PHVTD: Tryposomiasis - African Sleeping Sickness

economic impact of trypanosoma spp.

$1.5 billion in losses due to decreased milk and meat yields

2 groups of trypanosomes

-salivarian
-stercorarian

salivarian

life cycle stages develop in the vector foregit and parasites are transmitted when feeding

stercorarian

lifecycle stages develop in the vector hind gut and the parasite transmitted by contamination by wounds by insect faeces

epidemiology of trypanosoma spp.

glossina morsitans- savannah
glossina palpalis and tachinoides- riverine

parasite virulence of african trypanosoma

some parasitaemic animals e.g. T.brucei survive for long periods and increased oppertunit for infection of flues wheras other such as T.vivax kill their hosts quickly so theres a decrease in chances of fly infection

symptoms of trypanosma spp

stage 1- enlarged cervical lymph nodes and spleen, fever and headaches
stage 2- brain/cerebellum, behavioural and personality changesm confusion, fatigue coordination loss, severe immunosupression and risk of secondary infection

trypanosoma brucei lifecycle

-blood meal insect the metacyclic trpamastigotes
-transform into bloodstrean trypomatigotes
-multiply by binary fission in various bodily fluids
-tsetse fly takes a blood meal and they transform into procyclic trypomastigotes in idgut
-procyclic trypomastigotes leave the midgut and transform into epimastigotes
-multiply in the salivary glans they transform into meyacyclic trypomastigotes

trypanosoma brucei gambinse lifecycle

95% human disease (chronic)
main reservoir = humans
minor reservoir= dogs, cattle, pigs

trypanosoma brucei rhodesinse lifecycle

5% human disease (acute)
main reservoir = wildlife
minor reservoir= humans

trypanotolerant breeds

-bos indicus (cattle)
-sheep (ovis aries)
-goats (capra hircus)
-bos taurus (dwarf breeds)

negatives of trypan-tolerant animals

animals remain parasitaemic for long periods so they act as a reservoir for infection

trypanosoma brucei brucei distribution

regional distribution in west africa

trypanosoma vivax distribution

endemic in south america and caribbean sea

trypanosoma congolense

regional distribution in east africa