Post-Vaccination Sero-Monitoring of Peste des Petits Ruminants in Sheep and Goats in Karnataka: Progress towards PPR Eradication in India.

Peste des petits ruminants (PPR) presents economic challenges in enzootic countries impacting small ruminant productivity. The state of Karnataka, India, implemented a mass vaccination campaign in alignment with the PPR-Global Eradication Programme (GEP) and the National Strategic Plan for PPR eradication. This study was conducted from January to March 2023 to assess seroconversion in post-vaccinated goats and sheep at the epidemiological unit (epi-unit) level, aligning with the World Organisation for Animal Health (WOAH) and the Food and Agriculture Organization (FAO) guidelines in the PPR Global Control and Eradication Strategy (GCES). Before vaccination, 3466 random serum samples were collected from small ruminants of three age groups (6-12 months, 1-2 years, and >2 years) across 116 epi-units, spanning 82 taluks in 28 districts. Post-vaccination sero-monitoring included 1102 serum samples collected from small ruminants of the 6-12-month age group only, across 111 epi-units covering 64 taluks in 23 districts. The PPRV antibody status was determined using an indigenous hemagglutinin (H) protein monoclonal antibody-based competitive ELISA kit. Pre-vaccination, the PPR seropositivity rates were 55%, 62%, and 66% in the age groups of 6-12 months, 1-2 years, and >2 years, respectively, with a 61% PPRV antibody prevalence across all the age groups. Notably, 41% of the epi-units exhibited antibody prevalence rates of ≥70%, indicating a substantial population immunity, possibly attributed to the previous vaccination program in the state since 2011. In contrast, only 17% of the epi-units had below 30% seroprevalence rates, emphasizing the need for intensified vaccination. Statistical analysis of the data revealed significant correlations (p < 0.05) between the presence of PPRV antibodies and host factors such as species, breed, and sex. Post-vaccination seroprevalence in the 6-12 months age group was found to be 73.4%, indicating the use of an efficacious vaccine. On the evaluation of vaccination immunity in the 6-12 months age group, it was revealed that over 69% of the epi-units achieved a response surpassing ≥70%, indicating a significant improvement from 42% of the epi-units in pre-vaccination. For active PPR eradication, a mass vaccination campaign (>95% coverage) targeting small ruminant populations aged >4 months is advocated, aiming to achieve the desired herd immunity of >80%. This study offers crucial insights into PPR baseline seroprevalence/immunity status and vaccine efficacy, guiding national strategies towards a PPR-free India and further supporting the global eradication initiative.

Seroprevalence and associated risk factors of leptospirosis in bovine dairy farms in Telangana state, India.

The current cross-sectional study aimed to determine the seroprevalence of Leptospira infection in bovine dairy farms in the Telangana state of India, as well as the associated risk factors, in order to implement effective preventive measures for disease control. A total of 469 blood samples were collected from 67 herds/farms in different areas, covering 20 administrative districts in the state. These samples consisted of 253 from cattle and 216 from buffaloes. Questionnaires were used to collect data on host and epidemiological factors. The collected sera were tested using the gold standard serological test, the Microscopic Agglutination Test (MAT), which employed a panel of 18 reference serovars for Leptospira exposure. The statistical analysis of epidemiological data was carried out to identify the risk factors associated with Leptospira exposure. The overall observed seroprevalence at the animal and farm levels was 41.4% and 77.6%, respectively. The most prevalent anti-leptospiral antibodies were observed against the serogroups Icterohaemorrhagiae (32.4%), Pomona (22.2%), Javanica (19.1%), Australis (17.0%), Bataviae (15.5%), Autumnalis (12.9%), Hebdomadis (12.9%), and others, in the total reacting samples. At the animal level, the significant risk factors associated with exposure to Leptospira species were breed (p = 0.03) and health status (p = 0.03). Furthermore, the multivariate statistical analysis of farm factors revealed that farm size (p = 0.05), presence of dogs (p = 0.04) and rodents (p = 0.01) on the farm, use of fodder from wet soils (p = 0.04), and proximity to water bodies (p = 0.04) were significantly associated with exposure to Leptospira in the studied region. This study provides the first report from India highlighting the important risk factors at the herd/farm and animal level associated with Leptospira infections in cattle and buffaloes. The findings contribute to strengthening the one-health strategy by facilitating the design and planning of appropriate control measures to alleviate the burden of leptospirosis in bovines.

Towards Eradication of PPR: Disease Status, Economic Cost and Perception of Veterinarians in Karnataka, India.

In this study, we assessed the PPR disease status, its economic cost, the financial viability of vaccination, and the perspectives of field veterinarians on the PPR vaccination programme implemented in Karnataka state, India. In addition to secondary data, cross-sectional surveys undertaken during 2016-17 (survey I) and 2018-19 (survey II) from 673 sheep and goat flocks and data collected from 62 veterinarians were analysed. The economic costs and perceptions of veterinarians were analysed using deterministic models and the Likert scale, respectively, and the financial viability of vaccination programmes under the best (15%), base (20%), and worst-case (25%) PPR incidence scenarios, considering two different vaccination plans (plan I and plan II), was assessed. The disease incidence in sheep and goats was found to be 9.8% and 4.8% in survey I and survey II, respectively. In consonance with the increased vaccination coverage, the number of reported PPR outbreaks in the state declined significantly. The estimated farm-level loss of PPR varied between the surveyed years. Even under the best-incidence scenario, under vaccination plan-I and plan-II, the estimated benefit-cost ratio (18.4:1; 19.7:1), the net present value (USD 932 million; USD 936 million) and the internal rate of return (412%) implied that the vaccination programmes were financially viable and the benefits outweighed the cost. Though the majority of veterinarians perceived that the control programme was well planned and rolled out in the state, a few of them disagreed or were neutral towards the plan per se, towards the coordination between functionaries, the availability of funding, and the programme acceptance by farmers. Despite many years of vaccination, PPR still persists in the Karnataka state for various reasons and in order to eradicate the disease, a review of the existing control programme with strong facilitation from the federal government is needed.

Prevalence of anti-leptospiral antibodies and frequency distribution of Leptospira serovars in small ruminants in enzootic South Peninsular India.

BACKGROUND AND AIM: For understanding the epidemiology of leptospirosis, the confined abundance of several species of pathogenic leptospires and knowledge on the serovar(s) prevalent in the reservoir and carrier hosts may be a useful indicator of transmission to incidental/accidental hosts in a geographical niche. The present study was carried out to ascertain the frequency distribution of Leptospira serovars and the prevalence of anti-leptospiral antibodies in small ruminants (sheep and goats) in the epidemiological units (villages) in the coastal districts of enzootic regions in South Peninsular India. MATERIALS AND METHODS: A total of 1167 serum samples (sheep n=299 and goats n=868) from apparently healthy animals, randomly collected from various epidemiological units were tested in microscopic agglutination test (MAT) using 18 reference Leptospira serovars antigens. RESULTS: The overall seroprevalence of 40% (at 95% confidence intervals [CI]: 36.82-42.43) in small ruminants (44% [95% CI: 40.49-52.26] in sheep and 38% [95% CI: 34.96-41.41] in goats) was observed with the predominance of Icterohaemorrhagiae, Javanica, Australis, Hurstbridge, and Pyrogenes serogroup anti-leptospiral antibodies in the studied region. The Chi-squared test revealed that the presence of anti-leptospiral antibodies is significantly not independent (associated) across the administrative division (Chi-square=105.80, p<0.05) as well as for sheep (Chi-square=34.67, p<0.01) and goats (Chi-square=68.78, p<0.01). Among seropositive samples (n=462 reactors), the MAT was positive for more than one serovar in 73% of sheep (95/131) and 53% of goats (177/331), representing an overall 59% cross-reactive prevalence in small ruminants. The determined frequency distribution (varied among small ruminants) of the employed serovars representing major reactive serogroup was Icterohaemorrhagiae (29.87), Javanica (20.78), Australis (20.35), Hurstbridge (16.23), Pyrogenes (15.8), Djasmin (15.58), Bataviae (15.37), Autumnalis (14.5), Canicola (14.5), Hebdomadis (14.07), Shermani (13.64), Panama (13.42), Sejroe (12.77), etc. CONCLUSION: This study indicates alarmingly high seroprevalence of leptospirosis in small ruminants with existing endemicity in the studied region in South Peninsular India. Further, these prevalent serovars in the administrative division may be of use in the reference panels of antigens in the MAT in both humans and animal disease diagnostic laboratories for effective and timely diagnosis of leptospirosis and to combat the challenges in public health.

Seroprevalence study of peste des petits ruminants in sheep and goats in the northern region of India.

BACKGROUND AND AIM: Peste des petits ruminants (PPR) is a contagious, World Organization for Animal Health notifiable, economically important, transboundary morbilliviral disease of sheep and goats. Studying seroprevalence of PPR from different geographical areas under varying agro-climatic conditions may help in formulating effective and appropriate disease control strategies under the ongoing national PPR control program. The present cross-sectional study describes the prevalence of PPR virus antibodies in sheep and goats in the various epidemiological units in different states (Haryana, Himachal Pradesh [HP], Jammu and Kashmir [J&K], Punjab, Uttarakhand [UK], and Uttar Pradesh [UP]) of the northern region of India. MATERIALS AND METHODS: A total of 5843 serum samples (sheep [n=2463] and goats [n=3380]) were collected by stratified random sampling method from 322 epidemiological units in the studied region during 2017-2018 and tested for PPR virus (PPRV) antibodies by competitive ELISA. RESULTS: The results revealed that an overall seroprevalence of 44.05% (2574/5843) with 57.32%, 55.22%, 65.69%, 37.09%, 32.73%, and 29.35% prevalence of PPRV antibodies in small ruminants in Haryana, Punjab, UP, HP, J&K, and UK states, respectively. Further, Chi-squared test revealed an association of PPRV antibodies in goats (χ2=252.28, p<0.01) and sheep (χ2=192.12, p<0.01) across different states in the region. CONCLUSION: The seroprevalence in majority of the epidemiological units (n=130) in sheep and goats in the studied region had <30%. This necessitates comprehensive, rigorous, continuous vaccination and active surveillance programs for few more years to achieve the desired 70% seroprevalence level of PPRV antibodies in population and to make the northern region of India, as PPR free zone.