Leishmaniasis

Has a range of clinical presentations; cutaneous leishmaniasis is more common, but visceral leishmaniasis is more serious and can be fatal if left untreated.

Diagnosis is confirmed by various tests, including microscopic exam, culture, or molecular testing, depending on the type of leishmaniasis and test availability.

Possible treatments depend on clinical presentations, parasite species and strain, and the part of the world in which infection occurs.

Treatment is less effective and more toxic in immunocompromised than in immunocompetent people.

The leishmaniases are a group of protozoan diseases infecting humans and mammals, causing either skin lesions or injury to the spleen, liver, and bone marrow.[1]Reithinger R, Dujardin JC, Louzir H, et al. Cutaneous leishmaniasis. Lancet Infect Dis. 2007;7:581-596. http://www.ncbi.nlm.nih.gov/pubmed/17714672?tool=bestpractice.com [2]Chappuis F, Sundar S, Hailu A, et al. Visceral leishmaniasis: what are the needs for diagnosis, treatment and control? Nat Rev Microbiol. 2007;5:873-882, S7-S16. http://www.ncbi.nlm.nih.gov/pubmed/17938629?tool=bestpractice.com They are caused by the obligate intramacrophage protozoa of the genus Leishmania, and the main route of transmission is via the bite of the phlebotomine sand fly. Occasionally, infection occurs congenitally, through blood transfusion or organ/tissue transplantation, or by laboratory infection.[3]Killick-Kendrick R. The biology and control of phlebotomine sand flies. Clin Dermatol. 1999;17:279-289. http://www.ncbi.nlm.nih.gov/pubmed/10384867?tool=bestpractice.com [4]Herwaldt BL. Laboratory-acquired parasitic infections from accidental exposures. Clin Microbiol Rev. 2001;14:659-688. http://cmr.asm.org/content/14/4/659.full http://www.ncbi.nlm.nih.gov/pubmed/11585780?tool=bestpractice.com [5]Antinori S, Cascio A, Parravicini C, et al. Leishmaniasis among organ transplant recipients. Lancet Infect Dis. 2008;8:191-199. http://www.ncbi.nlm.nih.gov/pubmed/18291340?tool=bestpractice.com

The leishmaniases can be broadly classified into 2 major clinicopathologic presentations: cutaneous leishmaniasis and visceral leishmaniasis.[1]Reithinger R, Dujardin JC, Louzir H, et al. Cutaneous leishmaniasis. Lancet Infect Dis. 2007;7:581-596. http://www.ncbi.nlm.nih.gov/pubmed/17714672?tool=bestpractice.com [2]Chappuis F, Sundar S, Hailu A, et al. Visceral leishmaniasis: what are the needs for diagnosis, treatment and control? Nat Rev Microbiol. 2007;5:873-882, S7-S16. http://www.ncbi.nlm.nih.gov/pubmed/17938629?tool=bestpractice.com Cutaneous leishmaniasis is the more common form and may be subclassified into a range of different presentations, such as localized cutaneous leishmaniasis, diffuse cutaneous leishmaniasis, and mucosal leishmaniasis (mucosal is sometimes classified as a separate subtype on its own). Visceral leishmaniasis occurs when parasites disseminate through the reticuloendothelial system. It is potentially life threatening without treatment. Post-kala-azar dermal leishmaniasis may present months or years following treatment of visceral leishmaniasis.[6]Zijlstra EE, Musa AM, Khalil EA, et al. Post-kala-azar dermal leishmaniasis. Lancet Infect Dis. 2003;3:87-98. http://www.ncbi.nlm.nih.gov/pubmed/12560194?tool=bestpractice.com This condition exhibits a macular, maculopapular, or nodular rash. It is mainly found in Sudanese patients, less frequently in other Leishmania donovani-endemic countries, and, rarely, in L infantum-infected immunosuppressed patients. CDC: parasites - leishmaniasis external link opens in a new window CDC: parasites - leishmaniasis external link opens in a new window WHO: leishmaniasis external link opens in a new window[Figure caption and citation for the preceding image starts]: Phlebotomus papatasi sand flyImage courtesy of CDC; F. Collins [Citation ends].