Parasitic worms and the 50 pence pill

By Barney Wharam

In the developed world the idea of worm eggs in your poo seems pretty alien thanks to our flushing toilets, good sanitation and clean water supplies. Unfortunately this is not the case the world over. Worldwide over 1.5 billion people carry a helminth (worm) infection.

Parasitic worms tend to be most common in areas of the world where human faeces enter water supplies or are used as fertiliser for crops. Worm eggs from infected humans’ faeces are accidentally swallowed along with food or water, causing new infections. Although helminth infections kill relatively few people compared to malaria or HIV/AIDS, they cause massive amounts of disability; damaging the education, lifespan and productivity of those infected.

Water pump ACF by Julien Harneis

“Neglected Tropical Diseases” like helminth infections receive proportionally very little money from governments and companies compared to diseases that affect westerners. Thankfully, we have two powerful drugs which kill the five most important helminth species. Even better, a group of four pharmaceutical companies (GlaxoSmithKline, Merck, Pfizer and Johnson & Johnson) have agreed to donate vast quantities of these drugs.

A coordinated group of charities and governments are now handing out drugs on a colossal scale in sub-Saharan Africa. The distribution of these drugs has already almost eliminated “River Blindness” – a major disease in West Africa caused by a parasitic worm. But for this success to continue, 100 million people in West Africa need to be given a pill once each year. These drugs cost a mere fifty pence to make and distribute, an absolute bargain compared to most health initiatives.

So will we ever be able to rid the world of these nasty worms? Unfortunately, completely eradicating a whole population of parasites is often very hard. Most helminths infect livestock, wildlife and pets as well as humans, making it very difficult to kill the entire population. Also, in the same way that bacteria such as the infamous MRSA “hospital bug” are becoming resistant to our antibiotics, there are some signs that the helminths are becoming resistant to the two drug compounds used in our 50 pence pills. What makes it worse is that there are very few new drugs being successfully developed.

We are heading toward an impossible question – do we treat people now and risk blunting our only weapons because the worms become resistant? Is it ever ethical to withhold treatment to some people in order to better treat those in the future? Ultimately these diseases won’t really go away until everyone has access to clean water and adequate sanitation – a very difficult task in the poor, rural, isolated and politically unstable areas of the world.

Image: ‘Water pump ACF’ by Julien Harneis under creative commons license