http://www.chicagotribune.com/news/nationworld/chi-0703140248mar14,1,5656740.story?ctrack=1&cset=true

River parasite eats at children

Neglected scourge in Africa is cheap and easy to treat, but the `pennies cannot be found'

By Colleen Mastony
Tribune staff reporter

March 14, 2007

NASARAWA, Nigeria -- Flowing through the shantytowns and yam fields of this dust-choked region, the River Uke glimmers like a mirage, tiny white diamonds of sunlight dancing on its surface. As the temperature rises to 100 degrees, wiry boys run to the river and leap into its waters.

Ask the people of Nasarawa, and they say the river is the center of their lives. But the water hides a debilitating scourge: schistosomiasis, a disease spread by microscopic parasites that live in the river, burrow through skin and slowly infect organs, stunting children's growth and sometimes causing death.

The solution, experts say, lies with just one dose, once a year, of about three white pills called praziquantel. Studies show that a single dose--at a cost of 20 cents--can reverse up to 90 percent of the damaging health effects of schistosomiasis within six months of treatment.

But while Nigeria profits handsomely from its oil industry and giant pharmaceutical corporations donate millions every year to treat more prominent diseases in developing countries, no one has stepped forward to help mass-produce and distribute praziquantel, which costs 7 cents per pill to manufacture.

"The pennies cannot be found," said Frank Richards, a doctor who heads a program to study the disease at the Atlanta-based Carter Center.

Schistosomiasis, also known as snail fever or bilharzia, has become yet another plague--like intestinal worms, lymphatic filariasis and trachoma--running rampant in Africa, despite an inexpensive and readily available medicine. It is estimated that 200 million people suffer from the malady worldwide, a majority without treatment.

"These are forgotten diseases and forgotten people," Richards said.

The tropical disease is the second-most common in Africa behind malaria, and experts believe its numbers are rising. Development projects such as hydroelectric and irrigation dams provide the ideal environment, and increased construction has sparked outbreaks from sub-Saharan Africa to China.

Schistosomiasis rips through internal organs and leaves victims in misery. But because it usually isn't fatal, the disease remains largely untreated as governments fight killers such as malaria, tuberculosis and AIDS, which experts call "the big three."

The Carter Center, instrumental in battling the horrific Guinea worm and other neglected diseases across the globe, has launched a small but aggressive campaign against schistosomiasis. Armed with a grant of just $40,000 a year, a small band of doctors and workers has fanned out to distribute medicine to the remotest corners of Nigeria, a country with the highest numbers of "schisto" in the world.

Schistosomiasis plagues the poorest communities, places where people live without running water, latrines or basic sanitation. The parasite is carried and spread by snails that live in rivers and dams.

When mature, the parasite leaves the snail and enters the water, where it can penetrate the skin of people who are washing or swimming. Within several weeks, the parasite grows inside the blood vessels and produces thousands of eggs. The eggs travel to the bladder, lungs, liver and intestines, where they release an enzyme that eats through tissues.

The eggs eventually are discharged through urine or feces. When passed into water, the eggs hatch and infect the snails to restart the cycle.

In Nasarawa, a trash-strewn slum of densely packed concrete houses with rusting tin roofs, 63 percent of the children have blood in their urine, a sure sign that the worms' eggs are digging into the bladder. Children are most likely to become infected because they typically spend the most time playing in contaminated water.

Parents take children to local clinics. But doctors often have no way to treat the disease.

"The drugs are not available," said Dr. Emmanuel Miri, who runs health programs in Nigeria for the Carter Center. "You are faced with children urinating blood and there is nothing you can do."

Most of the 7,000 residents in Nasarawa eke out an existence, tilling fields of cassava, corn and rice. Few people have access to latrines or running water. Fewer can afford praziquantel, which costs 20 cents per dose to produce but is sold in local pharmacies for about $2.

The lack of treatment means the town's children are small and frail. Those who say they are 10 years old frequently look no more than 6.

Other ways to fight the disease have proven expensive or ineffective. A pesticide used to kill snails could be put in the water, but that chemical is more costly than praziquantel. A program to help the village build latrines might help, but experts don't believe that would stop the spread of the disease because, as Richards said, "it's hard to keep kids from peeing when they swim."

Though many know the river is contaminated, it is nearly impossible to avoid contact with its waters. On a recent day, women washed clothing on the rocky bank as men bathed nearby. Dozens of boys splashed in a deep pool.

Ishaya Emmanuel, 15, has seen blood in his urine, but he won't stop swimming in the river. "There is not enough water to wash and bathe," he said. After swimming, he often feels itchy, a sign that the worms likely are digging into his skin.

Acknowledging the shortage of praziquantel, the World Health Organization, or WHO, recommends that doctors ration the drugs. According to WHO guidelines, if testing finds that more than 50 percent of children have the disease, an entire village should be given praziquantel. If 50 percent to 20 percent have the disease, only children should receive the pills. If less than 20 percent have the disease, the village will not be treated.

Carter Center takes leading role

The Carter Center launched a program in 1999 with the government of Nigeria to treat the disease in three states. The program could afford to purchase 200,000 doses a year. So health officials devised a plan to rotate treatment, delivering pills to the most endemic towns, bringing down disease rates and then moving the drugs to other heavily infected areas.

In places where more than 50 percent of the population once suffered from the disease, rationing drugs brings infection rates to under 20 percent of the population in most communities. But when drugs are removed, rates of infection inevitably climb.

In Nasarawa, after the pills were withdrawn for two years, the rate of disease spiked to 63 percent.

On the riverbank or in classrooms, village children were hesitant to talk about the scourge. But when coaxed in private, they acknowledged having the symptoms.

`It was a stinging pain,' boy says

Ramalan Haruna, 13, a small boy in a dirty yellow T-shirt, saw blood and felt pain while urinating. "It was a stinging pain. I was worried when I saw the blood," Haruna said.

Adam Sulaiman, 12, has seen blood in his urine too. He complained to his parents, but a medicine they got for him did not work. "We will be happy when they give us drugs," Sulaiman said.

In February, government health workers returned to Nasarawa to distribute praziquantel. At a village health clinic, children held glass vials of urine samples--red with blood. The next day they were to receive the pills to treat the infection.

"When you treat a kid with praziquantel, they do better on their tests, they are more alert in the classroom. They grow taller and they gain weight. They do all the sorts of things that children like this are supposed to," Richards said.

Carter Center officials are searching for donors to expand the program. A Japanese foundation gives $40,000 per year, but it goes only so far.

Nigeria needs more praziquantel than any other country in the world. But while it works in cooperation with the Carter Center in the villages, the government of Africa's largest oil-producing country has yet to fulfill promises to provide more money.

Ex-President Jimmy Carter, who founded the Carter Center in part to treat neglected diseases, has twice asked the Nigerian government to help pay for pills. In a 2005 meeting, top government officials promised $2 million but never followed through, Carter Center officials said. Carter traveled again to Nigeria in February and received another pledge for $2 million-- half of what is needed.

"Each one of these children would require a 20-cent investment once a year," Richards said on the riverbank. "We should be able to afford that."

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cmastony@tribune.com

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READER CONNECTION

To find out more about the global fight against diseases, including snail fever, go to the Carter Center's Web site at cartercenter.org and the World Health Organization site at who.int

Schistosoma haematobium

Images:

Comparison of ova from 3 species infecting humans:
http://www.k-state.edu/parasitology/625tutorials/Trematodes01.html
Ova of Schistosoma haematobium
http://www.k-state.edu/parasitology/625tutorials/Schistosoma02.html
Ova of Schistosoma japonicum
http://www.k-state.edu/parasitology/625tutorials/Schistosoma03.html
Ova of Schistosoma mansoni
http://www.k-state.edu/parasitology/625tutorials/Trematodes04.html
Schistosoma mansoni mating pair
http://www.k-state.edu/parasitology/625tutorials/Schistosoma01.html

Schistomes_LifeCycle

Phylogeny:
Subclass Digenea, Order Strigeata

Preferred definitive host:
Humans

Reservoir hosts:
None

Vector/intermediate host:
Snails-Genus Bulinus or Genus Physopsis

Geographical location:
Africa and the Middle East

Organs affected:
Adults reside in the venules of the urinary bladder.

Symptoms and clinical signs:
Initial phase involves abdominal pain, bronchitis, enlargement of the spleen and liver, and diarrhea. Hematuria and pain on urination follow. Because of cellular damage to urinary bladder, malignant tumors may form. Kidneys themselves are sometimes damaged.

Treatment:
Metrifonate, Preziquantel, Niridazole.

Schistosoma mansoni

Images:

Phylogeny:
Subclass Digenea, Order Strigeata

Preferred definitive host:
Humans

Reservoir hosts:
Certain monkeys and rodents

Vector/intermediate host:
Snails-Genus Biomphalaria

Geographical location:
Northern Africa, Middle East, S. America

Organs affected:
Adults reside in the portal veins of the large intestine

Symptoms and clinical signs:
Initial phase involves abdominal pain, bronchitis, enlargement of the spleen and liver, and diarrhea. Egg deposition in venules of large intestine induces pseudotubercle formation, resulting in necrosis and ulceration. Cirrhosis and portal hypertension develop as liver becomes damaged. Splenomegaly occurs. Pseudotubercles may develop in the lungs or nervous system.

Treatment:
Oxamniquine, Praziquantel, Niridazole.

Schistosoma japonicum

Images:

Phylogeny:
Subclass Digenea, Order Strigeata

Preferred definitive host:
Humans

Reservoir hosts:
Rats, dogs, cats, horses, swine, and deer.

Vector/intermediate host:
Snails-Genus Onchomelania

Geographical location:
Japan, China, Taiwan, Philippines, Indonesia.

Organs affected:
Adults reside in veins of the small intestine.

Symptoms and clinical signs:
Initial phase involves abdominal pain, bronchitis, enlargement of the spleen and liver, and diarrhea. Fibrous nodules containing eggs accumulate on serosal and peritoneal surfaces of the small intestine. Splenomegaly occurs. Cirrhosis and portal hypertension due to live damage follow. Neurological disorders, such as coma or paralysis, may occur due to egg deposition in the brain.

Treatment:
Praziquantel