Protozoa 2

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Trypanosoma:

single cellular

flagellated (3 anterior flagella)

extra cellular

Kinetoplast: disc like structure within the mitochondria containing mitochondrial DNA

Life cycle:

- most cases have cycle within the tsetse fly vector = once infected, the fly is infected for life

*cattle are the most important host

Able to evade the immune system by using variable surface glycoproteins (VSG) = antigenic variation

Pathogenesis:

Degeneration of muscle tissue (oedema + wasting)

Myositis, myocarditis

Anaemia, low PCV

Loss of meat and milk production

Death if not treated

Lymph node enlargement

Zoonotic - Human African trypanosomiasis (sleeping sickness)

Leishmania:

transmitted by Phlebotomine sandflies

humans, dogs and wild rodents infected when taking a blood meal

Disease spectrum:

Cutaneous - parasites remain at site of inoculation causing long-term ulceration

Mucocutaneous - development of cutaneous leishmaniasis to mucosal tissue resulting in permanent damage

Visceral - parasites leave inoculation site and grows in liver and spleen (parasite invades organs causing fever and ulceration and enlargement) in dog - wasting, loss of hair and skin ulceration.

Summary:

•Kinetoplastids cause important global diseases of humans, livestock and companion animals.

•Large social and local economic impacts.

•Many important zoonotic diseases, livestock and companions animals are reservoirs.

•Most require vector, although can evolve to use new vectors.

•Global climate change / movement of people and animals is affecting the range of many diseases.