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