Ascaris LumbricoidesAscaris Lumbricoides

TaxonomyTaxonomy

Kingdom : Animalia Kingdom : Animalia

Phylum : NematodaPhylum : Nematoda

Class : RhabditeaClass : Rhabditea

Order : AscarididaOrder : Ascaridida

Family : AscarididaeFamily : Ascarididae

Genus : AscarisGenus : Ascaris

Species : lumbricoidesSpecies : lumbricoides

Common name : Common name : Round wormRound worm

Largest of intestinal nematodes .Largest of intestinal nematodes .

causative agent of ‘causative agent of ‘AscariasisAscariasis’. ’.

Distribution:- world wideDistribution:- world wide

Habitat:- small intestine, mainly jejunum.Habitat:- small intestine, mainly jejunum.

Introduction

Morphological formsMorphological forms

Adult worms : maleAdult worms : male

femalefemale Eggs : fertilisedEggs : fertilised

unfertilisedunfertilised

decorticateddecorticated Rhabditiform larva .Rhabditiform larva .

MORPHOLOGYMORPHOLOGY

Adult wormsAdult worms : cylindrical in shape : cylindrical in shape with tapering ends.with tapering ends.

Creamy white or pinkish. Creamy white or pinkish. Mouth of the worm is surrounded by 3 Mouth of the worm is surrounded by 3

lips (1 dorsal and 2 ventral) with lips (1 dorsal and 2 ventral) with minute teeth.minute teeth.

Life span is <1 yr.Life span is <1 yr.

Adult worms Lips of ascaris

smaller than female .smaller than female . Size : 15-30 cm in L Size : 15-30 cm in L

3-4 mm in D .3-4 mm in D . Curved tail contains a pair of Curved tail contains a pair of

‘‘copulatorycopulatory spiculesspicules’ .’ .

Adult male

Copulatory spicules

Adult male

Adult femaleAdult female

Size : 20-40 cm in L Size : 20-40 cm in L

2-6 mm in D .2-6 mm in D . Post. end is straight and Post. end is straight and

conical .conical . ‘‘vulvar waistvulvar waist’’ Eggs : 240,000/day .Eggs : 240,000/day .

Adult female

3 kinds : 3 kinds : FertilisedFertilised, , UnfertilisedUnfertilised and and DecorticatedDecorticated..

Fertilised eggFertilised egg :- oval in shape :- oval in shape measures 45 x 70 mc in Lmeasures 45 x 70 mc in L 35 x 50 mc in B.35 x 50 mc in B. Golden brown , Bile stained .Golden brown , Bile stained . Shell is thick with mammillated albuminous Shell is thick with mammillated albuminous

outer coat.outer coat. Contains an unsegmented ovum with clear Contains an unsegmented ovum with clear

crescentic space at each pole .crescentic space at each pole . Floats in sat. salt solutionFloats in sat. salt solution..

Egg

Unfertilised eggUnfertilised egg :- ellipsoidal in shape :- ellipsoidal in shape measures 78 x 105 mc in Lmeasures 78 x 105 mc in L 38 x 50 mc in B .38 x 50 mc in B .

Brown coloured , Bile stained , Thin shelled .Brown coloured , Bile stained , Thin shelled . Heaviest of all helminthic eggs , hence it Heaviest of all helminthic eggs , hence it

doesn’t float in sat.salt solution .doesn’t float in sat.salt solution .

Decorticated eggDecorticated egg :- Both fertilised and :- Both fertilised and unfertilised eggs sometimes may lack their unfertilised eggs sometimes may lack their albuminous coat and are colourless .albuminous coat and are colourless .

Fertilised egg Unfertilised egg

Albuminous layer

Egg shell

Ovum

Decorticated egg

Rhabditiform larvaRhabditiform larva : :

size : 250 mc in Lsize : 250 mc in L

14 mc in D 14 mc in D

actively motileactively motile

larvae hatch out in duodenumlarvae hatch out in duodenum

penetrates the intestinal mucosa penetrates the intestinal mucosa

Hatching out larva

PathogenesisPathogenesis

Source : soil , water , food contamined with Source : soil , water , food contamined with eggs.eggs.

Route : ingestionRoute : ingestion Infective form : embryonated eggsInfective form : embryonated eggs Host : manHost : man No intermediate and reservoir hosts . No intermediate and reservoir hosts .

Life cycleLife cycle

Manifestations due to of migrating Manifestations due to of migrating larva :larva :

Inflammatory and hypersensitvity reactions .Inflammatory and hypersensitvity reactions . Granuloma and eosinophilic infiltration.Granuloma and eosinophilic infiltration. Eosinophilic pneumonia Loeffler’s Eosinophilic pneumonia Loeffler’s

syndrome .syndrome . Symptoms : fever Symptoms : fever

cough cough

dyspneadyspnea

urticaria .urticaria .

Manifestations due to adultManifestations due to adult : :

Sporiative actionSporiative action : malnutrition : malnutrition growth retardation .growth retardation . Mechanical actionMechanical action : abdominal pain : abdominal pain intestinal obstructionintestinal obstruction intestinal perforationintestinal perforation Allergic reactionAllergic reaction : :

release ofrelease of ascaron ascaron fever

urticaria Angioneurotic edemaconjunctivitis

Intestinal obst. by adult worms

Peritonitis by intest. perforation

Ectopic ascariasisEctopic ascariasis : appendicitis : appendicitis

obst. jaundiceobst. jaundice

haemorrhagic pancreatitishaemorrhagic pancreatitis

liver abscessliver abscess

Ascaris in common bile duct Adult worms in liver

Lab diagnosisLab diagnosis

Parasitic diagnosisParasitic diagnosis : : demo . of eggs in feaces –direct microscopydemo . of eggs in feaces –direct microscopy formalin ether conc.formalin ether conc. demo . of larvae – in sputum , bronchial demo . of larvae – in sputum , bronchial

aspirationaspiration demo . of adult worms – barium meal .demo . of adult worms – barium meal . Sero diagnosisSero diagnosis : : Ab’s detected by IHA , IFA .Ab’s detected by IHA , IFA . used for diagnosis of loeffler’s syndrome .used for diagnosis of loeffler’s syndrome . Imaging methodsImaging methods : x – ray , ct scan , : x – ray , ct scan ,

ultrasound ultrasound

EpidemiologyEpidemiology

World wide distibution through out temperate World wide distibution through out temperate and tropical areas .and tropical areas .

¼th of the world population .¼th of the world population .

4040% % population in africa andpopulation in africa and asia .asia .

Poor sanitary conditions .Poor sanitary conditions .

TreatmentTreatment

MebendazoleMebendazole

pyrantel pamoatepyrantel pamoate

piperazine citrate .piperazine citrate .

ProphylaxisProphylaxis

Proper disposal of human faecesProper disposal of human faeces Avoid eating raw vegetables and saladsAvoid eating raw vegetables and salads Periodic treatment with antihelminthics .Periodic treatment with antihelminthics .