Extraintestinal Pathogenic Escherichia Coli Causes Necrohemorrhagic Pneumonia in Multiple Research Dogs.

Extraintestinal pathogenic Escherichia coli expressing cytotoxic necrotizing factor (CNF) 1 and 2 virulence factors is a rarely reported cause of acute, fatal necrohemorrhagic pneumonia in canines. A review of cases of necrohemorrhagic pneumonia in beagles at our facility between 2013 and 2021 revealed 21 dogs that died or were euthanized after acute onset lethargy, dyspnea, and hemorrhage. Some affected animals had recently been transported to the facility. In all dogs, lung lobes were discolored dark red and consolidated. Histologic lesions in 17 of these included alveolar necrosis, hemorrhage, edema, fibrin, acute inflammation, and intralesional colonies of bacilli. Lung was cultured for 10 dogs with E. coli isolated and CNF1 identified by virulence factor PCR in 7 of those. Based on these findings, extraintestinal E. coli should be considered an important cause of acute fatal necrohemorrhagic pneumonia in purpose-bred beagle research dogs and may be associated with a recent history of transport.

Society of Toxicologic Pathology Nonhuman Primate Special Interest Group: Idiopathic Femoral Head Chondrolysis in Nonclinical Research Macaques.

Idiopathic femoral head chondrolysis is a recognized condition in human adolescents and has previously been reported in two macaques at a biomedical research facility. A cluster of coxofemoral joint abnormalities consistent with this condition affecting seven cynomolgus macaques over a four-month period in 2016 and 2017 was observed at a single, nonclinical contract research facility, prompting enhanced physical examination screening efforts during animal receipt and pre-study evaluation to identify additional affected animals. This article summarizes the results of this investigation from November 2016 to March 2021, yielding 97 total cases for an overall incidence of 0.54% (97/17,898 macaques). Affected animals were presented with one or more of the following unilateral or bilateral findings on physical examination and/or diagnostic imaging: lameness, palpable coxofemoral joint abnormalities, femoral head atrophy with variable loss of articular cartilage and irregularity of the femoral head surface, enlarged joint space with effusion, and increased radiographic density of the femoral head. This condition prevented use of affected animals on study for 54% of the cases (52/97 animals). Recognition of this idiopathic condition is important in drug safety evaluation studies to distinguish it from test article-related effects.

Microwave Ablation: Comparison of Simultaneous and Sequential Activation of Multiple Antennas in Liver Model Systems.

PURPOSE: To compare microwave ablation zones created by using sequential or simultaneous power delivery in ex vivo and in vivo liver tissue. MATERIALS AND METHODS: All procedures were approved by the institutional animal care and use committee. Microwave ablations were performed in both ex vivo and in vivo liver models with a 2.45-GHz system capable of powering up to three antennas simultaneously. Two- and three-antenna arrays were evaluated in each model. Sequential and simultaneous ablations were created by delivering power (50 W ex vivo, 65 W in vivo) for 5 minutes per antenna (10 and 15 minutes total ablation time for sequential ablations, 5 minutes for simultaneous ablations). Thirty-two ablations were performed in ex vivo bovine livers (eight per group) and 28 in the livers of eight swine in vivo (seven per group). Ablation zone size and circularity metrics were determined from ablations excised postmortem. Mixed effects modeling was used to evaluate the influence of power delivery, number of antennas, and tissue type. RESULTS: On average, ablations created by using the simultaneous power delivery technique were larger than those with the sequential technique (P < .05). Simultaneous ablations were also more circular than sequential ablations (P = .0001). Larger and more circular ablations were achieved with three antennas compared with two antennas (P < .05). Ablations were generally smaller in vivo compared with ex vivo. CONCLUSION: The use of multiple antennas and simultaneous power delivery creates larger, more confluent ablations with greater temperatures than those created with sequential power delivery.

HISTOPATHOLOGIC FINDINGS IN FREE-RANGING CALIFORNIA HUMMINGBIRDS, 1996-2017.

A histopathologic study of free-ranging hummingbirds found in California, US was performed to identify mortality trends. Tissues from 61 wild hummingbirds representing five native California species collected by the San Diego Zoo from 1996 to 2016 or the Lindsay Wildlife Experience from 2015 to 2017 were histologically examined. Birds were either found dead or moribund at the time of submission or were euthanized due to unresolvable health issues. Long-term rehabilitated birds were excluded from this study. Lesions were sorted by organ, etiology, and gender. The most commonly affected organs were the lung (68%, 40/59), followed by the ingluvies (67%, 34/51) and the liver (54%, 33/61). While some birds had minimal or nonspecific lesions, 23% (14/61) had lesions primarily attributable to trauma, 16% (10/61) had lesions associated with bacteria, fungi, or viruses, 11% (7/61) had parasitic lesions, and 13% (8/61) had multifactorial concurrent processes. Infectious disease lesions included those associated with avian poxvirus, intestinal adenovirus, disseminated aspergillosis, bacterial septicemia, malaria ( Haemoproteus spp.), and mycobacteriosis. The most commonly identified parasitic infection was intestinal cestodiasis, for which there was no significant associated intestinal damage, although the large size of these cestodes may have affected digestion. The incidence of traumatic lesions did not vary significantly by sex, age, species, or sampling location. Other significant findings not related to disease or trauma, but not previously documented, were histologic evidence of a gallbladder and the presence of aortic ossification. Our study reported mortality trends at a population level for free-ranging hummingbirds found in California and identified the presence of intestinal adenovirus and two anatomic structures not previously described.