It was an announcement local doctors figured they might hear before long: that kids in Los Angeles County had been diagnosed with a mysterious virus known to have sickened hundreds of children in the U.S. this year.
On Wednesday, officials at the Los Angeles County Department of Public Health reported that a young patient who had been hospitalized at Children's Hospital Los Angeles with partial paralysis had tested positive for enterovirus D-68.
That same day, health officials in the city of Long Beach also reported a case of EV D-68, in an infant who was briefly hospitalized for unspecified symptoms but has recovered.
Previously, Los Angeles-area health agencies had not confirmed any cases of the virus, which epidemiologists have been familiar with for more than 50 years. The virus has been associated, rarely, with severe breathing troubles and, even more rarely, with neurological symptoms, including polio-like muscle weakness.
Because enterovirus infections are often mild, physicians rarely test for them and they usually go undetected. But this year, as outbreaks of illness associated with EV D-68 emerged in the Midwest, disease experts started seeking out infections and have found them in 500 severely sickened people in 42 states and the District of Columbia as of Wednesday, according to the U.S. Centers for Disease Control and Prevention.
The state health department had confirmed six additional cases in California as of Oct. 1, including four from San Diego County, one from Ventura County and one from Alameda County.
Most reported cases of severe illness from EV D-68 have involved respiratory distress, and children with asthma have been particularly susceptible. As of Wednesday, the Centers for Disease Control and Prevention said the virus has been detected in four patients who have died. The role that EV-D68 infection played in these deaths is unclear.
Cases of neurological symptoms associated with, but not necessarily caused by, EV D-68 infection have also emerged.
Speaking with reporters Wednesday, Children's Hospital Los Angeles infectious diseases chief Dr. Grace Aldrovandi said that the Los Angeles patient, who was between 5 and 10 years old, had arrived at the hospital in August with difficulty moving a limb.
The patient had experienced cold symptoms for about a week prior to the onset of the muscle weakness. After three weeks of treatment and rehabilitation, the child was discharged from the hospital — no longer infectious, but with some paralysis remaining.
"We're optimistic within time this child will have greater recovery, hopefully full recovery," she said.
Confirmation of the child's EV D-68 infection arrived from state laboratories Tuesday night. The hospital did not provide further details about the patient, such as which limb had been affected.
Disease researchers are keeping an eye on enterovirus-related paralysis cases, Aldrovandi said.
In February, California health officials reported on a small number of children in the state who had come down with polio-like illnesses since 2012. Two of those children tested positive for EV D-68. Public health officials have not determined whether their neurological symptoms were caused by the viral infection or were incidental.
On Tuesday, Colorado officials said the CDC was investigating at least 10 cases of children who developed limb weakness after a respiratory infection for possible involvement of enterovirus or rhinovirus, which causes the common cold.
Children's Hospital Los Angeles infectious disease specialist Dr. Pia Pannaraj said four of those children had tested positive for EV D-68, while the others had not.
There are many types of enteroviruses, all of which have the potential to result in paralysis, she said. Polio, ruled out in the Children's Hospital case, is in the enterovirus family.
There is no vaccine to prevent EV D-68 infection, and no antiviral medications are approved for its treatment.
Interim Los Angeles County health officer Dr. Jeffrey Gunzenhauser, on hand at Children's Hospital on Wednesday, emphasized that epidemiologists still had a lot to learn about EV D-68 and its prevalence.
The county is not planning to start routinely testing children for enteroviruses — typing of EV D-68 will continue to be used only to diagnose patients with very severe symptoms — so public health experts can't predict when they'll understand the extent of the virus' spread in Los Angeles or beyond, Gunzenhauser said.
"The presumption is, it's very common and most children don't develop serious symptoms," he said.
Pannaraj said the incidence of paralysis with other enterovirus infections was less than 1%, and that "it doesn't look like it's high" for EV D-68, either.
Gunzenhauser said that while "it's always concerning when we find something that causes severe symptoms in children," the public health department did not believe the illness reported Wednesday should be a cause of widespread alarm.
But he urged parents of children who do experience paralysis, or severe respiratory symptoms such as wheezing or other breathing difficulties, to take them to a doctor.
To prevent the spread of EV D-68, the Department of Public Health urges frequent hand-washing with soap and water for at least 20 seconds; avoiding touching the eyes, nose and mouth with unwashed hands; avoiding kissing, hugging or sharing eating utensils with people who are sick; and staying home when ill.
Aldrovandi said that in addition to the sample collected in from the child with partial paralysis, Children's Hospital had sent seven specimens, all from children with serious respiratory symptoms, to the state for EV D-68 testing. Results are pending.