In Ecuador in 1982, two
unidentified parasites were isolated from a squirrel and a sloth in a humid
tropical forest. However, few studies were done to fully identify them until
Grimald et al. (1992) began their research. After extensive testing, the unidentified
parasites were determined to belong to the Leishmania
braziliensis complex and were named Leishmania
equatorensis (Grimald et al. 1992).
Leishmania equatorensis is very
similar to Leishmania braziliensis with
the exception of only a couple different enzymes found while running an enzyme
electrophoresis test. Otherwise, they are undistinguishable to physical
appearance and behavior.
Leishmania
equatorensis is found in the liver and spleen of its
host. Leishmania equatorensis grows
at a slower rate than other Leishmania species
and has a lower intensity of parasites in the lesions. Hamsters were used for
this study due to their nature of being very susceptible to Leishmania infections. The hamsters
showed swelling without ulceration within one to three months after being
infected.
At the time of this
article’s publication, Leishmania
equatorensis had only been isolated from small mammals, but this does not
mean that the new strain of Leishmania isn’t
a threat. Six different kinds of Leishmania
have been isolated from human patients in Ecuador and cutaneous and
mucocutaneous Leishmania are endemic
there. Not enough research has been done on Leishmania
equatorensis to confidently say that it cannot use humans as hosts. Leishmania equatorensis also has the
same life cycle as other Leishmania
and so it can be a valuable parasite for studying other Leishmania species.
Citation
G.
Gabriel Jr., R. Kreutzer, Y. Hashiguchi, E. Gomez, T. Mimory, R. Tesh, 1992, Description
of Leishmania equatorensis Sp. N. (Kinetoplastida:
Trypanosomatidae), A New Parasite Infecting Arboreal Mammals in Ecuador, Mem.
Inst. Oswaldo Cruz, 87(2): 221-228
I think this is really interesting. Given the nasty nature of Leishmania I think its really good that they discovered a new strain. This way they can be wary of it, and maybe even be working on a treatment if this strain ends up being able to use humans as a definitive host.
ReplyDeleteIn your article you say the hamsters showed swelling without ulceration. Did the article say what was swelling? It just seems odd that it could swell without ulceration.
Is it possible that people have already been infected with Leishmania equatorensis and would never have known? Considering that that L. equatorensis is nearly identical in appearance to Leishmania braziliensis , and it sounds like they infect the same areas, I imagine that many doctors would assume it is L. braziliensis. The only way to note it may be if you actually run chemical analysis on the parasite, which I doubt happens very often in poor, third world areas.
ReplyDeleteStill, its a very interesting development! It would be interesting (probably expensive also!) to see if any human cases of L. braziliensis are actually Leishmania equatorensis.