Can small snails found in koi ponds cause bilharzia?

Small snails found in koi ponds can potentially contribute to the transmission of bilharzia, also known as schistosomiasis, if they are of the species that serve as intermediate hosts for the Schistosoma parasites. These parasites lay eggs in freshwater, which hatch and infect snails, leading to the release of larvae that can penetrate human skin. However, not all snails carry the parasites, so the risk depends on the specific species present in the pond. Proper pond management and hygiene can help mitigate this risk.