Schistosomes

• •They have one intermediate host which is the snail (- That’s why they have restricted geographical distribution).

• ** Various animals as dogs, cats, rodents, pigs, horses & goats, serve as reservoirs for S. japonicum, and dogs for S. mekongi.

• They are separate sexes (which is contrary to the other hermaphroditic خنثى trematodes) :

summery

** S. haematobium; Eggs

• large in urine ( in urinary bladder ) with terminal spine at posterior end.

• looks a like the egg of S. intercalatum,,(if u suspect between them , refer to the geographical distribution)

S. japonicum; eggs :

• typically oval or subspherical , with knob (vestigial spine) on side.

• - Differential Diagnose : it’s similar to S. mekongi.

• - S. japonicum eggs are sometimes carried to : (1) CNS , resulting in : headache, disorientation, amnesia & coma. (2) heart , resulting in : arteriolitis & fibrosis → enlargement & failure of Right ventricle.

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ذنيبة أبو

• - There is No vehicle of infection (( Its direct infection )) بدها ما المرض بتسبب نفسها هي يعنيناقل

• it will mature in the liver and became adults in ≈3 weeks , then reach a specific place depend on the type : - it will reach the mesenteric if its (S. mansoni & S. japonicum) - it will reach the bladder venous vessels if its (S. hematobium) where they live & ovulate for Duration of host's life ( they live through out the host life )

Schistosomes

Schistosomes

• ** Pathology :• - clinically , the Penetration of cercariae ( the

initial penetreation if the intact skin ) will result in transient dermatitis (swimmers' itch).

• - Adult worms are innocuous (not harmful) , even that they are coating themselves with host Ags to evade immune responses.

• - ((very important )) Deposition of eggs , is an inducer of pathological changes

Schistosomes

Schistosomes

INTESTINAL FLUKES

• Fasciolopsis buski (Giant intestinal fluke)• - Adult :- Lives attached to small intestinal mucosa of mammalian hosts (humans & pigs).- result in inflammation, ulceration & abscesses.

Fasciolopsis buski

• Eggs :• •Immature eggs are discharged into

intestine, passed in• stool & become embryonated in water.

Fasciolopsis buski

• Human Infection ( or the infective stage infection for human or pigs ) is by ingesting water plants (water chestnuts) contaminated with encysted metacercaria

Fasciolopsis buski

• ** Clinical Picture :- Light infectons: epigastric pain, nausea & diarrhea, esp. in morning.- Heavier infections: generalized edema &

ascites.** Treatment : Praziquantel

** Heterophyes heterophyes (Minute = very small intestinal fluke)

• - linked to fresh/brackish water fish ! ني سمك

Heterophyes heterophyes

• ** Clinical picture :• - Intestinal main symptoms: diarrhea &

colickyمغص abdominal pain.• Treatment : DOC is Praziquantel

** Metagonimus Yokogawai

Liver Flukes

• a. Fasciola hepatica• Mostly, the infection occurs from ingestion of

raw/undercooked watercress• Adult: leaf shaped• - Eggs : in stool , and It is notable that the eggs

are indistinguishable from those of F. Buski

Fasciola hepatica

• snails as the intermediate host would ingest it• here, their sole presence would elicit

hepatomegaly hence tenderness during palpation• * explains the upper quadrant pain• Medication: Praziquantel is not effective like the

case of F. Buski.• we instead Use Triclabendazole ( very

important )

Fasciola hepatica• Halzoun :Among the notable disease from such infection of F. Hepatica.It is a common disease in the Middle East as some people enjoys eating raw livers. These may contain immature flukes of F.Hepatic , which would lead to the disease.the (immature) flukes would attach itself at the pharyngeal mucosa; Dysphagia* Dsypnea* Edema* All pt are presented with Immune-allergic like symptoms in the eye, nose, ears, throat (airway obstruction)

b. Opisthorchis

• The old name is Clonorchis.• - It is of three types: 1. O. Sinensis - a.k.a

Chinese liver flukes.ingested by freshwater fish.• 2. O. Felinus - the word 'feline' refers to cat• 3. O. Viverini - related to dogscholangiosarcoma which is the tumor for connective tissue surrounding bile duct

The proper and effective medication would be Praziquantel

O. Sinensis

Lung Flukes

• A. Paragonimus Westermani• (transmitted by craps • Infects man and ( pigs , dogs).• infection may persist up to 20 years• The adult takes form, size and color of a coffee

bean

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