The N-Terminal Domain of Spike Protein Is Not the Enteric Tropism Determinant for Transmissible Gastroenteritis Virus in Piglets
Transmissible gastroenteritis virus, Spike gene, enteric tropism, reverse genetics, CRISPR/Cas9
Transmissible gastroenteritis virus (TGEV) is the etiologic agent of transmissible gastroenteritis in pigs, and the N-terminal domain of TGEV spike protein is generally recognized as both the virulence determinant and enteric tropism determinant. Here, we assembled a full-length infectious cDNA clone of TGEV in a bacterial artificial chromosome. Using a novel approach, the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) systems efficiently and rapidly rescued another recombinant virus with a 224-amino-acid deletion in the N-terminal domain of the TGEV Spike gene (S_NTD224), which is analogous to the N-terminal domain of porcine respiratory coronavirus. S_NTD224 notably affected the TGEV growth kinetics in PK-15 cells but was not essential for recombinant virus survival. In animal experiments with 13 two-day-old piglets, the TGEV recombinant viruses with/without S_NTD224 deletion induced obvious clinical signs and mortality. Together, our results directly demonstrated that S_NTD224 of TGEV mildly influenced TGEV virulence but was not the enteric tropism determinant and provide new insights for the development of a new attenuated vaccine against TGEV. Importantly, the optimized reverse genetics platform used in this study will simplify the construction of mutant infectious clones and help accelerate progress in coronavirus research.
Gang Wang, Rui Liang, Ziwei Liu, Zhou Shen, Jiale Shi, Yuejun Shi, Feng Deng, Shaobo Xiao, Zhen F. Fu, Guiqing Peng
Planning and preparing for public health threats at airports
Port health, infectious disease, travel, Globalization, Pandemic, airport
Abstract The ever-increasing speed and scope of human mobility by international air travel has led to a global transport network for infectious diseases with the potential to introduce pathogens into non-endemic areas, and to facilitate rapid spread of novel or mutated zoonotic agents. Robust national emergency preparedness is vital to mitigate the transmission of infectious diseases agents domestically and to prevent onward spread to other countries. Given the complex range of stakeholders who respond to an infectious disease threat being transmitted through air travel, it is important that protocols be tested and practised extensively in advance of a real emergency. Simulation exercises include the identification of possible scenarios based on the probability of hazards and the vulnerability of populations as a basis for planning, and provide a useful measure of preparedness efforts and capabilities. In October 2016, a live simulation exercise was conducted at a major airport in Ireland incorporating a public health threat for the first time, with the notification of a possible case of MERS-CoV aboard an aircraft plus an undercarriage fire. Strengths of the response to the communicable disease threat included appropriate public health risk assessment, case management, passenger information gathering, notification to relevant parties, and communication to passengers and multiple agencies. Lessons learned include: o Exercise planning should not be overly ambitious. In testing too many facets of emergency response, the public health response could be deprioritised. o The practical implementation of communication protocols in a real-time exercise of this scope proved challenging. These protocols should continue to be checked and tested by desk-top exercises to ensure that all staff concerned are familiar with them, especially in the context of staff turn-over. o The roles and responsibilities of the various agencies must be clear to avoid role confusion. o Equipment and infrastructure capacities must be considered and in place in advance of an actual incident or test, for example whether or not cell phone signals require boosting during a major event. Importantly, exercises bring together individuals representing organisations with different roles and perspectives allowing identification of capabilities and limitations, and problem solving about how to address the gaps and overlaps in a low-threat collaborative setting.
Lack of Transmission among Close Contacts of Patient with Case of Middle East Respiratory Syndrome Imported into the United States, 2014
Middle East respiratory syndrome, MERS-CoV, coronavirus, Contact Tracing, infection control, United States
In May 2014, a traveler from the Kingdom of Saudi Arabia was the first person identified with Middle East respiratory syndrome coronavirus (MERS-CoV) infection in the United States. To evaluate transmission risk, we determined the type, duration, and frequency of patient contact among health care personnel (HCP), household, and community contacts by using standard questionnaires and, for HCP, global positioning system (GPS) tracer tag logs. Respiratory and serum samples from all contacts were tested for MERS-CoV. Of 61 identified contacts, 56 were interviewed. HCP exposures occurred most frequently in the emergency department (69%) and among nurses (47%); some HCP had contact with respiratory secretions. Household and community contacts had brief contact (e.g., hugging). All laboratory test results were negative for MERS-CoV. This contact investigation found no secondary cases, despite case-patient contact by 61 persons, and provides useful information about MERS-CoV transmission risk. Compared with GPS tracer tag recordings, self-reported contact may not be as accurate.
Lucy Breakwell, Kimberly Pringle, Nora Chea, Donna Allen, Steve Allen, Shawn Richards, Pam Pantones, Michelle Sandoval, Lixia Liu, Michael Vernon, Craig Conover, Rashmi Chugh, Alfred DeMaria, Rachel Burns, Sandra Smole, Susan I. Gerber, Nicole J. Cohen, David T. Kuhar, Lia M Haynes, Eileen Schneider, Alan Kumar, Minal Kapoor, Marlene Madrigal, David L. Swerdlow, Daniel R. Feikin
Centers for Disease Control and Prevention
Infectious and parasitic diseases, Medicine
Porcine Epidemic Diarrhea Virus among Farmed Pigs, Ukraine
Porcine epidemic diarrhea, coronavirus, Ukraine, porcine epidemic diarrhea virus, Viruses, pigs
An outbreak of porcine epidemic diarrhea occurred in the summer of 2014 in Ukraine, severely affecting piglets
Akbar Dastjerdi, John Carr, Richard J. Ellis, Falko Steinbach, Susanna Williamson
Infection, Replication, and Transmission of Middle East Respiratory Syndrome Coronavirus in Alpacas
Middle East respiratory syndrome coronavirus, MERS-CoV, Viruses, experimental infection, replication, Transmission
Middle East respiratory syndrome coronavirus is a recently emerged pathogen associated with severe human disease. Zoonotic spillover from camels appears to play a major role in transmission. Because of logistic difficulties in working with dromedaries in containment, a more manageable animal model would be desirable. We report shedding and transmission of this virus in experimentally infected alpacas (n = 3) or those infected by contact (n = 3). Infectious virus was detected in all infected animals and in 2 of 3 in-contact animals. All alpacas seroconverted and were rechallenged 70 days after the original infection. Experimentally infected animals were protected against reinfection, and those infected by contact were partially protected. Necropsy specimens from immunologically naive animals (n = 3) obtained on day 5 postinfection showed virus in the upper respiratory tract. These data demonstrate efficient virus replication and animal-to-animal transmission and indicate that alpacas might be useful surrogates for camels in laboratory studies.
Danielle R. Adney, Helle Bielefeldt-Ohmann, Airn E. Hartwig, Richard A. Bowen
Experimental Infection and Response to Rechallenge of Alpacas with Middle East Respiratory Syndrome Coronavirus
coronavirus, Middle East respiratory syndrome, MERS-CoV, severe acute respiratory syndrome, SARS, Camel
We conducted a challenge/rechallenge trial in which 3 alpacas were infected with Middle East respiratory syndrome coronavirus. The alpacas shed virus at challenge but were refractory to further shedding at rechallenge on day 21. The trial indicates that alpacas may be suitable models for infection and shedding dynamics of this virus.
Gary Crameri, Peter A. Durr, Reuben Klein, Adam Foord, Meng Yu, Sarah Riddell, Jessica Haining, Dayna Johnson, Maged G. Hemida, Jennifer Barr, Myoung-don Oh, Deborah Middleton, Lin-Fa Wang
Advancements in Nucleic Acid Based Therapeutics against Respiratory Viral Infections
Nucleic acid therapy, siRNA, Ribozyme, aptamers, DNAzyme, Influenza virus, RSV, SARS-CoV, adenovirus, antiviral drugs
Several viruses cause pulmonary infections due to their shared tropism with cells of the respiratory tract. These respiratory problems due to viral infection become a public health concern due to rapid transmission through air/aerosols or via direct-indirect contact with infected persons. In addition, the cross-species transmission causes alterations to viral genetic makeup thereby increasing the risk of emergence of pathogens with new and more potent infectivity. With the introduction of effective nucleic acid-based technologies, post translational gene silencing (PTGS) is being increasingly used to silence viral gene targets and has shown promising approach towards management of many viral infections. Since several host factors are also utilized by these viruses during various stages of infection, silencing these host factors can also serve as promising therapeutic tool. Several nucleic acid-based technologies such as short interfering RNAs (siRNA), antisense oligonucleotides, aptamers, deoxyribozymes (DNAzymes), and ribozymes have been studied and used against management of respiratory viruses. These therapeutic nucleic acids can be efficiently delivered through the airways. Studies have also shown efficacy of gene therapy in clinical trials against respiratory syncytial virus (RSV) as well as models of respiratory diseases including severe acute respiratory syndrome (SARS), measles and influenza. In this review, we have summarized some of the recent advancements made in the area of nucleic acid based therapeutics and highlighted the emerging roles of nucleic acids in the management of some of the severe respiratory viral infections. We have also focused on the methods of their delivery and associated challenges.
Kumari Asha, Prashant Kumar, Melvin Sanicas, Clement A. Meseko, Madhu Khanna, Binod Kumar
Fine Tuning the Cytokine Storm by IFN and IL-10 Following Neurotropic Coronavirus Encephalomyelitis
central nervous system, Viral infection, JHMV, IFN-αβ, IFN-γ, IL-10
The central nervous system (CNS) is vulnerable to several viral infections including herpes viruses, arboviruses and HIV to name a few. While a rapid and effective immune response is essential to limit viral spread and mortality, this anti-viral response needs to be tightly regulated in order to limit immune mediated tissue damage. This balance between effective virus control with limited pathology is especially important due to the highly specialized functions and limited regenerative capacity of neurons, which can be targets of direct virus cytolysis or bystander damage. CNS infection with the neurotropic strain of mouse hepatitis virus (MHV) induces an acute encephalomyelitis associated with focal areas of demyelination, which is sustained during viral persistence. Both innate and adaptive immune cells work in coordination to control virus replication. While type I interferons are essential to limit virus spread associated with early mortality, perforin, and interferon-γ promote further virus clearance in astrocytes/microglia and oligodendrocytes, respectively. Effective control of virus replication is nonetheless associated with tissue damage, characterized by demyelinating lesions. Interestingly, the anti-inflammatory cytokine IL-10 limits expansion of tissue lesions during chronic infection without affecting viral persistence. Thus, effective coordination of pro- and anti-inflammatory cytokines is essential during MHV induced encephalomyelitis in order to protect the host against viral infection at a limited cost.
Coronaviridae and SARS-associated Coronavirus Strain HSR1
SARS-coronavirus, isolation, Sequence, plaque assay, real-time PCR, Italy
During the recent severe acute respiratory (SARS) outbreak, the etiologic agent was identified as a new coronavirus (CoV). We have isolated a SARS-associated CoV (SARS-CoV) strain by injecting Vero cells with a sputum specimen from an Italian patient affected by a severe pneumonia; the patient traveled from Vietnam to Italy in March 2003. Ultrastructural analysis of infected Vero cells showed the virions within cell vesicles and around the cell membrane. The full-length viral genome sequence was similar to those derived from the Hong-Kong Hotel M isolate. By using both real-time reverse transcription–polymerase chain reaction TaqMan assay and an infectivity plaque assay, we determined that approximately 360 viral genomes were required to generate a PFU. In addition, heparin (100 μg/mL) inhibited infection of Vero cells by 50%. Overall, the molecular and biologic characteristics of the strain HSR1 provide evidence that SARS-CoV forms a fourth genetic coronavirus group with distinct genomic and biologic features.
Elisa Vicenzi, Filippo Canducci, Debora Pinna, Nicasio Mancini, Silvia Carletti, Adriano Lazzarin, Claudio Bordignon, Guido Poli, Massimo Clementi
Pandemic, epidemic, SARS, Ebola, MERS, West Nile Virus