SARS-CoV-2 Rapidly Infects Peripheral Sensory and Autonomic Neurons, Contributing to Central Nervous System Neuroinvasion before Viremia.

Neurological symptoms associated with COVID-19, acute and long term, suggest SARS-CoV-2 affects both the peripheral and central nervous systems (PNS/CNS). Although studies have shown olfactory and hematogenous invasion into the CNS, coinciding with neuroinflammation, little attention has been paid to susceptibility of the PNS to infection or to its contribution to CNS invasion. Here we show that sensory and autonomic neurons in the PNS are susceptible to productive infection with SARS-CoV-2 and outline physiological and molecular mechanisms mediating neuroinvasion. Our infection of K18-hACE2 mice, wild-type mice, and golden Syrian hamsters, as well as primary peripheral sensory and autonomic neuronal cultures, show viral RNA, proteins, and infectious virus in PNS neurons, satellite glial cells, and functionally connected CNS tissues. Additionally, we demonstrate, in vitro, that neuropilin-1 facilitates SARS-CoV-2 neuronal entry. SARS-CoV-2 rapidly invades the PNS prior to viremia, establishes a productive infection in peripheral neurons, and results in sensory symptoms often reported by COVID-19 patients.

SARS-CoV-2 Survival in Common Non-Alcoholic and Alcoholic Beverages.

SARS-CoV-2, the causative agent of COVID-19, is known to be transmitted by respiratory droplets and aerosols. Since the virus is shed at high concentrations in respiratory secretions and saliva, SARS-CoV-2 would also be expected to be transmitted through activities that involve the transfer of saliva from one individual to another, such as kissing or sharing beverages. To assess the survival of infectious SARS-CoV-2 in common beverages, we quantified infectious virus by plaque assays one hour after inoculation into 18 non-alcoholic and 16 alcoholic beverages, plus saliva, and also 7 days later for 5 of these beverages. SARS-CoV-2 remains infectious with minimal reductions in several common beverages, including milk and beer. However, cocoa, coffee, tea, fruit juices, and wine contain antiviral compounds that inactivate SARS-CoV-2. Although hard liquors containing 40% alcohol immediately inactivate SARS-CoV-2, mixing with non-alcoholic beverages reduces the antiviral effects. In summary, SARS-CoV-2 can be recovered from commonly consumed beverages in a beverage type and time-dependent manner. Although aerosol or droplet transmission remains the most likely mode of transmission, our findings combined with others suggest that beverages contaminated with SARS-CoV-2 during handling, serving, or through sharing of drinks should be considered as a potential vehicle for virus transmission.

Interactions between La Crosse virus and bacteria isolated from the digestive tract of Aedes albopictus (Diptera: Culicidae).

Aedes albopictus (Skuse) is a potential vector for many arboviruses, including La Crosse virus (LACV), the leading cause of pediatric encephalitis in North America. Bacteria isolated from the midgut and diverticula of field-caught female Ae. albopictus were cultured and identified using 16S ribosomal RNA gene amplification and sequencing. Members of seven and six bacterial families were identified from the midguts and diverticula, respectively, with nearly half of the isolates identified to the family Enterobacteriaceae. Many are related to bacteria identified in other invertebrates, and several may represent previously unknown species or genera. Of the 24 isolated bacteria, 12 (50%) showed a significant reduction in infectivity of LACV for Vero cells. Inhibition of infectivity ranged from 0 to 44% and was not dependent on bacterial classification. The antiviral activity of these bacteria warrants further investigation as an alternate means to interrupt the LACV transmission cycle.

Survival of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and Herpes Simplex Virus 1 (HSV-1) on Foods Stored at Refrigerated Temperature.

Outbreaks of coronavirus infectious disease 2019 (COVID-19) in meat processing plants and media reports of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection on foods have raised concerns of a public health risk from contaminated foods. We used herpes simplex virus 1, a non-Biosafety Level 3 (non-BSL3) enveloped virus, as a surrogate to develop and validate methods before assessing the survival of infectious SARS-CoV-2 on foods. Several food types, including chicken, seafood, and produce, were held at 4 °C and assessed for infectious virus survival (herpes simplex virus 1 (HSV-1) and SARS-CoV-2) at 0 h, 1 h, and 24 h post-inoculation (hpi) by plaque assay. At all three time points, recovery of SARS-CoV-2 was similar from chicken, salmon, shrimp, and spinach, ranging from 3.4 to 4.3 log PFU/mL. However, initial (0 h) virus recovery from apples and mushrooms was significantly lower than that from poultry and seafood, and infectious virus decreased over time, with recovery from mushrooms becoming undetectable by 24 hpi. Comparing infectious virus titers with viral genome copies confirmed that PCR-based tests only indicate presence of viral nucleic acid, which does not necessarily correlate with the quantity of infectious virus. The survival and high recovery of SARS-CoV-2 on certain foods highlight the importance of safe food handling practices in mitigating any public health concerns related to potentially contaminated foods.

Assessment of Two Novel Live-Attenuated Vaccine Candidates for Herpes Simplex Virus 2 (HSV-2) in Guinea Pigs.

Treatment to ameliorate the symptoms of infection with herpes simplex virus 2 (HSV-2) and to suppress reactivation has been available for decades. However, a safe and effective preventative or therapeutic vaccine has eluded development. Two novel live-attenuated HSV-2 vaccine candidates (RVx201 and RVx202) have been tested preclinically for safety. Hartley guinea pigs were inoculated vaginally (n = 3) or intradermally (n = 16) with either vaccine candidate (2 × 107 PFU) and observed for disease for 28 days. All animals survived to study end without developing HSV-2-associated disease. Neither vaccine candidate established latency in dorsal root or sacral sympathetic ganglia, as determined by viral DNA quantification, LAT expression, or explant reactivation. Infectious virus was shed in vaginal secretions for three days following vaginal inoculation with RVx202, but not RVx201, although active or latent HSV-2 was not detected at study end. In contrast, guinea pigs inoculated with wild-type HSV-2 MS (2 × 105 PFU) vaginally (n = 5) or intradermally (n = 16) developed acute disease, neurological signs, shed virus in vaginal secretions, experienced periodic recurrences throughout the study period, and had latent HSV-2 in their dorsal root and sacral sympathetic ganglia at study end. Both vaccine candidates generated neutralizing antibody. Taken together, these findings suggest that these novel vaccine candidates are safe in guinea pigs and should be tested for efficacy as preventative and/or therapeutic anti-HSV-2 vaccines.

Route of Infection Influences Zika Virus Shedding in a Guinea Pig Model.

Due to the recent epidemic of Zika virus (ZIKV) infection and resulting sequelae, as well as concerns about both the sexual and vertical transmission of the virus, renewed attention has been paid to the pathogenesis of this unique arbovirus. Numerous small animal models have been used in various ZIKV pathogenicity studies, however, they are often performed using immunodeficient or immunosuppressed animals, which may impact disease progression in a manner not relevant to immunocompetent humans. The use of immunocompetent animal models, such as macaques, is constrained by small sample sizes and the need for specialized equipment/staff. Here we report the establishment of ZIKV infection in an immunocompetent small animal model, the guinea pig, using both subcutaneous and vaginal routes of infection to mimic mosquito-borne and sexual transmission. Guinea pigs developed clinical signs consistent with mostly asymptomatic and mild disease observed in humans. We demonstrate that the route of infection does not significantly alter viral tissue tropism but does impact mucosal shedding mechanics. We also demonstrate persistent infection in sensory and autonomic ganglia, identifying a previously unrecognized niche of viral persistence that could contribute to viral shedding in secretions. We conclude that the guinea pig represents a useful and relevant model for ZIKV pathogenesis.