The Evolutionary Pathway to Virulence of an RNA Virus

Publication date: 23 March 2017 Source:Cell, Volume 169, Issue 1 Author(s): Adi Stern, Ming Te Yeh, Tal Zinger, Matt Smith, Caroline Wright, Guy Ling, Rasmus Nielsen, Andrew Macadam, Raul Andino Paralytic polio once afflicted almost half a million children each year. The attenuated oral polio vaccine (OPV) has enabled world-wide vaccination efforts, which resulted in nearly complete control of the disease. However, poliovirus eradication is hampered globally by epidemics of vaccine-derived polio. Here, we describe a combined theoretical and experimental strategy that describes the molecular events leading from OPV to virulent strains. We discover that similar evolutionary events occur in most epidemics. The mutations and the evolutionary trajectories driving these epidemics are replicated using a simple cell-based experimental setup where the rate of evolution is intentionally accelerated. Furthermore, mutations accumulating during epidemics increase the replication fitness of the virus in cell culture and increase virulence in an animal model. Our study uncovers the evolutionary strategies by which vaccine strains become pathogenic and provides a powerful framework for rational design of safer vaccine strains and for forecasting virulence of viruses. Video Abstract Graphical abstract Teaser Understanding how an attenuated strain of polio evolved to become fully virulent provides a new framework for rational design of safer vaccines.
Source: Cell - Category: Cytology Source Type: research

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With Amy Rosenfeld Enterovirus D68 (EV-D68) was first isolated from children with respiratory disease in 1962. No outbreaks of infection were detected until the late summer and early fall of 2014, and then in 2016 and 2018. During these epidemics of respiratory disease, some children developed polio-like paralysis. We have recently published a paper showing […]
Source: virology blog - Category: Virology Authors: Tags: Basic virology Information acute flaccid myelitis astrocyte childhood paralysis enterovirus D68 neuron neurotropism poliovirus viral viruses Source Type: blogs
Only polio virus Type 1 persists, and only in Pakistan and Afghanistan. But now mutant vaccine viruses are paralyzing some unvaccinated children.
Source: NYT Health - Category: Consumer Health News Authors: Tags: Poliomyelitis Vaccination and Immunization Viruses Paralysis Epidemics Muslims and Islam Gates, Bill and Melinda, Foundation Afghanistan Pakistan World Health Organization Source Type: news
Carter Roberts’ motorized wheelchair didn’t arrive until the day he died. It had been a long time coming and his parents had fought hard to get it. The chair cost more than $32,000 and the insurance companies wouldn’t cover it, so the family went to court. One insurer eventually agreed to pay for some components of the chair but not the whole thing. And then none of it mattered anyway. On Sept. 22, 2018, the Roberts’ doorbell rang and the chair was delivered. Also on Sept. 22, 2018, Carter died, just three months shy of his sixth birthday. He had been largely paralyzed for the final two years of his...
Source: TIME: Health - Category: Consumer Health News Authors: Tags: Uncategorized Infectious Disease viruses Source Type: news
The country ’s health secretary said that government scientists had confirmed one case in the southern province of Lanao del Sur and were looking at another suspected case.
Source: NYT Health - Category: Consumer Health News Authors: Tags: Poliomyelitis Vaccination and Immunization Philippines World Health Organization Epidemics Source Type: news
Abstract During the early 1950s, Canada's efforts to prevent polio became heavily influenced by developments in the United States. America's foremost polio charity, the National Foundation for Infantile Paralysis, sponsored University of Pittsburgh researcher Dr. William McD. Hammon to evaluate the efficacy of a human blood fraction, gamma globulin (GG), to prevent paralytic polio. When the resulting clinical trial data appeared to show that the blood fraction offered some protection against the disease, Canadians embraced the concept for reasons of historical trust, parental demand, and public health pragmatism. ...
Source: Medical History - Category: History of Medicine Authors: Tags: Can Bull Med Hist Source Type: research
rke Tyler In 2014, the United States (US) experienced an unprecedented epidemic of enterovirus D68 (EV-D68)-induced respiratory disease that was temporally associated with the emergence of acute flaccid myelitis (AFM), a paralytic disease occurring predominantly in children, that has a striking resemblance to poliomyelitis. Although a definitive causal link between EV-D68 infection and AFM has not been unequivocally established, rapidly accumulating clinical, immunological, and epidemiological evidence points to EV-D68 as the major causative agent of recent seasonal childhood AFM outbreaks in the US. This review su...
Source: Viruses - Category: Virology Authors: Tags: Review Source Type: research
After a decades-long reduction in vaccine-preventable illnesses worldwide, there has been a reappearance of childhood illnesses once thought to be eradicated. This resurgence in illnesses such as polio and measles is a consequence of multifactorial events leading to decreased vaccination rates. A lack of resources in poor and war-torn countries, coupled with increasing global travel, and decisions to delay or defer vaccinations because of inaccurate studies further emphasized by media have combined to result in current state of frequent local and widespread epidemics, specifically the current outbreak of measles. As provid...
Source: Pediatric Emergency Care - Category: Emergency Medicine Tags: Review Articles Source Type: research
We are in the midst of a measles epidemic. As of July 25th, more than 1,100 cases have been reported in 30 states since the beginning of the year. That’s the highest number since 1992 — and since measles was declared eliminated in 2000. Given that measles is extremely contagious — the virus can linger in rooms even after a sick person has left — and can lead to serious complications, this is really alarming. There is a simple way to help: get more people immunized. How many children receive vaccines? Most children in the US are immunized. Only a little more than 1% of children have no immunizations....
Source: Harvard Health Blog - Category: Consumer Health News Authors: Tags: Children's Health Parenting Vaccines Source Type: blogs
Discussion Dengue is an important arboviral infection that affects about 40% of the world population. It is found mainly in topical and subtropical areas of the world mainly in developing countries but it range is spreading including the United States. A review of common arboviruses can be found here. It is a flaviavirus with 4 distinct serotypes named DENV-1 through DENV-4 and is spread by A. aegypti a day biting mosquito. Infection with one serotype confers immunity to that serotype but not the others. It does offer some protection for cross-infection but this only lasts a few months. Incubation period is 3-14 days with ...
Source: - Category: Pediatrics Authors: Tags: Uncategorized Source Type: news
False rumors that children are fainting or dying have led parents to turn away vaccinators, threatening the campaign to eradicate the disease.
Source: NYT Health - Category: Consumer Health News Authors: Tags: Poliomyelitis Vaccination and Immunization Pakistan Afghanistan Epidemics World Health Organization Children and Childhood Source Type: news
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