Space-Time Clustering and Climatic Risk Factors for Lumpy Skin Disease of Cattle in Uttar Pradesh, India, 2022

Abstract

Lumpy skin disease (LSD), a transboundary infectious disease, negatively impacts cattle health and production. The first LSD outbreaks were reported in India in 2019, and since then, LSD spread to over 15 states, including Uttar Pradesh. This study evaluated LSD cases reported by veterinarians in Uttar Pradesh, India, during 2022. Using scan statistics, Poisson models that accounted for the background cattle population were constructed to identify spatial, temporal, and space-time clusters. A negative binomial regression model was built to assess the impact of temperature and humidity on the incidence rate (IR) of LSD. A total of 112,226 cases across 33 districts were reported in 2022. A purely temporal cluster with higher-than-expected LSD rates was identified between August and October 2022. Several purely spatial clusters were identified in the western part of the state. A primary space-time cluster was detected in west Utter Pradesh between August and October 2022 that overlapped with the spatial clusters. The secondary cluster occurred between September and October 2022 in the eastern part of the state. A rise in humidity (incidence rate ratio (IRR) = 1.39; 95% CI: 1.30-1.49) and temperature (IRR = 1.16; 95% CI: 1.06-1.27) increased the IR of LSD, suggesting a seasonality of the outbreaks. The results of this study can aid animal health authorities in developing effective LSD prevention, surveillance, and control strategies among cattle in India.

Figure 1

Map describing the study region in Uttar Pradesh, India.

Figure 2

Incidence rate of lumpy skin disease per 100,000 cattle in Uttar Pradesh, India, 2022.

Figure 3

High-rate spatial clusters of LSD cases in Uttar Pradesh, 2022, identified by scan statistic. Retrospective analysis, scanning for clusters with high rates, using a discrete Poisson model.

Figure 4

High-rate space–time clusters of LSD cases in Uttar Pradesh in 2022, detected by the scan statistic. Retrospective analysis, scanning for clusters with high rates, using a discrete Poisson model.

Figure 5

Monthly trend in LSD incidence rate (per 10,000 cattle) and climatic factors in nine different agroclimatic zones in Uttar Pradesh in 2022. Semiarid southwestern plains (Agra), western plains (Baghpat), Terai (Bijnor), central western plains (Budaun), northeastern plains (Basti), Bundelkhand (Jalaun), central plains (Kanpur Nagar), eastern plains (Varanasi), and Vindhyachal (Mirzapur).