Epidemiology of Ascariasis.pptx..........................

Ascaris is a nematode genus of parasitic worms known as the "small intestinal roundworms". One species, Ascaris lumbricoides, affects human

1. ASCARIASIS PREPARED BY KRUPA MATHEW.M, ASSOCIATE PROFESSOR

2. TERMINOLOGIES PARASITE O rganism that depends on other organism for one/more of its metabolic requirements. HELMINTH refer to worms . SOIL TRANSMITTED HELMINTHS(STH) Worms transmitted through soil contaminated with faecal matter are called intestinal parasitic worms namely Round worms ( Ascaris lumbricoides) H ook worms ( Ancylostoma duodenale or Necator americanus)

3. 1. ASCARIASIS (ROUND WORM)

4. INRODUCTION Ascariasis is an infection of the intestinal tract caused by the adult Ascaris lumbricoides . Its n a me L u mb r i c o i ds is d e ri v ed f r om its resemblence with earth worm ( lumbricus meaning earth worm in latin ) It is the l a r g e s t n em a to d e ( r o u n d worm) parasitizing the human intestine. This worm is found in the small intestine of man (mainly in the jejunum and upper part of the ileum). They are in slight red or white in colour. They are 10 -15 cms in length

5. PRE V ALE N CE This is the most common human helminthic infestation 820 mill i on a f fe c ted world Wide W idely distributed in tropical and sub tropical areas They are more common in children than in adults • As many as 500 to 5000 adult worms may inhabit a single host Adult worms of A. lumbricoides

6. AGENT FACTORS Ascaris lumbricoids lives in the small intestine M ale -12-30 cm female-20-35 cm. They produc e 2,40,00 egg s per day . They become embryonated b e c o me i n fe c ti v e in 3 we e k s . Reservoir of infection : M an is the only reservoir Infective material : Faeces containing fertilised eggs.

7. HOST FACTORS Children are the most affected. They contribute to malnutrition resulting in growth retardation. Human habits: open air defecation , Chi l d r en c o n tam i n a ti n g th e ir h a n d s by p l a y i n g on the ground

8. ENVIRONMENT FACTORS Ascariasis is a “soil transmitted helminth ” T he eggs remain viable for months Factors favourable are: temperature, moisture clay soils are most favourable for development of worms. Period of communicability: U ntil all fertile females are destroyed and stools are negative

9. EPIDEMIOLOGICAL DETERMINANTS Ag e nt- Asca r is lumbricoid e s Environment -soil Host –children

10. MODE OF TRANSMISSION Transmitted by eggs that are passed in the faeces of infected people Eggs that are attached to fruits and vegetables Eggs in the c o n t amin a t ed water Eggs in the soil When vegetables are not cooked or Washed When children put their hands in the mouth without washing their hands there is greater chance

11. PATHOGENESIS There are two phases in ascariasis: 1. The blood-lung migration phase of the larvae 2. The intestinal phase of the adults Incubation period: Ranges from 18 days to several weeks Infective form Embryonated egg containing Rhabditi form larva

12. PATHOGENESIS( contd)

13. The blood-lung migration phase of the larvae In persons repeatedly infected with Ascaris the migrating larvae may lead to inflammatory and hypersensitivity reactions in the lungs There is formation of granuloma and eosinophilic infiltrates.It leads to fever, cough, dyspnoea, urticarial rash and eosinophilia The sputum may be blood-tinged, and may contain Ascaris larvae and Charcot-Leyden crystals. This condition is known as Loeffler’s syndrome

14. THE INTESTINAL PHASE OF THE ADULTS Adult worms produce various pathological lesions in the following ways Mechanical action Spoliative action Allergic reaction The presence of a few adult worms in the lumen of the small intestine usually produces no symptoms, but may give rise to vague abdominal pains or intermittent colic, especially in children

15. Heavy infection with a large number of worms causes impairment of host nutrition and growth retardation in children The severity of intestinal disease depend upon the worm load of the intestine and nutritional status of the host according to WHO > 50, 000 eggs per gram of feaces is a heavy infection

16. S Y MP T OMS No symptoms Stage 1: worm larvae in the bowels attach to bowel walls Stage 2: worm larvae migrate into the lungs: Fever and breathing difficulty Coughing and pneumo nia Stage 3: worms enter the small intestine and mature into worms and remain there to feed

17. Abdominal symptoms Abdominal discomfort, General malaise, weakness Intestinal blockage - may be partial or complete Severe abdominal pain Vomiting Restlessness Disturbed sleep Worm in stool Worm in vomit S Y MP T OMS (contd)

18. LABORATORY DIAGNOSIS Done by following methods 1. Parasitic diagnosis Demonstration of adult worm (passed through anus, mouth, nose ) Demonstration of eggs ( detected in stool ) Demonstration of larvae (detected in the sputum during the stage of migration 2. Sero -diagnosis: I ndirect haem -agglutination (IHA) And immuno -fluorescence antibody (IFA) test for the diagnosis of extra-intestinal – ascariasis like Loeffler’s syndrome Eosinophilia : It is seen in larval invasion stage

19. C O M PL I C A T IO NS Complications such as P rotein and Vit –A deficiency I ntestinal obstruction, A ppendicitis B iliary ascariasis, P erforation of the intestine, C holecystitis , pancreatitis and peritonitis, etc., may occur, in which biliary ascariasis is the most common complication.

20. T R E A TME N T Pyrantel pamoate, in a single dose of 11 mg per kilogram body weight (maximum 1 gm) Mebendazole in a dose of 100 mg twice daily for 3 days, and piperazine citrate in a dose of 75 mg per kg body weight daily for 2 days

21. PROPHYLAXIS Ascariasis can be prevented by Proper disposal of human faeces Avoidance of eating raw vegetables and salads Periodic treatment with an effective an t he l mint h ic in c o mmunit i es th at lack sani t ary facilities