Introduction
Schistosomiasis infections are seen in most parts of the world, contributing to morbidity and mortality. It is common in African countries, and the infection with Schistosoma haematobium causes squamous cell carcinoma and urothelial carcinoma of the urinary bladder. It is also responsible for female genital schistosomiasis, which causes infertility, and the patient is prone to acquiring the human immunodeficiency virus (HIV). However, there is less evidence on the pathogenesis of the virus as to how it causes cancer. Studies conducted have discussed the possible reasons. Therefore, treatment mainly focuses on a preventive form that involves preventive chemotherapy.
What Is the Mode of Transmission of Schistosoma Haematobium?
Infection occurs when contact with the skin through an infected water source. The infection occurs when the freshwater snails release larval forms of the parasite. Transmission occurs when an infected person contaminates a freshwater body through excreta which contains parasite eggs. These eggs hatch and penetrate the human body through the skin. The larvae develop inside the body to form adult schistosomes, the adult worms thrive in the blood vessels, and the females lay their eggs there. The parasite's life cycle continues by passing down a few eggs through urine or feces. The trapped eggs create an immune reaction inside the body leading to organ damage.
What Are the Symptoms of Urogenital Schistosomiasis?
The symptoms are caused by the body's immune reaction due to parasite eggs leading to inflammation, parenchymal tissue destruction, and granulomata. The typical symptom of urogenital schistosomiasis is hematuria (blood in urine). Fibrosis (a condition with thickening or scarring of the tissues) and fibrotic nodules called sandy patches are seen in the bladder and ureter. Advanced cases lead to kidney damage. Women experience vaginal bleeding, pain during sexual intercourse, genital lesions, and nodules in the vulva. In men, there may be long-term irreversible consequences, including infertility. Pathological changes may be seen in the prostate, seminal vesicles, and other organs.
What Is the Diagnosis of Urogenital Schistosomiasis?
The common investigation involves stool and urine tests, where they are examined for larvae or eggs of Schistosoma haematobium. The urine and stool samples are also examined for antibodies or antigens, which is a sign of active infection. The standard diagnostic tests involve a filtering technique that uses nylon, polycarbonate, or paper filters. In addition, chemical reagent strips are used in children who are infected by Schistosoma haematobium, which helps in the detection of microscopic blood in their urine. Serological and immunological tests may be used in low transmission or non-endemic areas which help in exposure, treatment, and follow-up.
Urogenital Schistosomiasis and Bladder Cancer:
The bladder undergoes morphological and molecular level changes when infected by Schistosoma haematobium. The females produce around three thousand eggs, and the remaining eggs cause lesions that lead to inflammation of the ureters and bladder. More than 50 % of cases show hematuria, organ deformities like narrowing down of ureters, hydronephrosis (swelling of one or both kidneys due to blockage), urinary tract and renal infections, and renal failure. Out of these, bladder cancer is a frequent complication in chronic urogenital schistosomiasis.
Studies have shown that different levels of host proteins, such as COX2, iNOS, EGFR, and TGFα, are markers for bladder cancer. The incidence is higher in the younger age group, which presents as well-differentiated squamous cell carcinoma and has a poor prognosis. The frequency and severity of chronic urogenital schistosomiasis depend on the duration and intensity of the infection. Carcinomas associated with urogenital schistosomiasis show cytological changes, genetic alterations, and chromosomal aberrations, and nitroso compounds have been used as etiologic agents.
Biomarkers Candidates for Bladder Cancer:
Biomarkers help in the early detection of malignancy and can help in providing a good prognosis. Promising candidates include estrogen-like and 8-oxodG-related metabolites. The malignant lesions found were related to both squamous cell carcinoma and urothelial cell carcinoma. Studies have shown that urogenital schistosomiasis is a risk factor for squamous cell carcinoma but not urothelial cell carcinoma. There were estrogen-like metabolites and DNA adducts in urogenital schistosomiasis-associated bladder cancer.
Urine Proteome in Urogenital Schistosomiasis:
Purified urine proteins analyzed by GeLC-MS/MS (mass spectrometric), which is separated by sodium dodecyl sulfate precast polyacrylamide gel electrophoresis, showed Th-2 type immune response in urogenital schistosomiasis samples. Proteins involved in inflammation and negative regulation of endopeptidase activity were seen in urogenital schistosomiasis-related bladder cancer. Proteins were seen in association with tumor growth, metastasis, metabolisms, cell adhesion, and immune response in cases of the bladder without infection.
How Can It Be Prevented and Controlled?
Based mainly on:
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Large-scale treatment of population at risk.
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Snail control.
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Access to clean water.
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Improved sanitation.
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Education on hygiene.
The world health organization (WHO) has provided a strategy for the large-scale population through preventive chemotherapy. Preventive chemotherapy involves the administration of the drug Praziquantel through periodic and targeted treatment of the affected populations.
Groups to be focused on:
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The age group of children attending preschool.
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School-going children in endemic areas.
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Adults in contact with risk factors such as fishermen, farmers, irrigation workers, or any other work that involves coming in contact with the infested water.
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Communities living close to endemic areas.
In areas with high transmission, frequent monitoring is essential preventive therapy may have to be repeated yearly. The frequency of infection in school-going children depends on the prevalence.
What Is the Treatment of Urogenital Schistosomiasis?
Praziquantel is used for the treatment of urogenital schistosomiasis. It is safe and cost-effective. There are chances of reinfection, but the severity is comparatively low and does not lead to complications. The disease can be easily treated and reversed. The principle is to reduce morbidity and mortality, and periodic treatments will cure mild undetectable symptoms and prevent previously infected people from developing severe complications.
Conclusion
Urogenital schistosomiasis is caused by Schistosoma haematobium, which drains the pelvic organs, bladder, uterus, and cervix veins. It is common in African countries, and the infection with Schistosoma haematobium causes squamous cell carcinoma and urothelial carcinoma of the urinary bladder. The standard diagnostic tests involve a filtering technique that uses nylon, polycarbonate, or paper filters. In addition, praziquantel is used for the treatment of urogenital schistosomiasis.
