“We're in a stage where it's difficult to say just how big this is, how long it will go on for and how widespread it will be,” Schuchat said. Testing for the condition is not widely available and there is no routine reporting.
The strain was first identified in 1962 in California and until recently has been very rarely reported in the U.S. Over the past few years, clusters have been reported in Japan, the Philippines, the Netherlands and the U.K., according to a study in the Journal of Clinical Microbiology.
Unlike other enteroviruses, which are also associated with mild respiratory illness, febrile rash illness and neurologic conditions, EV-D68 primarily causes respiratory illness. The CDC said physicians and nursing staff should consider laboratory testing for enterovirus when the cause of infection in a severely ill patient is unclear. Hospitals seeing increases in the number of patients with severe respiratory conditions are encouraged to contact state health departments or the CDC to help with typing.
Officials said they could not provide precise numbers of children reported to have had the virus. In August, Kansas City and Chicago hospitals alerted the CDC to unseasonable trends in pediatric ER visits in those cities.
In mid-August, the staff at Children's Mercy noticed increases in school-aged children visiting the ER because of severe asthma attacks, including children with no history of asthma.
“The clear scope and severity was unusual,” said Dr. Mary Anne Jackson, division director for infectious diseases at Children's Mercy Hospital of Kansas City. “We saw more cases in two days than the CDC saw in five years,” she said.
The National Enterovirus Surveillance System received only 79 EV-D68 reports between 2009 and 2013. Children's Mercy has since seen nearly 500 suspected cases, with most admitted to the hospital and 61 sent to the intensive-care unit, Jackson said in a phone interview. At its peak, she said that the hospital's bed capacity was “extremely taxed” and that staff were forced to mobilize additional resources to support the influx.
Of the samples the CDC has analyzed so far, EV-D68 was confirmed in 19 of 22 specimens from Kansas City and in 11 of 14 specimens from Chicago, Schuchat said. Patients ranged from 6 weeks to 16 years old and the median age was 4 to 5 years. No cases have been reported in adults.
There have been no deaths associated with the virus to date, but the CDC is raising the alert so physicians in all states can be prepared and know to watch for changes in expected seasonal patterns of severe respiratory illness and for wheezing or difficulty breathing in children.
The virus spreads through close contact with someone who is sick. Basic hygiene, such as washing hands and using disinfectant, can help reduce the spread. There's no specific treatment and many patients recover on their own. However, those with asthma may need additional care to stabilize their breathing patterns. Patients with severe respiratory illness may need to be hospitalized and receive intensive supportive therapy. No vaccine exists for the EV-D68, but the CDC says flu season is just around the corner and the seasonal flu vaccine can also help prevent against other infections.
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