So that's leishmania braziliensis. Then we
have visceral leishmaniasis, which is the
more serious disease in terms of mortality.
And this is called by leishmania donovani.
And again the lifecycle is very similar. We
have sandflies delivering flagellated forms
to the tissues by a bite again, but these
enter macrophages as before. You don't have
a lesion forming at the bite site, but then
these macrophages go to other tissues such
as the liver and other internal tissues, they
deliver the parasites to those organs where
they replicate, induce cell death and damage
the organs. That's why we call it visceral
leishmaniasis. And once again the sandflies
can pick up the flagellated forms, or the
amistigote forms from the infected host, whether
it’d be human or an animal and start the
cycle all over again. So this is visceral
leishmaniasis and again this is the one associated
with substantial death. And the manifestation
of visceral leishmaniasis, the disease is
called Kala-azar, which means black fever,
because the skin of the victims often turns
a dark color at the height of infection. It
has a 3 to 6 month incubation period, after
the time that the sandfly delivers the parasite
by a bite; it takes 3 to 6 months for the
symptoms of Kala-azar to become evident. And after
the black skin, or the black appearance of
the skin that gives the disease its name,
it is associated also with high fever and
splenomegaly, swollen spleen, sometimes swollen
liver and on this individual who has Kala-azar,
you can see the spleen and liver have been
outlined and you can see his belly is very
distended as a consequence of this damage
caused by replication of the parasite. Now this
infection is also associated with anemia.
You can also have congenital Kala-azar, if
you are infected while pregnant; the parasites
of course have the ability to go all over
in the circulation. They can certainly enter
the fetus and cause substantial damage there
as well. So this is something you absolutely
want to avoid, but in areas where the vector
is present and the parasite is present, very
difficult to avoid without good vector control.
After this entire infection is over, there
is an event called post Kala-azar dermal leishmaniasis.
About 20% of the infections proceed to this
point and these are associated with a most
unusual presentation. Here we show a gentleman's
face which is covered with these puffy swollen
lesions and this can occur all over the body.
It looks horrid if you look up the photographs
online you can see, interestingly and amazingly,
it all goes away after the parasite is gone.
So this is some kind of dermal reaction that
occurs well after the initial disease.