Schistosomiasis (also referred to as bilharzia or snail fever) is the result of infection by blood fluke (trematode worm) of the Schistosoma species.
Schistosomiasis is very common, affecting over 200 million people, with the vast majority (85%) in Africa. It is prevalent in tropical and subtropical areas, especially in rural regions 1,2.
There are five species of the blood fluke (trematode worm) Schistosoma species that cause disease in humans 1:
- Schistosoma haematobium
- S. mansoni
- S. japononicum
- S. intercalatum
- S. mekongi
Larvae are released from snails (intermediate host) into water and penetrate human skin (definitive host) exposed to the infected water. These larvae travel to the lungs (pulmonary schistosomiasis) and liver of the human host, where they reside until they mature. After maturation, the adult worm invades the bloodstream and deposited in local tissues, invoking a granulomatous response.
Schistosomiasis can manifest in a number of ways 3,4:
- schistosomiasis dermatitis (swimmer's itch)
- acute schistosomiasis (Katayama fever)
- chronic schistosomiasis
History and etymology
In 1851, Theodor Bilharz (1825-1862), a German physician, described Schistosoma haematobium 5, thus the alternative name 'bilharzia'. Katsurada, in 1904, recognized Schistosoma japonicum 5. In 1907, Sambon separated Schistosoma mansoni from Schistosoma haematobium 5.
- 1. Ferri FF. Ferri's Clinical Advisor 2016: 5 Books in 1 (Ferri's Medical Solutions). Saunders. ISBN:B00Z5KE8T4. Read it at Google Books - Find it at Amazon
- 2. Hotez P et-al. Manson's Tropical Diseases. Saunders Ltd. ISBN:0702051012. Read it at Google Books - Find it at Amazon
- 3. Warrell D, Cox TM, Firth J et-al. Oxford Textbook of Medicine: Infection (Oxford Textbooks In Public Health). OUP Oxford. ISBN:B009GHONOW. Read it at Google Books - Find it at Amazon
- 4. Goldman L, Schafer AI. Goldman's Cecil Medicine: Expert Consult Premium Edition - Enhanced Online Features and Print, Single Volume. Saunders. ISBN:1437716040. Read it at Google Books - Find it at Amazon
- 5. Silva LC, Maciel PE, Ribas JG, Pereira SR, Serufo JC, Andrade LM, Antunes CM, Lambertucci JR. [Schistosomal myeloradiculopathy]. (2004) Revista da Sociedade Brasileira de Medicina Tropical. 37 (3): 261-72. doi:10.1590/s0037-86822004000300013 - Pubmed