Vampire Bats in Southern States Could Spread ‘Zombie Deer Disease’ to Other Animals, Research Suggests

Experts are sounding the alarm over a potential new threat posed by vampire bats—the risk of them spreading chronic wasting disease (CWD), an incurable and fatal illness that primarily affects deer, elk, and moose. Commonly referred to as “zombie deer disease,” CWD is characterised by debilitating symptoms, including excessive drooling, severe weight loss, and coordination difficulties.

A recent study published in the Journal of Mammalogy investigated the possibility that common vampire bats (Desmodus rotundus) could facilitate the transmission of CWD to new populations. Conducted by Peter Larsen, who co-directs the Minnesota Center for Prion Research and Outreach (MNPRO), the research was partly motivated by his own experience after being bitten by a vampire bat during a 2022 field trip in Guyana. This brush with the bats raised questions about the types of pathogens they might carry.

CWD is caused by prions—abnormal proteins that attack the brain and nervous system. Since it was first identified in the 1960s, the disease has rapidly spread through various deer populations in North America, with notable occurrences in states like Texas and New Mexico, where prevalence rates in some mule deer populations have been recorded as high as 11%.

Climate change is further complicating the situation, as rising temperatures are expected to push the habitat range of vampire bats northwards from their native areas in Mexico and Central America. This migration could result in increased encounters between these bats and CWD-positive animals, escalating the risk of disease transmission. Larsen estimated that there is a 70% chance that vampire bats are already feeding on infected animals in Mexico.

The implications of such interactions could be dire. Not only is there concern regarding bats contracting the disease, but experts are also looking into the possibility that these bats could accelerate its spread or even lead to new mutations. This could pose an even greater threat to both wildlife and livestock. Brent Race, a scientist at the National Institutes of Health’s Rocky Mountain Laboratories, noted the potential for bats to become vectors for CWD, which warrants comprehensive investigation.

Symptoms of CWD can take a long time to manifest, sometimes taking months or even years. Infected animals might initially appear healthy, which presents significant challenges for livestock owners and wildlife managers aiming to identify and manage the disease in its early stages. The concern for those who raise livestock is particularly acute, given the potential financial consequences of infection.

Adding to the complexity is the way prions operate. Unlike viruses and bacteria that can undergo genetic mutations, prions change in structure and form within the digestive systems of their hosts. If vampire bats do become susceptible to CWD, there is a fear that the prion could evolve in a way that enhances its infectious potential. Such changes might make it easier for the disease to jump to other species, including domestic animals and possibly humans—a prospect that remains speculative but nonetheless alarming.

As researchers investigate the dynamics between vampire bats and CWD, the situation is evolving, and further studies will be vital. The potential for vampire bats to extend the reach of CWD presents a complex challenge that intertwines wildlife health, agricultural concerns, and public safety. The findings from these investigations will be crucial in shaping policy and management approaches in the years to come.

In a world grappling with multiple zoonotic diseases, the emergence of threats like CWD highlights the importance of understanding wildlife interactions with pathogens. As animal habitats shift due to climate change, vigilance and research will be key to preventing another public health crisis stemming from wildlife diseases.