Trypanosomes Flashcards
What is the main trypanosome species that infects humans?
T.cruzi
What are the main trypanosome species that infects livestock?
- T. brucei evansi
- T. equiperdum
What is a kinetoblast?
a single large mitochondrion associated with the base of flagellum
Characteristic of trypanosome and leishmania parasites
What kind of disease is african trypanosomiasis?
- Very serious disease of humans and livestock in sub-saharan africa
- causes substantial economic losses
What kind of parasite are trypanosomes?
- Protozoa
- Haemoflagellates
- live in the blood and lymph
What kind of fly can carry trypanosomes?
Tsetse fly
What is the main form of transmission for a trypanosome?
Salivarian transmission from a tstetse fly
What are some other routes of transmission for trypanosomes?
- Transplacental transmission
- Mechanical transmission via other blood-sucking insects (this is important for T.vivax)
- accidental infections in laboratories via needle sticks
- transmission via sexual contact
What are four important facts about tsetse flies?
- Obligatorily haematophagous (males and females)
- Females bear live young
- Up to 20% of flies are infected by trypanosomes
- They are infected for life
What are the three types of glossina vector species
Morsitans, Palpalis, Fusca
What are the three glossina species habitats?
- Palpalis- Riverine forest
- Fusca- Forest
- Morsitans- Savannah
What hosts carry African animal trypanosomiasis?
Cattle, horses, camels
What are the two most pathogenic parasite species (trypanosomes)
- T.vivax
- T.congolese
What are the clinical signs of nagala?
- Anaemia
- Weight loss
- Hair loss
- Poor Milk yield
- Abortion
- Paralysis
- Death
How may you diagnose nagala?
- Clinical signs
- The geographical location
- observing the blood
- ELISA antibody testing
When can chemotherapy be used?
for Sporadic trypanosomiasis when combined with anti-tsetse measures
What are the limitations of chemotherapy?
- More doses are needed than are available
- toxicity in certain host species
- development of drug resistance
What is the definition of trypanotolerance I?
ability of a few livestock breeds to survive, reproduce and produce in tsetsetrypanosome infested areas where others cannot, without recourse to use of chemical drugs
What is trypanotolerance II?
It helps to control the levels of parisiteamia by preventing the characteristic anaemia and production loss
What determines trypanotolerance II?
Determined by the 18 quantitative trait loci (stretches of DNA)
can also improve the tolerance through crossbreeding
What does T. brucei brucei cause?
Causes surra in camels, horses and dogs
(anaemia, weight loss and death)
How is T.brucei brucei transmitted?
Transmitted mechanically by biting flies
What does T. equiperdum cause?
causes dourine in horses and donkeys
(genital and abdominal oedema, emaciation)
How is T.equiperdum transmissed?
sexual transmission
What is Human african trypanosomiasis also known as?
sleeping sickness
What is the epidemiology of sleeping sickness?
- 779 new cases were recorded in 2022
- severe morbidity and mortality
- affects principally poor, rural areas
- 36 countries are affected
What are the two types of sleeping sickness?
- Trypanosoma brucei rhodesiense
- Trypanosoma brucei gambiense
What are the symptoms of early stage sleeping sickness?
- The haemolymphatic stage
- Non-specific symptoms (fever and headache)
- joint pain/ itching
What are the symptoms of secondary/late stage sleeping sickness?
This occurs after parasites cross the blood-brain barrier and enter the CNS
* Headache, Mental changes
* Disruption of the sleep cycle, coma and death
What is the principal reservoir for T. b. rhodesiense
Ungulates, but domestic cattle in agricultural areas
How may you diagnose Trypanosomes?
- Microscopy
- Agglutination testing
- PCR
- Field- appropriate diagnostics
How can you stage trypanosomiasis?
- Determine stage of infection
- Examine cerebrospinal fluid for elevated WBC, elevated Protein, visualisation of parasites
How can you treat human Trypanosomiasis?
Requires long hospital stays
Whare the current control options for Trypanosomiasis?
- Vector control
- Control in animal reserves
- Case finding and treatment
What would you use for tstetse trapping?
- Blue and or Black Cloth
- Odour baiting
- Insecticide treatments
Name two other methods of tsetse trapping
- Aerial spraying with insecticide
- Sterile insect technique
