Ascariasis.pptx medical parasitology ppt

medical parasitology

1. Ascaris Lumbricoides ( r ound w o r m ) By: Mr. Osman H. Ali

2. General Introduction Co mm on name “ r ound w o r m of ma n ” It is worldwide in distribution and most prevalent through out the tropics, sub-tropics and more prevalent in the malnourished people. Habitat : Small intestine (jejunum) of man.

3. Adult: Cylindrical tapering at ends. Creamy-white or pinkish in color. Longitudinal streaks on body. Mou t h a t an t . E nd. H a s t h r ee t oo t h ed l ips , 1dorsal and 2ventral. Dig e sti v e a nd r e s pi ra t o r y sy m pt om s f lo a t inside body cavity. Ascaron :- toxic fluid causing allergic reactions . Morphology

4. The lips of A. lumbricoides The three lips are seen end. At the anterior The margin of each lip is lined with minute teeth which are not visible at this magnification

5. Females measure 20-35 cm long with a straightened tail; males are smaller at 15-31 cm and tend to have a curved tail. Two equal size copulatory spicules in male. vulvar waist in female. Female lays nearly 200,000 eggs daily which are passed in feces.

6. Posterior end of a male A. lumbricoides , showing the curled tail. Adult female A. lumbricoides .

7. Adult worm of A. lumbricoides

8. Egg There are three kinds of the eggs fertilized eggs unfertilized eggs decorticated eggs Morphology

9. Fertilized egg: an average size 60×45µm Round or oval in shape bile stained&brown in color thick transparent shell Innermost- lipoidal vitelline membrane . Middle – thick transparent layer. Outermost – mammillated Albuminoid layer. large unsegmented ovum There is a clear crescentric space at each pole. Float in SSS. Morphology

10. Unfertilized egg Longer and slender than fertilized egg 90*55um. Bile stained and brown in colour. The shell and albuminous coat are thinner Lipoidal membrane is absent, Small atrophied ovum. Do not float in SSS. refractable granules various in size may be present. Morphology

11. Decorticated egg: Both fertilized and unfertilized eggs sometimes may lack their outer albuminous coats and are colorless

12. Site of inhabitation: small intestine Only single host No intermediate host. Infective stage: embryonated eggs Route of infection: by feco-oral-route. Life Cycle

13. Adult worms , live in the lumen of the small intestine. Eggs passed in faeces. Fertile eggs embryonate and become infective after 18 days to several weeks , depending on the environmental conditions (optimum: moist, warm, shaded soil). After infective eggs are swallowed , the larvae hatch , invade the intestinal mucosa , and are carried via the portal , then systemic circulation to the lungs .

14. Larva moult twice in the lungs (10 to 14 days), break capillary & penetrate the alveolar walls , ascend the b r onc h ial tree c ra wl the e pi g l o tti s , a nd ar e swa ll o w e d Upon reaching the small intestine, they develop into adult worms . After 12 weeks gravid female begin to discharge eggs in stools. Cycle is repeated.

15. Cause ascariasis. Due to adult worm and migrating larva. Mal nu tr i t i o n, night b l indn e ss, v it A d e f , g row t h retardation. Intermittent colicky pain in intestine. Mechanical obstruction. Wo r m s a re RE ST L ES S W AN D E RE R S. I nsi nu ate any aperture in their way. Crawl out of mouth, ear. naris Pathogenesis

16. Respiratory obstruction. Wandering adults may block the appendical lumen or the common bile duct and even perforate the intestinal wall which cause complications of ascariasis : intestinal obstruction Appendicitis biliary ascariasis (the most common one) perforation of the intestine C holecystitis (inflammation of the gallbladder ) , pancreatitis and peritonitis

17. Migrating larva In repeated infections ,During the migration through the lungs, the larvae may cause a inflammatory and hypersensitivity reactions. The symptoms of the pneumonia are low fever, cough, blood-tinged sputum, asthma The clinical manifestation is also called Loeffler’s syndrome

18. feces are examined for the ascaris eggs Direct fecal film: it is simple and effective and is the first choice recovery of adult worms: when adults or adolescents are found in feces or vomit and tissues. Barium meal can be done. Serology- detect ascaris antibody by IHA and IFA. Eosinophilia Ascaris pneumonitis: examination of sputum for Ascaris larvae is sometimes Di a gnosis

19. Treatment to ascariasis: pyrantel palmoate Mebendazole, are effective Sanitary disposal of feces. Hygienic habits such as cleaning of hands before meals. Health education. Prevention

20. Thank you.