Non-thrombotic pulmonary embolism of brain, liver, or bone marrow tissues associated with traumatic injuries in free-ranging neotropical primates

From 2016 to 2019, Southeastern Brazil faced an outbreak of yellow fever (YF) affecting both humans and New World primates (NWP). The outbreak was associated with a marked increase in traumatic lesions in NWP in the affected regions. Non-thrombotic pulmonary embolization (NTPE) can be a consequence of massive traumatic events, and it is rarely reported in human and veterinary medicine. Here, we describe NTPE of the brain, liver, and bone marrow in free-ranging NWP, highlighting the epidemiological aspects of these findings and the lesions associated with this condition, including data on traumatic injuries in wild NWP populations during the course of a recent YF outbreak. A total of 1078 NWP were necropsied from January 2017 to July 2019. Gross traumatic injuries were observed in 444 marmosets (44.3%), 10 howler monkeys (23.2%), 9 capuchins (31.0%), 1 titi-monkey (50.0%), and 1 golden lion tamarin (33.3%). NTPE was observed in 10 animals, including 9 marmosets (2.0%) and 1 howler monkey (10.0%). NTPE was identified in the lung and comprised hepatic tissue in 1 case, brain tissue in 1 case, and bone marrow tissue in 8 cases. Although uncommon, it is important to consider NTPE with pulmonary vascular occlusion during the critical care of traumatized NWP. In addition, this study highlights the importance of conservational strategies and environmental education focusing on One Health, not only to protect these free-ranging NWP populations but also to maintain the efficacy of epidemiological surveillance programs.