This document provides information about Giardia intestinalis and Trichomonas vaginalis. It discusses their taxonomy, morphology, life cycles, pathogenesis, clinical features, diagnosis, and treatment. For Giardia, key points are that it causes giardiasis and has a cyst infectious form, while Trichomonas causes trichomoniasis and infects the urogenital tract through sexual transmission. Both can be diagnosed microscopically and treated with metronidazole.

1. Giardia intestinalis
Dr. Md. Abdullah Yusuf
Assistant Professor (Microbiology)
Email: ayusuf75@yahoo.com

2. Leaning Objectives
• Taxomony
• History
• Morphology
• Life cycle
• Virulence Factors
• Pathogenesis
• Clinical Features
• Diagnosis
• Treatment

3. Taxonomic position
• Protozoa
• Mastigophora
• Diplomonadida
• Intestine

4. Similar Name
• Giardia intestinalis
• Giardia lamblia
• Giardia duodenalis

5. Disease Produce
• Giardiasis

6. History
• In 1681
– seen by Antonie van Leeuwenhoek
• In 1859
– Initially named as Cercomonas intestinalis by
Lambl
• In 1915
– renamed Giardia lamblia by Stites
– in honor of Prof. A. Giard of Paris and Dr. F. Lambl
of Parague

7. Habitat
• Small Intestine
–Duodenum
–Jejunum

8. Morphological Forms
• Trophozoites
–Pathogenic Form
• Cyst
–Infective Form

9. Morphology of Trophozoite
• Active, motile, feeding stage
• Pear-shaped
–in side view
• Badminton racket shaped
–in front view
• Causes the pathology in small intestine
• Has a cytoskeleton
–two nuclei
–4 pairs of flagella (8 flagellae)

11. Picture A is a line drawing of Giardia lamblia trophozoite.
Picture B is a trophozoite stained with trichrome.
Pictures C and D stained with iron hematoxylin

12. Morphology of Cyst
• Oval shaped
• Contains 4 nuclei
–2 nuclei in each side
• Axostyle present diagonally
• Resistant to chlorine and cold water
• killed by heat and desiccation
• removed by filtration

15. Picture A is a line drawing of the perfect G. lamblia cyst.
Picture B is stained with iodine.
Pictures C and D are stained with iron-hematoxylin

16. Life Cycle
• Infective Form
–Cysts
• Both cysts and trophozoites
–found in the feces
• In small intestine
–excystation releases trophozoites
–each cyst- 2 trophozoites)

17. Mode of Infection
• Ingestion of cysts in contaminated water,
food
• Fecal-oral route (hands or fomites)
• Homosexual Male
–Oral-Anal Sex (Gay community)

18. Life Cycle
• Trophozoites multiply by
–longitudinal binary fission
• Remaining in the lumen of proximal small
bowel
• Free or attached to mucosa by ventral
sucking disk
• Cysts are infectious
–when passed in the stool or shortly
afterward

19. Life cycle

20. Virulence factors
• Cytoskeleton
–Actin, myosin and tropomyosin
–Mediates mechanical adherence to
intestinal wall by ventral surface

21. Pathogenesis
• Ingestion of one or more cysts may cause
disease
• Mechanically blocking absorptive surface of
intestinal brush border
• Direct damage to intestinal epithelium
• trophozoite causes inflammation of the
duodenal mucosa
–leading to malabsorption of protein and
fat

22. Non-invasive Pathogen
• does not invade the mucosa
• does not enter the bloodstream

23. Clinical Features
• Varies from
–asymptomatic carrier to
–severe Loose motion and malabsorption
• Incubation period
–1 to 14 days (average of 7 days)
–Usually lasts for 1 to 3 weeks

24. Clinical Features
• Clinical Symptoms include
–Fatty diarrhea (Steatorrhoea)
–Abdominal pain
–Bloating
–Nausea
–Vomiting

25. Steatorrhoea
• Stool Characteristics
–Yellowish Colour
–Watery or Semisolid
–Greasy with excess fat
–Bulky
–Foul smelling

26. Cause of Steatorrhoea
• Block the common bile duct opening
(ampula of Vater)
• Hamper bile secretion
• Fat can’t absorb
• Passage of fat with stool

27. Clinical Features
• In chronic giardiasis
–symptoms recurrent with malabsorption
• Infection with G. lamblia
–independently associated with a risk of
stunted growth

28. Lab Diagnosis
Microscopic Examination of stool
• Wet Mount Preparation
–Detected in 50 to 70% cases with a
single specimen
–90% after three specimens

29. Lab Diagnosis
• Detection of antigen by ELISA or IFT
–using antibodies directed against either
cyst or trophozoite antigens
–Sensitivity 90 to 99% and specificity 95
to 100%

30. Treatment
• Metronidazole
• Secnidazole
• Tinidazole
• Ornidazole

31. Prevention
• Intake purified water
• Maintain food hygiene
• Maintain hand hygiene
• Personal hygiene after defaecation

32. Trichomonas

33. Species Name
Pathogenic species
• Trichomonas vaginalis
–cause diseases in genitourinary organs
–Called as urogenital flagellates

34. Species Name
Non-pathogenic species
• Trichomonas tenax
–commensal of mouth
• Trichomonas hominis
–commensal intestine

35. Disease Produce
• Trichomoniasis

36. Morphological Form
• Trophozoites

37. Habitat
• Female
–Vagina
• Male
–Prostate
• Found only in humans
–no animal reservoir

38. Site of Infection
• In women
–Vulva
–Vagina
–Cervix
• In men
–Prostate
–seminal vesicles
–Urethra

39. Morphological Form
• Trophozoite form
–Infective
–Pathogenic
–Diagnostic

40. Morphology of Trichomonas vaginalis
• Pear shaped trophozoites
• 3 to 5 flagellae present
• Oval nucleus
• Undulating membrane present
• No cystic stage

41. Route of Transmission
– Sexually Transmitted
– Swimming in infected pond water

43. Clinical Features
• Infective Form
–Trophozoites
• Disease
–Vaginitis in female
–Urethritis in male
• Asymptomatic cases more in male than
female
• Usually Male carrier & female is sufferer

44. Clinical Features of Vaginal
Trichomoniasis
• Local tenderness
• Vulval pruritus
• Severe itching and Burning sensation
• Foul smelling abnormal vaginal discharge
• Dyspareunia

45. Clinical Features
Characteristics of Vaginal Discharge
• Frothy
• Greenish yellow or cream-colored
discharge
• Profuse Watery discharge
• Foul-smelling
• accompanied by itching and burning

46. Lab Diagnosis
Specimen
• Female
–High vaginal swab or vaginal discharge
• Male
–secretion from urethra or prostate

47. Lab Diagnosis
Microscopic Examination
• Wet mount preparation
–Trophozoites form
–Shooting star like or typical Jerky
movement

48. Lab Diagnosis
• Culture
–In CPLM media
• Serological Tests
–IHA
–Gel Diffusion test
• Molecular Test
–PCR and DOT-blot tests are also
available

49. Treatment
• Metronidazole
–400mg tds for 7 days
• Secnidazole
–1000mg 2 tab stat
• Both the partners should be treated
–to prevent re-infection

50. Prevention
• Avoid penetrative sexual intercourse
• Avoid multiple sex partner
• Avoid swimming in infected pond water

51. Thank you