MRC-University of Glasgow Centre for Virus Research

‘Influenza’ might bring to mind seasonal vaccines or transmission from pigs and birds, but bats can also catch flu. So far, bat-specific strains of influenza virus have only been found in Central and South America, most often in fruit bats. A new study led by Dr Megan Griffiths looks at how bat flu (specifically H18N11 – quite different from influenza viruses which usually infect humans) spreads within another species: the common vampire bat. Vampire bats are particularly interesting because they interact with lots of other species (including livestock and humans) when they feed on blood, which provides lots of opportunities for disease transmission. By studying bat flu within vampire bats the team hope to learn about the risks of cross-species transmission and how to prevent it.

Bat flu was only discovered in 2011, so most studies haven’t been able to explore how the virus spreads over a long period of time. The team were able to use a 12-year dataset, which was originally collected to study a different virus, to build models of how influenza spreads within vampire bats. These bats can live for several years, so the team caught and sampled some bats multiple times during the study which allowed them to follow their individual journeys. This combination of long-term data collection and sampling at different scales allowed us to build a clearer picture of how bat immunity and seasonal forces influence transmission. The study period also covered a large-scale culling operation aimed at controlling rabies in vampire bat populations. Whilst bat flu wasn’t the target of this cull, the team show that influenza transmission halved during the culls – this was especially interesting because the culling operation wasn’t successful at reducing rabies cases.

Understanding how diseases spread in wildlife is crucial for preventing outbreaks in humans. The study shows that vampire bats are likely reservoir hosts of H18N11 influenza, and that regular peaks in flu infection provide ample opportunity for transmission to other species. Outbreaks of bat flu in other animals hasn't yet been observed which means that either the virus is not currently very good at infecting non-bat species, or it isn’t yet causing noticeable disease. Future work will need to look at species which have the most contact with vampire bats to see if they show any evidence of infection. The team also show that interventions (such as culling) for any wildlife disease need to be carefully considered for the unplanned impacts they might cause.

Find out more by reading the paper here: Dynamics of influenza transmission in vampire bats revealed by longitudinal monitoring and a large-scale anthropogenic perturbation

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First published: 6 February 2025