Epidemiologic profile and histopathological findings in Neotropical Primates during and after the yellow fever outbreak in Espirito Santo, Brazil

Yellow fever (YF) is a viral disease whose transmission involves non-human primates (NHP), mosquitoes, and humans. Between 2016 and 2018 occurred the largest YF outbreak in the last 100 years in Brazil. We analyzed epidemiologic profile and geographic distribution of epizootics and described most frequent histopathological findings in NHP that died during YF outbreak in the state of Espirito Santo. We consider 487 epizootics notifications registered at the State Health Department from January 2017 to July 2020. Throughout the state, 51 (65.4%) municipalities reported epizootics, with more cases in central and metropolitan areas. Reverse transcription polymerase chain reaction and immunohistochemistry were laboratory tests performed for diagnosis of yellow fever, with 160 (32.9%) positive results, 314 (64.5%) negative and 13 (2.7%) inconclusive. Histopathological findings were compared statistically between positive and negative animals for YF. The liver was the most affected organ. Hemorrhage, hepatocyte necrosis, steatosis, cholestasis and eosinophilic degeneration were statistically more frequent in positive animals. Tubular necrosis, nephritis, congestion and lymphoid hypoplasia on spleen were statistically correlated to positive animals. Knowledge of pathogenic aspect of YF is necessary to guarantee that samples from Neotropical primates are properly used for YF surveillance purposes, to ensure appropriate diagnoses and subsequent public health responses.