ViroKitty – LBI for Science Outreach and Pandemic Preparedness at the Medical University of Vienna

According to estimates, there are around 250,000 cats living in Vienna. Many of these cats are not just indoor pets but also roam freely outdoors. On top of that, our lovely cats still have basic instincts, which involve the hunting of small animals. Accordingly, nearly every cat owner is at some point cherished with a gift by their pet who was just successful in hunting their prey. These could be various small mouse species, shrews, as well as small birds. These abilities qualify cats as very helpful scientists, and here is why!

Why do we need to look for viruses and other pathogens in Vienna?

Intense surveillance for viral, bacterial or other pathogens mainly focuses on rural areas so far, mostly also in exotic environments that have a high level of biodiversity. On the contrary, surveillance efforts in urban areas, such as Vienna or other big cities, are often neglected or not even considered. Nonetheless, there are countless occasions where we are getting in contact with different species of wild animals also in the urban environment. Though direct contact with small rodents, rats or wild birds is usually uncommon, indirect contact with these animals through feces, urine, dust, or water happens more often than we are aware of it. The likelihood for these contact events is, apart from humans, drastically increased for pet animals, such as cats.

On top of that, not everyone is aware of the potential pathogens and infectious agents that may be circulating in these cat prey species. Whether rodents, birds, or other animals, cat prey may or may not contain significant amounts of pathogens. A detailed study monitoring pathogens in rodents in various habitats found that over 600 different viruses were present in approximately 2,500 samples from bats, rodents, and shrews in China (Chen et al., 2023).

But small animals that are suitable as cat prey and containing pathogens are common not only in China; this is also the case here in Austria. A few years ago, several pathogens that are potentially dangerous to humans were detected in rodents near Lake Neusiedl: Borreliosis, leptospirosis, and the Dobrava-Belgrade hantavirus (DOBV) (Jeske et al., 2021). In addition, the Puumala hantavirus, which also circulates in rodents, causes several dozen to ~200 cases of infection per year in Austria (Clark et al., 2026; Tscherne et al., 2025; Puumalavirus | MedUni Vienna)! More information on the Puumala hantavirus is also available in a recent Spotify-Podcast by Prof. Dr. Florian Krammer.

How can my cat help find viruses and bacterial pathogens?

This is precisely where our beloved cats come into play: Their hunting instinct makes cats ideal scientists! We, the Ludwig Boltzmann Institute for Science Outreach and Pandemic Preparedness (LBI SOAP) at MedUni Vienna, headed by Prof. Dr. Florian Krammer, have set ourselves the task of examining the “hunting trophies” of our beloved pets for pathogens. We collect dead small mammals, rodents, and birds, dissect these carcasses in the laboratory, and examine the various organs for a variety of different viruses (e.g., influenza, hantaviruses, and bornaviruses), as well as selected bacterial pathogens (e.g., leptospira). The aim is to obtain a detailed overview of the pathogens that these small animals in the city are infected with and then to draw attention to these dangers.

Now it’s up to you and your cat: Together with your cat, you can make an important contribution to scientific and virological research! We would be very grateful if you would notify us if your cat has brought home its prey. We at LBI SOAP will collect the carcass from you, examine it in the laboratory, and then let you know what species your cat has caught and whether and which pathogens we were able to find in the cat’s prey. Your contribution can significantly advance scientific understanding of the types of pathogens and viruses we encounter in urban areas. The findings will also enable us to provide more precise recommendations on how you can protect yourself and your cat from these pathogens.

Nevertheless, it is very important to us to emphasize that this should in no way be understood as a call to send your cat out hunting. On the contrary: if your cat brings home dead prey anyway, we would at least like to try to derive some scientific benefit from the carcass and analyze it scientifically. That way, at least the prey did not die in vain!

My cat brought home a dead animal – What now?

Have we sparked your interest and would you like to help us find out which animals and potential pathogens your cat regularly brings home? Then please get in touch with us! We appreciate every report!

Speed is of the essence – please report your find to us within 24 hours (via phone, WhatsApp or SMS) and store the carcass (if possible) in the refrigerator it is collected by us. The fresher it is, the more scientific potential the find has for us! You can find an illustrated instruction on how to safely pick up the animal carcass here on this website.

How to safely pick up cat prey carcasses without endangering your health is illustrated on the picture on the right. Please click on it to enlarge it.