Multidisciplinary approach to epizootiology and pathogenesis of bat rabies viruses in the United States.

Zoonotic disease surveillance is typically initiated after an animal pathogen has caused disease in humans. Early detection of potentially high-risk pathogens within animal hosts may facilitate medical interventions to cope with an emerging disease. To effectively spillover to a novel host, a pathogen may undergo genetic changes resulting in varying transmission potential in the new host and potentially to humans. Rabies virus (RABV) is one model pathogen to consider for studying the dynamics of emerging infectious diseases under both laboratory and field conditions. The evolutionary history of RABV is characterized by regularly documented spillover infections and a series of notable host shifts. Within this context, enhanced field surveillance to improve detection of spillover infections will require validated techniques to non-invasively differentiate infected from non-infected individuals. In this study, we evaluate the use of infrared thermography to detect thermal changes associated with experimental RABV infection in big brown bats (Eptesicus fuscus) in a captive colony. Our results indicated that 62% of rabid bats had detectable facial temperature decreases (-4.6°C, SD ± 2.5) compared with pre-inoculation baseline values. These data suggest potential utility for discriminating rabid bats in natural field settings. In addition, focusing upon RABV circulating in the United States between 2008 and 2011, we confirmed spillover events of bat RABV among carnivores and identified cross-species transmission events caused by four lineages of RABV associated with insectivorous bats. Additionally, our analysis of RABV glycoprotein sequences identified substitutions in antigenic sites that may affect neutralizing activity associated with monoclonal antibodies proposed for use in human post-exposure prophylaxis. This study provides a glimpse into RABV pathobiology and spillover dynamics among and between bats and a variety of mesocarnivores.

Construct validity in a high-fidelity prostate exam simulator.

BACKGROUND: All health care practitioners should be facile in the digital rectal exam (DRE) as it provides prostate, rectal and neurological information. The purpose of this study was first to justify our hypothesis that tissue elasticity is indicative of carcinomatous changes. Second, we employed urological surgeons to evaluate our prostate simulator in three ways: (1) authenticate that the elasticity of the simulated prostates accurately represents the range of normal prostate stiffness, (2) determine the range of nodule size reasonably palpable by DRE and (3) discern what degree of elasticity difference within the same prostate suggests malignancy. METHODS: Institutional Review Board-approved materials characterization, human-subjects experiments, histopathology and chart abstraction of clinical history were performed. Material characterization of 21 ex-vivo prostatectomy specimens was evaluated using a custom-built, portable spherical indentation device while a novel prostate simulator was employed to measure human-subject perception of prostatic state. RESULTS: From the materials characterization, the measurements of the 21 gross prostates and 40 cross-sections yielded 306 data points. Within the same prostate, cancer was always stiffer. Of the seven cases with an abnormal DRE, the DRE accurately identified adenocarcinoma in 85%. From the human-subjects experiments, the simulated prostates evaluated by urologists ranged in stiffness from 8.9 to 91 kPa, mimicking the range found on ex vivo analysis of 4.6-236.7 kPa. The urological surgeons determined the upper limit of stiffness palpated as realistic for a healthy prostate was 59.63 kPa while the lower limit of stiffness was 27.1 kPa. Nodule size less than 7.5 mm was felt to be too small to reasonably palpate. CONCLUSIONS: We found it is not the absolute elasticity of the nodule, but rather the relationship of the nodule with the background prostate elasticity that constitutes the critical tactile feedback. Prostate simulator training may lead to greater familiarity with pertinent diagnostic cues and diagnosis of prostate cancer.