Lecture 4 Trichomoniasis and Ectoparasites

Urogenital System Microbiology… Lecture 4 Trichomoniasis and Ectoparasites 1 _ First: Trichomonas vaginalis I. II. III. IV. Structure: - Oval, 7 X 15 µm, with single elongated nucleus - Has small cytosome (working as cell mouth). - Five flagella; arise near the cytosome: • 4 exit the cell • the fifth bends back & runs posteriorly Along the outer edge of undulating membrane - Axostyle: Supporting rod containing micro-Tubules, bisects the trophozoite longitudinally and protrudes through the posterior end… for Attachment. General features: - Can move in Jerky, non-directional movements - Can be grown on artificial media under anaerobic conditions at pH 5.5 to 6.0 (acidic ph.) • Vaginal pH is 4.5 so when this parasite effects the vagina it will rise its pH causing injury to vaginal mucosa - Lacks a cyst form (vs some other protozoa) …Only trophozoite - Can survive outside host for 1-2 hours on Moist surfaces. (Die in dry areas) - In urine, semen and water, it may be viable for up to 24 hours (it’s the most resistant protozoan) Epidemiology: - Transmitted by sexual contact - 25% of women infected, and in 30% - 70% of these infected women, there male partners are also infected - rare in virgins (because it’s sexual transmitted 😃) Pathogenesis: - Causes destruction of epithelium of GUT with Inflammatory reaction & petechial hemorrhages - For attachment it has: adhesins, Laminin-binding Protein, lectin-binding carbohydrates - Produces proteinases: degrade/destroys IgG & IgA, and Cause cytolytic effects - Affects the innate immunity: • Triggers TLR (toll-like receptors), which stimulate pro-inflammatory cytokines release • this will lead to influx of PMN (Polymorphonuclear Neutrophils) and CD4 cells - Humoral and cellular immune responses follow - Escape immune detection by changing surface Antigenic determinants 2 V. Clinical disease, Trichomoniasis - In females: • Vagina and cervix are the site of infection • Cause Persistent vaginitis • 50% of infected women are asymptomatic • Manifestation within 6 months after infection: – 75% discharge (thin, yellow, frothy) – 50% vulvar itching or burning – 50% dyspareunia (painful intercourse) – 50% dysuria – 10% disagreeable odor😷 – Red vaginal and endocervical mucosa (🍓strawberry cervix🍓), due to inflammation • Increase the Susceptibility to: HIV, and preterm birth (if it’s diagnosed during pregnancy) - In males: • Urethra and prostate are the sites infection • Also, seminal vesicles and epididymis, may be involved • Usually asymptomatic (the parasites are removed by Urination) … so when a female diagnosed, ask hair partner to do a test • Manifestations, if present: – Recurrent dysuria – Scant non-purulent discharge, Purulent urethritis is rare • Suspected as non-gonococcal urethritis (gonorrhea is ruled out because he has a negative gonorrhea culture and/or gram stain) VI. Diagnosis: - Wet mount preparation (motile organism) • Test sensitivity (SS)= 50% - 60% • Female specimen: Drop of vaginal discharge • Male specimen: Urethral exudate; urine sediment after prostate massage - Direct Immunofluorescent • Test sensitivity: 70%-90% - Culture, but requires several days, used for researches - Nucleic acid amplification (NAA) methods: • Most sensitive tests for diagnosis, but these methods are expensive and not available every where 3 VII. Treatment: - Oral metronidazole (cure >95%) in a single dose or over 7 days, used with these considerations: • Simultaneous treatment of sexual partners • Stop alcohol , contraindicated with metronidazole • Drug not used during the first trimester of Pregnancy • High dose for long time may be carcinogenic _ Second: Scabies (seven-year itch; Ectoparasite): I. II. III. IV. V. VI. The Cause: Sarcoptes scabiei (itch mite) Clinical picture: - Itching mainly at night + Pimple( ‫)بثرة‬rash - skin burrows on Wrist, between fingers, and waistline May appears as crusted scabies in immunocompromised Transmission: - Physical as in prisons - sexual contact Diagnosis: Detection of mites or their eggs Treatment - Permethrin: From neck – down ، leave it overnight, for Once time or repeated if required - Ivermectin & Benzyl Benzoate (alternative) - Antihistamine for itching. _third: Phthirus pubis I. General features: - It’s called: Pubic Lice or Crab Lice - The Condition is called : Pediculosis pubis; Phthiriasis pubis - It’s an Obligate Ectoparasite, Smaller than head and body lice with rounded body - Common in pubic hair; sometimes eyelashes - Develop itching, hypersensitivity, macules - Transmission: Direct contact, sexual contact or via clothes & towels - In children: an Evidence for Sexual abuse (Be aware, it’s a crime!) 4 II. III. Diagnosis: - Detection of: • nits (eggs) whitish/yellow • Nymphs (immature lice after hatching) • Adult lice. Treatment: - Nits & adult lice can be Removed by forceps Or hair cut - Topically Permethrin - Pyrethrin - Piperonyl butoxide (PBO; waxy white). - Alternative is Lindane (neurotoxic; careful in using It since is moderately hazardous). _ past years’ questions: - Trichomonas vaginalis is characterized by all of the following features except: A.jerky non-directional movement. B. It’s the most sensitive protozoan C. With five flagella. D. One Axostyle e. Lack of cyst form The answer: B 5