Leishmaniasis Piscopo & Azzopardi 2006 Flashcards
Piscopo & Azzopardi 2006 said that 4 points merit discussion regarding Leishmaniasa
- resistance to conventional drug treatment has developed in certain areas of the world, neccessitating a change of firts line agents
- rapid less invasive diagnostic procedures have been developed which are most useful in poorly resourced parts of the world
- despite advances in the understanding of the immunology of the disease and the unravelling of the *Leishmania *genome a vaccine is still not available
- Extent of disease in different individuals stresses the complex immunology of Leishmaniasis brought to the fore more recently with the adherent of HIV - leishmania
90% of Leishmaniasis are borne by which countries?
- Cutaneous Leishmaniasis
- Visceral Leishmaniasis
- Afghanistan, Pakistan, Syria, Saudi Arabia, Algeria, Iran, Brazil, Peru
- Bangladesh, India, Nepal, Sudan, Brazil
Desjeux 2001 suggested that global warming might have contributed to which observation?
Number of reported cases and geographical areas of leishmaniasis have increased.
Leishmania is what sort of organism?
protozoan
There are how many species of Leishmania?
And what is it about these species?
20
Each of which may cause a disease specific to the species and host response
Prevalence of Leishmaniasis differs by ___ ___
geographical area
Reservoirs of leishmaniasis are animals like ___ and ___ (____ cycle) and in countries such as Sudan ___ (____ cycle)
rodents and canines
zoonotic
humans
antrhoponotic
what is the vector of Leishmania?
Sand fly
The vector, the sand fly, ingests Leishmania protozoan in which form?
amastiogte
In the digestive tract of the sand fly the amastigote develops into a ______
promastigote
What form of Leishmania is injected into the susceptible host by the sand fly?
promastigote
Sand flies transmit Leishmania how?
in their vomit! regurgitate it
The promastigote develops into the amastigote form where in the human?
macrophages
How many different species of sand fly can transmit Leish?
70
What are the 2 main species of sand fly that can transmit the disease? and where are they associated with?
- Lutzomyia *- Americas
- Phlebotomous - *elsewhere
When does the sandfly characteristically bite?
at dusk
Infection is more commen in which gender? But why is this thought to be?
Men
may reflect an increased exposure to sand flies
Although the disease occurs irrespective of age, in the Mediterranean which age is thought to be particularly susceptible? How many cases do these account for?
who found this out?
children 1-4yrs
more than half of cases in these countries
Grech et al 2000
Untreated visceral leishmaniasis carries a mortality of ___%
70-95
Cutaneous leish can disseminate to involve the mucosa resulting in _______
death from secondary infection
what are the 3 main disease pathologies?
visceral
cutaneous
mucocutaneous
The pathology of leish expressed depends on what 2 things?
leishmania sp.
zymodeme (electrophoretic isoenzyme pattern)
The immune response to leish is ___ mediated
cell
leishmania is an intracelluar or extracellular organims?
intracellular
mainly replicating as amastigotes inside macrophages
the outcome of infection by leish will depend on what?
who discovered this?
whether the host mounts primarily a t-helper (TH1) or TH2 response
Heinzel et al 1989
Roberts et al 2000 discovered that host genetics inevitably influence the type of immune response, explain further?
Studies in humans and mice have shown that genes such as those coding for natural resistance associated macrophages protein 1, TNF, or the MHC are thought ot play a major role in the outcome of infection
Some cases are believed to harbour leish organisms for indefinite periods before the disease is expressed suggesting what sort of infection?
latent
costa et al 2002
parasites have also been detected in ____ after a clinical cure
lymph nodes
Epidemiolody true or false questions:
- *Leishmania *is endemic in Australasia?
- *Leishmania *can be transmitted through infected syringes?
- The epidemiology of L is tightly knit with the epidemiology of the sandfly
- the sandfly usually bites during the day
- The number of countries where L is endemic is set to increase with global warming?
- False - L is not endemic to Australasia
- True
- True
- False - sand fly does not bite during the day usually at dusk
- True
Visceral leishmaniasis true or false
- Is characterised by splenomegaly and pancytopenia
- carries a low mortality if not treated
- the organisms is characteristically extracellular
- fatalities are usually the result of secondary bacterial infections
- almost always responds to antimony products
- true
- false - visceral leish does not carry a low mortality if not treated, you are likely to die
- false - the organism is not extracellular it is intracellular neutrophils and macrophages
- true
- false - it does not always respond to antimony products
Immunology true or false
- an effective vaccine is available
- the body response to infection is t-cell mediated
- the disease manifestation depends oon L species and host response
- immunosuppression predisposes to l infection
- L organisms can remain dormant for years in the reticulo-endothelial system
- false - there is no efffective vaccine
- true
- true
- true
- true
Treatment true or false
- Liposomal amphotericin is effective but very expensive
- there are no oral medications to effectively treat L
- oral miltofisine is very effective in the treatment of kala azar
- cutaneous leish can be treated both by physical and pharmaological means
- leish in the immunosuprresed usually necessitates secondary prophylaxis
- True
- false - there are in fact oral medications to treat leish
- true
- true
- true
Diagnosis true or false
- Identification of amastigotes in tissue smears or histology are commonly used methods of diagnosis
- antibody towards K39 antigen is proving useful, especially in field diagnosis of visceral leish
- tissue cultures are used routinely
- splenic aspirates are very sensitive and usually safe
- leish PCR is useless on blood samples
- true
- true
- false - tissue cultures are not routinely used
- false - splenic aspirates are not safe
- false - PCR can be used on blood samples
