Electrocutions in Free-Ranging Platyrrhine Nonhuman Primates: Diagnostic Features for a Threatening Condition

Abstract

Electrical accidents pose a considerable threat to wildlife in anthropized regions, particularly arboreal mammals, as evidenced by cases of electrocutions in nonhuman primates (NHPs). This study characterized the frequency, anatomic distribution, and pathological features of electrocution injuries in free-ranging NHPs based on data retrieved from necropsy archives at the Veterinary Pathology and Forensics Laboratory, University of Brasilia, Brazil. Gross and microscopic evaluations were conducted to assess the nature and extent of electrothermal injuries, including burns and tissue damage. Between 2019 and 2022, electrocution accounted for 16.5% of NHP deaths, primarily affecting black tufted marmosets. Adult NHPs, regardless of sex, were predominantly affected, mainly in the rainy season. Limbs were the most commonly affected body parts, with double, triple, or multiple injury sites being common. Gross findings mostly included severe burns (Grades III and IV), ulcerative injuries, blisters, bone exposure, singed hair, and muscle exposure. Microscopic examinations unveiled epidermal necrosis, smudging of collagen fibers, stretched epidermal nuclei, blisters (epidermal honeycomb aspect), muscle necrosis, skin metallization, and hemorrhage and congestion within internal organs. Electrocution has emerged as a substantial cause of death in free-ranging NHPs, particularly in urban and peri-urban areas. The study underscores the need for public policy adjustments to mitigate the risks of electrocution in NHPs and enhance species conservation efforts in human-dominated landscapes.

Keywords: conservation; electric burns; marmoset; skin metallization; thermic injury.

Figure 1

Geographical distribution of electrocutions in nonhuman primates (NHPs) in the Federal District, Brazil, from 2019 to 2022.

Figure 2

General and pathological data on electrocuted nonhuman primates. (a) Species, sex, and age group of affected animals (n = 71). CP = Callithrix penicillata. SL = Sapajus libidinosus. AC = Alouatta caraya. (b) Number of electric injury points, affected anatomical regions, and degree of burns (n = 71). (c) Distribution of gross findings (n = 71). DUEI = Deep ulcerative electrothermal injury. SUEI = Superficial ulcerative electrothermal injury. TBI = traumatic brain injury. (d) Distribution of microscopic findings in the skin and adjacent muscle tissues (n = 61). SCF = smudging of collagen fibers. EDN = epidermal stretched nuclei. DED = dermoepidermal detachment (or blister formation). EHA = epidermal honeycomb aspect.

Figure 3

Anatomical distribution of regions affected by electrocution injuries in nonhuman primates.

Figure 4

Gross injuries in the skin of electrocuted marmosets. Grade of burns. (a) and (b) Grade IV burns characterized by blackned and charred tissues and burns affecting deep muscle tissues. (c) Grade III burn evidencing ulceration, exposure of muscle tissues and erythema adjacent. (d) Grade II burn showing scorched furs, edema, and small multifocal irregular blister areas (gray discoloration) in the palmar surface.

Figure 5

Gross injuries in electrocuted NHPs. (a) Black tufted marmoset, right upper limb. Deep ulcerative electrothermal injury with muscle and tendon exposure. (b) Black tufted marmoset, right pelvic limb. Blisters and singed hair. (c) Black tufted marmoset, left pelvic limb. Charred tissues, bone fracture and exposure, and amputation. (d) Bearded capuchin monkey, left upper limb. Skin erythema and swelling.

Figure 6

Histological findings in the skin of electrocuted NHPs. (a) Epidermal necrosis (arrowhead) and marked smudging of collagen fiber in the dermis (H&E, obj. 10x). (b) Epidermal stretched nuclei and dermoepidermal detachment (asterisk) (H&E, obj. 20x). (c) Epidermal honeycomb aspect (arrowheads) and subcorneal blister formation (asterisk) (H&E, obj. 10x). (d) Metallization of the epidermis (arrowhead) (PPB stain, obj. 20x).