Leishmaniasis



Leishmaniasis


Brian J. Hall, MD

Francisco G. Bravo, MD










Cutaneous leishmaniasis manifests as a typical round to oval painless ulcer on an exposed area of skin with a well-delineated elevated border. This patient spent 3 months in Peru and did not recall a bite. (Courtesy T. Sofarelli, PA-C.)






This lesion of cutaneous leishmaniasis demonstrates numerous amastigotes image within the cytoplasm of numerous histiocytes that filled the dermis.


TERMINOLOGY


Synonyms



  • Cutaneous leishmaniasis



    • Oriental sore (Asia), Uta (Andes), Chiclero ulcer (Mexico, typically involves ear), tropical sore, Bagdad boil, Baure ulcer, Delhi boil, Aleppo boil, Aleppo button


  • Mucocutaneous leishmaniasis



    • American leishmaniasis, Espundia (Amazon basin), Pian bois (northern Brazil), forest yaws


  • Visceral leishmaniasis



    • Kala-azar, black fever, dumdum fever


Definitions



  • Protozoal infection caused by intracellular parasites of Leishmania genera of Trypanosomatidae family


  • Old World leishmaniasis is caused by species located in India, Mediterranean, Middle East, Africa, and Asia (mainly causes cutaneous and visceral disease)


  • New World leishmaniasis is caused by species in Central and South America (causes cutaneous, mucocutaneous, and visceral disease)


ETIOLOGY/PATHOGENESIS


Environmental Exposure



  • Disease transmitted by animal reservoirs (dogs or rodents) to humans by bite of female sandfly (genera Phlebotomus and Lutzomyia)


  • Parasite has 2 different forms: Promastigote and amastigote


  • Amastigote or nonflagellated form is seen in human tissue



    • Ovoid in shape


    • Measures 3-5 µm in diameter


    • Contains a nucleus and kinetoplast



      • Kinetoplast is a unique form of mitochondrial DNA


      • Identification of kinetoplast allows for distinction from other commonly confused microorganisms


Infectious Agents



  • Caused by several species of Leishmania and divided into 4 main groups or complexes



    • L. tropica complex



      • Includes L. tropica, L. major, and L. aethiopica


    • L. mexicana complex



      • Includes L. mexicana, L. amazonensis, and L. pifanoi


    • L. braziliensis complex



      • Includes L. braziliensis, L. peruviana, L. panamensis, and L. guyanensis


    • L. donovani complex



      • Includes L. donovani, L. infantum, and L. chagasi


    • Complexes 1-3 cause cutaneous leishmaniasis


    • Complex 3 causes mucocutaneous leishmaniasis


    • Complex 4 causes visceral leishmaniasis


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Worldwide



      • ˜ 1,500,000 new cases of cutaneous leishmaniasis/ year


      • Occurs in Mexico, Central and South America (except Uruguay and Chile), Southern Europe, Asia, Middle East, and Africa


    • In USA



      • Rare cutaneous case reports in southern Texas

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Leishmaniasis
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