Role of India’s wildlife in the emergence and re-emergence of zoonotic pathogens, risk factors and public health implications

Abstract

Evolving land use practices have led to an increase in interactions at the human/wildlife interface. The presence and poor knowledge of zoonotic pathogens in India's wildlife and the occurrence of enormous human populations interfacing with, and critically linked to, forest ecosystems warrant attention. Factors such as diverse migratory bird populations, climate change, expanding human population and shrinking wildlife habitats play a significant role in the emergence and re-emergence of zoonotic pathogens from India's wildlife. The introduction of a novel Kyasanur forest disease virus (family flaviviridae) into human populations in 1957 and subsequent occurrence of seasonal outbreaks illustrate the key role that India's wild animals play in the emergence and reemergence of zoonotic pathogens. Other high priority zoonotic diseases of wildlife origin which could affect both livestock and humans include influenza, Nipah, Japanese encephalitis, rabies, plague, leptospirosis, anthrax and leishmaniasis. Continuous monitoring of India's extensively diverse and dispersed wildlife is challenging, but their use as indicators should facilitate efficient and rapid disease-outbreak response across the region and occasionally the globe. Defining and prioritizing research on zoonotic pathogens in wildlife are essential, particularly in a multidisciplinary one-world one-health approach which includes human and veterinary medical studies at the wildlife-livestock-human interfaces. This review indicates that wild animals play an important role in the emergence and re-emergence of zoonotic pathogens and provides brief summaries of the zoonotic diseases that have occurred in wild animals in India.

The elephant–livestock interface modulates anthrax suitability in India

“…These two data products, livestock density and the elephant niche, were then applied to the quantification of the elephant-livestock interface (see below), which delineates a sentinel interface only rather than a broader interface between livestock and wildlife more generally. The elephant niche was chosen because of the species's importance as both an anthrax sentinel [11,[28][29][30][31] and the common overlap of their range with that of grazing livestock in forest fringe areas [34]. In addition, we tested the validity of the elephant-livestock interface by substituting the modelled niche, which was based on GBIF observations, with the accepted species range according to IUCN data, which was obtained from the Socioeconomic Data and Applications Center (SEDAC) [46] at the same 30 arcmin resolution (see below).…”

“…This is because the Indian government is a federalist system and so investment in human and animal health services and surveillance is highly dependent on the commitments of individual states, which vary widely in resources and agenda over time. There is also regular detection of anthrax in wildlife in India, with a preponderance of reported cases in elephants [11,[28][29][30][31], although comprehensive formal surveillance of wildlife is almost non-existent and so anthrax occurrence is probably under-reported.…”

The wildlife-livestock interface modulates anthrax suitability in India

“…These two data products, livestock density and the elephant niche, were then applied to the quantification of the wildlife-livestock interface (see statistical methods description below). The elephant niche was chosen as the representative wildlife niche because of the species’ importance as both an anthrax sentinel(7,23–25,41) and the common overlap of their range with that of grazing livestock in forest fringe areas(29). However, the utility of this niche could not be compared to that of other species because of a corresponding lack of adequate observations of other species occurrences in GBIF.…”

“…India has a high burden of anthrax, with some regions experiencing annual or near annual outbreaks of disease(21,22). A significant number of these outbreaks occur in wildlife, with a preponderance of reported cases in elephants(7,23–26). Common points of interface in Indian settings include shared waterholes, salt licks and grazing meadows, particularly in the forest fringe areas.…”

Foodborne apicomplexan protozoa

“…Increasing urbanization has resulted in more interaction between humans, domestic and feral cats, and wildlife and has exposed previously underappreciated transmission routes for T. gondii (Singh and Gajadhar, 2014). Conversely, increased socioeconomic levels, improved hygienic conditions, intensive farming, frozen meat, and sterile cat food have reduced seroprevalence in many countries.…”