Entamoeba histolytica Trichomonas vaginalis

1. Entamoeba histolytica & Trichomonas vaginalis Cheng Yanbin School of medicine, Xi�an Jiaotong University

3. Agenda Introduction to the protozoa Entamoeba histolytic Trichomonas vaginalis

4. Protozoa Single-celled organisms (unicellular animals, Why?) Microscopic in size and various in shape Classification Important medical protozoa

6. The important protozoa Entamoeba histolytica Trichomonas vaginalis Giardia lamblia Leishmania donovani Malaria parasites Toxoplasma gondii

7. Entamoeba histolytic A world wide in distribution More often in tropical countries with poor sanitary conditions A commensal protozoa when human has a normal immune function. Invading host tissues and causing amoebiasis when human has a lower immune function

8. Morphology --- Trophozoite No regular in shape, 20~60�m in size. An active-moving trophozoite produce pseudopods (organelle) A spherical nucleus. Nucleolus in the center. peripheral chromatin Erythrophagocytosis Starting with a blank slide lets one focus on substance before style. PowerPoint has several standard �looks�, but customization is easy using the Slide and Title Master views. A standard size font is Arial 32.Starting with a blank slide lets one focus on substance before style. PowerPoint has several standard �looks�, but customization is easy using the Slide and Title Master views. A standard size font is Arial 32.

10. Morphology--- Cyst Spherical in shape & 10~20�m in diameter. 1~4 nuclei (similar to that of the trophozoite). Immature cyst (1 or 2 nuclei) has the glycogen vacuole & chromatoid body. No inclusions disappear In mature cyst (4 nuclei)---infective stage

12. Life cycle Trophozoites (Large bowel) Ingestion of cysts Cysts in feces Cysts survive in food, water Trophozoites Penetration of bowel In diarrhea or (Trophozoites carried dysenteric stools via blood to: ) Liver/lung / brain / other tissues

14. Characteristic of life cycle Basic model : cyst trophozoite cyst Parasitic location : large intestine (common) ; intestinal tissue or other tissues (occasional) Infective stage : mature cyst Trophozoite in diarrhea or pus ; Cyst in formed feces Infection : by ingestion of mature cyst

15. Pathogenicity and clinical features Pathogenesis Pathological changes ---- Large intestine and liver Clinical classification and features

16. Pathogenesis As a commensal protozoa Sometimes invade the colonic tissues through producing proteolytic enzymes necrosis ulcer may be carried to the extraintestinal organs by port circulation abscesses May spread to neighboring organs by direct extension or through the circulatory system.

18. Pathologic changes Colonic tissues : flask-shaped ulcers The destruction of trophozoites on mucosa may be shallow and small. While they enter the submucosa, they multiply and spread laterally give rise to extensive destruction. Extraintestinal tissues (liver) : abscess --- Anchovy-sauce type pus.

21. Clinical classification I 90% persons infected are carriers Intestinal amoebiasis Acute intestinal amoebiasis -- amoebic dysentery (bloody, mucus-containing diarrhea) + lower abdominal discomfort + tenesmus Chronic intestinal amoebiasis --- dyspepsia + weight loss + asthenia (common) / diarrhea

22. Clinical classification II Extraintestinal amoebiasis Liver : amoebic hepatitis + amoebic liver abscess --- pain in right-upper-quadrant + fever + marked tenderness of liver Lung : amoebic pulmonary abscess --- pain in chest + cough + fever Sometimes,E.h can be carried to other organs. Such as brain, skin and so on.

23. Laboratory diagnosis Fecal examination --- Wet mounts : Trophozoites in diarrhea feces. --- Wet mounts stained with iodine : Cyst in formed feces. Pus examination --- Trophozoites in aspirate pus from abscesses

24. Treatment For asymptomatic infections, diodoquin or paromomycin are drugs of choice For severe intestinal diseases or extraintestinal infections,drugs of choice are metronidazole or tinidazole, immediately followed by treatment with diodoquin,paromomycin

25. Prevention Food and water must be protected from feces contamination Food and drinking water must be cooked and boiled Pay attention to personal hygiene

26. Trichomonas vaginalis Worldwide in distribution The most common pathogenic protozoan of human in industrialized countries Transmission is by contact (by sexual intercourse). Sometimes, by indirect contact, such as sharing damp washclothes / swimming clothes.

27. Morphology (trophozoite) Pear-like (teardrop), 7~32 X 5~12�m One nucleus and a axostyle projected posterior out of the body. Undulating membrane on one side (one-third the length of the body). Basal body on anterior to nucleus and produce 4 anterior flagela and 1 posterior flagellum.

29. Life cycle Resides in the female lower genital tract and the male urethra and prostate. It replicates by binary fission. It transmitted among humans by sexual intercourse, or by indirect contact.

30. Pathogenesis The normal pH of the vagina is 4~4.5 and it is maintain by the activity of lactic acid-producing bacteria. When T.v live in the vagina, T.v can disrupt lactic acid-producing bacteria, causing the pH to rise above 5. The pathogenic bacteria survive in the vagina and developed fast. Inflammation or vaginitis.

31. Clinical features The incubation period is 5~28 days. In women, vaginitis with purulent discharge is prominent symptom, be accompanied by vulva and cervical lesions, abdominal pain, dysuria. In men, asymptomatic (common) ; urethritis, epididymitis and prostatitis (occasional)

32. Laboratory diagnosis Microscopic examination of wet mounts : detect actively motile organisms. In women, examination should be performed on vaginal and urethral secretions. In men, anterior urethral or prostatic secretions should be examined.

33. Treatment Treatment should include all sexual partners of the infected persons. The drugs of choice are metronidazole and tinidazole.