Bilharziasis

Generalities
Agent	Fluke worms: schistosoma haemotobium, S. mansoni, S. japonicum, S. intercalatum, S. mekongi
Incubation period	2-6 weeks
Period of transmissibility	- No person to person transmission - Infected human can excrete eggs for years
Reservoir	- Humans, rodents - Intermediate snail hosts: Bulinus (S. Haematobium), Biomphalania (S. Mansoni)
Modes of transmission	- Skin penetration of larvae (cercaviae) in contaminated water - Eggs of schistosoma leave the human body via urine and fees - Eggs hatch in water and liberate larva (miracidia) that penetrate into freshwater snail host (genus Bulinus or genus Biomphalania). Several weeks after, larva (cercariae) emerge from snails and penetrate human skin while swimming, wading, or washing…
Clinical presentation	- Parasite living in mesenteric / vesical veins - Urinary form: Hematuria (S. Haemotobium) - Intestinal/hepatic form: gastro-intestinal symptoms with or without hepato(spleno)megaly - Complications: chronic infection, malignancy
Resources
Case definition	MOPH circular no. 130 (2006)
Forms	- General reporting form - Bilharziasis investigation form
Data	Refer to "Surveillance data" webpage