As cases of pneumonia rise among children in China, the ruling class is now blaming it on “multiple pathogens,” and not a novel disease. The World Health Organization is investigating the illnesses and says that

WHO Investigates Mysterious Pneumonia Cases In Children In China

The first suspicion of Dr. Michael Osterholm, the director of the University of Minnesota’s Center for Infectious Disease Research and Policy (CIDRAP) is that this is “a series of already recognized respiratory pathogens,” due to the fact that illnesses are reportedly occurring in children. “If it was a new pathogen, it would be showing up in kids and adults equally, ” he told Fortune.

According to a report by NDTV World, influenza is one of the main causes of the spike in cases. National Health Commission spokesman Mi Feng said at a press conference on Sunday that rhinovirus, mycoplasma pneumonia, and respiratory syncytial virus are also circulating. Because of these pathogens, China should guarantee medicine supply and open more areas for medical treatment, Feng said.

Dr. Amesh Adalja, an infectious disease specialist and senior scholar at the Johns Hopkins Center for Health Security, agreed, telling Fortune that while information is still incredibly sparse, “it would not be surprising if it’s a constellation of various respiratory pathogens together causing clusters of illness.” Some reporting has pointed to mycoplasma pneumoniae, an atypical bacteria that can cause lung infection, as a potential cause, he said. It’s commonly known as “walking pneumonia.”

Doctors have been warning for weeks about a likely spike in “walking pneumonia” cases and local Chinese media have reported a steady rise in infections from mycoplasma among kindergarten and primary school children. While the germ tends to cause only mild colds in older kids and adults with robust immune systems, younger children are prone to develop pneumonia – with symptoms lasting for weeks. –NDTV World

The ruling classes have added that there is no need to restrict travel or implement further health protocols at this time. Schools in Beijing are also reporting high levels of absenteeism, even dismissing entire classes for at least a week if some students are ill and warning parents to be extra cautious, according to a report by Al Jazeera.