Researchers from CSH and vetmeduni have developed an interactive map of zoonotic pathogens in Austria spanning nearly half a century.
Identifying the interfaces where transmission occurs is one of the greatest challenges in combating zoonoses, diseases that are transmissible between animals and humans. “Our project started with the question: Can we characterize and visualize the zoonotic interfaces in Austria?” explains Amélie Desvars-Larrive from CSH and vetmeduni.
This initiative has resulted in the first comprehensive overview of zoonotic pathogen transmission in Austria, elucidating interactions among humans, animals, food sources, vectors such as ticks, and the environment, providing valuable insights into transmission chains. “It’s a complex system where most zoonotic pathogens can infect both humans and various animal species from different taxa,” the researcher notes.
EIGHT NEW ZOONOTIC PATHOGENS
The study, published in Nature Communications, also reveals an increase in the number of zoonotic pathogens in Austria, particularly over the past 20 years, with eight new species emerging, including the West Nile virus and Usutu virus. “Our network analysis suggests an elevated risk of pathogen transmission at interfaces between humans and cattle, and humans and food,” Desvars-Larrive elaborates.
Initially, researchers conducted a systematic literature review of all documented zoonotic pathogens in Austria from 1975 to 2022. “From this, we constructed a network outlining relationships among zoonotic pathogens, their hosts, vectors, and often neglected infection sources such as contaminated environments, like sandboxes, or contaminated food sources in Austria,” explains Desvars-Larrive.
The results of this analysis were transformed into an interactive zoonosis map of Austria by CSH data visualization expert Liuhuaying Yang, now accessible to the public.
FROM MEAT TO TICKS
The researchers identified certain sources playing disproportionately significant roles in the zoonotic pathogen exchange—such as chickens, cattle, sheep, and some meat products —capable of transmitting and potentially spreading a relatively large number of zoonotic pathogens.
Out of 197 different zoonotic pathogens documented from 1975 to 2022, 187 were found in a total of 155 different vertebrate hosts. Eleven pathogens were present in environmental media such as sandboxes. Fifteen pathogens, mainly bacteria like Listeria, Escherichia, and Salmonella, were found in food—more than half in meat and meat products. Additionally, 24 disease agents were detected in vectors such as mosquitos or ticks. “Ticks transmit more diseases—16 different pathogens—than any other vector,” explains Desvars-Larrive.
NEW PATHOGENS
New pathogens in Austria include the West Nile virus, first detected in 2016, and the Usutu virus, present since 2001 and first detected outside Africa at that time. Both viruses primarily affect birds but can be transmitted to humans through mosquito bites and have also been found in horses.
SIX COMMUNITIES
“When we looked at which vertebrate hosts, foods, and environmental sources share which pathogens, we found that the network in Austria is organized into six communities,” says Desvars-Larrive, with humans sharing the most pathogens with domestic and farm animals like dogs, cats, and cows.
“For instance, we found turkeys share more pathogens with food sources than with other bird and poultry species,” the scientist further explains. Wild boars, dogs, cats, and some rodents, meanwhile, act as “bridges” between different communities, potentially facilitating easier disease spread within the network.
RAISING AWARENESS
This new network-based approach provides valuable insights into zoonotic transmission chains and can facilitate the development of strategies against zoonoses. “Understanding which actors in the zoonotic network are more influential than others could be very helpful in zoonosis surveillance programs, serving as potential risk indicators,” says Desvars-Larrive.
“With our interactive map, we aim to educate and spark curiosity,” the researcher remarks. “While we all encounter various pathogens, only a few lead to illness, so there’s no need for excessive concern.” Nevertheless, promoting awareness is crucial—for example, understanding the importance of cleaning knives between different food items to prevent cross-contamination. “If bitten by a tick, it’s prudent to remain vigilant in the following weeks, as ticks transmit a range of diseases to humans and animals, often with symptoms appearing weeks later,” Desvars-Larrive advises.
AUSTRIA IN NUMBERS
Currently, Austria has around nine million inhabitants, with numbers rising. The country’s wildlife comprises about 45,870 species, including 110 mammal species. Moreover, 35 percent of Austria’s 3.9 million households keep pets. The nation’s livestock includes approximately 1.8 million cattle, 2.5 million pigs, and over 100 million poultry that are slaughtered each year, alongside about 130,000 valid hunting licenses. These figures provide an impression of the many interfaces between humans and animals alone.
IMPROVING DATA AVAILABILITY
“We’re only seeing the tip of the iceberg in our data—only those zoonoses that have been diagnosed. For instance, leptospirosis, still relatively rare in Austria, can mimic flu-like symptoms. If not clearly diagnosed as leptospirosis, it won’t show up in the data,” explains Desvars-Larrive.
Coordinated epidemiological surveillance mainly focuses on notifiable diseases, often overlooking non-regulated zoonotic pathogens circulating in the country.
For example, while SARS-CoV-2 is reportable in both humans and animals, it isn’t classified as a zoonosis in publications focused on human cases, thus not included in this data. Furthermore, the lone study examining SARS-CoV-2 in Austrian animals did not address its zoonotic potential.
Having more centralized and comprehensive data under the One Health approach, linking human, animal, and environmental health, is crucial for controlling and preventing zoonotic infectious diseases. There have been numerous efforts in this direction, especially since the SARS-CoV-2 pandemic, but significant hurdles remain, such as legal issues regarding data exchange. Particularly, environmental aspects of zoonoses are often underrepresented, complicating efforts to gain a complete picture. “With our network, however, we have provided an initial overview of the zoonotic interfaces among humans, animals, food, and the environment in Austria, which can facilitate the development of One Health strategies against zoonoses,” concludes Desvars-Larrive.
