Bilharzia Prevention Tips
The Integration of Schistosomiasis
Since 1996, The Carter Center has been working with the national River Blindness Program developing a community distribution network in country to distribute the drug Mectizan® in parts of Nigeria. In 1998 the program began investigating the idea of targeting additional diseases through the same distribution channel, an approach that had never been done before.
Soon after the investigation started lymphatic filariasis was found to be preventable when Mectizan treatment was combined with the drug albendazole. By March 2000, communities in the Plateau and Nasarawa states, endemic for both river blindness and lymphatic filariasis, were being treated with the combined drug therapy. Simultaneously, the Center's groundbreaking approach was discovering that schistosomiasis control could be integrated too. That same year, urinary schistosomiasis was added, and today approximately 300 villages that receive the drug praziquantel also receive albendazole and Mectizan.
Transmission of Schistosomiasis
Schistosoma haematobium (urinary schistosomiasis) and S. mansoni (intestinal schistosomiasis) are microscopic parasites found in standing water.
Children are at greatest risk of becoming infected with this destructive disease because schistosomiasis is easily contracted while bathing or swimming in contaminated water. However, this disease can be transmitted simply through contact with contaminated water while performing daily chores, such as washing laundry, fetching water, and herding animals.
The parasite that causes schistosomiasis lives for years in veins near the bladder or intestines, where it lays thousands of spiny eggs that tear and scar tissues of the intestines, liver, bladder, and lungs. Damage to the urinary tract and intestine causes blood vessels to break creating internal bleeding. The blood resulting from internal bleeding carries the parasite eggs, which then enter the urine and stool.
When infected people, often children, urinate or pass feces in the water, the eggs are immediately released into the community water source. The eggs infect fresh water snails, such as the Bulinus, which than becomes an intermediate host. Inside the snails, the parasites develop and multiply; they are now able to re-enter the skin infecting new victims and continuing the cycle.
In the village of Kwa'al, Nigeria, like most rural communities in the developing world, there is only one water source. There are no alternatives if the source becomes contaminated. It is not a choice between the contaminated water and clean water for bathing, laundry, playing, or drinking; it is a choice between water contaminated with schistosomiasis and no water at all.
The blood in urine and stools is only one symptom of the damage caused by the infection. Victims of schistosomiasis suffer from stunted growth and poor school performance, as well as bladder dysfunction, kidney disease, and premature death. There is also increasing evidence of high rates of bladder cancer due to repeated schistosomiasis infections. The WHO states that bladder cancer is 32 times more prevalent in some areas of Africa than in the United States. Fatality usually occurs as a result of bladder cancer or intestinal bleeding.
Sadly, school-aged children shoulder the majority of schistosomiasis' consequences, especially poor growth and impaired cognitive function. For communities already burdened by poverty and ravaged by scourges such as malaria and HIV/AIDS, schistosomiasis is especially devastating.
Strategies Against Schistosomiasis
Although schistosomiasis is not eradicable, the disease can be prevented and transmission controlled with a single, annual dose of praziquantel. Community health workers conduct rapid assessments to determine the prevalence of schistosomiasis in a given village.
A dipstick is used to detect the presence of blood in the urine of children and the proportion of infected children in a village determines the treatment plan for that community.
Nigeria's Schistosomiasis Control Program, in partnership with The Carter Center, began in 1999 in two Nigeria states, Nasarawa and Plateau, expanding to Delta state in 2004. Since 1999, more than 70,000 treatments have been distributed to nearly 400 villages in the three states. Although this success is remarkable, more than 6 million praziquantel tablets are still needed every year to treat those in just two of the states; the need for Delta state is unknown as the area is still being evaluated. Unlike Mectizan, used to fight river blindness, and albendazole, one of two drugs used to fight lymphatic filariasis, no company donates praziquantel, so the Center's distribution is limited to the drugs it can afford to purchase.
Furthermore, there is a limited supply of praziquantel; only 89 million tablets are made when there is a need of 423 million. Nigeria needs more than any other country; approximately 43 million tablets. Not everyone who needs the drug can get it, which is yet another harsh reality for some of the most poverty stricken areas of the world. To ration the limited supply, the program follows the WHO distribution guidelines:
* When a village reports more than 50 percent of children have blood in their urine, only then does everyone get treatment.
* When 20-50 percent of children have bloody urine, only the children get treated.
* When less than 20 percent of children have symptoms, no one in the village gets pills.
This is a tragic situation, but there is hope. Studies of those treated show that, within six months of receiving praziquantel, up to 90 percent of the damage due to infection can be reversed. In the past, praziquantel has been used successfully to treat millions of people at risk for or infected with schistosomiasis in Brazil, Egypt, and China.
With success in these two Nigerian states, when sufficient funds are secured, the next step is to help extend the Schistosomiasis Control Program to all of Nigeria. The Carter Center hopes the hard work and success of its partners in Nigeria will kick start a nation-wide initiative to address the quiet plague of schistosomiasis.
Schistosomiasis (Bilharzia) Control and Prevention:
Nigeria is the most schistosomiasis-endemic country in Africa and among the most highly effected in the world. Yet until the Nigeria Ministry of Health and The Carter Center launched the schistosomiasis program in 1999, no one had been effectively addressing the disease in Nigeria.
Building on the existing community-based approach and drug distribution systems used in the river blindness and lymphatic filariasis programs in Nigeria, the Schistosomiasis Control Program was founded. Since 1999, the Center has been helping the state ministries of health distribute the drug praziquantel and provide health education to prevent the disease in villages in two Nigeria states, Nasarawa and Plateau. In 2004, the Center expanded its work to include the Delta state.
Preliminary surveys conducted in 1999 identified alarming needs: 1-in-5 school-aged children in Nigeria had blood in their urine and more than 90 percent of the tested villages were in need of treatment with praziquantel-because everyone, not just children, in the village should receive praziquantel.