Programmable Inhibition and Detection of RNA Viruses Using Cas13.

The CRISPR effector Cas13 could be an effective antiviral for single-stranded RNA (ssRNA) viruses because it programmably cleaves RNAs complementary to its CRISPR RNA (crRNA). Here, we computationally identify thousands of potential Cas13 crRNA target sites in hundreds of ssRNA viral species that can potentially infect humans. We experimentally demonstrate Cas13's potent activity against three distinct ssRNA viruses: lymphocytic choriomeningitis virus (LCMV); influenza A virus (IAV); and vesicular stomatitis virus (VSV). Combining this antiviral activity with Cas13-based diagnostics, we develop Cas13-assisted restriction of viral expression and readout (CARVER), an end-to-end platform that uses Cas13 to detect and destroy viral RNA. We further screen hundreds of crRNAs along the LCMV genome to evaluate how conservation and target RNA nucleotide content influence Cas13's antiviral activity. Our results demonstrate that Cas13 can be harnessed to target a wide range of ssRNA viruses and CARVER's potential broad utility for rapid diagnostic and antiviral drug development.

Genomic epidemiology reveals multiple introductions of Zika virus into the United States.

Zika virus (ZIKV) is causing an unprecedented epidemic linked to severe congenital abnormalities. In July 2016, mosquito-borne ZIKV transmission was reported in the continental United States; since then, hundreds of locally acquired infections have been reported in Florida. To gain insights into the timing, source, and likely route(s) of ZIKV introduction, we tracked the virus from its first detection in Florida by sequencing ZIKV genomes from infected patients and Aedes aegypti mosquitoes. We show that at least 4 introductions, but potentially as many as 40, contributed to the outbreak in Florida and that local transmission is likely to have started in the spring of 2016-several months before its initial detection. By analysing surveillance and genetic data, we show that ZIKV moved among transmission zones in Miami. Our analyses show that most introductions were linked to the Caribbean, a finding corroborated by the high incidence rates and traffic volumes from the region into the Miami area. Our study provides an understanding of how ZIKV initiates transmission in new regions.

Zika virus evolution and spread in the Americas.

Although the recent Zika virus (ZIKV) epidemic in the Americas and its link to birth defects have attracted a great deal of attention, much remains unknown about ZIKV disease epidemiology and ZIKV evolution, in part owing to a lack of genomic data. Here we address this gap in knowledge by using multiple sequencing approaches to generate 110 ZIKV genomes from clinical and mosquito samples from 10 countries and territories, greatly expanding the observed viral genetic diversity from this outbreak. We analysed the timing and patterns of introductions into distinct geographic regions; our phylogenetic evidence suggests rapid expansion of the outbreak in Brazil and multiple introductions of outbreak strains into Puerto Rico, Honduras, Colombia, other Caribbean islands, and the continental United States. We find that ZIKV circulated undetected in multiple regions for many months before the first locally transmitted cases were confirmed, highlighting the importance of surveillance of viral infections. We identify mutations with possible functional implications for ZIKV biology and pathogenesis, as well as those that might be relevant to the effectiveness of diagnostic tests.

Post-traumatic Growth and Resilience among American Medical Students during the COVID-19 Pandemic.

The ongoing COVID-19 pandemic has caused significant psychological impact on medical professionals, including medical students, many who have been caring for patients on the frontlines. Understanding how medical students perceive their stressful life experiences is important as the mental health of these future physicians directly impacts their ability to care for patients. We assessed for post-traumatic growth and resilience in the face of traumatic events among a cohort of medical students that attended a medical school located in an early epicenter of the COVID-19 pandemic. Between October 29, 2020 and December 1, 2020, medical students at the Icahn School of Medicine at Mount Sinai in New York City were surveyed on various stressful life events, including COVID-19. We identified specific resilience behaviors, including establishing a supportive social network, relying on a moral compass, and using cognitive flexibility, that medical students commonly used to cope with traumatic experiences. Compared with students who perceived COVID-19 as their most stressful life event, students who perceived other events, such as family issues or serious illness, as most stressful experienced less COVID-related stress (t = -2.2, p = .03), greater posttraumatic growth (t = 4.3, p < .001), and demonstrated more resilient behaviors including establishing and nurturing a supportive social network (t = 2.2, p = .03), developing brain fitness (t = 2.2, p = .03), and finding meaning and purpose in things (t = 2.9, p = .006). This suggests that stressful experiences prior to or in parallel with COVID-19 encouraged posttraumatic growth and development of resilience behaviors that were protective to COVID-19-related stress.

Evidence of Ebola Virus Replication and High Concentration in Semen of a Patient During Recovery.

In one patient over time, we found that concentration of Ebola virus RNA in semen during recovery is remarkably higher than blood at peak illness. Virus in semen is replication-competent with no change in viral genome over time. Presence of sense RNA suggests replication in cells present in semen.

Literacy limitations to psychological evaluation tools: The case of MU.

Introduction to the reader In this case, a survivor of torture presents with symptoms clinically consistent with both major depressive disorder (MDD) and post-traumatic stress disorder (PTSD). During her evaluation, a validated psychological questionnaire for PTSD was administered verbally through a translator and accurately identified this diagnosis. However, a self-administered (read and completed by the client) questionnaire for MDD vastly underestimated the severity of her symptoms and failed to diagnose her with depression. The client had not completed grade school, so it is likely that her literacy level impacted the accuracy of this questionnaire. This highlights one of the many limitations that exist when administering psychological surveys. Through understanding these limitations, forensic evaluators can develop ways to identify, mitigate, and overcome limitations of these useful tools.