SCHISTOSOMA JAPONICUM

Prepared by:

MOHD KHAIRUL AMRAN BIN MOHAMMAD

KAMALRU AZMAN BIN DAUD

Bsc. In Medical Laboratory Technology

Faculty Of Health Science

University Teknology Mara (UiTM)

Introduction • Schistosoma japonicum is digenic trematode "digenic" means that its lifecycle includes two hosts : 1-Definitive host 2-Intermediate host

• Intermediate host of S. japonicum are snails of the genus Onchomelania hupensis spp.

• S. japonicum occurs in Southeast Asia and western Pacific countries (including China, the Philipines and Indonesia).

• Apart from humans S. japonicum infect a wide range of animals including cattle, dogs, pigs, and rodents.

Epidemiology

• Schistosomiasis is an important cause of disease in many parts of the world, most commonly in places with poor sanitation.

• School-age children who live in these areas are often most at risk because they tend to spend time swimming or bathing in water containing infectious cercariae.

• S. japonicum occurs in Southeast Asia and western Pacific countries (including China, the Philipines and Indonesia).

Stage of Shistosoma japonicum

i. Egg and miracidiumii. First stage (mother) sporocystiii. Second stage (daughter) sporocystiv. Cercariav. Schistosomulumvi. Adult schistosome

Morphology : egg

Characteristic

Egg

Shape Round to ovoid

Size 40~60 m × 55~80 m

Miracidium Contains one miracidium

Spine Present, small and lateral and often unrecognizable.Inconspicuous

Operculum Present but lack

Cercaria is infective stage

Has a body and a forked tail and has 5 pairs of penetrating glands in the body

Emerges from daughter sporocysts

Escapes from the snail

Infects man by skin penetration

Cercaria

Morphology of adult worm

Male Female

Shape Elongated cylindrical with shorter and thicker & sickle-like

Longer and slender than the male

Size 10-20 x 0.5-0.55mm 12-26x 0.1-0.3mm

Color Gray white The female is much dark.

Organ Oral sucker at top near by ventral sucker.

Has a longitudinal groove-gyncophoral canal in which the female normally resides.

Seven testes are situated one by one, each has a delicate defferens which combine to form the vas deferens and dilate to become a seminal vesical opening in the genital pore just behind ventral sucker

The vitellaria are located in the posterior part of the body surrounding the cecum.

The ovary lies in the mid-portion of the body.

The uterus lies in the anterior portion of the body filled with 50-300 eggs arranged in a single row, arising from ootype to genital pore behind the ventral sucker.

Oral sucker

Esophagus

ventral sucker

Genital pore

Testes

cecum

uterus

Mehlis gland

Ootype

Ovary

Oviduct

Vitelline duct

Intestine

Vitellaria

Gynecophoral canal

Male adult

Female adult Female adult

Different characteristics of Schistosomes

Diagram of the Life Cycle of Schistosoma japonicum

adult (♂ & ♀) in the portal vein system

Eggs passed in feces into

water via intestinal

ulsers

Miracidium hatches from egg swims actively

to penetrate intermediate host (Oncomelania

sneil)

Forming mother sporocysts then produced daughter sporocysts in

snail tissue

Daughter sporocysts

forming cercariae

and escapes

from snail into water

Shistosomolum migrate into portal circulation and mature in the mesenteric veins forming adult Schistosoma japonicum

Cercariae penetrate human skin and leave its tail, forming shistosomolum and first enters the systemic circulation

Pathogenesis• The adult worms do not multiply.• The egg is the main cause of pathology in

schistosomiasis.• The eggs penetrate the blood vessel by secreting

proteolytic enzymes.• Many eggs are stranded in the tissues or are

carried by the blood stream to other organs of the body.

• Location of S. japonicum in the mesenteric veins.• S. japonicum, present mainly in the superior

masenteric vein and its branches.• Pathology produced by S. japonicumis is greater• Some eggs find their way into the lumen of the

bowel and appear in the faeces.

Due to the cercaria and schistosomulum ( adolescent ):

1.The cercarial dermatitis appears.2.Petechiae and rashes ensue. 3.The migration of the adolescents may induce localized

pneumonitis and urticaria.

Due to adults:1.The mechanical effect and toxic effect of adults and

their metabolites cause mesenteric phlebitis, hepatitis, and abdominal pain.

2. The immune complex may cause the damage to the kidney, schistosome nephritis results from type III allergy, the esinophile increase in peripheral blood.

Pathology

Due to eggs:

The most serious damage is done by eggs. 1. Liver cirrhosis (pipestem fibrosis) 2. Splenomegaly3. Ascites 4. Granuloma 5. Ulceration

Clinical manifestations a) Initial phase: i. Fever, ii.Dry cough (pneumonitis), .iii.Urticaria

b) Acute stage: i. Chill and malaise.ii.Dysentery, blood in stool, pus and mucus.

c) Chronic stage: i. Fatigue sand strength deteriorate.ii.Loss of weight and interest.iii.Retardation of both physical and mental growth in

children.iv.Spleen and liver enlargement, anemia, v.In women menopause, sterility and abortion may

occur. vi.This stage may last from several years to 20 years.

d) Terminal stage:

i. Portal vein hypertension syndrome,

ii.Abdomen distention looks like a big drum,

iii.Emaciation looks like a fire wood Ascites,

iv.Varicosity, splenomegaly and anemia.

v.The patients die of secondary infection, upper

digestive tract bleeding, hepatic coma.

e) Ectopic lesion:

i. The damage to the central nervous system

(brain, spinal) may cause paralysis (monoplegia,

hemiplegia ).

Lab diagnosis The symptoms, signs and history of living in

endemic areas only give a presumptive diagnosis. The definitive diagnosis depends on the pathogen examination.

1. Stool examination: - Direct fecal smear for acute stage - Concentration method:

Water sedimentation method and miracidia hatching test can be done at same time.

2. Biopsy can be done by proctoscope for terminal stage.

3. Immunological tests are subsidiary for reference only.

Prevention:• 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

excreta• Protect of susceptive people: Avoid the contact with schistosome-infected water

Treatment:1.Praziquantel is most active against adult worms administered orally form in one or two doses

from 40–60 mg/kg body weight.2.Artemether is prevents the development of adult

worms