As spring approaches, there are reports of outbreaks of avian flu throughout Northeast Asia. Again, China appears to be the source of the contagion, although strains have been detected in various countries. Fortunately, the virus does not appear to be more virulent than it was in previous outbreaks. That is no reason to be complacent, however: Viruses are always mutating and the current strain could quickly become more dangerous.

There have been five annual epidemics of the H7N9 avian flu virus since it was first identified in 2013. That year, 135 people were infected. The following year, infections peaked at 320 people and the numbers have decreased each year since then. Until now. Thus far, 460 people have been reported to have been infected with the virus between October and February, one-third of the entire number of cases reported over the five-year period.

The virus is powerful. During the first four epidemics, 88 percent of people infected developed pneumonia, 68 percent were admitted to hospital intensive care units and 41 percent of those admitted died. Symptoms start with high fever and cough, progress to pneumonia and terminate in multiple-organ failure. While that progress is worrisome, scientists are quick to note that the vectors of transmission are largely restricted to contact with infected poultry. There are some reports of human-to-human spread, but they are limited and generally occur among sick people and their caregivers. This means hospitals and medical personnel need to be especially cautious, but the risk of a widespread pandemic remains low. Researchers warn that the virus could mutate, however, and surveillance agencies need to be especially attentive to that possibility.