Actually, most of you reading this – do. It’s almost certainly not going to hurt you.
In parts of Lancashire in the UK the current advice is to boil your water, due to a very low level of Cryptosporidium detected at Franklaw water treatment works in Preston. This advice should be followed – why risk getting Cryptosporidiosis (diarrhoea, stomach pains, cramps and low fever) when you don’t have to? Although the infection is generally not serious in healthy people, in some, and in those who are immunocompromised (cancer patients on chemotherapy, babies and young children, older people) a more severe form of the disease can develop (with symptoms including chronic diarrhoea).
It’s a faff to boil water before using it, and surely some people are alarmed and upset by the risk of infection, but relatively, we’re lucky. Low levels of one genus of parasite, one water treatment works contaminated temporarily, the means to kill the parasite, and free care in the event that infections do occur. But, parasites in our drinking water – it’s a surprise to get a small taste of the way most people have to live.
There are many parasites and genera, including Cryptosporidium, that cause disease by infecting people through their water supply: Entamoeba histolytica, Dracunculus medinensis, Schistosoma, Giardia duodenalis, Cyclospora cayetanensis, Toxoplasma gondii, Cystoisospora belli, Blastocystis hominis… the list goes on. And these are just (just!) some of the parasites – there are plenty of bacteria and viruses too…
This infographic from the Center for Disease Control shows all the countries where they recommend that we do not drink the tap water – most countries, and where most people live. The Millenium Development Goals drinking water target has been met – now 89% of the world’s people have access to ‘improved water sources’, but the remaining 748,000,000 people don’t. People in rural areas and those who are poor are less likely to have access to safer water.
The world-wide battle to kill parasites in drinking water continues. Most parasites can be killed by boiling drinking water, but many people do not have the resources to boil water. Filtering the water removes many parasites, but effective filters are expensive, and make-shift filters are less effective. Addition of chemicals, such as chloride, kills many organisms, but not others. UV irradiation of water can kill organisms, but doesn’t work with cloudy water, few people have access to such facilities, and UV irradiation using sunlight is less reliably effective. For many people, infection by parasites is inevitable; people in rural areas and those who are poor are less likely to be able to make their water safer.
Many people do not have the resources to be diagnosed with an infection. If they are diagnosed, many cannot be treated. Cryptosporidosis in severe cases is treated by supportive care (rehydration). Supportive care is not available to many people; severe dehydration can lead to death. Amoebiasis can be treated with amaoebicides but many people don’t have access to them. There is no treatment for Dracunculiasis (guinea worm disease), and removal of the worm is difficult. Schistosomiasis can be treated, but many people don’t have access to medication… You get the idea.
Parasitology is an under-researched subject and an under-funded medical field. Much of the funding and research there is goes on malaria (as much of it should), but that leaves other diseases neglected and we just aren’t spending enough money on dealing with these preventable and eradicable diseases. There are programs for prevention, treatment and eradication of some of these parasitic infections, these programs will also reduce bacterial and viral infections. Cleaner water, improved sanitation, access to medical care and more research are all essential if we want to save lives.