Association between skin parasitism and a granulomatous inflammatory pattern in canine visceral leishmaniosis

In this work we examined 76 stray dogs from an area of endemic visceral leishmaniosis, in order to determine whether the presence of skin inflammation or a specific inflammatory pattern could be taken as indicative of infection with Leishmania chagasi, and whether the parasite burden in the skin could be associated with the intensity or the nature of the inflammatory process. Inflammatory infiltrates were observed in the skin of 51 out of 55 animals with diagnosis of leishmaniosis, and in 17 out of 21 animals without signs of infection. Amastigotes were identified in the skin of 29 out of the 55 animals with diagnosis of leishmaniosis. Granuloma and a monomorphic macrophage inflammatory infiltrate, and not a mixed focal or mixed diffuse inflammation, were significantly associated with skin parasitism, both in terms of frequency (P=0.015 in the Chi-square test) and intensity (P=0.005 in the Kruskal-Wallis test). A low parasite burden was associated with a multifocal inflammatory pattern.