Can Bird Flu Spread Between People?

H7N9 bird flu person to person transmission seems possible in limited cases

/ Author:  / Reviewed by: Robert Carlson, M.D Beth Bolt, RPh

(RxWiki News) When H7N9, a strain of bird flu, began infecting people in China last spring, officials and scientists worldwide tried to quickly learn more about this new virus.

So far, the evidence has suggested the virus is spread through contact with infected poultry. A new study explored the possibility of the virus spreading from human to human.

This Chinese study closely investigated two bird flu patients and found evidence that prolonged and direct exposure may allow H7N9 to spread from person to person. This new information highlights the importance of careful handling of bird flu patients.

"Wash your hands with soap and water."

This study, led by Xian Qi, PhD, of the Jiangsu Province Center for Disease Control and Prevention in Jiangsu, China, focused on two patients who developed H7N9 during March 2013.

Person to person transmission was suspected between these two patients, a father and daughter located in Eastern China. According to the study authors, the father, aged 60, fell ill five to six days after his last exposure to poultry.

His daughter, aged 32, had no known exposure to poultry, but did provide her father with bedside care after he became ill. The study authors described this contact as "prolonged, direct, and unprotected exposure." Six days after she last visited her father, she became ill herself.

To examine the details of these bird flu infections, the patients and 43 of their close contacts were tested for presence of H7N9. Dr. Qi and team also relied on hospital data and interviews to determine the history of the patients' exposure to the virus.

The researchers analyzed samples taken from the two patients, and discovered that the H7N9 strains they were infected with were almost genetically identical.

None of the patients' other contacts tested positive for H7N9.

The history of the patients' exposure combined with the genetic similarities between their H7N9 infections led Dr. Qi and team to conclude that the virus was most likely spread between the two people directly. However, as no further contacts of either patient became ill, the signs do not point to widespread human to human transmission of H7N9.

"The infection of the daughter probably resulted from contact with her father (the index patient) during unprotected exposure, suggesting that in this cluster the virus was able to transmit from person to person," the study authors wrote.

"Our findings, however, indicated that the virus has not gained the ability for efficient sustained transmission from person to person," noted Dr. Qi and team.

According to the World Health Organization (WHO), there have been 134 confirmed H7N9 infections and 43 deaths. The latest H7N9 patient was reported on July 20 in Hebei Province, which was the first newly confirmed case since May 29.

This new research represents a very small study focusing on an isolated case. Further research needs to be completed to confirm the findings.

However, the study does highlight the importance of vigilance from healthcare workers and family contacts alike when providing care to patients.

This study was published August 6 in the BMJ. No conflicts of interest were reported.

Review Date: 
August 6, 2013
Last Updated:
August 7, 2013