​Infectious Diseases and Microbiology - Schistosomiasis​( Schistosoma mansoni)

​Infectious Diseases and Microbiology - Schistosomiasis
​( Schistosoma mansoni) 
Schistosomiasis is a parasitic disease.
 Schistosoma mansoni is a nonsegmented flatworm or fluke belonging to the Trematode class which causes schistosomiasis.
There are three prevalent species of human schistosomes: S mansoni, S japonicum, and S haematobium.
Snails serve as intermediary hosts. Humans are the ultimate hosts. Cercariae enter the human skin, mature into adults, and deposit eggs that are excreted in urine (haematobium) or stool (mansoni and japonicum). 

The regions where the disease is commonly found are Africa, South America, the Middle East, the West Indies, and Puerto Rico for S. mansoni; China, Japan, and the Philippines for S. japonicum; and Africa, the Middle East, and India for S. haematobium. Swimmer's itch occurs when cercariae from avian and mammalian species of Schistosoma penetrate the skin.

 Following the entrance of cercariae into the skin, a temporary rash characterized by itching and the presence of little raised bumps may develop. Acute symptoms consist of elevated body temperature and shivering. The prevalence of chronic diseases in adults varies depending on their geographical region. Schistosoma mansoni and Schistosoma japonicum result in abdominal pain, bloody diarrhea, and hepatosplenomegaly. Schistosoma haematobium induces the symptoms of blood in urine, painful urination, and blockage, and is linked to bladder cancer.

 Following the invasion of the skin, the organism infiltrates the bloodstream and then travels to the lungs. Each of the three primary human schistosome parasites resides within a specific region of the venous plexus that drains either the intestines or bladder, depending on the particular species. Specifically, S mansoni inhabits the mesenteric veins of the colon, S japonicum resides in the mesenteric veins of the small bowel and colon, and S haematobium is found in the veins surrounding the bladder and pelvic organs. Additionally, all three parasites are capable of producing eggs. 

The pathogenesis of this condition arises from the immune system's reaction to the eggs, leading to the formation of abscesses, fibrosis, granulomas, and scarring. The eggs secrete hydrolytic enzymes that degrade tissue and facilitate the shedding process.

The presence of eggs in pee or stool is a distinctive trait.
 Praziquantel is an effective therapy option. Prevention entails implementing effective waste management practices, refraining from swimming in freshwater bodies located in regions with a high prevalence of the disease, and eliminating snail populations.

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