First molecular identification of Leishmania major in Phlebotomus papatasi in an outbreak cutaneous leishmaniasis area in Iraq

Leishmaniasis: Recent epidemiological studies in the Middle East

Leishmaniasis, one of the most neglected tropical diseases (NTDs), is the third most important vector-borne disease worldwide. This disease has a global impact and severity of the infection and is greatest in the Middle East. The agent of infection is a protozoan parasite of the genus, Leishmania, and is generally transmitted by blood-sucking female sandflies. In humans, there are three clinical forms of infection: (1) cutaneous (CL), (2) mucocutaneous (ML), and (3) visceral leishmaniasis (VL). This review aims to discuss the current epidemiological status of leishmaniasis in Saudi Arabia, Iraq, Syria, and Yemen with a consideration of treatment options. The elevated risk of leishmaniasis is influenced by the transmission of the disease across endemic countries into neighboring non-infected regions.

Antibody Responses to Phlebotomus papatasi Saliva in American Soldiers With Cutaneous Leishmaniasis Versus Controls

Leishmania major, transmitted in Iraq by the bite of a sand fly Phlebotomus papatasi, causes cutaneous leishmaniasis (CL). The sand fly saliva is immunogenic, with both systemic humoral and cellular human immune responses resulting from natural exposure. 248 Americans who developed L. major infection in Iraq were sex, race/ethnicity, year of Iraq deployment-matched to controls without CL. Using a case-control study design, we compared sand fly saliva-specific human IgG levels and recognized antigens between the two groups. Serologic responses to Ph. papatasi salivary gland homogenate were studied with ELISA and Western blot, using serial samples obtained from before travel, during CL treatment (CL) or at time of return to US (controls), as well as (for CL cases) six to 24 months after return to non-endemic US. The mean change in optical density (MCOD), reflecting the change in sand fly saliva-specific IgG before and after exposure in Iraq, was 0.296 (range -0.138 to 2.057) in cases and 0.151 (range -0.454 to1.085) in controls, p<0.001. Low levels of sand fly saliva specific antibody were noted in CL cases by 7-8 months after return to the US. The most frequently recognized Ph. papatasi salivary antigens were MW30 (PpSP32) and MW64, although other salivary proteins recognized were MW12/14, 15, 18, 28, 32, 36, 42, 44, 46, 52. Logistic regression suggested that MW15, 28 and 42 were associated with the largest effect on the MCOD. MW30 was the most frequently recognized antigen suggesting a role as biomarker for sand fly exposure and CL risk. Anti-Ph. papatasi saliva IgG waned within months of return to the US. We also discuss vector antigenic saliva proteins in the context of CL presentation and identify some salivary antigens that may correlate with less lesion area, ulcer versus papule/plaque, race among those with CL.