SCHISTOSOMIASIS Flashcards
Caused by some species of blood flukes in the genus Schistosoma.
Schistosomiasis
Schistosomiasis is also known as
- Bilharziasis
- Snail fever
- Katayama fever
Transmitted by a tiny snail in Schistosomiasis
Oncomelania quadrasi
Schistosomiasis: Infective stage/terminal larval stage that emerge from an infected snail host
Cercaria
Free-swimming ciliated larval stage on which a parasitic fluke passes from egg to its first host, typically a snail
Miracidium (egg hatches in 3-4 days)
Schistosomiasis is caused by blood flukes of 3 types
- Schistosoma mansoni- infects GI tract
- Schistosoma japonicum- endemic in the Philippines
- Schistosoma haematobium- infects GU tract
Schistosomiasis Incubation period
2-6 weeks after exposure
Schistosomiasis Mode of transmission
bathing, swimming, wading, or washing in contaminated water
Schistosomiasis EARLY S/SX
IFDBA
- Initially – transient pruritic rash
- Fever
- DIARRHEA
- BLOODY STOOLS
- Abdominal pain (liver/spleen area)
Schistosomiasis LATE SIGNS
H, A, S, L, E/A (HASSLE)
H- hepatomegaly
A- anemia (liver is affected)
S- splenomegaly
L- lymphadenopathy/ lymphadenitis
E/A- enlargement of abdomen
Schistosomiasis Dx exam
KATO KATZ METHOD/ FECAL SMEARS (STOOL EXAM)
Schistosomiasis DRUGS OF CHOICE
PRAZIQUANTEL (BILTRICIDE) - all species: six months treatment (ALTERNATIVE DRUG: ALBENDAZOLE)
- Oxamniquine – S. Mansoni
- Metrifonate – S Haematobium
Schistosomiasis PATHOGENESIS
- The larvae are released from infected snails into freshwater
- Humans become infected when they come into contact with contaminated water
- Larvae penetrate the skin
- Migrate through the bloodstream to reach the liver, where they mature into adult worms
- Male and female worms’
pair and produce eggs - Eggs are released into the bloodstream
- The eggs travel to various
organs, where they can become lodged in the tissues - Immune response and inflammation
- Abdominal pain; pruritus; fever; diarrhea; fatigue; bloody stools.
