Ascaris Lumbricoides

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. Adult male • smaller than female . • Size : 15-30 cm in L 3-4 mm in D . • Curved tail contains a pair of ‘copulatoryspicules’ . Adult male Copulatory spicules

8. Adult female • Size : 20-40 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. 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. 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 andasia . • Poor sanitary conditions .

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

25. ANY QUERY