Giardia and Trichomonas by Dr. Rakesh

1. Intestinal, Oral and Genital Flagellates
Dr. Rakesh Prasad Sah
Assistant Professor, Microbiology

2. • Intestinal E. histolytica
• G. lamblia
• Cryptosporidium
• Urogenital Tract Trichomonas vaginalis
• Blood and Tissue Plasmodium
• Toxoplasma
• Trypanosoma
Protozoa

3. • Phylum: SARCOMASTIGOPHORA
• Subphylum: MASTIGOPHORA
• Class: ZOOMASTIGOPHORA
• The parasites belonging to this group possess
one or more whip-like flagella. (Organ of
locomotion)
• So they are known as flagellates.
Introduction

4. • Depending on their habitat, they are placed
under two groups.
– Lumen dwelling flagellates : Intestinal /Oral
/Genital tract parasite.
– Hemoflagellates : Blood & Tissue parasite.
• Leishmania spp : RE cells
• Trypanosoma brucei : Connective tissue & blood
• Trypanosoma cruzi : RE cells & blood
CLASSIFICATION

5. Group Parasites Habitat
Lumen-dwelling
flagellates
Giardia lamblia Duodenum and jejunum
Trichomonas vaginalis
Trichomonas tenax Vagina and Urethra
Trichomonas hominis Mouth
Chilomastix mesnili Large instestine (cecum)
Enteromons hominis Large instestine (cecum)
Retrortamonas Large instestine (colon)
Dientamoeba fragilis Large instestine (cecum and
colon)
Hemoflagellates Leishmania spp R.E. Cells
Trypanosoma brucei Connective tissue and blood
Trypanosoma cruzi R.E. cells and blood
Flagellates

6. Giardia lamblia

7. • Duodenum & the upper
part of the jejunum.
• THE ONLY PROTOZOAN
PARASITE FOUND IN
THE LUMEN OF
HUMAN SMALL
INTESTINE.
HABITAT

8. • GEOGRAPHICAL DISTRIBUTION : m/c protozoan pathogen,
worldwide distributed.
• EPIDEMIOLOGY :
• Areas with poor sanitation , especially tropics & subtropics.
• Common in younger age group.
• Traveller’s diarrhea is common among visitors caused by giardiasis
through contaminated water.
GEOGRAPHICAL SPREAD & EPIDEMICS

9. Introduction

10. • It exists in two forms –
– Trophozoit (Vegetative form)
– Cyst (Infective form)
Morphology
S.No. Trophozoite Cyst
Half tennish racket/heart shaped
with 8 flagella
An oval (egg-shape) body in shape
14µmx7µmx4µm 12µmx7µm
Contain two nuclei Contain 4 nuclei

11. • It exists in two forms –
– Trophozoit (Vegetative form)
– Cyst (Infective form)
Morphology

12. • Tennis racket or heart shaped or pyriform shaped.
• Dorsal surface – convex
• Ventral surface – concave & having sucking disk (for attachment)
• 14 μm x 7μm x 4μm
• Anterior end – broad & rounded
• Posterior end – tappers to a sharp point.
• Bilaterally symmetrical :
– Nuclei – 1 pair
– Flagella with blepharoblast – 4 pair
– Axostyle – 1 pair (along the midline)
– Parabasal / Median body – 1 pair ( transverse & posterior to sucking
disc)
• Falling leaf motility around its long axis.
TROPHOZOITE

13. Introduction

14. TROPHOZOITE

15. • Round or oval in shape.
• Surrounded by hyaline cyst wall.
• 12μm x 7μm.
• Axostyle – diagonally placed, form a deviding line
within cyst.
• 4 nuclei – clustered at one end or at opposite
poles (each pairs).
• Remnants of flagella and margins of the sucking
disc may be seen inside the cytoplasm of a young
cyst.
• An acid environment often causes the parasite to
encyst.
CYST

16. Introduction

17. Introduction

18. • Discovered by Karapetyan :
• Giardia together with yeast (Candida
guillermondi)
• Medium :
– Chick embryo extract
– Human serum
– Hottinger’s digest (tryptic meat digest)
– Hank’s solution
CULTIVATION

19. • Common in younger age & uncommon in adult,
suggesting that an efficient immunity has
developed.
• Both humoral & cell mediated immunity are
important.
• RISK FACTORS :
– IgA deficient person (hypo- or agammaglobulinaemia)
– Blood group A
– Achlorhydria
– Malnutrition
– Use of cannabis
– Chronic pancreatitis
– Immune defects (19A deficiency)
IMMUNITY & RISK FACTORS

20. • Infection is occured by ingestion of cyst in
contaminated food & water.
• Direct transmission from person to person
may occure in children, male homosexuals,
mentally ill persons.
MODE OF TRANSMISSION

21. Introduction

22. LIFE CYCLE

23. Introduction

24. • Giardia passes its life cycle through one host.
• Infective form – mature cyst (10 to 100 cysts are enough to infection).
• Ingestion of the cyst via food or drink.
• Within 30 min of ingestion, the cyst hatches out into two trophozoites.
• They multiply in enormous numbers by binary fission & colonise in
duodenum.
• They live in the duodenum & upper part of the jejunum, feeding by
pinocytosis.
• During unfavourable condition, encystment occurs usually in the colon. A
thick resistant wall is
• secreted by the parasite.
• The cystic cell is then divided into two within the cyst wall.
• Cysts are passed in stool (may be 200,000) & remain viable in soil & water
for several weeks.
Introduction

26. Introduction

27. Introduction
Traumatic & irritative effect

29. • With the help of sucking disc they adhere to the convex surface of
epithelial cells & crypts of intestinal mucosa.
• It doesn’t invade the tissues.
• May cause abnormalities of villous architecture by apoptosis.
• Capable of producing harm by the toxic effect (VSSP- Variant Specific
Surface Proteins), irritative effect & spoliative action (by diverting the
nutriments).
• To avoid the high acidity of proximal duodenum, Giardia often localizes in
the biliary tract (gall bladder).
PATHOGENESIS

30. Incubation Period :- 2 weeks
CLINICAL FEATURES
• Giardiasis
• Silent cases without any symptoms.
• Intestinal :
– Enteritis & Enterocolitis
– Malabsorption syndrome (Steatorrhoea)
– Mucus diarrhea
– Dull epigastric pain
– Flatulence
– Chronic enteritis
– Acute enterocolitis
• General :
– Fever
– Anaemia
– Weight loss
– Allergic manifestations.
– Chronic cholecystopathy.
• Chronic cholecystopathy

32. STOOL EXAMINATION

33. STOOL EXAMINATION
Trophozoite

34. STOOL EXAMINATION

35. STOOL EXAMINATION
Cyst

36. Enterotest

38. Introduction

41. Trichomonas Vaginalis

42. Introduction
•Genus Trichomonas has three species:-
Trichomonas
Trophozoite Cyst
Differs from other flagellates

43. History and Distribution
• First observed by Donne(1836) in vaginal secretion.
• Prevalence of Trichomoniasis varies from 5% patients at
hospital to 75% in sexual workers.

44. Introduction
• Trichomonas infects the urogenital tract.
• Sexually transmitted infection known as Trichomoniasis.
Habitat
• Females : vagina, cervix, bartholin’s gland, urethra and urinary
bladder.
• Males : urethra, prostate anterior preputial sac

45. Introduction

46. Morphology
 Ovoid or pear shaped
 10 to 30μm long and 5 to 10μm broad
 Undulating membrane
 Costa
 4 ant. flagella & 5th running along
undulating membrane
 Axostyle
 Jerky motility
 Binary fission
 Infetive form : trophozoite
 Culture : CPLM medium (cysteine,peptone,liver,maltose)

47. Structure of Tricomonas
vaginitis

50. Life Cycle
 The life cycle consist
only of a trophozoite
stage.
 Transmitted by
direct contact during
sexual intercourse.
 None venereal
transmission is rare.

51. Trichomoniasis
Mode of infection ; STD
reservoir for this species - human genital
tract
Sexually transmitted infection of the
urogenital tract
Vaginitis in women- site of infection –
vagina,urethra
Urethritis in men - site of infection –
urethra,prostate
Trichomonas vaginalis is the etiologic agent of Trichomoniasis.

52. Pathogenesis
• Incubation Period :- 4 days to 4 weeks
Infects/adherent to squamous epithelium but not columnar
epithelium
Secretes  cystein proteases, adhesins, lactic acid and acetic acid
Disrupts Glycogen levels and rises the pH of vaginal fluid (> 4.9)
It is not an invasive parasite

53. Pathogenesis
Causes petachial haemorrhage and mucosal capillary dilation
(strawberry mucosa), metaplastic changes and desquamation of
vaginal epithelium.
Intracellular edema and “ chicken like epithelium” is
the most characteristic feature.
Is an obligate parasite and can not live without close association with
the vaginal, urethral, or prostatic tissues

54. Clinical Features
• Infection  asymptomatic MALES
• Urethritis
• Epididymitis
• Prostatitis
• Burning after urination or ejaculation
• Burning of urethra
• Slight discharge from urethra

55. Clinical Features
• In Females
• Discomfort during intercourse
• Vaginal Discharge (Severe pruritic vaginitis with an offensive,
yellowish green, often frothy discharge)
• Dysuria and dyspareunia.
• Cervical erosion is common
• Itching and swelling of labia
• Vaginal odor (foul or strong smell)

57. Microscopic Examination
• Wet Mount :- Vaginal or
Urethral discharge
• Permanent Stain: with
acridine orange,
papanicolaou & Giemsa
stains
DFT :- more sensitive than wet mount

58. Culture
• Gold Standard & more sensitive (95%)
• Temp 35-370C & pH 5.5. -6.0
• CPLM (Cysteine-peptone-liver-maltose)
medium
• PEM (Plastic envelope medium)
ELISA
Mol. Test