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Brazil: Man dies due to novel parasitic infection - Crithidia

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  • Brazil: Man dies due to novel parasitic infection - Crithidia

    Published Date: 2019-10-03 10:47:17
    Subject: PRO/AH/EDR> Crithidia - Brazil: new Leishmania-like parasite in humans
    Archive Number: 20191003.6707368

    CRITHIDIA - BRAZIL: NEW LEISHMANIA-LIKE PARASITE IN HUMANS
    ************************************************** ********
    A ProMED-mail post
    http://www.promedmail.org
    ProMED-mail is a program of the
    International Society for Infectious Diseases
    http://www.isid.org

    Date: Tue 1 Oct 2019
    Source: US National Institutes of Health News releases [abridged, edited]
    https://www.nih.gov/news-events/news...aniasis-people [Edited]


    Leishmaniasis is a parasitic disease found in parts of the tropics, subtropics, and southern Europe. It is classified as a neglected tropical disease and is often transmitted by the bite of some sand flies. The most common forms of leishmaniasis are cutaneous, which causes skin sores, and visceral, which affects several internal organs (usually spleen, liver, and bone marrow).

    During the last several decades, researchers have described rare cases of patients co-infected with both _Leishmania_ and other groups of protozoan parasites that usually infect insects, including _Crithidia_. The current study of parasites isolated from a Brazilian patient confirms that _Crithidia_ parasites also can infect people.

    Case report
    -----------
    The 63-year-old patient initially sought treatment for the symptoms of visceral leishmaniasis, including weight loss, fever, anemia, and an enlarged liver and spleen. However, after 8 months of standard leishmaniasis treatment, the patient's symptoms had not improved. The patient developed widespread skin lesions with poorly defined edges (unlike the small lesions with well-defined edges that sometimes appear after treatment for visceral leishmaniasis) and ultimately died.

    To determine the cause of disease, researchers cultured parasites taken from the patient's bone marrow and skin lesions, sequenced their genomes, and discovered that the parasites were not closely related to known disease-causing _Leishmania_ parasites. Instead, they were more closely related to _Crithidia fasciculata_, a parasite that usually colonizes mosquitoes.

    To confirm that these _Crithidia_ parasites could infect mammals, the researchers exposed mice to the parasites isolated from the patient, both intravenously and by injection into the skin, and found that both types of parasite infected the liver. The parasites collected from the patient's skin also caused skin lesions in the mice.

    The study raises concerns that the Brazilian patient might not be an isolated case. If _Crithidia_ infections represent an emerging infectious disease in people, there will be an urgent need to develop novel effective treatments, the researchers write. They expressed concern that the disease may be mosquito-borne because _Anopheles_ and _Culex_ mosquitoes can host the _Crithidia_ parasite. More research will be needed to find other human cases, confirm the parasite's range and host species, and discover potential treatments, the authors note.

    --
    Communicated by:
    ProMED-mail
    <promed@promedmail.org>

    [The news release above refers to
    Maruyama SR, de Santana AKM, Takamiya NT, et al. Non-_Leishmania_ parasite in fatal visceral leishmaniasis-like disease, Brazil. Emerg Infect Dis. 2019; 25(11); https://wwwnc.cdc.gov/eid/article/25/11/18-1548_article.

    _Crithidia_ are monocellular, protozoan parasites usually found in insects (https://en.wikipedia.org/wiki/Crithidia_fasciculata).

    For a phylogenetic map showing the genetic distance between _Trypanosoma_, _Leishmania_, and _Crithidia_ spp see: Runckel C, DeRisi J, Flenniken ML. A draft genome of the honey bee trypanosomatid parasite _Crithidia mellificae_. PLoS ONE 9(4): e95057; https://doi.org/10.1371/journal.pone.0095057.

    It would be interesting to know if the patient had _Leishmania_-specific antibodies, which are almost always present in visceral leishmaniasis in immunocompetent patients. Even though the patient was HIV negative, he/she may have been immunocompromised. - Mod.EP

    HealthMap/ProMED-mail map of Brazil: http://healthmap.org/promed/p/6]
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