Almost a quarter of Nigerians suffer from bilharzia, an infection spread by swimming or bathing in water contaminated with urine and feces, according to new research by Niger’s Ministry of Health.

Some three million of Niger’s 13.4 million people have been diagnosed as suffering from the parasitic skin infection, also known as schistosomiasis. It causes rashes and flu-like symptoms, can create urinary problems and damage the bladder, liver, lungs, bowel and nervous system.

Parasitic diseases thrive in areas with poor water supply, sanitation and housing, according to the World Health Organisation (WHO).

And Niger, a vast and landlocked country on the southern fringe of the Sahara desert, has the lowest number of wells and toilets per capita in the world.

Four out of every five Nigerians live in the countryside where at least 40 percent of them depend on basic wells for water and the bush for toilet.

Niger’s government, in conjunction with the nongovernmental organisation Schistosomiasis Control Initiative (SCI), has said it is responding to the data by constructing a new laboratory devoted to the disease in Niamey, and distributing drugs for treatment.

WHO said on Thursday that an estimated one billion people worldwide - one sixth of the world’s population - are affected by one or more parasitic disease.