Ascariasis-1, Roundworm disease, parasitology.pptx

Presentation on ascariasis, Sources - Textbook of medicine - KVK, Panickers Textbook of parasitology

1. Ascariasis John Joseph M Roll No. 30

2. Ascariasis , commonly termed Roundworm disease is a parasitic infection caused by the nematode Ascaris lumbricoides. It is primarily an infection of the intestinal tract but may migrate to other organs causing extraintestinal effects. Most common helminthic infection; 820 million cases recorded annually, with 12 million acute cases, 20,000 or more deaths Distributed worldwide, most common intestinal parasite in India. Infection rates are high in children of 3-8y, adults acquire some resistance

3. Host & Reservoir of infection – Man Transmission - food & water contaminated with feces containing fertilised egg - children playing in mud can transmit eggs to mouth through dirty fingers - eggs can get airborne with dust and are inhaled and swallowed Incubation period – 18 days to several weeks

4. Morphology Cylindrical, with tapering ends Male worms – 15-30cm length x 2-4mm diameter Female worms – Larger than males, 20-40cm x 3-6mm Lifespan – 6-12 months A single worm can lay more than 2,00,00 eggs per day which are passed in feces

5. Infection occurs when the egg containing rhabditiform larva is swallowed On reaching the duodenum the eggs hatch, rhabditiform larvae are released They penetrate the intestinal mucosa, enter the portal vein and are carried to the liver Then passing through the hepatic vein, inferior vena cava enter the right side of the heart reaching the lungs In 10-15 days larvae develop in the lungs, pierce lung capillaries and reach the alveoli The larvae crawl up or are carried up the respiratory passage and swallowed Larvae develop into adults in the small intestine, and the gravid female lays eggs which are eliminated in stool to repeat the cycle

6. Clinical features are produced either by migrating larvae or by adult worms 1 . Symptoms due to migrating larvae The worms may migrate to ectopic sites such as stomach, nasal cavity, biliary tree, pancreatic ducts, respiratory passages, urogenital tract etc. Respiratory – cough, hemoptysis(may contain Charcot-Leyden crystals), wheezing Hepatomegaly, may show centrilobular necrosis Rarely may reach the brain causing convulsions

7. 2 . Symptoms due to adult worms a. Nutritional effects Light infections are asymptomatic Moderate infection – Pica, diarrhea, abdominal distension, bruxism(grinding of teeth) In high worm loads, proper digestion and absorption of food are impaired resulting in PEM, Vit-A deficiency, Loss of appetite Infected children have voracious appetite but remain malnourished Abnormalities of jejunal mucosa – shortening of villi, elongation of crypts, round cell infiltration of lamina propria Changes are reversed on elimination of worms

8. b . Toxic effects Due to hypersensitivity reaction to worm antigens Fever, urticaria, wheezing, conjunctivitis, angioneurotic edema c. Mechanical effects Due to masses of worms causing occlusion or infiltration of single worm into a vital area Adult worms live in upper part of the small intestine This can stimulate reflex peristalsis causing recurrent colicky abdominal pain Occlusion by clumping of worms leads to volvulus, intussusception, obstruction, intestinal perforation

9. d . Wandering effects The worms are restless wanderers, they tend to probe into any aperture they find and wandering is enhanced when the host is ill, particularly when febrile(>39 o C) Wandering upwards into biliary or pancreatic duct causing acute biliary obstruction, pancreatitis May enter the liver causing liver abscess Entry into trachea causing respiratory obstruction, lung abscess Downward migration causing appendicitis

10. Diagnosis Adult worms Adult worms are visible in stool or sputum Barium meal shows adult worms in small intestine Plain x ray shows masses of worms in gas filled loops, intestinal obstruction Pancreatobiliary worms can be detected by USG, endoscopic retrograde cholangiopancreatography

11. Larvae Larvae can be demonstrated in sputum when they cause Loeffler’s syndrome, or more frequently in gastric washings Charcot-Leyden crystals in sputum on microscopic examination Chest x ray – patchy pulmonary fibrosis Eggs Demonstration of eggs in feces, bile by microscopic examination

12. Serological tests Ascaris antibody is detected by Indirect hemagglutination Indirect fluorescent antibody ELISA Blood examination Shows eosinophilia in early stages

13. Treatment Benzimidazole drugs – Albendazole, Mebendazole(contraindicated in pregnancy). Side effects – Nausea, vomiting, dizziness, abdominal pain Pyrantel pamoate(safe in pregnancy) Ivermectin Partial intestinal obstruction should be managed with nasogastric suction, IV fluids , antihelminthics (Piperazine) If the mass of worms remains in the same position or there is complete obstruction with rising puls , toxemia surgery is indicated

14. Prevention Preventing fecal contamination of soil Treatment of crops with water containing Iodine(200 ppm for 15 min) Avoid eating raw vegetables Health education pertaining to personal hygiene and environmental sanitation Treatment of infected persons Mass deworming campaigns in endemic areas

15. Homoeopathic therapeutics Aconite Belladonna Cina China Colocynthis Digitalis Ferrum met Graphites Ignatia Merc sol Nux vomica Sabadilla S pigelia Silicea Veratrum album