- Ascaris lumbricoides, also known as the roundworm, is the largest nematode parasite that infects the human small intestine. It is distributed worldwide. - Male roundworms are 15-30cm long while females are 20-40cm long. Females can produce up to 27 million eggs and lay up to 200,000 eggs per day that are passed in feces. - Roundworm infection causes a range of symptoms from mild abdominal pain to intestinal obstruction, depending on whether the larvae or adult worms are causing the issues. Diagnosis involves identifying eggs or larvae in stool or gastric samples. Treatment involves anthelmintic drugs while prevention focuses on sanitation practices.

1. Ascaris lumbricoides
Dr.Riyaz

2. Ascaris
• k/a round worm
• Largest nematode parasite in human intestine
• Lumbricodes = Earthworm
• Distributed world wide
• Lives in small intestine

3. Morphology
• Large cylindrical worms with tapering ends
• Anterior end is more pointed
• Pale pink or flesh colored when inside the
body
• White outside the body
• Mouth  3 fine denticulated lips
– One dorsal
– Two ventero lateral

4. Differentiate
Male
• 15-30cms in length
• 2-4mm thick
• Posterior end curved to
form hook
• 2 copulatory spicules
Female
• 20-40cms in length
• 3-6 mm thick
• Posterior end straight and
conical
• Vulva is placed mid ventrally in
genital girdle or vulvar waist at
the junction of anterior and
middle 1/3 rd of the body
• Vulva leads to single vagina
• Single vagina leads to 2 genital
tubules

7. Beauty of the Worm!
• 27 million eggs
• 2,00,000 eggs/ day
• Eggs passed in feces
• Fertilized /
embryonated eggs
– infective
• Unfertilized / non
embryonated eggs
– Non infective

8. Fertilized eggs!
• Spherical / ovoid
• Bile stained
• Floats in salt solution
• 60-75 x 40-50nm
• Enclosed in shell
– Outer coarse mamillated albuminous coat
– Thick transparent middle
– Inner lipoidal vitelline membrane
• Large unsegmented ovum
• Coarse lecithin granules
• Ovum fully fills the egg except the cresenteric pole

9. Unfertilized eggs!
• Longer
• Elliptical
• Thin shell
• Scanty irregular albumin
• Ovum atrophic
• Heavy and sinks in salt solution

10. Life cycle!

11. Inside man!

12. Clinical features!
• Due to larval migration
– Allergic reaction  infiltration of eosinophils,
macrophages and epitheloid cells  pneumonia
• Low grade fever, dry cough, asthmatic wheezing,
urticaria, eosinophilia, mottled lung
• Sputum  charcot leyden crystals
• Larvae in sputum
• More in gastric washings
Loeffler’s
syndrome

13. Clinical features!
• Due to adult worms
– Spoliative / Nutritional effects
• Heavy worm infestation > 500 worms
• Interfere with absorption
– PEM
– VIT A
• Loss of appetite
• Listless
• Alteration in jejunal mucousa and shortening of villi

14. Clinical features!
• Due to adult worms
– Toxic effects
• Due to hypersensitivity to worm antigens
– Fever
– Urticaria
– Angioneurotic edema
– Wheezing
– conjunctivitis

15. Clinical features!
• Due to adult worms
– Mechanical effects
• Reflex peristalsis
• Recurrent severe abdominal pain
• Clumps to mass
– Volvulus
– Intussusception
– Intestinal obstruction

16. Wanderers!
• Biliary tract
• Pancreas
• Liver  abscess
• Oesophagus
– Nose
– Mouth
• Trachea
– Respiratory obstruction
– Lung abscess
• Appendix
• Peritonitis
– Weak spots

17. Diagnosis
• Larvae in sputum
• Larvae in gastric washings
• Charcot leyden crystals
• Eosinophilia
• Demo of egg in feces
• Worm passing out
• Skin test with ascaris antigen  not very effective
• Barium contrast radiography

23. Treatment
• Pyrantel pamoate
• Albendazole
• Mebendazole
• Piperazine citrate

24. Prevention
• Night soil
• Iodine 200ppm irrigation for 15mins

25. Thank you!!