Welfare and health management practices implemented during a sheep pox outbreak in indigenous sheep flocks: A case study from Tamil Nadu, India

Introduction

Sheep farming is essential to the livelihoods of marginal and landless farmers since it improves household nutrition and generates a substantial amount of revenue. With 74.26 million sheep, India has the fourth-largest sheep population in the world, behind China, Australia, Sudan, and Iran, according to the 2019 livestock census (Manjunatha Reddy et al., 2024) [3] . Sheep farming in India is a major sector of agriculture, especially for small and marginal farmers, owing to its minimal investment needs and adaptability to diverse environments. India significantly contributes to the improvement of rural lives and food security through sheep production. Sheep farming has potential, but it also has limitations, including poor market accessibility, diseases, and insufficient infrastructures. Efficient management methods are crucial for maximising output and health, involving appropriate healthcare and nutrition (Bhanuprakash et al., 2011) [1] . In India, infectious diseases significantly impact sheep farming, leading to considerable morbidity and mortality, which in turn cause economic losses for farmers. These diseases affect sheep of all ages and are influenced by various factors such as season, sex, and breed. Key issues include poor hygiene, inadequate veterinary care, and intensified farming, which leads to problems like respiratory infections and specific viral infections like sheep pox. Morbidity and mortality rates peak during the rainy season due to increased prevalence of diseases (Pavan kumar et al., 2021; Tadesse et. al., 2022) [7,11] . Sheep pox is a highly contagious viral disease caused by Sheeppox virus (genus Capripoxvirus). It primarily affects sheep, leading to symptoms such as fever, skin lesions, respiratory distress, weight loss, and, in severe cases, mortality, which results in decreased productivity, increased veterinarian costs, and substantial economic losses. The disease is seasonally prevalent, with the highest incidence during the rainy seasons (Pavan kumar et al., 2021) [7] . The current study reports the incidence of sheep pox and its welfare and health management in indigenous sheep flocks located in the Thoothukudi District of Tamil Nadu.

Materials and Methods

The current study examined eight indigenous sheep flocks with the total strength of 1200 in Thalaiyal Nadanthan Kulam village, Kayathar block, Kovilpatti taluk, Thoothukudi district of Tamil Nadu. The sheep showed signs of pyrexia, anorexia, dullness, rhinitis with mucopurulent nasal discharge, and cutaneous lesions throughout a 10-day period, and 19 animals died during June 2021. Clinical examinations and necropsy were carried. Samples including nasal swabs, pock lesion swabs, whole blood, and tissues from affected organs were collected from clinically affected animals and submitted to the Central University Laboratory, TANUVAS, Madhavaram, Chennai for confirmatory diagnosis.

Results and Discussion

In this study, the affected sheep were of both sexes and all age groups, and the disease occurrence was during the month of June with 1.58% mortality (19 deaths) and 5.75% morbidity (69 cases), which concurred with the earlier reports of seasonal peaks during monsoon. The low mortality (1.58%) and containment through ring vaccination align with effective prompt interventions reported in similar Tamil Nadu outbreaks (Manimaran et al., 2017; Roy et al., 2008) [4,8] . The affected animals presented with pyrexia, anorexia, dullness, rhinitis, mucopurulent nasal discharge, and cutaneous papules predominantly noticed on the face, nostrils (Fig. 1&2), tail base (Fig. 3), ear lobes, and dispersed all over the body. Postmortem examination (Fig. 4) revealed pock lesions in the respiratory tract viz., trachea (Fig. 5) and lungs, and also in the tongue (Fig. 6) and kidney (Mondal et al., 2004) [5] . Pathological findings, such as pock lesions in respiratory tract and internal organs, are consistent with previous reports from indigenous breeds in the region (Sivaseelan et al., 2005; pathological study on Mecheri flock) [10] . Ring vaccination (Fig. 7) indicating immunizing susceptible animals in a defined radius around affected flocks rapidly builds an immune barrier to halt transmission. In the described case, vaccinating 6600 sheep within an 8 km radius prevented further spread. (Omkar et al., 2024) [6] . Since sheep pox is viral, no specific antiviral exists; antibiotics (e.g., broad-spectrum like oxytetracycline or penicillin) target secondary bacterial infections that exacerbate lesions, pneumonia, and mortality (Fig. 8). Oral immune boosters (e.g., vitamins, minerals, or herbal supplements) support recovery by enhancing immunity during the acute phase. In comparable Tamil Nadu outbreaks, affected animals received antibiotic courses, leading to clinical recovery in survivors, mirroring the low mortality (1.58%) (Gomes et al., 2023) [2] . Isolating infected animals until -recovery prevent the spread of infection. Thorough cleaning and disinfection of sheds, equipment, and surroundings reduces environmental persistence of the pox virus and its spread. For welfare the Five Freedoms ensured ethical management during outbreak like providing balanced rations and clean water to combat anorexia/pyrexia-related dehydration; adequate shelter/space (Fig 9 & 10) to reduce discomfort from lesions and overcrowding; pain alleviation through supportive care and minimal handling to limit stress/fear; and space for rest/normal behavior. Post-outbreak recommendation for yearly vaccination in endemic areas is crucial. In high-risk areas, routine immunization builds herd immunity, reducing future incidence and economic losses to farmers (Senthilkumar and Thirunavukkarasu 2010; Yogisharadhya et al., 2011) [9,12] .

Conclusion

Infectious diseases like sheeppox, pneumonia, bluetongue, and PPR continue to devastate sheep farming in India, inflicting high morbidity (10-30%) and mortality rates across all ages, breeds, and seasons, compounded by poor hygiene, overcrowding, seasonal migrations, and inadequate veterinary care, resulting in severe economic losses from livestock deaths, reduced productivity, and treatment costs. Effective control demands urgent implementation of mandatory vaccinations, enhanced biosecurity measures, improved housing hygiene, and widespread farmer education programs to mitigate endemic outbreaks, particularly in vulnerable backyard and migratory flocks. Adopting these holistic strategies will safeguard sheep health, enhance farmer livelihoods, and sustain India's vital small ruminant sector.

Disclaimer (Artificial Intelligence)

Author(s) hereby declare that NO generative AI technologies such as large language models (ChatGPT, COPILOT, etc) and text-to-image generators have been used writing or editing the manuscript.

Acknowledgement

AcknowledgementThe authors thank the sheep farmers and Animal Husbandry Department, Tamil Nadu involved in the outbreak response, and TANUVAS for diagnostic and institutional support.

References

1. Bhanuprakash V, Hosamani M, Singh RK. Prospects of control and eradication of capripox from the Indian subcontinent: a perspective. Antiviral Res. 2011;91(3):225-232.
2. Gomes AR, Ranganatha S, Chandranaik BM, Praveen Kumar GR, Kavitha G, Sumathi BR, et al. Study of an epidemic of sheep pox and foot rot in indigenous sheep of Karnataka. Pharma Innov. 2023;12:2468-2472.
3. Manjunatha Reddy GB, Krishnappa VK, Siddalingaiah CD, Rao S, Nayakvadi S, Harlipura Basavarajappa CK, et al. Epidemiological, pathological, and molecular studies on sheeppox disease outbreaks in Karnataka, India. Microorganisms. 2024;12(7):1373.
4. Manimaran K, Mahaprabhu R, Jaisree S, Hemalatha S, Ravimurugan T, Pazhanivel N, et al. An outbreak of sheep pox in an organized farm of Tamil Nadu, India. Indian J Anim Res. 2017;51(1):162-164.
5. Mondal B, Hosamani M, Dutta TK, Senthilkumar VS, Rathore R, Singh RK. An outbreak of sheep pox on a sheep breeding farm in Jammu, India. Rev Sci Tech. 2004;23(3):943-950.
6. Omkar MR, Gomes AR, Ratnamma D, Chandranaik BM, Sudha G. Capripoxvirus diseases in India. Indian J Vet Anim Sci Res. 2024;53(2):1-8.
7. Pavan Kumar C, Ramesh P, Sundar N, Veere Gowda B. Epidemiological studies on sheep bacterial respiratory tract infections in and around Proddatur, YSR Kadapa, Andhra Pradesh. Pharma Innov J. 2021;10:629-632.
8. Roy P, Purushothaman V, Sreekumar C, Tamizharasan S, Chandramohan A. Sheep pox disease outbreaks in Madras Red and Mechery breeds of indigenous sheep in Tamil Nadu, India. Res Vet Sci. 2008;85(3):617-621.
9. Senthilkumar V, Thirunavukkarasu M. Economic losses due to sheep pox in sheep farms in Tamil Nadu. Tamil Nadu J Vet Anim Sci. 2010;6:88-94.
10. Sivaseelan S, Rani RU, Kathiresan D, Purushothaman V. Report on several outbreaks of sheep pox in Tamil Nadu. Indian J Small Rumin. 2005;11(2):194-195.
11. Tadesse B, Hamid M, Hamid A. Transmission dynamics and economic impacts of sheeppox and goatpox disease outbreak in Chifra district of Afar Region, Ethiopia. Heliyon. 2022;8(6):e09603.
12. Yogisharadhya R, Bhanuprakash V, Hosamani M, Venkatesan G, Balamurugan V, Bora DP, et al. Comparative efficacy of live replicating sheeppox vaccine strains in ovines. Biologicals. 2011;39(6):417423.