This week in research.

The purpose of this retrospective study was to determine the prevalence of nonvital incisor teeth in small breed dogs. Intraoral maxillary and mandibular radiographs of the incisor teeth obtained between January 1, 2017 and December 31, 2021 in 287 dogs previously diagnosed as having nonvital teeth and weighing <10 kg were reviewed. A total of 2682 incisor teeth were assessed and were diagnosed as nonvital if one of the following radiographic criteria was met: widened pulp canal; widened apical periodontal ligament space; periapical radiolucency; internal root resorption; external root resorption; and changes in the trabecular bone pattern around the root apex. Of the 287 dogs, 74 (25.8%) had only 1 nonvital incisor and 57 (19.9%) had 2 or more nonvital incisors. Two hundred fifty out of 2682 incisors (9.3%) evaluated were nonvital, with the maxillary incisors being 2.1 times more likely to be nonvital (95% CI [1.6-2.9]) compared to mandibular incisors. While both periodontitis ( P = .002) and class 3 malocclusion ( P = .02) significantly increased the likelihood of nonvital incisors as well, age, sex, and body weight had no significant impact. Diagnosis and treatment of nonvital teeth in the dog are important, because if these are left untreated, infection and pain may ensue. The results reported here will assist veterinarians in providing optimal therapy for dogs with nonvital incisors by increasing the index of suspicion and facilitating earlier diagnosis in animals at increased risk.

Chronic wasting disease (CWD) is an expanding prion disease of cervids. CWD prions persist in the environment, are shed in excreta, and accumulate in tissues of infected cervids, raising concerns about its zoonotic potential. Using cynomolgus macaques, we explored the zoonotic potential of CWD. Although most inoculated macaques remained asymptomatic, sensitive in vitro prion amplification assays revealed low levels of prions in macaque tissues. Inoculation of transgenic mice and bank voles with macaque tissues induced prion disease, achieving 100% transmission rates upon serial passage. One interpretation of these findings is that CWD prions retain infectivity across species and that primate infection may manifest atypically while still enabling transmission. Our results challenge earlier conclusions that minimize the zoonotic risk of CWD and underscore the need for continued surveillance.

Introduction This pilot study aimed to compare sonographic findings at thoracic sites used to detect pneumothorax in canine cadavers. Methods Intubated frozen–thawed cadavers without pre-existing sonographic evidence of pneumothorax were included. Control, unilateral and bilateral pneumothorax groups were created, with the latter induced by infusion of air (3 mL/kg) under ultrasound guidance. Four blinded sonographers (two experts and two novices) evaluated positive-pressure-ventilated (PPV) cadavers placed in sternal recumbency. Lung sliding and B-lines were assessed at the chest tube site (CTS) and caudo-dorsal border (CDB), while the abnormal abdominal curtain sign (AACS) was evaluated along the abdominal curtain sign (ACS). When absence of lung sliding was noted, operators searched for a lung-point (LP). Presence or absence of pneumothorax was recorded for the CTS, CDB, AACS, combined CTS + LP, and CDB + AACS + LP (Modified PLUS). Post-study right and left horizontal beam radiography was used as the reference standard to quantify pneumothorax volume by a board-certified radiologist. Results were analyzed by Fisher’s exact test with a statistical significance set at p < 0.05. Results Mild pneumothorax was present in 10/16 hemithoraces, scant pneumothorax in 3/16, and no pneumothorax in 3/16. Combined accuracy, sensitivity, and specificity of all operators was 22% (9–40), 4% (0–20), 100% (54–100) for both CTS and CTS + LP; 53% (35–71), 42% (23–63), 100% (54–100) for CDB; 31% (16–50), 15% (4–35), 100% (54–100) for AACS; and 56% (38–74), 46% (27–67), 100%(54–100) for Modified PLUS, respectively. There was a significant difference in identification of pneumothorax between the CTS and CDB ( p = 0.00027), and CTS and Modified PLUS ( p = 0.0012) and between CTS + LP and Modified PLUS for all operator comparisons ( p = 0.00012). Discussion The site assessed (CDB vs. CTS) for lung sliding and the sonographic signs (AACS, lung sliding) evaluated with different POCUS protocols can influence the accuracy of diagnosing pneumothorax in PPV canine cadavers placed in sternal recumbency.