Lakshmisai Palluru¹*, Jalajakshi Kopparthi¹, Venu Ravipati¹, Ananda Kumar Aryasomayajulu¹ and Ravikanthreddy Poonooru²

¹College of Veterinary Science, Sri Venkateswara Veterinary University, Tirupati 517 502, India
²IDivision of Animal Sciences, University of Missouri, Columbia, MO 65211, USA

*Corresponding Author: Lakshmisai Palluru, College of Veterinary Science, Sri Venkateswara Veterinary University, Tirupati 517 502, India.

Received: September 18, 2026; Published: October 08, 2026

Abstract

Cystic echinococcosis (hydatidosis) is an important zoonotic parasitic disease of considerable veterinary, public health and economic significance worldwide. The disease is caused by the larval stages of Echinococcus spp., which have a complex life cycle involving ungulates and other mammals as intermediate hosts and domestic or wild carnivores as definitive hosts. The present study investigated the prevalence, epidemiological distribution and molecular characteristics of Echinococcus spp. in slaughtered sheep from the Rayalaseema region of Andhra Pradesh, India. A total of 3,683 slaughtered sheep from abattoirs located across eight districts were examined for hydatid cysts, of which 87 were positive, resulting in an overall prevalence of 2.36%. Tirupati recorded the highest district-level prevalence at 4.20% (25/595), whereas Sri Satya Sai recorded the lowest at 1.17% (5/424). The prevalence was higher in ewes (3.07% (45/1464)) than in rams (1.90% (42/2219)). Hydatid cysts were detected more frequently in the lungs (1.25% (46/3683)) than in the liver (1.11% (41/3683)). Among the 87 cysts examined, 39 (44.83%) were fertile, 28 (32.18%) were sterile and 20 (22.99%) were calcified. Prevalence increased with age, reaching 4.47% (41/917) in sheep older than 5 years compared with 1.19% (19/1587) in sheep aged 0–3 years. Significant differences were observed according to sex (P 0.05) and age (P 0.01). Molecular characterization was performed by PCR amplification of a partial fragment of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene, followed by sequence analysis. The isolates were confirmed as Echinococcus granulosus and clustered within the G1/G3 genotype group. These findings demonstrate the continued circulation of cystic echinococcosis among sheep in Rayalaseema, while the occurrence of fertile cysts suggests that infected sheep may contribute to the local transmission of Echinococcus granulosus fertile cysts suggests that infected sheep may contribute to the local transmission cycle of E. granulosus.

Abbreviations:  Hydatidosis; Meat-Borne Zoonotic Disease; Echinococcus granulosus; Rayalaseema Region; Mitochondrial Cytochrome Oxidase 1 Gene (COX1)

References

1. Tamarozzi F., et al. “Epidemiological distribution of Echinococcus granulosus s. l. infection in human and domestic animal hosts in European Mediterranean and Balkan countries: a systematic review”. PLOS Neglected Tropical Diseases8 (2020): e0008519.
2. Denizhan V and Karakuş A. “Investigation of the prevalence of hydatid cysts and liver condemnation losses in sheep and goats slaughtered in Van Province, Türkiye”. Manas Journal of Agriculture Veterinary and Life Sciences1 (2025): 24-30.
3. Moudgil AD., et al. “Hydatidosis in slaughtered sheep and goats in India: prevalence, genotypic characterization and pathological studies”. Journal of Helminthology 94 (2020): e27.
4. Singh BB., et al. “Molecular epidemiology of echinococcosis from food producing animals in north India”. Veterinary Parasitology3-4 (2012): 503-506.
5. Singh BB., et al. “Prevalence and morphological characterisation of Echinococcus granulosus from north India”. Journal of Parasitic Diseases1 (2014): 36-40.
6. Pednekar RP., et al. “Molecular and morphological characterisation of Echinococcus from food producing animals in India”. Veterinary Parasitology1-2 (2009): 58-65.
7. Soulsby EJL. “Helminths, Arthropods and Protozoa of Domesticated Animals”. 7^th Oxford: Blackwell Scientific Publications (1982): 119-124.
8. Mohanty S., et al. “Staining of hydatid elements: a useful adjunct in the diagnosis of hydatid disease”. Tropical Doctor3 (2016): 174-176.
9. Abdel-Baki AAS., et al. “Prevalence and characterization of hydatidosis in Najdi sheep slaughtered in Riyadh city, Saudi Arabia”. Saudi Journal of Biological Sciences7 (2018): 1375-1379.
10. Roostaei M., et al. “Prevalence and fertility survey of hydatid cyst in slaughtered livestock in Hamadan abattoir, Western Iran, 2015-2016”. Avicenna Journal of Clinical Microbiology and Infection2 (2017): e43361.
11. Mehmood N., et al. “Comprehensive account on prevalence and characteristics of hydatid cysts in livestock from Pakistan”. Korean Journal of Parasitology2 (2020): 121.
12. Khan SN., et al. “Cystic echinococcosis: an emerging zoonosis in southern regions of Khyber Pakhtunkhwa, Pakistan”. BMC Veterinary Research1 (2021): 139-149.
13. Haleem S., et al. “Incidence, risk factors and epidemiology of cystic echinococcosis: a complex socioecological emerging infectious disease in Khyber Pakhtunkhwa, Province of Pakistan”. BioMed Research International 2018 (2018): 5042430.
14. Gudewar J., et al. “Molecular characterization of Echinococcus granulosus of Indian animal isolates on the basis of nuclear and mitochondrial genotype”. Molecular Biology Reports6 (2009): 1381-1385.
15. Beigh A., et al. “Epidemiological and molecular characterization of Echinococcus granulosus isolated from small ruminants in Kashmir Valley, India”. Iranian Journal of Parasitology3 (2021): 357-365.
16. Mahami-Oskouei M., et al. “Molecular characterization and sequence analysis of Echinococcus granulosus from sheep isolates in East Azerbaijan province, northwest of Iran”. Journal of Parasitic Diseases3 (2016): 785-790.
17. Sharma et al. “Molecular characterization of Echinococcus granulosus cysts in North Indian patients: identification of G1, G3, G5 and G6 genotypes”. PLoS Neglected Tropical Diseases 6 (2013): e2262.
18. Thompson RCA. “The taxonomy, phylogeny and transmission of Echinococcus”. Experimental Parasitology4 (2008): 439-446.
19. Deplazes P., et al. “Global distribution of alveolar and cystic echinococcosis”. Advances in Parasitology 95 (2017): 315-493.
20. World Health Organization. “Echinococcosis [WHO]”. Geneva: World Health Organization (2021).

Citation

Citation: Lakshmisai Palluru, et al. “Molecular Characterization of Hydatid Cysts in Slaughtered Sheep from the Rayalaseema Region of Andhra Pradesh". Acta Scientific Veterinary Sciences 8.3 (2026): 31-38.

Copyright

Copyright: © 2026 Lakshmisai Palluru, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.