A recent outbreak of a new strain of avian influenza (bird flu) has killed at least 17 people in China since the first cases in humans were reported in late March. No cases of the H7N9 virus have yet been reported outside of that country, but in the US, precautions are being taken anyway. The US Centers for Disease Control and Prevention (CDC) issued new guidance to doctors and other health care workers yesterday, warning them to "consider the possibility of avian influenza A(H7N9) virus infection in persons" manifesting symptoms. Those include high fever and cough, which can quickly progress to severe pneumonia and death. The guidance also recommends treatment using specific antiviral drugs.

The CDC held a conference call with healthcare professionals on Thursday to brief them on the virus, which a spokesperson said was part of the agency's "routine preparedness measures for an outbreak with pandemic potential," as Bloomberg Businessweek reported. So far, neither the CDC nor the World Health Organization have yet said that the outbreak in China is in danger of becoming an international pandemic. "While there have been no cases of H7N9 in the United States, CDC is following this situation closely and coordinating with domestic and international partners," a CDC spokesperson told The Verge.

The US has been "taking standard pandemic preparedness precautions," since April 11, when it received a sample of the virus from China to allow pharmaceutical companies to begin developing a vaccine. "This is a serious public health situation and it’s possible that a pandemic could start if this virus were to change to spread easily between people," reads the CDC's FAQ on the subject, which was posted today. "CDC is preparing for that possibility." The CDC has also warned Americans visiting China or residing in the country not to touch birds, pigs, or other animals and to make sure meat and poultry they eat is fully cooked, as human cases of the virus appear to be limited to direct transmission from birds.

The World Health Organization, for its part, said that the virus was contained in its latest monthly risk assessment report last Friday, writing, "at this time, there is no information to indicate international spread of this virus. However, it is possible that an infected person, who may or may not have symptoms, could travel to another country." So far, the virus doesn't appear to be capable of human-to-human transmission, but if that changes, the risk of international spread is heightened.