IFNAR1 and cutaneous leishmaniasis: IFNAR1−/− mice infected with LRV1-positive strains of L. V. guyanensis developed markedly attenuated skin lesions compared with WT control mice, demonstrating that in chronic non-healing cutaneous leishmaniasis exuberant amounts of type I IFNs (triggered by the activity of the Leishmania RNA virus) are counterprotective (26).