News briefs

Changes to bat habitats facilitate Hendra virus spillover risk

Research from Griffith University, published in Nature, examined 25years of data on land‐use change, bat behaviour, and spillover of Hendra virus from bats to horses in subtropical Australia and revealed that human activities are causing bats to adopt behaviours previously linked to short term nutritional stress, and that this change in behaviour is increasing the risk of Hendra virus spillover. Previous correlational studies associate spillover with broad‐scale habitat destruction and encroachment of people into natural landscapes, increasing opportunities for contact between wildlife, domestic animals, and people. The current study highlights that habitat destruction, agriculture and people were important in broadly determining where risk was high, but not simply because encroachment directly led to increased opportunities for contact as previously assumed. Instead, the researchers found that flying foxes responded to land‐use change by shifting their distribution and invoking behaviours that they would normally use to avoid climate‐driven starvation associated with El Niño events, such as feeding on introduced plants in horse paddocks. This was causing them to shift into agricultural areas that did not provide native food over winter. Extensive clearing of forests that flower in winter has led to a reduction in the number of years when abundant flowering occurs, reducing the reliability of this natural source of protection and increasing the risk of spillovers. “We propose that restoration of this critical habitat will restore functioning ecosystems, improve the health of flying foxes, reduce their reliance on urban and agricultural areas, and protect horses and people against spillover of Hendra and other viruses,” said lead author Dr Peggy Eby, from the University of New South Wales.

https://www.nature.com/articles/s41586‐022‐05506‐2

Nasal vaccine strategy could improve COVID‐19 protection

Researchers from the Centenary Institute and the University of Sydney have developed a new nasal vaccination strategy that induces potent lung immunity and protection against severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). The approach has been tested successfully in mice and has the potential to be a powerful tool for enhancing protection against coronavirus disease 2019 (COVID‐19) infection and minimising ongoing viral spread. Made up of the SARS‐CoV‐2 spike protein and an adjuvant called Pam2Cys (a molecule that helps stimulate a stronger immune response in the body), which was developed by Professor Richard Payne, National Health and Medical Research Council Investigator in the University of Sydney's Faculty of Science, the new vaccine was delivered via simply breathing in through the nose. It prompted substantial levels of neutralising antibodies and increased T cell responses in the lungs and airways of the mice that were tested. In the mice study, the new vaccine was delivered nasally, making its way through the respiratory tract, adhering to the tissues of the nasal cavity, airways and lungs. Testing showed the generation of high levels of protective antibodies in the airways and increased T cell responses in the lungs (T cells help destroy SARS‐CoV‐2‐infected cells). Significantly, none of the vaccinated mice became infected with COVID‐19. “Our vaccine differs from most current COVID‐19 vaccines in that it enables generation of an immune response directly in those areas of the body that are likely to be the first point of contact for the virus — the nose, airway and lungs. This may help explain the vaccine's effectiveness,” said lead author Dr Anneliese Ashhurst, a research fellow at the University of Sydney and the Centenary Institute. The study was published in Nature Communications.

https://www.nature.com/articles/s41467‐022‐34297‐3