Wildlife–livestock–human interfaces are becoming central to emerging disease prevention

A new review argues that the next generation of infectious-disease prevention must focus more explicitly on the places where wildlife, livestock, people and altered environments overlap. Deforestation, agricultural expansion, climate change, urbanisation, wildlife trade and global movement are reshaping these interfaces and increasing opportunities for pathogen spillover, amplification and re-emergence.

The review examines the wildlife–livestock–human interface (WLHI), as a critical epidemiological zone for emerging and re-emerging infections. It combines evidence from global outbreaks with examples from India and argues that surveillance should increasingly integrate animal, human and environmental data rather than operate through separate sectoral systems.

Spillover is driven by changing ecosystems

The central argument is ecological. Wildlife–livestock–human interfaces arise where the ranges and resource use of wildlife, domestic animals and people overlap. Deforestation, conversion of natural habitats into agricultural land and grazing areas, and competition for shared water and food sources can increase direct and indirect contact between species. Pathogens may then move through shared environments contaminated with faeces, saliva, aerosols or other biological material, even without direct contact between wildlife and livestock.

The review identifies climate change, land-use change, agricultural intensification, global trade and wildlife commerce as interacting rather than independent drivers of disease emergence.

Wildlife remains an important source of emerging zoonoses

The authors cite previous estimates indicating that a large proportion of newly emerging zoonotic diseases have wildlife origins and use examples including Ebola, West Nile fever, hantavirus infection, rabies, Japanese encephalitis and Nipah virus to illustrate different transmission pathways.

• Nipah virus: bats → pigs → humans;

• avian influenza: aquatic birds → poultry → humans;

• West Nile virus: birds → mosquitoes → humans;

• Japanese encephalitis: aquatic birds/pigs → mosquitoes → humans;

• hantaviruses: rodents → humans;

• plague: rodents → fleas → humans.

These exemples make the broader point that wildlife reservoirs are frequently connected to humans through livestock, vectors or environmental intermediaries, rather than through simple direct transmission.

Livestock can become an epidemiological bridge

Domestic animals may amplify pathogens that originate in wildlife populations. The review uses the 1998–1999 Malaysian Nipah outbreak as a classic example: fruit bats associated with disrupted habitats infected pigs, which subsequently transmitted the virus to farmers. Human mobility then contributed to wider spread.

Agricultural intensification may increase this bridging role. Large concentrations of genetically similar animals can facilitate transmission once a pathogen enters a herd or flock, while farms located close to wildlife habitat may create repeated opportunities for cross-species exposure.

This mechanism is relevant well beyond zoonoses. The review also cites economically important animal diseases such as African swine fever, foot-and-mouth disease and peste des petits ruminants as examples in which wildlife–livestock interactions can influence disease maintenance or spread.

Climate change is modifying vector and reservoir geography

Environmental change can also alter disease risk without requiring closer physical contact between wildlife and farms. Increasing temperatures and changing rainfall patterns can expand the geographical range of mosquitoes and other arthropod vectors and may shorten pathogen development times within vectors. The review links these processes to changes in the distribution of diseases such as malaria and dengue. Weather variation can also affect rodent populations and therefore human exposure to hantaviruses.

Habitat fragmentation can produce equally complex effects. Changing predator–prey relationships, wildlife density and biodiversity may alter the abundance of competent reservoir hosts and vectors.

Antimicrobial resistance belongs in the same framework

The wildlife–livestock interface is not limited to viruses and classical zoonoses. The review places antimicrobial resistance among the major pathogen-related drivers of emerging disease risk. Resistant bacteria can circulate between livestock, wildlife, humans, food and contaminated environments.

The authors highlight the emergence of the mcr-1 colistin-resistance gene, first described in China in 2015 across pigs, food products and humans, as an illustration of cross-sector dissemination. The implication is that AMR surveillance should increasingly incorporate environmental and animal reservoirs rather than remaining primarily hospital-centred.

Buffer zones may become an important prevention tool

One of the more distinctive recommendations concerns ecological buffer zones. The authors argue that maintaining or restoring transition zones between natural habitats, livestock production and human settlements can reduce some opportunities for cross-species contact. They cite areas of India where deforestation, agricultural encroachment and livestock grazing near wildlife-rich habitats have increased interactions between animals and people.

The review specifically links the 2018 Nipah outbreak in Kerala to landscapes where fruit orchards, human settlements and bat roosting areas occurred in close proximity, using this as an example of how environmental configuration can influence spillover risk.

Surveillance remains too fragmented

The most important operational weakness identified by the authors is fragmentation of surveillance. Human medicine, veterinary services, wildlife monitoring and environmental surveillance frequently collect information separately. The review argues that future systems should integrate epidemiological, veterinary, wildlife and environmental data, ideally with pathogen genomics and longitudinal ecological studies.

The authors also advocate real-time data sharing, rapid diagnostic capacity in rural areas, coordinated training of veterinarians, healthcare workers and environmental specialists, and stronger international exchange of outbreak information.

Wastewater and environmental molecular surveillance, including qPCR and digital PCR, are cited as increasingly useful complementary tools for detecting circulating pathogens before conventional clinical surveillance identifies large outbreaks.

The review ultimately argues for a shift in emphasis. Most disease-control systems become fully mobilised only once infection is detected in livestock or humans. But by that stage, the pathogen may already have crossed ecological and species barriers. A more preventive strategy would concentrate surveillance before spillover, particularly in landscapes undergoing rapid ecological change, areas of intensive livestock production, biodiversity hotspots and regions where wildlife, animals and people regularly share resources.

Nevertheless, emerging infections are rarely the consequence of one isolated factor. They arise from the convergence of pathogen biology, animal populations, human behaviour and environmental change.