cyst on the livers was firm, calcified and strong when it was about to be cut off. Microscopically, hydatid cyst structure overlying organs had a fibrous layer on the external (pericyst), an acellular eosinophilic laminated membrane layer on the middle (ectocyst) and a germinal layer internally (endocyst) and protoscolices were also seen in a lung section. Fibrous layer had infiltration of epitheliod macrophages, lymphocytes and eosinophils showed inflammatory reaction response to hydatid cyst layer and cellular infiltration was lessened when they went away from hydatid cysts. Histopathology of lung infected with hydatid cyst displayed massive alveolar damage, some alveoli was emphysematous, congested capillary, hemorrhage and atelectasis in the fibrous layer. In hydatid cyst infected liver histology, there was hemorrhage, hepatocyte degeneration and cytoplasmic swelling with dilation of nucleus in fibrous layer. Microscopically, hydatid cyst infected heart had not a visible protoscolices and it had weak germinal and lamination layer followed by lymphocyte and epitheloid macrophages infiltration. The total annual direct financial loss due to hydatid cyst was estimated at 86,209.63 Ethiopian birr. Hereafter, this study helps to stress the economic consequences and pathological patterns of hydatid cysts at abattoir, and creation of public awareness and control of stray dogs in order to reduce infection by the parasite were suggested recommendation.