Many of the pathogens such as harmful protozoans, bacteria, and viruses among birds and bats exhibit a correlation with temperature and rainfall (climate change), according to a comprehensive Europe-wide study.
The study compiled data on over 75 pathogenic microbes, spanning nearly 400 bird species and 40 bat species across Europe. The analysis of this data, combined with climatic factors, highlighted a strong connection between pathogen occurrence and temperature or rainfall.
Lead author Yanjie Xu, from the Finnish Museum of Natural History at the University of Helsinki, notes, “In general, pathogenic bacteria thrive in warm and dry climates, whereas pathogenic viruses favour moist conditions.”
The link between climatic factors and pathogens was particularly pronounced among the 17 pathogen taxa with the most available data. The associations observed were diverse.
TEMPERATURE
University lecturer Arto Pulliainen, from the University of Turku Institute of Biomedicine, explains, “Temperature showed a positive association with the occurrence of avian flu virus, malaria parasites, and bacteria responsible for chlamydia, salmonella, Q-fever, and typhus in both birds and bats.”
RAINFALL
Rainfall exhibited both positive and negative associations with pathogen occurrence. For example, increased rainfall raised the likelihood of Usutu, Sindbis, and avian flu viruses, as well as salmonella bacteria.
Thomas Lilley, an academy research fellow from the Finnish Museum of Natural History, points out, “Usutu and Sindbis viruses are carried by mosquitoes, and higher rainfall can lead to the proliferation of mosquito-friendly wetlands. Similarly, avian flu and salmonella are prevalent among waterfowl, for which wetlands are crucial.”
ALTERING RISK OF INFECTIOUS DISEASES
This extensive study, which analyzed data from over 700 research papers and nearly half a million observations, reinforces the notion that climate change can significantly alter the risk of infectious diseases. Climate change affects the distribution patterns of both pathogens and their wildlife hosts. Bird distribution, for instance, is shifting northwards at a rate of over a kilometre per year. Additionally, climate change influences pathogen occurrence in various environments, including water bodies.
Aleksi Lehikoinen, senior curator at the Finnish Museum of Natural History, reflects, “There’s a possibility that thermophilic pathogens may become more prevalent in northern Europe due to climate change.”
