Enterovirus D68

Enterovirus 68 (EV68, EV-D68, HEV68) is a member of the Picornaviridae family, an enterovirus. First isolated in California in 1962 and once considered rare, it has been on a worldwide upswing in the 21st century. It is suspected of causing a polio-like disorder called acute flaccid myelitis. EV68 is one of the more than one hundred types of enteroviruses, a group of ssRNA viruses containing the polioviruses, coxsackieviruses, and echoviruses. It is unenveloped. Unlike all other enteroviruses, EV68 displays acid lability and a lower optimum growth temperature, both characteristic features of the human rhinoviruses. It was previously called human rhinovirus 87 by some researchers. Since the year 2000, the original virus strains diversified and evolved a genetically distinct outbreak strain, clade B1. It is Clade B1, but not older strains, which has been associated with AFM and is neuropathic in animal models. Since its discovery in 1962, EV68 had been described mostly sporadically in isolated cases. Six clusters (equal to or more than 10 cases) or outbreaks between 2005 and 2011 have been reported from the Philippines, Japan, the Netherlands, and the states of Georgia, Pennsylvania and Arizona in the United States. EV68 was found in 2 of 5 children during a 2012/13 cluster of polio-like disease in California. In 2016, 29 cases were reported in Europe (5 in France and Scotland. 3 each in Sweden, Norway and Spain). Cases have been described to occur late in the enterovirus season (roughly the period of time between the spring equinox and autumn equinox), which is typically during August and September in the Northern Hemisphere. Children less than 5 years old and children with asthma appear to be most at risk for the illness, although illness in adults with asthma and immunosuppression have also been reported. In August 2014, the virus caused clusters of respiratory disease in the United States. By mid-October 691 people in 46 states and the District of Columbia had come down with a respiratory illness caused by EV-D68. Five children died. EV68 almost exclusively causes respiratory illness, which varies from mild to severe, but can cause a range of symptoms, from none at all, to subtle flu-like symptoms, to debilitating respiratory illness and a suspected rare involvement in a syndrome with polio-like symptoms. Like all enteroviruses, it can cause variable rashes, abdominal pain and soft stools. Initial symptoms are similar to those for the common cold, including a runny nose, sore throat, cough, and fever. As the disease progresses, more serious symptoms may occur, including difficulty breathing as in pneumonia, reduced alertness, a reduction in urine production, and dehydration, and may lead to respiratory failure.