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1. Protozoa and Helminthes 28-Jan-16 1 Microbiology of GIT

2. Intestinal Helminthes 1. Nematodes (roundworms) Ascaris lumbricoides Trichuris trichiuria STH Hookworms 2. Cestodes (tapeworms) Taenia saginata - The Beef Tapeworm Taenia solium - The Pork Tapeworm Hyminlopes spss 3. Trematodes (flukes) Schistosomiasis - Bilharzia . Fasciola hepatica 28-Jan-16 2 Microbiology of GIT

3. Nematodes Nematodes are cylindrical hence the common name roundworm Soil-transmitted helminth (STH) infection is highly endemic in tropical and subtropical areas of sub-Saharan Africa, Asia and Latin America where up to 2 billion people have active infections. Neglected by the global health community because most affected are among the most impoverished infection causes chronic ill health with insidious clinical presentations 28-Jan-16 3 Microbiology of GIT

4. 1. Ascaris lumbricoides Infection with this roundworm is extremely common The annual incidence of infection being greater than 1500 million cases Morphology The adults are large white, or pinkish-white, cylindrical roundworms The eggs consist of a thick transparent inner shell which is covered in a thick, warty, albuminous coat. 28-Jan-16 4 Microbiology of GIT

5. Life cycle Have a direct life cycle, with no intermediate hosts Infection occurs on ingestion of raw food, such as fruit or vegetables, that is contaminated with these infective eggs. The eggs then hatch in the small intestine, to release the L2 rhabditiform larvae L2 larvae penetrate the intestinal wall, entering the portal blood stream, and then migrate to the liver, then heart, then after between 1 to 7 days, the lungs. 28-Jan-16 5 Microbiology of GIT

6. Here they moult twice on the way to form the L4 larvae Out of the blood vessels, entering the bronchiole They then enter the throat and are swallowed, finally ending up in the small intestine where they mature and mate, to complete their life cycle. Pathology of Infection. 1. Pathology Associated with the migration of Larvae Simultaneous migration of the larvea through the lungs may give rise to a severe haemorrhagic pneumonia.

7. Often associated with allergic hypersensitivity reactions such as asthmatic attacks, pulmonary infiltration and urticaria and oedema of the lips 2. Pathology associated with adult parasites in the Intestine The mass of worms may block the intestine and need to be surgically removed. Adult parasites often leave the small intestine to enter other organs Bile duct 28-Jan-16 7 Microbiology of GIT

8. Diagnosis Definitive diagnosis is by demonstration of The characteristic eggs in faecal samples Identifying adult worms passed out spontaneously by the host. 28-Jan-16 8 Microbiology of GIT To the appendix, or through the intestinal wall, both conditions which may cause a fatal peritonitis Vomited up or emerging through the nose Enter the trachea they may cause suffocation .

9. Unfertilized (left) and fertilized (right) Ascaris lumbricoides eggs. The unfertilized eggs are longer and narrower than fertilized eggs. The fertilized eggs have a thick and bumpy outer wall which is stained golden brown with bile. (SOURCE: PHIL 411/4821 - CDC/Dr. Mae Melvin) 28-Jan-16 9 Microbiology of GIT

10. 2. Hookworms Ancylostoma duodenale :- Native to parts of Southern Europe, North Africa and Northern Asia, parts of Western South America. Necator americanus :- Native in Central and Southern Africa, Southern Asia, Australia and the Pacific Islands. It has been estimated that there are 1200 million cases of hookworm infection in man annually S ymptomatic infections with accompanying anaemia . 28-Jan-16 10 Microbiology of GIT

11. Morphology The anterior end of the parasites are formed into a buccal Necator have capsules equipped with four cutting plates on the ventral margins Ancylostoma have pairs of teeth on the ventral margin of the capsule. The eggs are bluntly rounded, thin shelled, and are almost indistinguishable between the different species 28-Jan-16 11 Microbiology of GIT

12. 28-Jan-16 12 Microbiology of GIT

13. Life cycle 28-Jan-16 13 Microbiology of GIT

14. Pathology of Infection . Preferred site of infestation is in the upper layer of the small intestine Pathology associated with the presence of the adult parasite in the intestine H ookworm mouthparts penetrate blood vessels, and the parasites obtain nutrition by sucking blood 28-Jan-16 14 Microbiology of GIT

15. The gross pathology of the disease is very dependent on the intensity of infection. The continuous loss of blood leads to a chronic anemia Severe retardation in growth and development, both physical and mental, in infected children, and a general weakness

16. Egg of Hookworm Identify characteristic eggs in feacal samples. Note the eggs of N. americanus and A . duodenale are morphologically identical. Diagnosis 28-Jan-16 16 Microbiology of GIT

17. Treatment and Control Albendazole Mebendazole 28-Jan-16 17 Microbiology of GIT

18. 3 . Trichuris trichiura (whipworm) It is distributed worldwide More frequent in areas with tropical weather and among children. Morphology The thin(whip-like end ) is the end that the worm threads into the mucosa of the colon. The widened, pinkish gray region of the body is the posterior, and it is the end that contains the parasite’s intestines and reproductive organs. 28-Jan-16 18 Microbiology of GIT

19. Eggs contain polar plugs (also known as refractile prominences) at each end. 28-Jan-16 19 Microbiology of GIT

20. Life cycle and transmission Unembryonated eggs ( unsegmented ) are passed in the faeces In the soil, these eggs develop into a 2-cell stage (segmented egg) and then into an advanced cleavage stage Infective eggs are ingested by way of soil contaminated hands or food and hatch inside the small intestine, releasing larvae into the gastrointestinal tract. 28-Jan-16 20 Microbiology of GIT

21. These larvae burrow into a villus and develop into adults (over 2–3 days). They then migrate into the cecum and ascending colon where they thread their anterior portion (whip-like end) into the tissue mucosa and reside permanently for their year-long life span. About 60 to 70 days after infection, female adults begin to release unembryonated eggs

22. Life cycle of Trichuris trichiura 28-Jan-16 22 Microbiology of GIT

23. Clinical Disease Abdominal pain and distention, bloody or mucous-filled diarrhoea , and in children rectal prolapse may occur T enesmus (feeling of incomplete defecation, generally accompanied by involuntary straining ). While damage may be done to the GI tissue and appendicitis may be brought on 28-Jan-16 23 Microbiology of GIT

24. 28-Jan-16 24 Microbiology of GIT The embedding of the worms into the ileo-cecal region may make the host susceptible to bacterial infection. Growth retardation, weight loss, nutritional deficiencies, and anemia

25. Lab Diagnosis A stool examination reveals the presence of typical whipworm eggs . Typically , the Kato-Katz thick-smear technique is used for the identification of the Trichuris trichiura eggs in the stool sample. Colonoscopy has been shown to be a useful diagnostic tool, especially in patients infected by only a few male worms Treatmets Mebendazole 28-Jan-16 25 Microbiology of GIT

26. 4. ENTEROBIUS VERMICULARIS (PIN WORM OR THREAD WORM) Small white worm with thread-like appearance. The worm causes enterobiasis . Infection is common in children. Morphology Has male and female adult 28-Jan-16 26 Medical parasitology

27. Infection is by ingestion of eggs containing larvae with contaminated raw vegetables. Mode of infection By direct infection from a patient (Fecal-oral route). Autoinfection: the eggs are infective as soon as they are passed by the female worm. If the hands of the patient get contaminated with these eggs, he/she will infect him/herself again and again. Aerosol inhalation from contaminated sheets and dust. 28-Jan-16 27 Medical parasitology

28. Life cycle Adult worm lives in the large intestine. After fertilization, the male dies and the female moves out through the anus to glue its eggs on the peri -anal skin. This takes place by night. The egg contains larva. When the eggs are swallowed, they hatch in the small intestine and the larvae migrate to the large intestine to become adult. 28-Jan-16 28 Medical parasitology

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30. Life cycle of E . vermicularis 28-Jan-16 30 Medical parasitology

31. Clinical presentation The migration of the worms causes allergic reactions around the anus and during night it causes nocturnal itching ( pruritus ani ) and enuresis. The worms may obstruct the appendix causing appendicitis. Lab Diagnosis Eggs in stool: Examination of the stool by direct saline smear to detect the egg: this is positive in about 5% of cases because the eggs are glued to the peri -anal skin. 28-Jan-16 31 Medical parasitology

32. 2. Peri -anal swab: The peri -anal region is swabbed with a piece of adhesive tape ( cellotape ) hold over a tongue depressor. The adhesive tape is placed on a glass slide and examined for eggs. The swab should be done in the early morning before bathing and defecation. Treatment Mebendazole ; Piperazine

33. Morphology of Enterobius vermicularis adult female They are small white worms with pointed tail swollen cuticle at anterior end prominent esophageal end bulb 33 28-Jan-16 Medical parasitology

34. Egg of E. vermicularis 28-Jan-16 34 Medical parasitology

35. Geographical Distribution :- T. saginata World wide distribution where cattle are raised and beef is eaten raw or under cooked. Very common in Ethiopia T. solium Not widely distributed as T saginata . Common in all areas where raw or partially cooked pork is eaten. Not reported from Ethiopia Taenia species 35 28-Jan-16 Medical parasitology

36. Taenia saginata Scolex (head):- Quadrate, with four suckers, no hooks, no rostellum on scolex Size-2mm across 36 Medical parasitology 28-Jan-16

37. Transmission and life cycle Humans become infected by ingesting raw or undercooked meat infected with cystcerus larvae: Beef- T saginata 37 Medical parasitology 28-Jan-16

38. 38 28-Jan-16 Medical parasitology

39. Clinical manifestation T. saginata Taeniasis . Usually asymptomatic but may cause dizziness, abdominal pain, diarrhea, headache and nausea. Proglottids obvious in feces. Proglottides have a strong tendency to crawl from the anus during the day when its host is active 39 Medical parasitology 28-Jan-16

40. Laboratory Diagnosis Detecting eggs in faeces Identifying macroscopically gravid segments in faeces scolex recovered from clothing or passed in faeces . In addition T.saginata - ova on perianal skin ( cellotape slide) 40 Medical parasitology 28-Jan-16

41. Egg : T.saginata 41 Medical parasitology 28-Jan-16

42. Opportunistic Intestinal Parasites 28-Jan-16 42 Microbiology of GIT

43. Opportunistic Intestinal Parasites Strongyloides stercoralis It is endemic in the southeastern USA, South America, sub-Saharan Africa, and Southeast Asia The geographic range of Strongyloides infections overlap with that of Hookworm Morphology Rhabditiform larvae Filariform larvae Eggs hatch in the intestine (not usually passed in stool specimens). 28-Jan-16 43 Microbiology of GIT

44. Life cycle:- Infective third stage filariform larvae penetrate skin, enter the lymphatics or bloodstream. Larvae migrate to the lungs, break out of lung capillaries into alveoli. After maturation, larvae travel to the pharynx, are swallowed, and return to the intestine. Larvae mature to adults and attach to the mucosa of the small intestine. 28-Jan-16 44 Microbiology of GIT

45. Parthogenetic females only - no parasitic males. Females produce viable eggs. Eggs hatch in mucosa. Larvae: Are passed in feces, live in the soil, mature into a free-living adult males and females, which produce eggs Rhabditiform larvae feed in soil and develop into infective stage larvae which penetrate the skin; First stage larvae develop into infective stage larvae in the intestine (autoinfection). 28-Jan-16 45 Microbiology of GIT

46. Opportunistic Intestinal Parasites…… Life cycle 28-Jan-16 46 Microbiology of GIT

47. Major pathology and symptoms : Skin – allergic reactions; raised, itchy, red blotches at the site of larval penetration. Lungs – pneumonia . Intestinal - abdominal pain, diarrhea, vomiting, weight loss, anemia, eosinophilia . Death occurs in immunosuppressed patients due to heavy autoinfection. 28-Jan-16 47 Microbiology of GIT

48. Hyperinfection with S. stercoralis results in invasion of larvae into the colonic submucosa , lymphatics , and blood vessels, with an associated mononuclear infiltrate. There are many adult worms, larvae, and eggs in the crypts of the duodenum and ileum. Worms of all stages may be found in other organs, including skin and lungs, and may even be found in large numbers in sputum. 28-Jan-16 48 Microbiology of GIT

49. Diagnosis : Recovery and identification of larvae in the feces. Recovery and identification of eggs in duodenal drainage 28-Jan-16 49 Microbiology of GIT Treatment:- Thiabendazole