Complications of Schistosomiasis
Most people who are infected with schistosomes do not experience any symptoms. However, in some cases, the parasites can cause several health problems. These include:
– Urinary tract infections: Schistosomes can cause inflammation and scarring of the urinary tract, leading to recurrent urinary tract infections.
– Bladder cancer: Schistosomes can cause changes in the bladder cells, leading to bladder cancer.
– Kidney damage: Schistosomes can cause scarring and blockages in the kidneys, leading to kidney failure.
– Severe anemia: Schistosomes can damage red blood cells, leading to severe anemia.
– Damage to liver and spleen: Schistosomes can cause scarring in the liver and spleen.
– Lung symptoms: Some people infected with schistosomes may develop symptoms similar to those of tuberculosis (TB), including chest pain, coughing up blood, fever, weight loss, breathlessness, and fatigue.
Problems during pregnancy:
If a woman is infected with schistosomes when pregnant, the parasites can travel through the placenta to infect her unborn baby. If this happens, it can lead to severe complications for both mother and child. For example, if the parasites infect the baby’s lungs shortly before or after birth, this could cause respiratory distress leading to pneumonia or fluid in the lungs (pleural effusion).
Prevention of schistosomiasis:
There is no vaccine available to prevent schistosomiasis. However, several things can be done to reduce the risk of infection:
– Avoid contact with freshwater where Schistosoma larvae may be present, for example, by not swimming or wading in lakes, rivers, or other bodies of freshwater.
– If you do come into contact with fresh water, avoid submerging your entire body and try to keep your head and shoulders above the water.
– Wear shoes and clothes that cover as much skin as possible when visiting areas where schistosomiasis is common.
– Use insect repellent to reduce the risk of getting schistosomiasis from an infected mosquito bite.
– Avoid eating raw food, predominantly plants, washed in contaminated water, or drinking untreated freshwater.
– Only drink treated or bottled water. Water purification tablets can also make untreated water safe to drink.
Treatment of schistosomiasis:
The treatment of schistosomiasis is with praziquantel. The medication kills the worms but must be taken several times in a short time and then at regular intervals to ensure that all the parasites are killed and that they do not return.
People often take this drug during periods of heavy rainfall when there is a greater risk of contact with the parasite. The drug does not have any lasting effects on the body, so there are no serious long-term side effects after taking it.
– an antihelminthic with a mechanism of action similar to that of thiabendazole. It is available in tablet form for oral administration or in solution for direct application to the skin. The recommended dose is usually 40 mg/kg single dose repeated once at four weeks or 400mg/m2 up to a maximum of 2g daily for three days in children over six years and adults.
According to the Centers for Disease Control and Prevention, there are no significant side effects. People who take praziquantel sometimes experience mild gastrointestinal problems such as vomiting or diarrhea. Praziquantel can also cause low blood calcium levels, an infrequent side effect.
Praziquantel has been associated with a higher rate of reinfection than albendazole; however, this may reflect differences in compliance and drug adherence rather than efficacy.
Salvage therapy:
If praziquantel is given within 2–4 months after metacercariae entered the body, it prevents further damage to the liver, and it would be possible to recover from anemia.
Salvage therapy is contraindicated if more than four months elapsed after infection since it will not help in treating liver damage already done by the parasites.
Schistosomiasis (also known as bilharzia, bilharziosis, or snail fever) is a parasitic disease caused by trematode worms of the Schistosoma type. The eggs of these worms are deposited on aquatic plants and animals such as freshwater snails, where they hatch into larvae that infect certain species of freshwater snail that live in water bodies such as ponds and streams.
The larvae develop into free-swimming, an infective stage called cercariae, which seeks out and penetrates human skin upon contact to enter the bloodstream. Typically cercariae do not invade the body themselves. Still, instead, they release a specific chemical that triggers nearby cells of the skin to release a larva into the skin in a process called escheatment.
The larva then matures into an adult worm that lives in blood vessels or the intestines. Other species of schistosome cause disease in other vertebrates, including birds.
The male and female worms mate in the veins of the mesentery. The male worm dies after mating, but females can survive for many years by producing eggs carried through the bloodstream to the liver, where they are processed and destroyed. Some pass through the liver to form cysts in other organs such as the lung, brain, bladder, etc.;
this is called extra-hepatic schistosomiasis. If left untreated, both types of infections may lead to severe damage to the internal organs over time, sometimes resulting in death. Symptoms include fever, chills, cough, wheezing, blood in the stool or urine, and liver or spleen enlargement.
Symptoms of schistosomiasis in the brain:
headache, muscle weakness, seizures, problems with balance and walking, changes in mood or behavior, swelling around the brain (cerebral edema), coma.
There is no vaccine currently available for schistosomiasis.
Treatment of schistosomiasis involves taking an antihelminthic drug such as praziquantel to kill adult worms. Treatment must be repeated regularly, typically every 2–4 weeks for several months, to ensure that all the parasites are killed and that they do not return.
People often take this drug during periods of heavy rainfall when there is a greater risk of contact with the parasite. However, the drug does not have lasting effects on the body and cannot prevent reinfection.
Praziquantel is the drug of choice for the treatment of schistosomiasis. It is a safe and effective drug used in both children and adults. It is typically given as a single dose, and most people experience few side effects. These include nausea, vomiting, or diarrhea. Praziquantel can also cause low blood calcium levels, an infrequent side effect.
Praziquantel has been associated with a higher rate of reinfection than albendazole; however, this may reflect differences in compliance and drug adherence rather than efficacy.
Schistosomiasis mode of transmission:
1. people can get infected through recreational activities such as swimming or washing in contaminated water;
2. inadequate disposal of human feces, which can contaminate the water source;
3. living near unsafe water sources such as shallow, stagnant ponds where snails are abundant.
4. poor sanitation and lack of piped water supply to homes increase exposure to schistosome eggs in the environment through contamination with feces or urine from an infected person or pet animal.
5. use of unscreened or improperly treated water for drinking, cooking, or washing hands also increases the risk of infection;
6. people in close contact with infected people (such as family members and sexual partners) are at increased risk of getting the disease.
7. some animals such as dogs and cats can become infected by eating infected freshwater snails and pass the infection on to humans.
8. there is no vaccine currently available for schistosomiasis.
9. treatment of schistosomiasis involves taking an antihelminthic drug such as praziquantel to kill adult worms. Treatment must be repeated regularly, typically every 2–4 weeks for several months, to ensure that all the parasites are killed and that they do not return.
10. people often take this drug during periods of heavy rainfall when there is a greater risk of contact with the parasite. However, the drug does not have lasting effects on the body and cannot prevent reinfection.
11. praziquantel is the drug of choice for the treatment of schistosomiasis. It is a safe and effective drug used in both children and adults. It is typically given as a single dose, and most people experience few side effects. These include nausea, vomiting, or diarrhea. Praziquantel can also cause low blood calcium levels, a scarce side effect.
12. praziquantel has been associated with a higher rate of reinfection than albendazole; however, this may reflect differences in compliance and drug adherence rather than efficacy.
Schistosomiasis is estimated to affect 207 million people worldwide. It mainly occurs in tropical and subtropical areas – especially sub-Saharan Africa – the Caribbean, Brazil, Venezuela, and Central America.
However, it can also occur along the Nile River and in the Arabian Peninsula, Afghanistan, Pakistan, Iran, India (Andhra Pradesh), Thailand, and other East Asian countries such as Laos and Vietnam.
Pathophysiology of schistosomiasis:
Schistosomiasis infections are acquired by penetration of free-swimming larvae called cercariae released from infected freshwater snails. When the parasites penetrate the skin, they travel through blood vessels to reach organs like the liver, lungs, intestines, and bladder.
These locations are known as “paratenic hosts” because these schistosomes do not mature into adults there. However, male and female worms pair up and mate once they have reached their destination organ. As a result, females continue to grow larger than males.
The females lay eggs that pass out of the body with urine or feces to fertilize freshwater snails, where their embryonic cycle begins again via miracidia. The life cycle is completed when new cercariae are released from infected snails and penetrate the skin of another human.