Enterovirus Outbreak on the Decline

The severe respiratory illness that infected more than 1000 children across the United States is starting to wane.

Most states are now reporting reduced activity from enterovirus D68 (EV-D68), including less frequent emergency room visits and fewer confirmed cases, according to the US Centers for Disease Control and Prevention (CDC). The latest assessment indicates 1105 confirmed cases across 47 states and the District of Columbia.

A total of 39 states and the District of Columbia have reported low or declining disease activity, though 7 states are still reporting elevated activity.

“By the end of fall, enterovirus infections are expected to decline,” the CDC said in a press release. “At about the same time, respiratory illnesses caused by other viruses, like influenza and respiratory syncytial virus, will become more common.”

As a result of increased activity from those other respiratory illnesses, the CDC said it will become more difficult for hospitals and medical facilities to infer whether reported illnesses are due to EV-D68.

Thus far, 2 fatalities have been attributed to EV-D68. Four other children who died tested positive for the virus, though it remains unknown what role, if any, EV-D68 played in their deaths.

On October 10, 2014, 21-month-old Michigan child Madeline Reid died due to complications related to EV-D68 and a stomach virus. New Jersey child Eli Waller, 4, died of the virus on September 4, 2014, though he showed no symptoms prior to his death.

Most of the reported increase in enterovirus activity is attributed to a new testing process, which was put in place in mid-October. The more efficient process has sped up testing from about 40 specimens per day to up to 180 per day, which has allowed the CDC to report results for new specimens within a few days of receiving them.

Since the dawn of the EV-D68 outbreak in August, the CDC has tested 1163 specimens, with approximately half of them testing positive for EV-D68 through October 10, 2014. Roughly one-third of those specimens tested positive for a rhinovirus or an enterovirus other than EV-D68.

Because routine laboratory tests are unable to pinpoint specific strains of enterovirus, the majority of hospitals and clinics can only perform tests to evaluate whether a patient has a virus that fits broadly into the enterovirus or rhinovirus category. With the hopes of developing more accurate testing, researchers at the Washington University School of Medicine recently sequenced the genome from EV-D68.

“Having the DNA sequence of this virus enables additional research,” said senior study author Gregory A. Storch, MD, in a press release. “It can be used to create better diagnostic tests. It also may help us understand why this epidemic seems to be producing severe and unusual disease, and why it’s spreading more extensively than in the past.”