Echinococcus granulosus

 Echinococcus granulosus Common name:- Dog tapeworm, the Hydatid worm.Geographical distribution:- World wide, it is most commonly found in thosecountries where sheep and cattle raising constitutes an important industry andthere is close association between man, dog and sheep.Morphology:-) Adult worm 2) Egg 3) Larval form1) Adult werm:- It is a small tapeworm measures 3-6 mm in length. Itcomprises of scolex (head), neck and strobila (Body)a) Scolex:- It bears four suckers and protrusible rostellum with twocircular rows of hooks.باہر نکالن)-b) Neck :- It is short and thick.c) Strobila:- Consisting of 3 segments (4th if present.) the firstsegment is immature second is mature and 3rd and 4th if present aregravid.The terminal segment is biggest, measuring 2-3 mm in length and

Also read :Psora, sycosis, syphilis

2) Eggs:- Shape ovoid.Size:-Length 32-36 umBreadth 25-32 umEgg shell-outer covering is called as egg shell.Oncosphere embryo: is situated centrally hexacanth, embryowith 3 pairs of hooks.> Embryophore:- Is the layer between oncosphere and egg shell.Yolk material is present in between the space of egg shell andembryosphore.> The egg is infective to man, cattle, sheep, and other herbivorousanimals.HookletssatTTakewain factz6→Benia lunglivezINTEgooglEgg yolk.2Embayophote→ oncosphereDEFig:-Egg of cechnicoccusYolk materia.>Larval form:- Found within the hydatid cyst developing insideintermediate host>It represents the structure of the scolex of the future adult worm andremains invaginated within a vascular body.> On entering the definite hos, the scolex with four suckers and ostellarhooklets becomes evaginated and develops into an adult worm.Life cycle: The wom passes its life-cycle into two host,a) Definitive host:- Dog, wolf, fox and jackal. The adult worm livesin the small intestine of these animals who discharges large no. ofeggs in their leaces.Intermediate host:- Sheep, pig cattle, horse, goat and man Thelarval stage is passed in these animals and man giving rise tohydatid cyst-Parascology (HSCHI

Also read :Diseases Caused by Bacteria/Virus/Protozoa

Fig:- Life cycle of ecchnicoccus> The eggs are discharged with the feaces of definitive hostsThese are swallowed by intermediate host sheep, while grazing infield and by man due to intimate handling of infected dogs.In the duodenum, hexacanth embryo are hatched, about 8hrs. afteringestion, the embryo bore their way in intestinal wall and entersradicles of portal vein.The embryo are carried to the liver to be arrested in sinusoidalcapillariesSome of embryos may pass through hepatic capillaries, enters thepulmonary circulation and filters out in lungs.> Few may pass through pulmonary capiliaries and enters intogeneral circulation and lodge in various organs.> Whenever the embryo settles it forms hydatid cyst. The younglarvae being transformed into a hollow bladder.Parasitology (H.S.C) 13> From the inner side of cyst, brood capsule with a no. of scolices adeveloped.A hydatid cyst developed from a single egg contain thousandscolicesA fully developed scolices is an end product and its presence insid> These hydatids when ingested by dog are capable of growing inthe hydatid cyst is a sign of a complete biological developmentadult worm in about 6-7 weeks and cycle is repeated.Life span- of adult worm in canine host is 6 month.Of larval form - many years.Pathogenecity:- Hydatid cyst in manMode of infection:- The eggs in dog facces is ingested by man in. foll. ways.EctocystEndocyst <(Germinallayer)PREinfecting agent:- Eggs in dogs faeces.Portal of entry:- Ailimentary canal.Sites of entry:- Ailmentary canal.→Protoscolex• Hydatid'sFig:- Hydatid.a) By direct contact with infected dogs.b) By allowing the dog to feed from same dish.c) By taking uncooked vegetable contaminated with infected canfacces.Evolution (pathogenesis) of hydatid cyst:-Isand.The cyst wall secreted by embryo consists of 2 layers.-a. Outer circular layer:-(eçtocyst)It is laminated hyaline membrane having thickness upto limm. It appearslike white of hard--boiled egg.LOCATIt is elastic and when incised curls on itself exposing the mecontaining brood capsutes and daughter cyst.Inner or Germinal layer (endocyst) :-Itis cellular and consists of noprotoplasmic inass.javaof nuclie embeddedParasitology (HSC)It is very thin and measures about 22-25 um in thickness. It is vitallayer of cyst andGive rise to brood capsules with scolices2 Secretes the specific hydatid fluid3. Forms the outer layer.Composition and character of hydatid fluid:-1) Clear colourless fluid2) Specific gravity low 1.005 1.0103) Reaction acidic Ph-6.74) Contains NaCl, sodium sulphate, sodium phosphate and sodium andcalcium salt of succinic acid.5) Antigenic.6) Highly toxic, when absorbed gives rise to anaphylactic symptoms.7) Hydatid sand:- A granular deposit found to settle at the bottom.It consist of liberated brood capsule free scolices and loosehooklets...Acephalocysts:-Sometimes brood capsules are not developed and if developedare without any scolices. These cysts are sterile and called acephalocyst.ndogenous daughter cyst formation:- in hyatid cyst is the result of growth ofmany years.The daughter cyst develops inside the mother cyst and may arise fromdetached fragment of germinal layer.The daughter cyst consists of outer protective layer and an innergerminative layer from which brood capsule and scolices arises and evengrand daughter cyst may be developed.Exogenous cyst formation: Which is found in bonc hydalid where growthoccurs in an outward direction.High intracystic pressure causes herniation or rupture of both thegerminal and laminated layers through some weakened part.Development of brood capsules and scolices:-> Brood capsule sprout from the germinal layer.>It is first spherical than hecomes vacuolated and transformed into avesicle.> The scolices numbering 5-20 or more develop within these capsule.>A fully developed scolices represents the further head of the adult wermwith suckers and a circle of hooklets invaginated inside the scolices.>InIn growing hydatid cyst all stages of development of scolices are found.>The scolices may remain attached to the wall by means of pedicles ormay remain free inside the cavity of cyst and forms the grains of hyatidsand.Parasitology (H.S.C) 15Reaction of the host:-> Where the embryo settles an active cellular reaction consisting ofmonocytes, giant cells and cosinophils takes place around the parasite.> The large no. of parasite may be destroyed by phagocytic activity of thesecenscells▸ Some embryo escapes and develops hydatid cyst.> The cellular reaction in these cases, disappears followed by appearance offibroblast and formation of new blood vessels which are transformed intofibrous tissues. This forms an enveloping fibrosis layer around thegrowing embryo is known as pericysts.> Pericyst emerges gradually into surrounding healthy tissue and theparasite drives its nourishment through it.Rate of growth of hydatid cyst:- Very slow and at the end of year it is 4 cm indiameter.Distribution of hydatid cyst:- Commonly involved organ is liver because itforms 1" filter than lung and other various organs after entering in blood.Clinical features:-i) It cyst is superficial then there is visible swelling2) The disease remains symptomatic for many years only detected atautopsy.3) Pressure effect on surrounding rissue.4) Rupture of hydatid cyst is associated with anaphylactic symptoms andfoueation of sec. echinococcosis.Lab diagnosis:-Casoni's reaction:-It is hyper sensitivity test introduced by Casoni in 1911> Intradermal injection of 0.2 ml of fresh hydatid fluid produces a largewheal (5cm in diameter) with multiple pseudopodia,> In all positive cases, which disappears in 1 hr.> Sterile normal saline is injected in other arm for control.> Hydatid fluid from human cases or from animal used as antigen.1) Blood examination:- Eosinophillia2) Serological test:-a) Precipitin testbi Complimcal fixation test are carried out with hydatid antigen.Parasitology tH.SC) i

Also read :𝔽𝔼𝕍𝔼ℝ 𝔻ℝ𝕌𝔾 𝕀ℕ ℍ𝕆𝕄𝔼𝕆ℙ𝔸𝕋ℍ𝕐

Also read :BARGAIN