What Is Schistosomiasis?
WHO (World Health Organization) describes bilharzia mostly as schistosomiasis. It is both an acute and chronic disease where the symptoms appear when the body reacts to the parasite’s presence, but the complications persist for a long period of time. The disease affects different parts of our body (the lungs, the brain, and the nervous system), and the area of damage will depend on the parasite species.
Schistosomiasis is not usually fatal, but it is a chronic disease that seriously damages the internal organs. Also, there are some types of bilharzia that affect mammals and birds, such as water buffalo.
How Does Schistosomiasis Get Transmitted?
The infection starts when a person comes in contact with freshwater because certain types of water carry the worm. The parasites enter the body while washing, swimming, drinking, paddling, or eating food that has been washed in contaminated water.
The infective form of the worm is known as cercariae. As it emerges from the snails, they pass through a person’s skin when in the water and develop into adult worms in the individual’s blood. Depending on the type of worm, schistosomiasis affects different parts of the body.
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Intestines.
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Liver.
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Lungs.
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Spleen.
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Spinal cord.
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Brain.
The infection cycle begins when the worm’s eggs enter the water through the urine and feces of humans who already have the infection. Over time, the eggs hatch in the water and release tiny larvae, which reproduce inside the water snails. When the water snails get infected, the cercariae worms are released. These worms can survive for up to two days.
The cercariae worms enter the bloodstream by penetrating the human skin. Then they travel through to the lungs, liver, around the bowel and bladder. After a few weeks, the worms mature, mate, and start producing eggs. These eggs pass through the bladder walls and the intestine and eventually leave the body through feces or urine.
A person cannot pass schistosomiasis on to another person. Humans become infected only through contaminated water where the snails live.
Where Does Schistosomiasis Occur?
Schistosomiasis occurs in places where these parasites survive. The places where the parasite lives are,
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Egypt.
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Nile Valley.
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South America.
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The Caribbean.
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Southeast Asia.
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Middle East Yemen.
What Are the Symptoms of Schistosomiasis?
The worm type and the stage of infection will determine the impact of the disease. The symptoms occur when the body starts to react to the worm’s eggs.
Acute Stage:
The symptoms start to appear after 14 days and 84 days. Approximately after three weeks to eight weeks of infection, the person may experience:
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Fever.
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Rash.
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Breathing difficulties.
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Body aches.
Chronic Stage:
At the early stage, many people do not show symptoms, but as the disease progresses, they may start to develop signs and symptoms. These later stage symptoms also depend on the type of parasite involved. When the parasites affect the liver or intestines, the following symptoms occur. They are,
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Blood in the feces.
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Diarrhea.
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Liver fibrosis.
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Intestinal ulcers.
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Portal hypertension.
When the parasites affect the urinary system, there may be blood in the urine, a high risk of bladder cancer and painful urination, and anemia may also develop over time. In rare cases, the parasite affects the central nervous system. At the same time, children may have stunted growth and reduced capability to learn.
How Is Schistosomiasis Diagnosed?
When a person experiences any symptoms or thinks they may have been contacted with contaminated water, then visit a doctor or infectious disease or tropical medicine specialist. The doctor will ask the following to the patient to come to a diagnosis. They are,
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Where have you traveled?
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How long have you been there?
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Were you in contact with contaminated water?
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What were the symptoms when these first appeared?
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Was there an itchy rash or blood in the urine?
The doctor may ask for the following tests to be taken:
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Stool or Urine Sample - It indicates whether there are any eggs, and the worm takes about one and half months to mature.
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Blood Sample - It may not show reliable results until six to eight weeks after exposure.
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Biopsy - When there are intestinal symptoms, a biopsy of the rectum is needed, even when urine and blood tests are negative. They can also have a bladder biopsy.
A person who is returning home should have a checkup after three months, even when there are no symptoms, because the symptoms may show up later.
How Is Schistosomiasis Treated?
There is no vaccine for schistosomiasis, but the treatment itself can help reduce the infection. A short course of Praziquantel medication is usually effective when a person tests positive and if the individual has not experienced any significant damage or complications.
Praziquantel also helps with advanced stages of schistosomiasis, but it does not prevent re-infection. So, people living in high-risk areas can take a single oral dose of Praziquantel to reduce the chance of infection and further complications. In addition, those people will need this treatment yearly for several years.
How Can Schistosomiasis Be Prevented?
Avoid contact with fresh water in areas where there is more contamination. People should take care during,
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Swimming unless in a chlorinated pool or seawater.
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Eating food that is washed in contaminated water.
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Drinking water.
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Bathing.
Iodinated water does not kill parasites. People living or traveling to the disease prevalent areas should drink only bottled water or boiled water.
Any slight contact with contaminated water can lead to infection; for this reason, people should bathe in boiled water. Store the water for two days before using it to wash.
Ways to reduce the chance of becoming infected in high-risk areas include:
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Providing drug treatment to the population.
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Snail Control: Redesigning the irrigation schemes to make it hard for the snails to proliferate. The other option is to introduce predators, like crayfish.
People who travel to or spend time in an area where schistosomiasis is prevalent should seek medical advice when symptoms appear or if they think they might be exposed to freshwater or the parasite.
Conclusion:
Schistosomiasis is a rare disease that is seen in developing nations but has been significantly ignored. This disease has limited healthcare access, and also one particular affordable medicine has been used successfully in people to treat the disease. So this disease has to be taken seriously and should be given priority at local, national, and international levels.
