Histopathologic Patterns and Susceptibility of Neotropical Primates Naturally Infected With Yellow Fever Virus.

Yellow fever is an important zoonotic viral disease that can be fatal for both human and nonhuman primates. We evaluated histopathologic changes in free-ranging neotropical primates naturally infected with yellow fever virus (YFV) compared with uninfected cohorts. The most frequent lesions in primates infected with YFV were hepatic changes characterized by midzonal necrosis with lipidosis and mild inflammation including lymphocytes, macrophages, plasma cells, and infrequently neutrophils. Importantly, severe necrotizing hepatic lesions were often observed in Alouatta sp. (howler monkeys), whereas Callithrix sp. (common marmosets) had nearly no hepatic changes. Moderate to severe hepatic necrosis was present in 21/23 (91%) of the YFV-positive Alouatta sp. compared with 10/29 (34%) of the YFV-positive Callithrix sp. (P < .0001; odds ratio = 20). Similarly, hepatitis was more intense in Alouatta sp. compared with Callithrix sp. Furthermore, the frequency of YFV infection was significantly higher in Alouatta sp. compared with Callithrix sp. or Sapajus sp. (capuchin monkeys). Therefore, these data support the notion that Alouatta sp. is highly susceptible to infection and YFV-induced lesions, whereas Callithrix sp. is susceptible to infection but has a lower frequency of YFV-induced lesions.