Schistosomiasis

August 25, 2008

Over the last few weeks, I have been working with various teams on different hospital wards. The medical service beds are commonly full, (10 beds per room) and so additional beds and patients are placed in the middle of the room (3 can be accommodated). If those are full, they are placed on cots in the hallway. If those fill up, then they double up patients on one bed.

I was surprised that more patients on the medical ward, during my rounds, have complications from schistosomiasis than from HIV. Probably because KCMC has an excellent endoscopy program( an endoscopy costs about $12) and so patients are referred here from other centers. Schistosomiasis (also known as Bilharzia) is the disease caused by a blood born fluke (trematode) of the genus Schistosoma. Snails are the intermediate hosts. Adult schistosome worms were first discovered in an Egyptian patient in 1851 during an autopsy carried out by Dr. Theodore Maximilian Bilharz.

The Medical Ward room I rounded in had 3 female patients with end stage complications from schistosomiasis. They all had liver failure, and I palpated their spleens almost to their pelvis. 2 of them needed endoscopy to coagulate their bleeding esophageal and stomach veins. One patient had 5 liters of fluid drained from her abdomen, and yet she still had such significant ascites, she looked like she was carrying a term pregnancy. All of the women were 20-30 years old.

The Male Medical Ward room had 3 teenage boys, all recovering from bloody vomiting. They also had presumed schistosomiasis. Presumed because the tests required to confirm are prohibitively expensive. At some point once the chronic manifestations occur, there is no cure. It is difficult to predict that point for any given patient.

From the Schistosomiasis Control Initiative (http://www.schisto.org):

Light infections with schistosomiasis can be asymptomatic, and many people may live their lives without knowing they have ever been infected. However, globally, up to 120 million of the estimated 200 million infected people are believed to be symptomatic, and as many as 20 million may well be suffering severe consequences of their infection. The annual deaths associated with schistosomiasis are estimated at 20,000.

The first obvious symptom of infection is blood in the urine (hematuria). Early signs of morbidity which manifest in school age children are anemia, impaired growth, impaired development, poor cognition, and substandard school performance. However none of these signs and symptoms are due solely to schistosomiasis, and so a diagnosis on clinical presentation is difficult.

In terms of Women’s Health, schistosomiasis can wreak havoc on the female genital tract. Diagnosis is made by the presence of schistosome eggs and/or worms in the upper and/or lower genital tracts. Possible consequences include hypogonadism, retarded puberty, infertility, cancer, ectopic pregnancy, anemia due to chronic blood loss, miscarriage and preterm delivery, increased risk for sexually transmitted diseases (including HIV), and vesicovaginal fistula.

The most common method of transmission occurs when humans wade or swim in lakes, ponds and other bodies of fresh water which are infested with the snails. Thus, children and fisherman are at high risk of being infected. The parasite, when present in the water, bores through the skin and enters the bloodstream. The bladder is a favorite site of infestation. And in some endemic areas, a diagnosis is made based on observing blood in a child’s urine.

According to the Carter Center:

Schistosomiasis can be controlled now by one of the great miracle medical discoveries of the 1980s: the oral medicine praziquantel. Now that costs of the medicine have dropped from more than $2 USD per dose to 18 cents, great strides can be made in treating schistosomiasis.

Studies of those treated show that within six months of receiving a dose of praziquantel, up to 90 percent of the damage due to the schistosomiasis 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.

Too late for my patients, but there is hope for other Tanzanian children: August 29^th is the official start of the mass deworming project in the Kilimanjaro Region, the first to occur in a few years. All school age children will receive praziquantel and albendezole (to treat other worms). Only one dose is needed (more is ideal, but only one is required). This will also be paired with a massive immunization campaign.