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  1. 1. Toxoplasma gondii Trichomonas vaginalis Dr Kamran Afzal Classified Microbiologist
  2. 2. Toxoplasma gondii
  3. 3. What is Toxoplasma gondii ? <ul><li>Class Sporozoa </li></ul><ul><li>Protozoan parasite capable of infecting all vertebrates </li></ul><ul><li>Remains alive in soil for up to a year, consumed by cats and other hosts </li></ul><ul><li>Toxoplasma in meat can be killed by cooking at 152ºF (66ºC) or higher or freezing for a day in a household freezer </li></ul>
  4. 4. Morphology
  5. 5. Toxoplasma - Organelles
  6. 6. Transmission <ul><li>Felines are primary (definitive) hosts: only sexually reproductive in feline gut epithelium, disperses through oocysts in feces </li></ul><ul><li>Vertebrates are the intermediate host </li></ul><ul><ul><li>Amphibians, fish, reptiles and all warm-blooded animals including man </li></ul></ul><ul><li>There are 3 principal ways Toxoplasmosis is transmitted: </li></ul><ul><ul><li>Ingestion of food or water or inhalation of dust contaminated with a very resistant form of Toxoplasma called the ‘oocyst’ </li></ul></ul><ul><ul><li>Consumption and handling of undercooked or raw meat from infected animals </li></ul></ul><ul><ul><li>Directly from pregnant mother to unborn child </li></ul></ul><ul><ul><ul><li>Transplacental Transmission - Tachyzoites multiply within the placenta and spread to the fetus </li></ul></ul></ul>
  7. 7. Transmission <ul><li>Human/Congenital Transfer </li></ul>
  8. 8. Toxoplasmosis Cycle
  9. 9. Toxoplasmosis Cycle
  10. 10. The Toxoplasma life cycle
  11. 11. Factors determining infection prevalence <ul><li>Climate </li></ul><ul><li>Dwelling among cats </li></ul><ul><li>Working with soil/poor hygiene </li></ul><ul><li>Cuisine including rare or undercooked meats </li></ul>
  12. 12. Oocyst <ul><li>Cats shed oocysts for only 1-2 weeks following infection </li></ul><ul><ul><li>Oocysts sporulate and become infective in 1-5 days </li></ul></ul>
  13. 13. Tachyzoites
  14. 14. Latent Bradyzoite cysts confer life-long infection <ul><li>Bradyzoites are resistant to all currently available drugs </li></ul><ul><li>Bradyzoites (not tachyzoites) are resistant to low pH and digestive enzymes during stomach passage </li></ul><ul><li>Cysts form in brain and skeletal muscle </li></ul><ul><li>Bradyzoite cyst persist in the immune host </li></ul><ul><li>Protective cyst wall is finally dissolved and bradyzoites infect tissue and transform into tachyzoites </li></ul><ul><li>Bradyzoite cysts are highly infective if ingested </li></ul>
  15. 15. Tachyzoite – Bradyzoite conversion
  16. 16. Symptoms <ul><li>Majority of cases are asymptomatic </li></ul><ul><li>There are two populations at high risk for infection with Toxoplasma; pregnant women and immunosuppressed individuals </li></ul><ul><li>Congenital infections occur in about 1/1000 pregnancies of which </li></ul><ul><ul><li>5-10% result in miscarriage </li></ul></ul><ul><ul><li>8-15% result in serious brain and eye damage to the fetus </li></ul></ul><ul><li>Blindness, retino-chorditis, hydrocephalus, loss of hearing, seizures and mental retardation are common symptoms of toxoplasmosis in congenitally infected children </li></ul><ul><ul><li>Death in severe cases </li></ul></ul>
  17. 17. <ul><li>In immunocompetent adults, toxoplasmosis, may produce flu-like symptoms, sometimes associated with lymphadenopathy </li></ul><ul><li>In immunocompromised individuals, infection results in generalized parasitemia with involvement of brain, liver, lung and other organs, and often death </li></ul>
  18. 18. Congenital toxoplasmosis <ul><li>Both the probability and severity of the disease depend on when the infection takes place during pregnancy </li></ul><ul><li>Early: low transmission, but severe disease </li></ul><ul><li>Late: high transmission, but more benign symptoms </li></ul><ul><li>Children who are asymptomatic at birth often can develop disease later on </li></ul>
  19. 19. Toxoplasmosis Disease
  20. 20. Does T. gondii affect people? <ul><li>YES, it modifies the behavior of the host </li></ul><ul><li>Mild flu-like symptoms initially, then the parasite becomes dormant in the brain (or other tissues) </li></ul><ul><li>Psychomotor disturbances and intracerebral calcification </li></ul><ul><li>Long-term personality changes </li></ul><ul><li>Mechanism in brain = unknown; speculated to be elevated dopamine levels caused by altered cytokine levels </li></ul><ul><li>(brain’s local immune response against T. gondii ) </li></ul>
  21. 21. Laboratory Diagnosis <ul><li>Serological Testing—ELISA tests </li></ul><ul><ul><li>IgG and IgM </li></ul></ul><ul><ul><li>Titers of IgG can last for years </li></ul></ul><ul><ul><li>Titers of IgM usually persist for only 12 weeks </li></ul></ul><ul><li>Toxoplasmosis IHA Test </li></ul><ul><li>Biopsy and histopathology </li></ul><ul><li>Immunofluorescence </li></ul><ul><li>PCR </li></ul>
  22. 22. Serology workup Antibody testing Antibody testing may be Followed by prenatal PCR or by CT or MRI scans
  23. 23. Treatment <ul><li>Antibiotics </li></ul><ul><ul><li>Potentiated Sulfa Drugs </li></ul></ul><ul><ul><ul><li>Acute infections benefit from pyrimethamine or sulphadiazine </li></ul></ul></ul><ul><ul><li>Clindamycin and Spiramycin are successful alternatives </li></ul></ul>
  24. 24. Prevention and Control <ul><li>Cook all meat and fish thoroughly </li></ul><ul><li>Freezing at -14 o C for several hours kills tissue cysts </li></ul><ul><li>Wash hands thoroughly after preparing raw meats and fishes </li></ul><ul><ul><li>Pork is reported to be the most common meat infected </li></ul></ul><ul><li>Pregnant women are advised to avoid cat litter or gardening , handle uncooked and undercooked meat carefully </li></ul><ul><ul><li>Have another person clean the litter box </li></ul></ul><ul><li>Immunocompromised individuals should use the same caution with cat litter and cooking of meats </li></ul>
  25. 25. Trichomonas vaginalis
  26. 26. Trichomonas vaginalis <ul><li>Phylum Parabasalia </li></ul><ul><li>Trichomonas vaginalis is a flagellated protozoan </li></ul><ul><li>Median axostyle; up to 5 flagellae </li></ul><ul><li>Trophozite is the only stage present in the life cycle </li></ul><ul><li>It is 7-30 µm long by 5-10µm wide </li></ul><ul><li>It can survive outside the body at temp as low as 15 0 C for up to 48 hours </li></ul>
  27. 27. Morphology
  28. 28. Prevalence <ul><li>Most common cause of vaginitis world wide </li></ul><ul><li>It is cosmopolitan in distribution, however prevalence is not uniform because of sanitary and hygiene habits </li></ul><ul><ul><li>20-40% in Women </li></ul></ul><ul><ul><li>10% in Men </li></ul></ul>
  29. 29. Transmission <ul><li>It lives in the reproductive and urinary systems of humans </li></ul><ul><ul><li>Human is the only host </li></ul></ul><ul><ul><li>More specifically it is found in the vagina and urethra of women, and in the prostate, seminal vesicles, and urethra of men </li></ul></ul><ul><li>It is more common in women, and hard to find in men because most are asymptomatic </li></ul><ul><li>By sexual contact </li></ul><ul><li>Transfer to neonates from infected mothers </li></ul><ul><li>T. vaginalis can live in moist clothing for 1-2 days </li></ul><ul><li>In very rare instances it has passed through sharing wet towels, washing of clothes together or sharing bathing suits </li></ul>
  30. 30. Trichomonas vaginalis Life Cycle
  31. 31. Why is it Pathogenic in Females? <ul><li>Natural flora (bacteria) keep the pH of the vagina at 4-4.5 and ordinarily this discourages infections </li></ul><ul><li>T. vaginalis can survive at a low pH </li></ul><ul><li>Once established it causes a shift towards alkalinity (pH 5-6) which further encourages its growth </li></ul>
  32. 32. Three main types of vaginitis <ul><ul><li>Bacterial vaginosis </li></ul></ul><ul><ul><ul><ul><li>About 50% of vaginitis cases </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Gardnerella or a mixed anaerobes </li></ul></ul></ul></ul><ul><ul><li>Trichomoniasis </li></ul></ul><ul><ul><ul><ul><li>About 20% vaginitis cases </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Trichomonas vaginalis </li></ul></ul></ul></ul><ul><ul><li>Candidiasis </li></ul></ul><ul><ul><ul><ul><li>About 25% of vaginitis cases </li></ul></ul></ul></ul><ul><ul><ul><ul><li>C. albicans (80-92%) </li></ul></ul></ul></ul>
  33. 33. Vaginitis Differentiation
  34. 34. Vaginitis Differentiation Normal Trichomoniasis Candidiasis Bacterial Vaginosis Symptom presentation Itch, discharge, 50% asymptomatic Itch, discomfort, dysuria, thick discharge Odor, discharge, itch Vaginal discharge Clear to white Frothy, gray or yellow-green; malodorous Thick, clumpy, white “cottage cheese” Homogenous, adherent, thin, milky white; malodorous “foul fishy” Clinical findings Cervical petechiae “strawberry cervix” Inflammation and erythema Vaginal pH 3.8 - 4.2 > 4.5 Usually < 4.5 > 4.5 KOH “whiff” test Negative Often positive Negative Positive NaCl wet mount Lacto-bacilli Motile flagellated protozoa, many WBCs Few WBCs Clue cells ( > 20%), no/few WBCs KOH wet mount Pseudohyphae or spores if non- albicans species
  35. 35. Clinical Examination
  36. 36. What is Trichomoniasis? <ul><li>SYMPTOMS AND SIGNS </li></ul><ul><li>Tirchomoniasis also known as “Trich”, that causes itchy, burning, and inflammatory symptoms in women </li></ul><ul><li>Symptoms usually occur within 4 to 20 days of exposure </li></ul><ul><li>Vulva may be hyperemic, pruritic and edematous </li></ul><ul><li>The vaginal and cervical mucosa is erythematous, and punctate to petechial lesions are seen </li></ul><ul><li>When these are seen on the cervix – Strawberry cervix </li></ul><ul><li>Eventually there is disintegration of vaginal epithelial lining </li></ul><ul><li>Some patients exhibit dysuria and dyspareunia with a profuse vaginal discharge </li></ul><ul><li>The discharge is yellowish gray or green in color and foul smelling </li></ul>
  37. 37. Clinical Diagnosis <ul><li>Speculum examination (Clinical) </li></ul>
  38. 38. Laboratory Diagnosis <ul><li>Wet preparation detects 70-80% </li></ul><ul><ul><li>Diagnosis is confirmed by finding highly motile trichomonads on microscopic exam using a wet saline mount </li></ul></ul><ul><ul><li>Can also be found in urine </li></ul></ul><ul><ul><ul><li>Also seen in elevated pH </li></ul></ul></ul>
  39. 39. <ul><li>Immunofluorescence </li></ul>
  40. 40. <ul><li>PAP Smear </li></ul><ul><ul><li>H and E Stain </li></ul></ul>
  41. 41. <ul><li>Rapid diagnostic strips </li></ul><ul><li>ICT </li></ul>
  42. 42. <ul><li>Gold standard is Trichomonas culture </li></ul><ul><ul><li>Culture is most sensitive </li></ul></ul><ul><ul><li>Diamonds media </li></ul></ul><ul><li>PCR </li></ul>
  43. 43. Treatment <ul><li>Single dose of Metronidazole 2 gm once, or </li></ul><ul><li>Metronidazole PO 500 mg TDS for 7 days </li></ul><ul><li>For recurrent Trichomoniasis </li></ul><ul><ul><li>Metronidazole x 7 days and </li></ul></ul><ul><ul><li>Repeat, if still positive then give Metronidazole 2 gm BD x5d </li></ul></ul><ul><li>Tinidazole or Miconazole used if resistant </li></ul><ul><li>Metronidazole is contraindicated in the first trimester </li></ul><ul><ul><li>Intravaginal Clotrimazole 100mg vaginal suppository QID x7d </li></ul></ul><ul><li>Reinfection can happen almost immediately </li></ul><ul><li>Treat the male sexual partner </li></ul><ul><li>Prognosis  full recovery (100%) </li></ul>
  44. 44. Prevention <ul><li>Trichomoniasis may occur solely or in conjunction with other STDs, such as gonorrhea, chlamydia, syphilis and HIV </li></ul><ul><li>Personal hygiene </li></ul><ul><li>Barrier precautions </li></ul>