The New Avian Influenza A (H7N9) Virus: What Clinicians Should Know

Alicia M. Fry, MD, MPH


May 09, 2013

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In This Article

Avian Influenza A (H7N9)

On April 1, 2013, the World Health Organization (WHO) reported 3 human infections with a new avian influenza A (H7N9) virus in China. Since then, additional human cases in China have been reported. Although mild illness in human cases has been seen, most patients have had severe respiratory illness and some people have died. To date, the new H7N9 virus has not been detected in people or birds in the United States.

An investigation by Chinese authorities is ongoing. The H7N9 virus has been detected in poultry in China and in environmental samples. Many of the human cases of H7N9 are reported to have had contact with poultry; however, some cases had no reported contact with poultry. Ongoing investigations suggest that most people have been infected with H7N9 after having contact with infected poultry or contaminated environments. China also is following up on close contacts of people infected with H7N9 to try to assess whether human-to-human spread of this virus is occurring. At this time, no evidence of sustained person-to-person spread of the H7N9 virus has been found.

Clinicians advising patients who are traveling to China should be aware that CDC does not recommend against travel to China at this time. CDC also does not recommend prescribing antiviral drugs for prophylaxis or self-treatment of H7N9 influenza. Travelers should follow standard precautions to avoid touching birds, pigs, or other animals; eat only food that is fully cooked, including poultry; and practice good hand hygiene. For more information, see Avian Flu (H7N9).

The CDC is following the situation closely and working with domestic and international partners to develop a vaccine candidate virus that could be used to make a vaccine if it is needed.

Although no data are available on early neuraminidase inhibitor treatment of persons infected with H7N9 virus, laboratory testing with functional assays indicates that H7N9 viruses are susceptible to neuraminidase inhibitors (oseltamivir and zanamivir), but resistant to adamantanes (amantadine and rimantadine).

Rapid detection and characterization of novel influenza A viruses remain critical components of national efforts to monitor for cases in the United States.

Clinicians are reminded to consider influenza as a possible diagnosis when evaluating patients with acute respiratory illnesses, including pneumonia, even outside of the typical influenza season.

This text summarizes CDC interim guidance for clinicians in the United States. Full CDC interim guidance for clinicians is available here (Information for Health Professionals).