China to help Africa to curb schistosomiasis

SHANGHAI (Reuters) - China is to help sub-Saharan Africa tackle schistosomiasis, also known as snail fever, a disease that kills some 280,000 Africans each year, by improving treatment of human waste and perhaps even replacing water buffalo with tractors.

Management of excrement is important to control the disease as it is caused by worms, called schistosoma, that are shed in stools and end up in irrigation drains, rivers and ponds. Getting rid of buffalo, host to 90 percent of the worms, is also key.

China hopes to pass on its own experience at a regional meeting next month, also to be attended by the Philippines, Laos, Cambodia and Indonesia.

While the generic drug praziquantel can treat the illness, it is costly for rural Africans. The tiny parasitic worms burrow through the skin of farmers tending crops and children and women who swim and perform household chores in infested freshwater rivers and ponds.

“We will share with them our methods so they can design their solutions according to their own situation,” Zhou Xiaonong, director of China’s National Institute of Parasitic Diseases in Shanghai, said in an interview.

“We are discussing ways to sell praziquantel to Africa. They cannot afford to buy. They need 200 million tablets a year. But there are only six manufacturers globally. Capacity is limited.

The focus is on prevention as much as on treatment.

“We will train their personnel and help build their capacity in designing latrines, tapping human and animal excrement for biogas, and sterilizing it,” Zhou said.


And water is the critical element.

The worms burrow into snails where they multiply and change into a form that can infect as many as 43 species of mammals once the snails finally release them.

“Within 10 seconds, the worms can burrow through your skin. You won’t feel a thing but by nightfall, you will have an itch and your skin will be inflamed,” Zhou said. “In one case, a parent dipped a child lightly into water to cool the child off in summer, and with just one dip, the child got infected.”

In the human body, the worms live in blood vessels where the females release eggs that are excreted.

Half the worms end up in the intestines and are shed in stools, while the remainder stay in the liver and other organs, causing fibrosis, or hardening, and even cancer. Patients can live for years, but suffer from extreme fatigue and cannot work.

China redesigned irrigation drains to get water flowing faster to stop the proliferation of snails. It also designed latrines that sterilized excrement and, through subsidies, encourages farmers to replace water buffalo with tractors.

China has reduced its prevalence of snail fever cases to below 400,000 a year out of 207 million worldwide, according to World Health Organization statistics.

“Over 180 million people are infected in sub-Saharan Africa. Of the parasitic diseases, it is second to malaria as a public health problem,” said Lester Chitsulo, a parasitologist with the WHO’s unit for Control of Neglected Tropical Diseases in Geneva.

Chitsulo hopes that China, which makes almost all the active ingredients in praziquantel, can donate the drug to Africa.