First assessment of weeks-to-negative processing fluids in breeding herds after a Senecavirus A outbreak.

Senecavirus A (SVA) causes vesicular disease in swine and has been responsible for a rampant increase in the yearly number of foreign animal disease investigations conducted in the United States. Diagnostic investigations for SVA are typically performed by sampling animals individually, which is labor-intensive and stressful. Developing an alternative aggregate sampling method would facilitate the detection of this virus at the population level. In a preliminary study, SVA was detected in processing fluids (PF) collected in a breeding herd before and after outbreak detection. The objective of this study was to estimate the average number of weeks PF remain SVA-positive after an SVA outbreak. Ten farrow-to-wean breeding herds volunteered to participate in this studyby longitudinally collecting PF samples after an SVA outbreak was detected and submitting samples for RT-rtPCR testing. The PF samples from the 10 farms were SVA-positive for an average of 11.8 weeks after the outbreak. Here, we show that testing of PF may be a cost-effective method to detect SVA and help halt its spread in SVA-endemic regions.

False-positive incidental lesions detected on contrast-enhanced breast MRI: clinical and imaging features.

PURPOSE: To identify demographic and imaging features of MRI-detected enhancing lesions without clinical, ultrasound, and mammographic correlation associated with false-positive outcomes, impacting patient care. MATERIALS AND METHODS: A retrospective multi-institutional study of imaging studies and patient's chart review of consecutive women with MRI-detected enhancing lesions without clinical, mammogram, or ultrasound correlation between January and December 2018, who underwent MRI-guided biopsy. According to the BI-RADS lexicon, lesions' frequency and imaging features were recorded. The demographic and imaging characteristics variables were correlated with histopathology as the gold standard and an uneventful follow-up of at least one year. Univariate logistic regression analysis was used to explore the correlation between the baseline variables such as age, genetic mutation, family history of breast cancer, personal history of breast cancer, MRI indication, background parenchymal enhancement, and MRI characteristic of the lesion with the false-positive results in main data and subgroup analysis. RESULTS: Two hundred nineteen women (median age 49 years; range 26-85 years) with 219 MRI-detected enhancing lesions that underwent MRI-guided vacuum-assisted biopsy during the study period fulfilled the study criteria and formed the study cohort. Out of 219, 180 lesions (82.2%) yielded benign pathology results, including 137 benign outcomes (76%) and 43 high-risk lesions (24%). Most demographic and imaging characteristics variables did not help to differentiate malignant from benign lesions. The variables that showed statistically significant association with true-positive results in univariate analyses were age (OR 1.05; 95% CI 1.02-1.08; p = 0.0015), irregular mass-lesion shape when compared with oval/round mass lesion (OR 11.2; 95% CI 1.6-78.4; p = 0.015), and clumped and clustered ring of enhancement when compared with homogeneous (OR 3.22, 95% CI 1.40-7.40; p = 0.0058). For participants with mass breast lesion, the hyperintense signal on the T2-weighted sequence (compared to the normal fibroglandular signal) was significantly related to the false-positive result (OR 0.13; 95% CI 0.02-0.76; p = 0.024). CONCLUSION: Young patients, oval/round mass-lesion shape, and homogeneous pattern of non-mass enhancement showed the strongest association with false-positive results of enhancing lesions depicted by MRI. For participants with mass breast lesion, T2-bright mass lesion showed significant association with false-positive result. It may impact the patient's management with a suggestion of follow-up rather than interventional procedure when these demographic and imaging parameters are present, consequently decreasing the patient's anxiety and health care costs.

Ecology of Porcine Astrovirus Type 3 in a Herd with Associated Neurologic Disease.

Astroviruses (AstVs) cause disease in a wide variety of species. Porcine AstVs are highly genetically diverse and conventionally assigned to five genetic lineages (PoAstV1-5). Due to the increasing evidence that porcine astrovirus type 3 (PoAstV3) is a cause of encephalomyelitis in swine and to elucidate important ecologic characteristics, the infection dynamics and environmental distribution of PoAstV3 were investigated in a herd with PoAstV3-associated neurologic disease. Over a 22 week period, the frequency of PoAstV3 fecal shedding varied by pig and age. The peak detection by RT-qPCR of PoAstV3 on fecal swabs (95%; 61 of 64) occurred at 3 weeks of age. The lowest frequency of detection was at 21 weeks of age (4%; 2 of 47); however, the frequency increased to 41% (19 of 46) at the final sampling time point (25 weeks of age). Viremia was rare (0.9%: 4 of 433). Detection in oral fluid was consistent with 75% to 100% of samples positive at each time point. Pens and feeders also had a high rate of detection with a majority of samples positive at a majority of sampling time points. Based on the data presented, PoAstV3 can be consistently detected in the environment with a majority of pigs being infected and a subset intermittently shedding the virus in feces out to 25 weeks of age. These findings suggest the importance of as-yet unidentified risk factors associated with the development of PoAstV3-associated polioencephalomyelitis.

Detection and Cellular Tropism of Porcine Astrovirus Type 3 on Breeding Farms.

Astroviruses cause disease in a variety of species. Yet, little is known about the epidemiology of a majority of astroviruses including porcine astrovirus type 3 (PoAstV3), which is a putative cause of polioencephalomyelitis in swine. Accordingly, a cross-sectional study was conducted on sow farms with or without reported PoAstV3-associated neurologic disease in growing pigs weaned from those farms. Additionally, a conveniently selected subset of piglets from one farm was selected for gross and histologic evaluation. The distribution of PoAstV3 in the enteric system was evaluated through in situ hybridization. PoAstV3, as detected by RT-qPCR on fecal samples, was frequently detected across sows and piglets (66-90%) on all farms (65-85%). PoAstV3 was detected subsequently at a similar detection frequency (77% vs 85%) on one farm after three months. Viral shedding, as determined by the cycle quantification value, suggests that piglets shed higher quantities of virus than adult swine. No link between gastrointestinal disease and PoAstV3 was found. However, PoAstV3 was detected by in situ in myenteric plexus neurons of piglets elucidating a possible route of spread of the virus from the gastrointestinal tract to the central nervous system. These data suggest PoAstV3 has endemic potential, is shed in the feces at greater quantities by suckling piglets when compared to sows, and infection is widespread on farms in which it is detected.