Windows into leishmaniasis epidemiology in the United States: September 2021 through August 2022

Leishmaniasis is a rare disease in the United States, with an estimated annual incidence of dozens of cases occurring primarily in travelers, migrants, and military personnel. True disease incidence is unknown, since leishmaniasis is not a nationally notifiable condition. Here, we describe the results of molecular leishmaniasis over a 1-year interval (September 2021 to August 2022) when our laboratory served as the primary national reference laboratory for molecular diagnosis of civilian leishmaniasis. We tested 218 specimens submitted from 36 states yielding 94/186 (50.5%) positive cases with species or species complex-level identification and 18 novel mini-exon alleles. Most species belonged to subgenus Viannia (75.6%) and associated with cutaneous or mucocutaneous disease. Cases were associated with recent travel (18.1%), travel timing unspecified (7.4%), migration (7.4%), remote travel (2.1%), military (1.1%), or unknown history (63.8%). These data illustrate the clinical utility of molecular testing for leishmaniasis and provide unique insight into disease epidemiology. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was approved by the University of Washington Institutional Review Board (STUDY00013877). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Sequences have been deposited to Genbank (accessions [OR026045][1]-[OR026086][2]) with metadata available in BioSample accessions SAMN35159702 - SAMN35159803 (BioProject PRJNA974035). Deidentified, patient-specific molecular data are available upon request with appropriate human subject approvals. [1]: /lookup/external-ref?link_type=GEN&access_num=OR026045&atom=%2Fmedrxiv%2Fearly%2F2023%2F05%2F28%2F2023.05.23.23290303.atom [2]: /lookup/external-ref?link_type=GEN&access_num=OR026086&atom=%2Fmedrxiv%2Fearly%2F2023%2F05%2F28%2F2023.05.23.23290303.atom