Question: What type of parasite has been the one that has most affected people and yourself, and have you been infected before by a parasite you have been working on?

Erin Pallott answered on 25 Mar 2025:

There are some different ways to answer this.
Malaria is the deadliest parasitic disease by number of deaths (600,000 a year). It is caused by a single-celled parasite that infects blood cells.
Other parasites are not as deadly, but infect many people. Toxoplasma is another single-celled parasite that does not cause much harm in healthy people, but up to a HALF of the world’s population could have been infected by it before (or still!).
Roundworm (Ascaris) is also a really common infection. This is a worm (15-30cm) long, and still infects over 1 billion people today. We have drugs to kill parasites, but many people are at risk of reinfection due to unclean water/food and lack of water sanitation.

I have never been infected with a parasite I have worked on! But in the UK, pinworm is one of the most common infections. About 20% of kids will catch it at least once, but it’s easily treated with medicine and handwashing. It is common in toddler ages, so many of you might have had it but don’t remember!