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What is avian influenza A (H7N9)?
H7N9 is an influenza virus sometimes found in birds. It does not normally infect humans. Like all influenza viruses, there are different strains of H7N9. In March 2013, China reported human and bird infections with a new strain of H7N9 that is very different from previously seen H7N9 viruses.
Is the new H7N9 virus infecting humans?
Yes. Until recently, H7N9 viruses had never been detected in people. Between March 31 and May 14, 2013, China reported 131 cases of human infection with the new H7N9 virus and 34 deaths. There are no reported cases in the United States.
Does the virus pose any risk to New Yorkers at this time?
No cases of human or bird infection with this H7N9 virus have been detected in New York City or anywhere else in the United States. At this time, the risk to people in the United States is considered low, but healthcare organizations, government agencies, and the private sector are preparing in the event the virus reaches the U.S.
How are people getting infected?
The virus has been found in poultry in China in some of the same areas where human infections have occurred. Human infection with bird flu viruses are rare, but have occurred, usually after close contact with infected birds (live and dead) or environments contaminated with the bird flu virus. Evidence suggests that most people who have been infected with the H7N9 virus were infected in these ways.
Infected birds may shed virus in their droppings or their mucus. A person may become infected after touching an infected bird or being in an environment contaminated with the virus and then touching his or her eyes, nose, or mouth. There is evidence that infection also may occur if the virus becomes airborne, such as when an infected bird flaps it wings. Someone who breathes in airborne virus could become infected.
What are the symptoms of H7N9 illness?
Illness begins with high fever and cough. Many of the cases have progressed to very serious illness, including severe pneumonia, acute respiratory distress syndrome (ARDS), septic shock and multiple organ failure, leading to death. There also have been reports of milder illness and one report of a person who tested positive for the virus but possibly did not have any symptoms.
Is H7N9 spreading from person to person?
To determine whether there has been person-to-person spread of the virus, Chinese and other health authorities are following up close contacts of infected people. So far, thousands of close contacts have been checked, and there is no evidence that the virus is spreading from person to person.
Is it possible that H7N9 will spread from person to person?
Yes. Based on what is known about human infections with other bird flu viruses, it is possible that there will be some limited person-to-person spread. Health officials are watching closely to determine whether this virus gains the ability to spread easily from one person to another. Sustainable human-to-human spread is needed for a pandemic to start.
Is there a vaccine for the new H7N9 virus?
No, there is no vaccine. The Centers for Disease Control and Prevention (CDC) and others are working to develop one.
Are there medicines to treat illness caused by the virus?
Yes, the same medicines used to treat seasonal flu are being used to treat this virus. These include Tamiflu® and Relenza®.
Is the new H7N9 virus resistant to antiviral drugs?
No. The CDC received an H7N9 virus sample from China on April 11, 2013. Antiviral resistance testing indicates that the virus would be susceptible to Tamiflu® and Relenza®, the two antiviral drugs used to treat seasonal flu.
Influenza viruses are always changing. Some of these changes can result in viruses becoming resistant to one or more influenza antiviral drugs, so these medications may not always be fully effective. The H7N9 viruses found in China are very different from previously seen H7N9 viruses, and there is much that is not known about their properties. In addition, the virus is still evolving. As new H7N9 viruses are found, the CDC will conduct tests to determine susceptibility to existing antiviral drugs. The CDC currently recommends Tamiflu® and Relenza® for treatment of H7N9.
Is it possible that human cases of H7N9 will be found in the United States?
Yes. The most likely scenario would be H7N9 infection in a traveler from China. Many people travel between China and the United States. The Health Department has alerted New York City healthcare providers to be on the lookout for flu symptoms in travelers returning from China. The CDC has issued guidance for isolating, testing and treating such patients. However, since this virus does not seem to be spreading easily from person to person, a few United States cases with travel links to China would not change the risk of infection for the general public.
How are H7N9 infections diagnosed?
There are currently no tests available over the counter or at a doctor’s office that can quickly detect and distinguish between the H7N9 virus and other flu viruses. However, the Health Department’s Public Health Laboratory can perform a more sophisticated test that specifically detects H7N9 virus.
Is it safe to eat poultry and poultry products in the United States?
Yes. There is no evidence of H7N9 in poultry in the United States. Routine testing is done in poultry farms and markets. This particular bird flu virus has not been identified outside of China. As always, poultry and eggs should be cooked well before eating.
Should I delay or cancel my trip to China because of H7N9 flu
Since H7N9 is not spreading easily from person to person at this time, there is no advisory against travel to China.
What precautions should I take if I am traveling to China
The Health Department advises travelers to China to take some common sense precautions, like not touching birds or other animals and washing hands often. Travelers should also avoid visiting live poultry markets. Eating poultry or poultry products such as eggs poses no threat of H7N9 infection.
Should I get a prescription for antiviral drugs before I travel to China?
At this time, the Health Department does not recommend prescribing antiviral drugs for prevention or self-treatment of H7N9 flu. Travelers to China should follow common sense precautions to protect themselves and monitor their health during and after their trip. Anyone with fever, cough or shortness of breath within 10 days of traveling to China should see a doctor and tell the doctor about their recent trip.
What has New York City done to address the threat of H7N9?
The New York City Health Department is following the H7N9 situation closely and coordinating with domestic and international partners, including the New York State Health Department, the CDC and the World Health Organization.
The Health Department also is taking the following steps to protect the health of New Yorkers:
- Daily communication with the CDC to ensure the most up-to-date information is available to help guide planning and response.
- Communication with the CDC Quarantine staff at NYC ports of entry to facilitate response to suspect cases among persons returning from China.
- Communication with health providers to share CDC guidance on detecting and reporting suspect cases, arranging laboratory testing and implementing appropriate infection control, treatment and prevention measures.
- Ongoing surveillance for influenza occurring in New York City, including:
- surveillance for influenza-like illness (ILI) occurring in people coming to emergency departments and selected sentinel provider offices throughout the City (ILINet Surveillance System)
- routine testing of clinical samples acquired through the ILINet Surveillance System
- daily monitoring of ILI via syndromic surveillance systems, including emergency department visits, school health nurse visits and 911 ambulance dispatches
- Testing at the Public Health Laboratory of samples submitted from any patients meeting CDC criteria for suspected H7N9 infection, with the ability to rapidly ship specimens to the CDC for samples whose test results are suggestive of H7N9.
The New York City Health Department also remains in regular contact with public health partners, including the CDC, which is taking routine preparedness measures, including:
- developing a candidate vaccine virus that could be used to make vaccine if it becomes necessary
- distributing a new test kit developed by the CDC that can detect the virus and be used by other public health laboratories
- conducting animal studies to learn more about the severity of disease associated with the virus and how the virus spreads
- conducting studies on blood samples to see whether there is any existing immunity to the virus in the population
- conducting ongoing testing to determine H7N9 susceptibility to the licensed influenza antiviral drugs, oseltamivir (commercially known as Tamiflu®) and zanamivir (Relenza®) as well as investigational antiviral drugs
Where can I get more information
For more information about H7N9 influenza, visit: