1. Ascaris Lumbricoides

2. Taxonomy Kingdom : Animalia Phylum : Nematoda Class : Rhabditea
Order : Ascaridida
Family : Ascarididae
Genus : Ascaris
Species : lumbricoides

3. Introduction Common name : Round worm
Largest of intestinal nematodes .
causative agent of ‘Ascariasis’.
Distribution:- world wide
Habitat:- small intestine, mainly jejunum.

4. Morphological forms
Adult worms : male
female
Eggs : fertilised
unfertilised
decorticated
Rhabditiform larva .

5. MORPHOLOGY
Adult worms : cylindrical in shape with tapering ends.
Creamy white or pinkish.
Mouth of the worm is surrounded by 3 lips (1 dorsal and 2 ventral) with minute teeth.
Life span is <1 yr.

6. Adult worms
Lips of ascaris

7. Curved tail contains a pair of ‘copulatory spicules’ .
Adult male
smaller than female .
Size : cm in L
3-4 mm in D .
Curved tail contains a pair of ‘copulatory spicules’ .
Adult male
Copulatory spicules

8. Post. end is straight and conical . ‘vulvar waist’
Adult female
Size : cm in L
2-6 mm in D .
Post. end is straight and conical .
‘vulvar waist’
Eggs : 240,000/day .
Adult female

9. Egg 3 kinds : Fertilised, Unfertilised and Decorticated.
Fertilised egg :- oval in shape
measures 45 x 70 mc in L
35 x 50 mc in B.
Golden brown , Bile stained .
Shell is thick with mammillated albuminous outer coat.
Contains an unsegmented ovum with clear crescentic space at each pole .
Floats in sat. salt solution.

10. Unfertilised egg :- ellipsoidal in shape
measures 78 x 105 mc in L
38 x 50 mc in B .
Brown coloured , Bile stained , Thin shelled .
Heaviest of all helminthic eggs , hence it doesn’t float in sat.salt solution .
Decorticated egg :- Both fertilised and unfertilised eggs sometimes may lack their albuminous coat and are colourless .

11. Egg shell
Ovum
Albuminous layer
Unfertilised egg
Fertilised egg

12. Decorticated egg

13. larvae hatch out in duodenum penetrates the intestinal mucosa
Rhabditiform larva :
size : 250 mc in L
14 mc in D
actively motile
larvae hatch out in duodenum
penetrates the intestinal mucosa
Hatching out larva

14. Pathogenesis Source : soil , water , food contamined with eggs.
Route : ingestion
Infective form : embryonated eggs
Host : man
No intermediate and reservoir hosts .

15. Life cycle

17. Manifestations due to of migrating larva :
Inflammatory and hypersensitvity reactions .
Granuloma and eosinophilic infiltration.
Eosinophilic pneumonia Loeffler’s syndrome .
Symptoms : fever
cough
dyspnea
urticaria .

18. Manifestations due to adult :
Sporiative action : malnutrition
growth retardation .
Mechanical action : abdominal pain
intestinal obstruction
intestinal perforation
Allergic reaction :
release of ascaron
fever
urticaria
Angioneurotic edema
conjunctivitis

19. Intestinal obst. by adult worms
Peritonitis by intest. perforation

20. Ectopic ascariasis : appendicitis
obst. jaundice
haemorrhagic pancreatitis
liver abscess
Ascaris in common bile duct
Adult worms in liver

22. Imaging methods : x – ray , ct scan , ultrasound
Lab diagnosis
Parasitic diagnosis :
demo . of eggs in feaces –direct microscopy
formalin ether conc.
demo . of larvae – in sputum , bronchial aspiration
demo . of adult worms – barium meal .
Sero diagnosis :
Ab’s detected by IHA , IFA .
used for diagnosis of loeffler’s syndrome .
Imaging methods : x – ray , ct scan , ultrasound

23. Epidemiology
World wide distibution through out temperate and tropical areas .
¼th of the world population .
40% population in africa and asia .
Poor sanitary conditions .

24. Treatment Prophylaxis
Mebendazole
pyrantel pamoate
piperazine citrate .
Prophylaxis
Proper disposal of human faeces
Avoid eating raw vegetables and salads
Periodic treatment with antihelminthics .

25. ANY QUERY