Arthur Greene
Who would win in a fight between a crocodile, a shark, a lion and a freshwater snail?
Probably not the snail – but it may surprise you to hear that freshwater snails in fact kill more people every year than all the others combined.
The World Health Organization (WHO) estimates that between 20,000 and 200,000 people die every year as a result of an infection transmitted by the snail.
Meanwhile, Statista estimates that crocodiles kill about 1,000 people every year, while lions kill 22 and sharks only manage about six.
The reason so many people are killed by snails is that many are infected with schistosomiasis, or “snail fever”, and carry a helminth (worm), which can infect a person.
Snails actually catch schistosomiasis from humans, so it’s a vicious circle.
When an infected human relieves themselves into a body of water – be it a lake, river or even puddle – they release helminth eggs into their faeces or urine. The snail then catches the disease when they come into contact with the water.
That same snail will go on to release the helminth’s larvae clones into another body of water. If a person’s skin so much as enters that water, the larvae can penetrate them and infect them with schistosomiasis.
The disease is most common in Africa, but has been detected in Asia and South America too. It’s treatable and largely non-deadly, with WHO estimating that up to 250 million people are infected with it at any one time.
