PARASITOLOGY

Basal body

Kinetoplast

Glycosomes Nucleus

Marginal flagellum

Undulating membrane

Free flagellum

Mitochodrion

Mature Trypanosoma brucei

Slender form

Intermediate form

Stumpy form

Procyclic form

Forms of T. brucei

• Figure 2.1A mature
  Trypanasoma brucei. The
  African trypanosome has a
  single free flagellum, an
  undulating membrane,
  a single nucleus, a
  kinetoplast and basal
  body. The mature
  trypanomastigote form
  is normally found within
  the body fluids of the
  mammalian host. The
  other forms are part of the
  growth and development
  that occurs in both the
  mammalian and arthropod
  hosts.

Zooflagellated protozoa:

n Free-living and sessile forms in either marine or fresh water.

n Parasitic forms inhabit plants, invertebrates and vertebrates; often have complex

life-cycles.

Approximately 25% of zooflagellates are parasitic. The majority have two hosts in their

life-cycle. An intermediate host (normally a vector) and a definitive host. Examples of

parastic zooflagellates:

n Trypanosoma brucei, causal agent of African sleeping sickness, see Fig. 2.1.

Single flagellum and nucleus; large undulating membrane; a basal body (kineso-

tome) and a kinetoplast (a large mitochondrion-like structure); transmitted by the

tsetse-fly; no sexual reproduction, only asexual reproduction.

n Leishmania donovani, transmitted by biting sandflies, causes skin damage to humans.

PARASITOLOGY