British tourists headed for southern Europe have been warned of a growing health risk of schistosomiasis, a tropical disease, which is increasing at a sharp rate due to the emergence of a parasitic flatworm, according to a new study from KU Leuven University. 

The research highlights that the threat is expected to become more prevalent due to climate change, due to the fact that freshwater snails that transmit the parasite are now able to survive in several southern European countries.

Schistosomiasis, also known as bilharzia, is the fastest-spreading infectious disease after malaria, with over 200 million infections annually. 

Contraction of the disease occurs through swimming in contaminated freshwater bodies such as rivers, ponds and lakes. Typical symptoms include a skin rash, anaemia, abdominal pain and blood in urine or stools. More worryingly, if left untreated the disease is also known to lead to infertility, bladder cancer, liver fibrosis and developmental delays in children. 

Biologists from KU Leuven, the Royal Museum for Central Africa and the University of Copenhagen have studied the temperature ranges within which the freshwater snail can survive. 

“We find that these snails can easily adapt to new conditions," explained Tim Maes from KU Leuven. "They can thus easily colonise new regions like Europe."

The data was then combined with models predicting European climate over the next century to estimate the future distribution of the snail. As such, the analysis indicates that large parts of Spain, Portugal, France, Italy and Greece will have climates conducive to its survival.

Due to climate change, an increasing number of tropical infectious diseases are being introduced to Europe. Schistosomiasis has been found on the French island of Corsica since 2013 and more recently in the city of Almeria in Spain. 

While other research has shown the parasite itself is able to survive in a temperate climate, Tine Huyse, researcher from KU Leuven and the Royal Museum for Central Africa, argued that “you need all three elements, snail, parasite and humans, to complete the infection circle.”

While travellers from Africa bringing the parasite to Europe do not yet present a large risk, “because of climate change, in the future, the three elements will all be thriving in the European climate, allowing the infectious disease to spread,” Huyse continued. 

Sudinfo argued that the “increasing threat” of schistosomiasis in southern Europe underscores the “broader impacts” of climate change on public health.