Sloth World Report: Animal Welfare Findings and Neocropsy Analysis

Gastric Dilation in sloths, often progressing to volvulus, is a life-threatening condition reported in captive two-fingered sloths. There are multifactorial issues commonly known as dysbiosis. Predisposing factors involve improper diets, low temperature, and husbandry practices. Symptoms can vary from subtle to acute (Oliveira et al., 2024a).

Hyperkeratotic gastritis, particularly identified in recent studies of two-fingered sloths, is a rare, chronic condition characterized by thickening of the stomach lining (hyperkeratinization of the squamous epithelium) and excessive proliferation of the gastric mucosa. It involves chronic inflammation, likely linked to immune-mediated responses to captivity stress or dietary issues. This is a classic of chronic stress, poor nutrition, and health. Peritonitis, also mentioned in the report, occurs as a secondary complication of another abdominal disease rather than as a primary process (De et al., 1999a; de Stefani Munaó Diniz & Oliveira, 1999). Specific reference ranges for Vitamin A levels in sloths have not been established in the available scientific literature. However, clinical reports indicate that symptoms such as hyperkeratosis are more frequently associated with stress and inadequate nutrition, as documented in medical case studies of captive individuals (Almeida V.C. et al., 2023; De et al., 1999b; Digeronimo et al., 2023; Oliveira et al., 2024b). Stress, habitat changes, captive duration, and long-hour transportation can cause all the gastrointestinal symptoms previously reported in the pathological report (Thacher et al., n.d.).

It is also important to mention that one individual presented symptoms of gastrointestinal disease prior to being transported and was still transported from one country to another, resulting in easier sickness transmission and a lack of animal welfare. The reports openly mention that individuals experienced stress during transportation.

Myelomalacia is a recognized neuropathology in mammals; the most reported mechanisms are severe spinal trauma, hypoxia-ischemia, and embolic disease (Lin et al., 2023). In sloths, this kind of damage can be associated with rough handling, falls, or thoracolumbar injuries (Esplin, DlXON, M. WOODBURY, 1946). Due to their low metabolic rate and unique thoracic biomechanics, even partial cord injury may have a disproportionate impact on mobility and ventilation (Vigil-Esquivel et al., 2021), which could possibly explain many of the other findings in the pathological report.

Spinal cord hemorrhage in sloths is rare but serious condition often linked to trauma, infection or falls, rescue centers have reports spinal injuries after falling, leading to hemorrhage paralysis or euthanasia if untreated (Almeida V.C. et al., 2023; Burns et al., 2012; Chinchilla-Barboza et al., 2021). Sloths’ unique vertebral anatomy, with fewer cervical vertebrae and a specialized structure, may increase vulnerability to such damage (Chinchilla-Barboza et al., 2021). Spine damage often requires supportive care, and severe hemorrhage leads to poor prognosis even in humans (Almeida V.C. et al., 2023; Burns et al., 2012). In particular, there has been one report of Streptococcus agalactiae causing septicemia leading to hemorrhage in the brain (Yoshida et al., 2022). Necropsy examinations confirmed the presence of Streptococcus gallolyticus. While this bacterium is generally recognized as a gut commensal in mammals, particularly ruminants, it has been documented to cause septicemia under stress conditions (Cruz et al., n.d.). The clinical manifestations are most frequently associated with endocarditis (Gray et al., 2025). Furthermore, reports indicate that certain subspecies may be implicated in sepsis and meningitis in neonatal care settings (Hurrell & Ayyash, 2021).

The necropsy report noted spinal injuries, with conspecific aggression or trauma initially considered as possible causes. However, the frequency of such injuries appears unusually high, so they try to dismiss it as a cause. Nevertheless, behavioral records indicate that males were housed together along with several other sloths. It is well established that male sloths are highly territorial and prone to aggressive interactions, whereas females generally tolerate only brief contact during breeding (Care, 2021; Cliffe, n.d.; Dial, 2019; Dial et al., 2026; The Educated ZooKeeper LLC, 2021). Housing wild-caught sloths, each with established territories prior to capture, in shared enclosures inevitably increases the risk of aggression, which can result in severe trauma and significant injuries (Cliffe, n.d.; Dial, 2019; Dial et al., 2026). The practice of housing sloths together reflects a lack of consideration for the species’ natural history and territorial behavior. Housing several individuals together is recommended only if they have sufficient space (Dial, 2019; Dial et al., 2026).

Pulmonary congestion in sloths can occur secondary to another underlying disease, such as pneumonia, sepsis, or trauma (Vigil-Esquivel et al., 2021). Bronchopneumonia in sloths is a significant respiratory condition linked to bacterial infections; the literature specifically has reported Bordetella bronchiseptica, exacerbated by stress, poor housing, or captivity acclimation (Hammond et al., 2009). Although the agent is not mentioned in the reports, the specific bacterial agents identified in the lungs included Citrobacter, Enterococcus gallinarum, Escherichia coli, and Acinetobacter. Pathologists also frequently noted unidentified rods and coccobacilli in lung tissues, but none were confirmed to be Bordetella. Studies on two and three-fingered sloths report E. coli and Citrobacter isolates (Fernandes et al., 2022). E. gallinarum is not explicitly documented in sloths and may relate to captive exposure rather than the natural microbiome (Chaverri et al., 2025). Acinetobacter lacks direct sloth reports (Chaverri et al., 2025) but causes nosocomial respiratory infections in exotic mammals, aligning with the sloth bronchopneumonia reported (Baranzelli et al., 2013; van der Kolk et al., 2019).

On secondary bacterial pathogenic infection, Aliarcobacter butzleri, Aeromonas hydrophila and Pseudomonas aeruginosa there is no direct link to sloths, but its presence in rehab settings via contaminated water or food can be a proven risk of dysbiosis in stressed individuals (Fernandes et al., 2022; Miller et al., 2024). Quarantine and water hygiene are key preventives (Dial et al., 2026).

Finally, the report identified nutritional and mineral deficiencies, specifically involving Vitamin A and copper. However, no published reference ranges exist for sloths, making it difficult to assess the clinical relevance of these findings. Given the multiple stressors and symptoms documented throughout these reports, these deficiencies may represent incidental observations rather than primary pathological factors.