Heavy Rainfall and Flooding Could Fuel the Spread of Infections: Scientists Warn of Risks for Europe

Heavy rainfall and flooding in Europe may increase the risk of infectious disease outbreaks, according to a review of studies published in the journal Eurosurveillance.

Scientists analyzed 14 studies published between 2018 and 2025 and found an association between extreme rainfall and a range of infectious diseases. These included campylobacteriosis, leptospirosis, infections caused by pathogenic strains of Escherichia coli, vibriosis, hantavirus infections, Legionnaires’ disease, cryptosporidiosis, and malaria.

One of the main mechanisms involves water contamination. Following heavy rainfall and flooding, sewage and pollutants from agricultural areas can enter drinking-water sources, rivers, and coastal areas. For example, in the UK, cases of infection with pathogenic E. coli were reported after heavy rainfall. Researchers suggested that the bacteria may have reached fields from neighboring areas where sheep were kept. In Norway, heavy precipitation may have contributed to the contamination of a drinking-water reservoir and a subsequent outbreak of campylobacteriosis.

People who come into contact with floodwater during cleanup operations or agricultural work face a particular risk. Such exposure has been linked, among other conditions, to leptospirosis. In Italy, cases of vibriosis were reported after severe flooding, while several other countries recorded increases in intestinal infections in flood-prone areas.

The researchers also found an association between extreme rainfall and outbreaks of diseases transmitted by mosquitoes and other vectors. Standing water left behind by floods can create favorable breeding conditions for insects capable of transmitting diseases such as West Nile fever and dengue.

In some cases, the effects of flooding extended beyond the usual disease season. For example, in flood-prone areas of Ireland, the number of infections caused by E. coli and Cryptosporidium increased. In five Balkan countries, rates of hemorrhagic fever associated with hantaviruses rose following the 2014 cyclone, which brought heavy rainfall and flooding.

However, the researchers noted that the available evidence remains limited. Most studies were conducted in northwestern Europe, while methods for assessing rainfall, flooding, and disease incidence varied between studies.