More research into animal diseases needed

University of Sydney scientists have argued for more research into major infectious diseases shared between wildlife and livestock, in order to better evaluate risks and improve responses to disease epidemics in animals and humans.

The claim follows a study published by the university in the journal Proceedings of the National Academy of Sciences, described by the authors as “the most comprehensive overview of research on infectious diseases at the wildlife-livestock interface to date”. The study aimed to identify which diseases and types of animals were most prevalent in published literature; measure how research has changed over time; and see how the diseases and animals involved differ by geographic region.

Through analysis of almost 16,000 papers, the team found that just 10 diseases have accounted for half of the published research in this area over the past century. The bulk of this research has focused on known zoonoses — diseases that are shared between animals and humans — to the detriment of studies on diseases affecting only animals, according to the researchers.

“In the case of emerging diseases, we tend to react to large outbreaks of disease in humans, rather than preventing or managing the infection [at the source] in animals, likely because we still don’t know a lot about the role of these microbes in the ecology of wildlife and livestock disease,” said co-author Dr Siobhan Mor.

Co-author Dr Anke Wiethoelter added that research into the impact of disease on wildlife “remains very poorly funded”. Ironically, she said, “this also means we know less about the diseases that could be a precursor to infectious diseases in humans”.

“In the case of Hendra virus in Australia, for instance, there are still big question marks around how the virus is transmitted between bats and horses, and factors influencing its transmission,” Dr Wiethoelter said. “And we now know that bats can harbour many germs, but the research investment into wildlife disease ecology simply isn’t there.”

Such research investment may increase sporadically, but typically only when certain diseases are receiving high levels of media coverage. Two diseases in particular — avian influenza and bovine tuberculosis — were found to have a strong association between frequency of publication, media attention and funding levels.

“Public interest comes and goes,” said Dr Mor, “but without sustained investments, research on this important interface suffers.”

Image caption: Little red flying foxes hanging in a close group, in Maitland NSW. This species of megabat, native to northern and eastern Australia, is a source of zoonotic viruses that are potentially fatal to humans if spread through livestock, including Hendra virus. Image by Mdk572 under CC BY-SA 3.0.

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