Leishmaniasis in a Dog Native to Colorado

A 1-year-old dog from Colorado was diagnosed with leishmaniasis, confirmed through ELISA, PCR, and histologic identification. Despite treatment, the dog's condition worsened, leading to euthanasia. The dog's dam and a littermate also had high antibody titers, suggesting possible vertical transmission or endemic presence in Colorado. This case, the first of its kind in a dog with no travel history outside the state, underscored the need to consider leishmaniasis in dogs with similar symptoms in non-endemic areas and called for further research to determine if the disease is now endemic in Colorado and to identify potential vectors.