Trypanosomiasis and Leishmaniasis Infections Flashcards
what type of organism is responsible for trypanosoma and leishmania
kinetoplastida
the haemoflagellates
what is a kinetoplast
unicellular
single flagellum
what are the 3 parasites that cause african trypanosomiasis
t congolense
t vivax
t brucei brucei
what are the most important hosts of african trypanosomiasis
cattle
infect pigs sheep and goats
how does african trypanosomiasis spread
tsetse flies
what is the pathology of african trypanosomiasis
Muscle tissue degeneration of edema and wasting
Myocarditis
Anemia (low PCV)
Less production (milk & meat)
Chancre at bite site
Fatal if not treated
Splenomegaly
Hepatomegaly
what happens to the muscle tissue with trypanosoma
muscle wasting
edema
myocarditis
how is trypanosoma diagnosed
thick blood film – microscopy
giemsa stained blood smear
concentration of buffy coat – smear
species specific PCR
what is the significance of skin dwelling trypanosoma
Can live in the skin without obvious blood parasites
Can be transmitted from the skin as tsetse flies feed not only on blood but also lymph and interstitial fluid
Skin is an important reservoir
To improve diagnosis must include the skin
how is trypanosoma treated
Samorin and Berenil
Expensive
Increasing resistance
35million doses/year
Highly toxic
Many poor quality counterfeits and frequent misuse
how are tsetse flies controlled using insecticides
Pour on
Aerial spraying
Expensive
Environmental issues
Insecticide resistance
Lack of specificity
what disease does t equiperdum cause
dourine covering disease
variant of t brucei
sexually transmission
inflammation of external genital areas, skin lesions and paralysis
what disease does t evansi cause
surra in camels and horses
fever, weakness and lethargy, weight loss and anemia
which variant of trypanosoma is zoonotic
t brucei
what are the early and late stages of human africa trypanosomiasis
early: parasite in blood/lymph symptoms often confused with malaria
late: parasite in blood/lymph and CSF neuro disturbances
what is the variant of trypanosoma that causes chagas disease
t cruzi
what are the signs of chagas disease
Chronic
- Weakness
- Exercise intolerance
- Increased heart rate
- Abnormal heart rhythms
- Fluid accumulation
Acute
- Fever
- Lethargy
- Diarrhea
- Loss of appetite
- Swollen lymph nodes
- Enlarged liver or spleen
- Seizures
- Sudden death
what is the vector of chagas
kissing bugs
triatomine bug
how is chagas treated
in humans benznidazole and nifurtimox
but in animals ?
what leishmania species cause cutaneous leishmaniasis
l tropica
l major
l mexicana (new world)
what leishmania species cause mucoutaneous leishmaniasis
l braziliensis
what leishmania species cause visceral leishmaniasis
l chagasi
what is the spectrum of leishmania cutaneous disease
long term ulceration and bite site
what is the spectrum of leishmania mucoucutaneous disease
development of cutaneous leishmaniasis to mucosal tissue
what is the spectrum of leishmania visceral disease
parasite leave incoulation site and grows in liver, spleen
most severe form of disease
how is leishmaniasis transmitted
sandflies
what is the lifecycle of leishmaniasis
Metacyclic enters bloodstream
Invades macrophages and becomes amastigote
Amastigote replicates
Amastigotes burst host cell and re invade uninfected phagocytic cells
Infected macrophages taken up by sandfly
Transform to promastigote and divide
Migrate to proboscis and attach to epithelial cells
Transform to metacyclics (not attached)
what does visceral leishmaniasis cause
loss of hair, skin ulceration, wasting
how is lieshmaniasis diagnosed
Clinical signs are not totally specific
Detection of parasites in lesions/lymph node/bone marrow biopsies
ELISA to detect antibodies (low sensitivity)
PCR based on biopsies or lesion material
Long pre-patent period >6 months
what is the importance of leishmaniasis in the UK
Zoonosis
Cases now being seen
Due to re-homing from endemic regions
Pet travel scheme
No vector so not transmitted
what is the importance of leishmaniasis in north america
Only found in foxhounds and hunting dogs
Rare in companion animals
Risk of blood transmission to owners and family
Rare imported cases
Limited to Eastern and Southern states
No known vectors
Transmission by cuts and transplacentally?
how is leishmaniasis treated and prevented
Long prepatent period — months to years
Treatment with meglumine antimonate and/or allopurinol
Not 100% curative and frequent relapses
Require annual follow up blood tests
Put down
Issues with transmission to humans
Insecticide collars
Vaccine available for dogs over 6 months
