Systemic

The patient may initially complain of abdominal pain, diarrhea or dysentery and fever. Blood tests may reveal eosinophilia. He may also complain of fatigue, lethargy and skin sores and itching.

CNS

Neurological involvement may present with headaches, nausea, paresthesia, seizures, signs of muscle weakness and paraplegia.

Genitourinary

If the genital involvement is present, genital sores and ulceration may occur. Females may suffer with post coital bleeding and irregular menstruation. If the infection has spread to the bladder or urinary tract, cystitis, urethritis and glomerulonephritis may be present. In these cases, the patient may complain of pelvic pain, hematuria, dysuria, urinary frequency, etc.

Work up includes a physical exam and a detailed history, which my reveal any recent or old history of swimming, camping, travelling to any endemic area, etc.

Laboratory Tests

• Complete blood count
• PCR
• Serology
• Antigen tests: A reagent strip using monoclonal antibodies to detect somatic schistosome antigens in urine has a sensitivity of more than 85% and is suitable for use in the field [9]. 
• Urine and stool analysis
• LFTs
• Kidney function tests

Imaging Studies

• X-ray abdomen
• Ultrasound
• Urography
• Intravenous pyelography
• CT Scan
• Endoscopy (for varices)

Test Results

Test results may confirm the presence of eggs or adult worms wherever present and also the degree of damage they have done.

Once diagnosis has ben made and confirmed by appropriate tests, treatment is immediately begun. Praziquantel is the treatment of choice for all three species (of the worm) [3].

Praziquantel can be used in pregnant and lactating women [10]. In schistosomiasis with neurological involvement, glucocorticoids and anticonvulsants may be added if needed.

In cases of acute schistosomiasis if the patient is treated quickly with antihelminthics, prognosis is very good. All of the complications of the disease can be avoided. But, if the disease has progressed to chronic state, many systems may get involved and prognosis becomes less positive.

It should be noted that even in chronic state, however, with a continued treatment of 3-6 months to even years, many systemic manifestations of the disease may significantly improve. Renal and intestinal pathology also improves with treatment as, usually, do brain lesions (depending upon their location and size) [6].

Most of the mortality comes from hepatic cirrhosis, caused by S.mansoni in Latin America, Africa and the Middle East, and S.japonicum and S.mekongi in East Asia [7]

Complications

Complications of schistosomiasis are widespread. They can be divided systemically:

Gastrointestinal

• Obstruction and/or bleeding
• Cancer of liver or gall bladder
• Malnutrition
• Hepatic schistosomiasis- the second most common cause of esophageal varices [8].

Renal

• Hematuria
• Kidney failure 
• Pyelonephritis

Neurological

• Paralysis
• Transverse myelitis

Urogenital

• Spontaneous abortions
• Bladder cancer
• Hemospermia
• Infertility

Systemic

• Portal hypertension
• Anemia
• Sepsis

Schistosomiasis is an infection caused by Schistosoma species which are worms belonging to phylum Platyhelminthes. These trematodes are second only to malarial parasites as far as endemics are concerned.
                                                          
The life cycle of these worms involves an asexual cycle that occurs in freshwater snails, which serve as the intermediate host to the parasites. The sexual cycle occurs in humans, who serve as their definitive hosts.

The free-swimming young, known as the Cerceria (pl: cercariae), may enter the human host by penetration through the skin. Once they enter, they may move to the gut, vessels, liver, or anywhere else in the body, and the sexual cycle begins.

The cercariae then differentiate into the larva, enter the blood circulation, reach and settle into an organ and mature into adult forms. By now, symptoms may not appear.

The eggs laid by the schistosoma adult females penetrate through gut or bladder wall and colonise there. At this stage, symptoms usually appear.

When the eggs pass out through urine or stool and enter fresh water again, they may hatch, penetrate into the snails (intermediate host) and the asexual cycle begins again.

Types

There are five medically important species of Schistosoma. These are:

• S.mansoni
• S.japonicum
• S.intercalatum
• S.mekongi
• S.haematobium

Schistosoma mansoni, Schistosoma japonicum and mekongi affect the gastrointestinal tract, whereas Schistosoma haematobium affects the urinary tract [3].

Incidence

It affects almost 210 million people worldwide [1]. Around 200,000 people die of this disease every year.

Age

Studies reveal that although this disease may occur at any age, infants and children are at higher risk because of a less developed immune system. Congenital infection has been defined; Shistosomiasis has been detected in the placenta and newborns have been diagnosed with the disease, thus confirming congenital infection [2].

Sex

Mainly due to increased exposure to potential sources of the worm, males are at a greater risk of contracting this disease.

Schistosomiasis develops when the the worms start to reproduce and multiply. Eggs penetrate the vascular endothelium and travel via the blood to various organs, most commonly affected are the gut, liver and urinary bladder.

Once settled, the parasites cause damage and widespread eosinophilia occurs. The damage is due both to digestion of tissue by proteolytic enzymes produced by the egg and to the host inflammatory response that forms granulomas in the venules [3]. In the acute phase, symptoms are relatively mild. But if the infection progresses to chronic stage, granulomas formation and fibrotic changes occur.

Local tissue invasion of eggs brings about the release of toxins and enzymes and provokes a TH-2 mediated response [4]. The immune response to S.mansoni and S.japonicum eggs in the liver causes the severe pathology of schistosomiasis [5].

Schistosomiasis can be prevented by taking certain precautionary measures such as avoiding swimming, bathing or drinking directly from fresh water in endemic areas. Human waste should be properly eradicated and sprays and other insecticides should be used to kill the snail hosts wherever possible.

Schistosomiasis is the name of an infection caused by parasitic worms of the genus Schistosoma. It is also called Bilharzia, Katamaya Syndrome and Snail Fever. These worms may enter a person's body through contaminated water which is filled with Schistosoma species that are excreted into the water by infected snails, hence the name Snail Fever.

Once the parasitic worms have entered the body, they may cause an infection that presents with varying signs and symptoms, most common of which are diarrhoea, fever and abdominal pain. In some cases, patients may present with skin, genital or neurological symptoms as well.

Schistosomiasis is a very common infection by parasitic worms that live in freshwater, particularly in endemic areas like Africa and some parts of Latin America and Asia. The disease may begin with fever and bowel disturbances but may progress to liver and kidney damage, genital ulceration, skin infections and even neurological problems.

If you live in or have traveled to an endemic area and may have come in direct contact with fresh water there, and suddenly developed any of the symptoms mentioned above, it is recommended that you should visit a doctor immediately to get tested for schistosomiasis.

1. Fenwick A. The Global Burden of Neglected Tropical Diseases. Public Health 2012 126(3):233-6. 
2. Nour NM. Schistosomiasis: Health effects on women. Reviews in obstetrics and gynaecology. 2010;3:28-32
3. Warren L. Michael W, Harriet L, eds. Review of Medical Microbiology and Immunology. 11th edition. Chap.55 358-60
4. Coutinho HM, Acosta LP, Wu HW, et al. Th2 cytokines are associates with persistent hepatic fibrosis in human Schistosoma japonicum infection. J Infect Dis. Jan 15, 2007. 195(2);288-95 
5. Pearce EJ, MacDonald AS: The immune biology of schistosomiasis. Nat Rev Immunol 2:499, 2002
6. Vennervald BJ, Dunne DW. Morbidity in schistosomiasis:an update. Cur Opin Infect Dis. Oct 2004: 17(5);439-47 
7. Ross AG et al.: Schistosomiasis. N Engl J Med 346:1212, 2002 p.771.
8. Robbin and Cotran Pathological Basis of Disease. 8th edition. 2004 p.247
9. Ten Hove RJ, Verweij JJ, Vereecken K, et al. Multiplex real time PCR for the detection and quantification of S.mansomi and S.haematobium infection in stool samples collected in Northern Senegal. Trans R Soc Trop Med Hyg. 2008;102:179
10. Olds GR. Administration of praziquantel to pregnant and lactating women. Acta Trop, May 2003:86:(2-3):185-95