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whyyou- t1_j3ap4d0 wrote

Leishmania infects a type of cell known as phagocytes, they’re part of the innate immune system and “eat” bacteria, parasites and cellular detritus (very basic functions) meanwhile HIV infects T-CD4 cells wich are part of the acquired immune system and are vital because they act as regulators (akin to an administrator) without them you can have other defensive cells but they won’t do anything; that’s why an advanced HIV infection basically collapses the entire immune system.

As to sexual transmission; the parasite has 2 phases, one is the amastigote wich is replicative and lives within the phagocyte; when the sandfly drinks infected blood it also takes some of these infected cells and inside the insect these amastigotes turn into promastigotes wich are the infectious stage. As you see this bug needs an insect to complete it’s cycle and turn itself infectious so the human / human transmission is very rare, that’s why it’s not considered an STI.

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whyyou- t1_j3aqgeu wrote

Leishmania is endemic in some areas but it’s not pandemic due to its need of a vector (the sandfly) that cannot reproduce in some areas.

Why is it easier to treat than HIV?, well the HIV can insert itself into the DNA of its host cell making it extremely difficult to completely eradicate; we can only control the mature viruses but we cannot remove its genetic code from infected cells; as for leishmaniasis, it’s a parasite for wich we have several medications and can be completely eradicated (but it’s not easy, sometimes lengthy IV treatments are needed).

Does the immune system have defenses against Leishmania?? Yes, the infected cells can express some particles in its membrane wich makes them recognizable to the acquired immune system, the infected cells are surrounded by a bunch of other cells causing a “granulomatous inflammation” containing the infection in a single place (most of the times, not always effective) that we can see in the form of skin ulcers or lumps inside the organs (depends of the leishmania type).

Can it be contain by the immune system to a single place? Yes. Can it resolve without treatment? Most likely not.

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robotisland OP t1_j3fvj2o wrote

This is great info! Thanks so much!

So leishmania can only infect immune cells that are phagocytes, right?

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