The mysterious respiratory illnesses that are reportedly wreaking havoc in hospitals in China are now raising concerns for the medical community across the country and impacting Washington D.C., according to reports.

FOX 5 DC has learned that hospitals, emergency rooms, urgent care locations and clinics are reportedly seeing an uptick in sick visits.

The World Health Organization (WHO) is also reportedly reviewing data from China after video surfaced showing several groups of people apparently being treated for what’s being described as a mystery respiratory illness, predominantly impacting children. Chinese health officials are also insisting the surge in respiratory illnesses is caused by the flu and known pathogens.

On Thursday, Chinese health officials told the WHO that they have not detected any “unusual or novel diseases” regarding an increase in respiratory illnesses and pneumonia in children.

According to the WHO, outside scientists said the situation called for close monitoring, but they were not convinced that the recent spike in respiratory illnesses in China signaled the start of a new global outbreak.

The arrival of new flu strains or other viruses capable of triggering pandemics typically starts with undiagnosed clusters of respiratory illness, according to the WHO. Both SARS and COVID-19 were first reported as unusual types of pneumonia.