 Giardia lamblia (pathogenic)- small intestine.  Trichomonas vaginalis (pathogenic)- occurs in reproductive and urinary system of people.  Trichomonas tenax- endocommensal in mouth (tooth sockets).  Pentatrichomonas hominis- endocommensal in large intestine and cecum.  Chilomastix mesnili (endocommensal)- lives in the large intestine.

 CLASS- ZOOMASTIGOPHERA  The parasites belonging to this group of protozoa possess one or more flagella giving them the power of motility.

 These are classified according to their habitat into TWO groups: 1.Intestinal,oral & genital flagellates. 2.Blood & tissue flagllates.

 World wide  Habitat: Duodenum and the upper part of the jejunum of the man.

MORPHOLOGY  Exits in two phases: A) Trophozoite B) Cyst

 When viewed flat,the shape of the trophozoite is like that of badminton racket.  The dorsal surface is convex & the ventral surface is concave like a sucking disc.  The size of the trophpzoite is 14 micrometer long & 7 micrometer broad.  All organs of the body are paired. Thus there are two axostyles,two nuclei and four pairs of flagella.

 It is oval in shape and measures 12 micrometer long and 7 micrometer. Giardia intestinalis

 In the trophozoite stage the parasites multiplies in the intestine of manby binary fission.  When conditions in the duodenum are unfavourable,encystment occurs,usually in large intestine.  During encystment the cell divides into two cyst.  Infection of man is brought by ingestion of cyst.  Within 30 min. of ingestion the cyst hatches out two trophozoites which then miltiply in enormous numbers and colonise in the duodenum.

 With the help of the sucking disc the parasites attach itself on the epithelial cells of the intestine and may cause disturbance, leading to malabsorption of fat.  The patient may complain of persistent looseness of bowels, and mild steatorrhoea.

 A microscopic examination of freshly passed stools for demonstration of trophpzoites and cyst.  Giardia trophozoites may be seen in the bile.

 These are the common flagellates of the tropics and are frequently observed in diarrhoeic stools.  They exist only in the trophozoite phase & there is no cystic phase.  These are pear shaped bodies & measure 10 to 12 micrometer in length.  There are 3 to 5 anterior flagella that are free.

 There are single oval nucleus at the round anterior end  The base is supported by a rod like structure, the costa.  The axostyle runs down the middle of the body & ends in the pointed tail like extremity.

 According to their habitat it ts classified into the following species:  A) Trichomonas hominis  B) Trichomonas tenax  C) Trichomonas vaginalis

 These flagellates are of no pathogenic importance except for T. vaginalis which is found in large numbers in leucorrhoeic discharge of females.  In case of man, T. vaginalis infection is sexually transmitted disease causing Urethritis.

 It lives in the reproductive and urinary system of people.  More specifically it is found in the vagina and urethra of women, and in the prostate, seminal vesicles, and urethra of men.  It is more common in women, and hard to find in men because most are asymptomatic.  It is cosmopolitan in distribution, however prevalence is not uniform because of sanitary and hygiene habits (depends on surroundings).  20-40% in Women  15% in Men

 It is pathogenic and causes Vaginitis.  Suffix means “inflamed” or “inflammation of “  So inflammation of the vagina.  Also can be called Trichomoniasis.  Emphasis on a organism.  Etiological agent  organism that causes something.

 Usually none.  Particularly in males. They don’t show symptoms.  In females it ranges from: chaffing, itching, frothing/clear/creamy discharge that is profuse from vagina (leukorrhea).

 Eventually females get a disintegration of vaginal epithelial lining.  Natural flora (bacteria ) keep the pH of the vagina at and ordinarily this discourages infections.  T. vaginalis can survive at a low pH.  Once established it causes a shift toward alkalinity (pH 5-6) which further encourages its growth.  There is a tendency to explain stillbirths, spontaneous abortions, morbidity to women who have vaginitis. 

 Sexual contact.  Soiled clothing/linens; sharing of wash cloth, clothing, etc.  T. vaginalis can live in moist clothing for one day!  Also seems to show up in small children: so probably not transmitted sexually.  The role of toilets? Feasible but no real evidence.

29  Motile trichomonads seen on saline wet mount  Vaginal pH >4.5 often present  Positive amine test  Culture is the “gold standard”  Pap smear has limited sensitivity and low specificity  DNA probes  Male diagnosis - Culture  First void urine concentrated  Urethral swab

30 Saline: 40X objective PMN Trichomonas* Squamous epithelial cells PMN Trichomonas* Yeast buds