PARASITOLOGY

Multiflagellates

n Trichomonas vaginalis(single host), lives within the vagina, prostrate and urethra;

transmitted via sexual intercourse.

n Giardia lamblia(single host), lives in gut; transmitted via drinking water, see Fig. 2.2.

The terminology used to name the various stages found in flagellates is based on the

characteristics of the flagellum, its position and arrangement within the body, and the

position of the kinetoplast and was proposed by Hoare and Wallace in 1966.

n Amastigote: represent rounded forms with no external flagellum, eg Leishmania.

n Promastigote: the flagellum arises from near to an antinuclear kinetoplast and emerges

from the anterior end, eg Leptommonas.

n Opisthomastigote: these have a post-nuclear kinetoplast. The flagellum arises near it

and emerges from the posterior end of the body, eg Herpetomonas.

n Epimastigote: the kinetoplast is alongside the nucleus, the flagellum arises near it,

emerges from the side of the body and runs along a short undulating membrane, eg

Blastocrithidiaand stages of Trypanosomaand Herpetomonas.

n Trypanomastigote: these have a post-nuclear kinetoplast. The flagellum arises near

it, emerges out from the side of the body and runs along an undulating membrane,

eg Trypanosoma. The trypanomastigotes are the final developmental stage of the

Trypanosomaand Herpetomonas.

n Choanomastigotes: these have an antinuclear kinetoplast. The flagellum arises from a

funnel-shaped pocket and emerges from the anterior end of the body, eg Crithidia.

n 2.4 SPORE-FORMING PROTOZOANS

Phylum Apicomplexa, Class Coccidea eg Eimeria, Plasmodium, Sarcocystis, Toxoplasma, see

Fig. 2.3.

PROTOZOA

Adhesive disk

Median body

Kinetosome

Nucleus

Anterior flagellum

Posterior falgellum

Axostyle

Ventral flagellum

Caudal flagellum

• Figure 2.2Giardia
  intestinalis, a
  multiflagellated binucleate
  protozoan with a central
  axostyle that may assist in
  maintaining a constant
  shape. The normal habitat
  of Giardiais the lumen of
  the intestine.