Epidemiology, pathology & immunology of leishmaniasis

Which leishmania is anthriponotic?

L.tropica

What increases risk factors for contracting leishmaniasis?

• Sex (male increased risk)

• poverty

• poor sanitation

• malnutrition

• living in close proximity to animals

• dog ownership

• living in overcrowded households

• migration into endemic area

  • urbanization management 

What are some of the signs for canine leishmaniasis?

Not all dogs show clinical signs because some breeds are resistant (-Whereas Rottweilers, boxers, German shepards are susceptible to disease the Ibizan Hound appears resistant)

Symptomatic dogs:

Weight loss

skin lesions

lymphadenopathy

fever

anemia

splenolegaly

How does Feline Leishmaniosis present itself in cats?

Caused mainly by L.infantum in southern europe

Often asymptomatic unless immunicompromised

What possible other reservior species for leishmania?

Livestock and horses.

What do you call the wildlife reservoir?

Sylvatic reservior

What wildlife reservior hosts contract L.panamensis, L.guyanensis?

Dog, sloth, opossum, ant eater

What causes spillovers of leishmania from wildlife reserviors?

Clearing forests for frontier farming

> Edge of natral foci with human dwellings

> Spillover of L.GUYANENSIS in tperi-domestic transmission cycle in brazil

What Prevention methods to stop the transmission?

1. personal protection

sandfly bite prevention:

•Insecticide treated bed nets (LLINs)

•Long clothing/ no exposed skin -> insecticide impregnated fabrics

•Use of ectopic insecticides

•Prevent going outdoors between dusk and dawn.

2. VECTOR POPULATION CONTROL

   1. RESERVIOR POPULATION CONTROL

Skin lesions on exposed body parts caused by which CL complex?

L.tropica, L.najor complexes (old)

L.mexicana, L.brazillensis complexes (New)

What is Leishmanization ?

Inoculation with the use of live parasite

in 1970-80s promastigotes of L.major were grown in vitro and inoculated as a form of vaccination

but often resulted in persistenet lesions

not used that much anymore

Which complex causes mucocutaneous leishmaniasis?

L.braziliensis complex

Which complex causes Visceral Lerishmaniasis (Kala-azar)?

L.donovani, L.infacntum (old world)

L.infantum (new world)

•fever, weight loss, lymphadenopathy, anemia; later hepatosplenomegaly with darkening of skin

•

•Cause of death is a compromised immune system => co-infections

What diagnotics do we have for leishmania?

Parasitological: microscopic examination of bone marrow or splenic aspirate, buffy coat samples or tissue sample from CL, Parasite isolation an dculture invitro or in vivo

Serology: ELISA, Lateral flow stips

Flourescent Ab test

Direct agglutination test

Molecular: PCR and qPCR

What are the treatment options for Leishmania?

Pentavalent Antimonals: drug resistence

What treatment options are there for Canine L?

Which T-cell activates macrophages?

TH1 

How does T-helper subset have different outcomes in disease?

TH2 onset: Causes disease: high IL-4, HIGH IgG no IFNy: chronic infection

TH1: Infection clearedhigh IFNy and no IL-4 disease wiill be resolved

How does leishmania manipulate the host immune system?

Impairment of antigen presentation

Impaired of proinflammatory cytokine secretion

Inhibition of NO production (blocking iNOS)

Induction of immunosuppressive IL-10, TGF-beta

What is the role of NO (nitric oxide) in the the immune response of TH1?

Directly killing the parasites, dampening their metabolic activity, and indirectly controlling their proliferation by limiting the recruitment of permissive host cells

The production of NO is induced by IFN-y which is in very high levels in a TH1 immune response