Researchers call for rigorous wildlife surveillance to prevent disease outbreak

caged lemur
Without the proper surveillance of the wildlife trade and adequate monitoring, the authors argue that diseases are likely to spread again. Image: Pixabay

An internationally recognised standard for managing wildlife trade based on known disease risks should be established to prevent the outbreak of new infectious diseases such as SARS-CoV-2, the virus that causes coronavirus (COVID-19), experts say.

Writing in Science, the international group of researchers including Head of the University of Melbourne Vet School, Professor Anna Meredith, have recommended a new model of wildlife disease surveillance that focuses on the environments where animal-to-human transmission is most likely.

Zoonotic diseases – viruses that have jumped from animals to humans – are responsible for the coronavirus outbreaks, including SARS, MERS and now the COVID-19 pandemic. Other deadly viruses have arisen as the result of ‘spillovers’, with HIV originating in nonhuman primates, Ebola coming from bats and H5N1 and H1N1 influenza strains coming from birds and pigs respectively.

The researchers note that 60 per cent of emerging infections disease (EIDs) are zoonotic in nature, and more than 70 per cent of these have an origin in wildlife.

Researchers say virus spillovers are far more likely to occur in situations where humans come into close contact with wildlife.

The paper calls out the poor and inhumane conditions in which hunted or farmed wildlife is kept – conditions that are dirty, cramped and compromise the immune systems of animals – making it easier for disease to spread. Whether it is for subsistence or trade, when humans come into contact with unfamiliar species or when nonendemic species are mixed, that place is likely to become a ‘zoonotic hotspot.’

Without the proper surveillance of the wildlife trade and adequate monitoring, the authors argue that diseases are likely to spread again.

“We really need to bridge the gap between research and effective surveillance that triggers a rapid response,” Professor Meredith said.

“We know that many diseases like COVID19 are zoonotic but we don’t focus enough on the animal side of the human-animal zoonotic equation. We need to improve the way we test and track pathogens that can jump from wildlife to cause disease in humans and look at how humans and wildlife interact to mitigate the risks of another spillover, such as we have seen with COVID-19.

“We also need to develop disease detection capabilities in areas that have a higher risk. South East Asia, Africa and Central and South America carry the burden of EID risk, yet 78 of all reference laboratories (62 per cent) are in Europe and North America.”

The researchers do not believe that punitive restrictions on wildlife trade are the way to address the problem, acknowledging that this would likely force wildlife trade underground and make surveillance more difficult.

Similarly, they argue that a centralised model of disease surveillance is also unlikely to be workable, both in managing funding and responding quickly.

“A centralised approach may sound the most efficient but in reality it can be slow and the subject of political whims. We need effective laboratory testing capacity at or near locations where humans and wildlife interact,” Professor Meredith said.

"Modern improvements in testing technology, for example by using portable DNA sequencing devices, could be used to rapidly detect wildlife pathogens in local testing centres, with wildlife and healthcare workers trained to conduct tests safely and submit results."

Rather, the researchers call for a more decentralised model that is cost-effective and empowers locals, acknowledging that the wildlife trade provides income for so many millions that any top-heavy approach could do more harm than good.

“In order to have cooperation this needs to be a locally-driven response that empowers local wildlife and public health professionals to test for diseases year-round, at the source, and importantly without criminalising public participation in screening programs,” Professor Meredith said.

Technological advances in the decade since the H1N1 bird flu virus have led to the development of rapid, in-the-field testing and genome sequencing, allowing for easier testing in remote areas.

Professor John Fazakerley, Dean of the Faculty of Veterinary and Agricultural Sciences said the work highlights the inextricable connections between human, animal and environmental health that are at the heart of the faculty’s One Health research.

"Understanding the multiple interactions between these three health domains is crucial to preventing and controlling future outbreaks of infectious disease and establishing more exacting standards for wildlife surveillance constitutes a vital piece of that work,” Professor Fazakerley said.

The authors recommend:

  • Decentralised modes for detecting pathogens
  • Publicly accessible, centralised, curated system for monitoring pathogens
  • An internationally recognised standard for managing wildlife trade based on known disease risks should be established.

By giving more parties a stake in the effort, researchers say decentralisation is more likely to succeed in garnering geographically representative participation that explicitly includes the most at-risk and under-resourced regions.