Umm Al-Qura University بسم الله الرحمن الرحيم Umm Al-Qura University Health Sciences College at Al-Leith Department of Public Health Lecture (13)

Schistosoma

Objectives 1/ Know of Schistosoma parasites classification and Geographical distribution. 2/ Study of Schistosoma parasites External Morphology , Habitat, Life cycle, Mode of Transmission, Pathogenicity. 3/ Show Symptoms of Schistosomiasis disease. 4/ Show Laboratory diagnosis of Schistosoma parasites. 5/ Know of Treatment and prevention.

Schistosoma haematobium Schistosoma japonicum بلهارسيا المجاري البولية بلهارسيا المستقيم Schistosoma mansoni بلهارسيا المجاري البولية

Schistosoma Male & Female

1- A genus of Trematodes, Schistosoma, commonly known as blood-fluke, are parasitic flatworms responsible for a highly significant group of infections in humans termed schistosomiasis. 2- Schistosomiasis is considered by the World Health Organization as the second most socioeconomically devastating parasitic disease, (after malaria), with hundreds of millions infected in a worldwide.

Distribution

Causal Agents: Schistosomiasis is caused by digenetic blood trematodes. The three main species infecting humans are Schistosoma haematobium, S. japonicum, and S. mansoni., can cause cercarial dermatitis in humans

1- schistosomiasis is the being a major source of morbidity and mortality for developing countries in Africa, South America, the Caribbean, the Middle East, and Asia. 2- More than 207 million people, 85% of who live in Africa, are infected with schistosomiasis and an estimated 700 million people are at risk of infection in 76 countries where the disease is considered endemic, as their agricultural work, and recreational activities expose them to infested water.

3- Globally, 200,000 deaths are attributed to schistosomiasis annually 4- Transmission is interrupted in some countries

Snail hosts The different species of Schistosoma have different types of snails serving as their intermediate hosts; these hosts are as follows: 1- Biomphalaria for S. Mansoniقوقع بلهارسيا المجاري البولية)). 2- Oncomelania for S. japonicum. 3- Bulinus for S. haematobium. قوقع بلهارسيا المستقيم)

Biomphalaria snails

Bulinus snails

Oncomelania snails

Life cycle

Life cycle

Mansoni egg

Heamatobium egg

cercaria

cercaria

Life cycle

Symptoms Symptoms of schistosomiasis are caused by the body’s reaction to the worms’ eggs. Intestinal schistosomiasis 1- abdominal pain, 2- diarrhoea 3- and blood in the stool. 4- Liver enlargement is common in advanced cases, and is frequently associated with an accumulation of fluid in the peritoneal cavity and hypertension of the abdominal blood vessels. In such cases there may also be enlargement of the spleen.

The classic sign of urogenital schistosomiasis is: 1-haematuria (blood in urine). 2- Fibrosis of the bladder and ureter, 3- and kidney damage. 4- Bladder cancer.

5- In women, urogenital schistosomiasis may present with genital lesions, vaginal bleeding, pain during sexual intercourse and nodules in the vulva. 6- In men, urogenital schistosomiasis can induce pathology of the seminal vesicles, prostate and other organs. This disease may also have other long-term irreversible consequences, including infertility.

Diagnosis 1- Schistosomiasis is diagnosed through the detection of parasite eggs in stool or urine specimens. 2- Antibodies and/or antigens detected in blood or urine samples are also indications of infection.

Treatment Safe and effective medication is available for treatment of both urinary and intestinal schistosomiasis. Praziquantel, a prescription medication, is taken for 1-2 days to treat infections caused by all Schistosoma species.

Prevention and Control 1- Drink safe water. 2- Avoid swimming in freshwater when you are in countries in which schistosomiasis occurs. 3- Chemicals used to eliminate snails in freshwater sources.

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