SchistosomiasiSchistosomiasiss
Dept. Of Infectious Disease
Shengjing Hospital
IntroductionIntroduction
Schitosoma japonicum inhabits in the portal v
enous system
Skin contact with water contaminated by cerc
aria
The basic pathologic lesion is the egg granul
oma in the liver and colon
IntroductionIntroduction Acute schitosomiasis:fever,enlargement and ten
derness of the liver,eosinophilia,and dysentery
Chronic schitosomiasis : fibro-obstructive lesion
around the portal vessels
Late stage: giant spleen, ascites, hypertension o
f portal venous system
EtiologyEtiology
Mature worms: Dioecious
Female :long and thin.
Male:short and thick
Eggs: miracidia in it
Life cycleLife cycle
adult worm passing eggs egg into fresh water cercariae miracidia
penetrate into the body of the snail (intermediate host) oncomelania
EpidemiologyEpidemiology
Source of infection: humans and mamm
als (especially cattle) infected by schistoso
me
Route of transmission: three major factor
s* are responsible for the occurrence of sc
histosomiasis
Susceptibility : everyone is susceptive. E
specially peasant and fisherman
Three Major FactorsThree Major Factors
The method of disposal of human
excreta
The presence of the snail intermed
iate host
The contact with cercaria-infected
water
PathogenesisPathogenesis
It belong to a kind of allergic reaction(ra
pid & delayed)
Formation of granuloma produced by e
ggs (Hoeplli sign)
Concomitant immunity
Ectopic lesion (lung & brain)
PathologyPathology
Colon: acute -mucosa congestion, edema and egg granuloma chronic-fibro obstructive lesion Liver: acute -enlargement of the liver and egg granuloma on it chronic-portal liver cirrhosis Other organs: lung and brain, etc Systemic symptoms:
Clinical ManifestationsClinical Manifestations
Acute SchistosomiasisAcute Schistosomiasis
Mainly occurs during July to SeptemberThe history of contact with schistosome-inf
ected water.Schistosome dermatitis Incubation period: 23-73 days, average 1
month
Acute SchistosomiasisAcute Schistosomiasis Clinical manifestations come out after 4 to 8 weeks
of infection, similar to the time from egg to adult wor
m (40 days)
Fever: intermittent, maintain weeks to months
Allergic reaction:urticaria, angioneuroedema, enla
rgement of lymph nodes and eosinophilia
Digestive syndromes: abdominal pain, diarrhea wi
th pus and blood, constipation or diarrhea
Hepatosplenomegaly
Chronic SchistosomiasisChronic Schistosomiasis
Asymptomatic: most person are asympto
matic
Symptomatic: the most common syndrom
e is abdominal pain with intermittent diarrhe
a.
hepatosplenomegaly
Terminal stage of schistosomTerminal stage of schistosomiasisiasisLiver cirrhosis is the prominent syndrome of t
his stage
According to the manifestations , it can be div
ided into three types:
The type of giant spleen
The type of ascites
The type of dwarf
Ectopic Lesion Ectopic Lesion Schistosomiasis in lungs:
found in acute schistosomiasis, by egg depo
sition. Symptoms are light and signs are not c
lear
Schistosomiasis in brain:
Acute type: encephalomeningitis
Chronic type: focal epilepsy
Laboratory FindingsLaboratory Findings
Blood Routine TestBlood Routine Test
Acute stage :eosinophilia is characteristic ch
ange.WBC raise to 10-30G/L
Chronic stage:eosinophil slightly or moderat
e rise
Terminal stage: WBC and platelets are lowe
r
Liver Function TestLiver Function Test
Acute stage: serum globulin rise, ALT
slightly rise
Chronic stage: most patients have a normal
liver function, especially asymptomatic
Terminal stage: serum ALB descend caused
by liver cirrhosis
Stool Test Stool Test
The discovery of eggs in stool is the evidence of
diagnosis by direct smear or other methods
Imaging test B-ultrasound: the degree of liver cirrhosis
CT: the image of liver and brain
X-ray: chest; esophagus; and gastrointestinal
tract
Biopsy by Rectal Biopsy by Rectal EndoscopeEndoscope
Immunological Test Intracutaneous test
Circumoval precipition test
ELISA and IHA etc.
Monoclonal antibody technique
ComplicationsComplications
Complications of Liver Complications of Liver CirrhosisCirrhosis
Varicosity of esophagus-fundus-stomach
Hemorrhage of upper gastrointestinal tract
Hepatic encephalopathy (HE)Spontaneous bacteria peritonitis (SBP)
Complications of intestinal tract
Appendicitis
Intestinal obstruction and cancroid change
DiagnosisDiagnosis
Epidemiologic date: occupation, history of travel to endemic area, contact with infected water
Clinical date:
Acute stage; chronic stage; terminal stageLaboratory findings:
Blood Rt; characteristic eggs in feces; biopsy; positive immunological test
Differential DiagnosisDifferential Diagnosis
Acute schistosomiasis: typhoid fever; amebic liv
er abscess; tubercular peritonitis; miliary tuberc
ulosis; bacillary dysentery; malaria;etc. etiology
test and X-ray of chest are diagnostic.
Chronic schistosomiasis:anicteric viral hepatitis;
amebic dysentery; chronic bacillary dysentery;
Terminal schistosomiasis: portal liver cirrhosis a
nd necrosis liver cirrhosis
PrognosisPrognosis
Factors affect the prognosis:
The continuance of infection
The last of pathogenesis
The age of the patients
The complications
TreatmentTreatment
Pathogenic Treatment Praziquantel is the best choice of drug for the th
erapy of schistosomiasis Dose:
chronic schistosomiasis
10mg/kg, tid. Po, for 2 days, total 60mg/kg
Acute schistosomiasis
10mg/kg,tid. po,for 4 days, total 120mg/kg Vice reaction: slight and short.
TreatmentTreatment
Heteropathy
Acute schistosomiasis: rest, nutrition, and s
upportive theraphy. Cortical hormone can be
used in minidose for severe toxic symptoms.
Terminal schistosomiasis: treated as liver c
irrhosis, and treat for complications
PreventionPrevention
Control of the source of infection:
Treat the patients and domestic animal at the same time.
Cut off the route of transmission:
Snail control
Sanitary disposal of human excretaProtect of susceptive people:avoid the cont
act with schistosome-infected water