Emerging and Miscellaneous Viral Infections

• The infectious diseases described in this chapter are either: (1) diseases of humans or other animals generally transmitted through contact with the secretions or excretions of rodents (hantaviruses, arenaviruses, and encephalomyocarditis virus), swine (hepatitis E virus), monkeys (Ebola virus), or bats (systemic coronaviruses);(2) common diseases of humans where the role of companion animals in transmission has been investigated (enteroviruses, SARS-CoV-2);(3) diseases of significant importance to the agricultural industry (foot-and-mouth disease virus, vesicular exanthema, encephalomyocarditis virus);or (4) significant diseases of potential prey of dogs and cats (rabbit hemorrhagic disease virus). • Clinical illness has not always been confirmed in dogs and cats with these infections, but evidence of seroconversion to these viruses exists. • In some cases, concern has been raised in the possible role of dogs and cats in zoonotic transmission;this has been heightened by the COVID-19 pandemic. • In general, research suggests that dogs and cats do not play a major role in transmission of these viruses, but the potential exists should new viral variants emerge. © 2021 Elsevier Inc. All rights reserved.

Midline1 is a Critical Regulator of Viral Myocarditis

Introduction: Infections by viruses including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could cause viral myocarditis. Innate immunity to viral nucleic acids mediates antiviral immunity as well as inflammatory organ injury. However, the innate immune mechanisms that control the pathogenesis of viral myocarditis are unclear. Method(s): To understand the role of the E3 ligase Midline1 in controlling viral myocarditis, wild-type and Midline1 knockout mice were infected with coxsackievirus B3 (CVB3) or encephalomyocarditis (EMCV) for inducing viral myocarditis. Mice survivals and heart functions were monitored by transthoracic echocardiography, and hearts were harvested for histology analysis. Real-time PCR, western blotting, co-immunoprecipitation, enzyme-linked immunoassay, luciferase assay, flow cytometry, over-expression and knockdown techniques were used to understand the molecular mechanisms of Midline1 in regulating type I interferon production after virus infection in this study. Result(s): We find that Midline1 is induced by RNA viruses with heart tropisms CVB3 and EMCV. Knockdown or deletion of Midline1 in human or mouse macrophages enhances production of type I interferon (IFN) in response to double strand (ds) RNA, RNA viruses CVB3 or EMCV. Importantly, deletion of Midline1 protects mice from viral myocarditis induced by CVB3 or EMCV due to enhanced type I IFN production in vivo. Mechanistically, we show that Midline1 recruits protein phosphatase 1A (PPM1A) to dephosphorylate TANK binding kinase 1 (TBK1), which inactivates TBK1 to block TBK1 from interacting with its upstream adaptor mitochondrial antiviral signaling (MAVS), thereby dampening antiviral signaling during viral infections. Moreover, Midline1 stabilizes PPM1A by inducing K63-linked ubiquitination of PPM1A. Conclusion(s): Our results indicate that Midline1 serves as a negative regulator of viral myocarditis by downregulating innate immune activation induced by RNA viruses CVB3 and EMCV. Our data reveal that Midline1 is a critical regulator of innate immunity in viral myocarditis, thereby identifying a potential therapeutic target for treating viral induced cardiovascular diseases.

Organic Electrochemical Transistors as Versatile Tool for Real-Time and Automatized Viral Cytopathic Effect Evaluation.

In-vitro viral studies are still fundamental for biomedical research since studying the virus kinetics on cells is crucial for the determination of the biological properties of viruses and for screening the inhibitors of infections. Moreover, testing potential viral contaminants is often mandatory for safety evaluation. Nowadays, viral cytopathic effects are mainly evaluated through end-point assays requiring dye-staining combined with optical evaluation. Recently, optical-based automatized equipment has been marketed, aimed at the real-time screening of cell-layer status and obtaining further insights, which are unavailable with end-point assays. However, these technologies present two huge limitations, namely, high costs and the possibility to study only cytopathic viruses, whose effects lead to plaque formation and layer disruption. Here, we employed poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (Pedot:Pss) organic electrochemical transistors (OECTs) for the real-time, electrical monitoring of the infection of cytolytic viruses, i.e., encephalomyocarditis virus (EMCV), and non-cytolytic viruses, i.e., bovine coronavirus (B-CoV), on cells. OECT data on EMCV were validated using a commercially-available optical-based technology, which, however, failed in the B-CoV titration analysis, as expected. The OECTs proved to be reliable, fast, and versatile devices for viral infection monitoring, which could be scaled up at low cost, reducing the operator workload and speeding up in-vitro assays in the biomedical research field.

Development of a Multiplex RT-PCR Assay for Simultaneous Detection of Four Potential Zoonotic Swine RNA Viruses.

Swine viruses like porcine sapovirus (SaV), porcine encephalomyocarditis virus (EMCV), porcine rotavirus A (RVA) and porcine astroviruses (AstV) are potentially zoonotic viruses or suspected of potential zoonosis. These viruses have been detected in pigs with or without clinical signs and often occur as coinfections. Despite the potential public health risks, no assay for detecting them all at once has been developed. Hence, in this study, a multiplex RT-PCR (mRT-PCR) assay was developed for the simultaneous detection of SaV, EMCV, RVA and AstV from swine fecal samples. The PCR parameters were optimized using specific primers for each target virus. The assay's sensitivity, specificity, reproducibility, and application to field samples have been evaluated. Using a pool of plasmids containing the respective viral target fragments as a template, the developed mRT-PCR successfully detected 2.5 × 103 copies of each target virus. The assay's specificity was tested using six other swine viruses as a template and did not show any cross-reactivity. A total of 280 field samples were tested with the developed mRT-PCR assay. Positive rates for SaV, EMCV, RVA, and AstV were found to be 24.6% (69/280), 5% (14/280), 4.3% (12/280), and 17.5% (49/280), respectively. Compared to performing separate assays for each virus, this mRT-PCR assay is a simple, rapid, and cost-effective method for detecting mixed or single infections of SaV, EMCV, RVA, and AstV.