Influenza (the flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness and at times can lead to death. Some people, such as older people, young children, and people with certain health conditions are at high risk for serious flu complications. The best way to prevent the flu is by getting vaccinated each year.
Epidemiology and Statistics
The new A (H7N9) virus is an avian influenza virus. Human infections with avian influenza are rare but have occurred in the past, most commonly after exposure to infected poultry. However, this is the first time that this avian flu subtype (H7N9) has been found in people.
Most reported cases had severe respiratory illness. To date there is no evidence of person-to-person transmission. Because this virus is not related to any previously circulating viruses, there is no population immunity. There is also no way to predict what it would take for this virus to become easily transmitted from human to human.
As of April 7, 2013, there have been 21 reported cases of A (H7N9) influenza in China (10 in Shanghai, 6 in Jiangsu Province, 2 in Anhui Province, and 3 in Zhejiang Province). Six individuals have died. A (H7N9) influenza has not been detected in people or birds in the United States.
Patients with illness compatible with influenza who also meet either of the exposure criteria below should be tested for influenza using RT-PCR:
- Patients with recent travel to countries where human cases of novel influenza A (H7N9) virus infection have recently been detected, especially if there was recent direct or close contact with animals (such as wild birds, poultry, or pigs) or where influenza A (H7N9) viruses are known to be circulating in animals. Currently, China is the only country that has recently reported novel influenza A (H7N9) human cases; OR
- Patients who have had recent contact with confirmed human cases of infection with novel influenza A (H7N9) virus.
Specimens should be sent directly to the Monterey County Public Health Laboratory for RT-PCR testing. For more information on what specimens to collect and any necessary forms, contact the Monterey County Public Health Laboratory at 831-755-4516.
For hospitalized individuals and high-risk outpatients (<5 years of age, ≥65 years of age, and those with certain underlying medical conditions) with suspected influenza, including suspected novel H7N9 virus infection, clinicians should start empiric treatment with influenza antiviral medications (oseltamivir or zanamivir) as soon as possible, without waiting for laboratory confirmation.
Because it has been shown to cause severe respiratory illness in cases identified so far, healthcare personnel caring for patients under investigation for novel influenza A (H7N9) virus infection should adhere to Standard Precautions plus Droplet, Contact, and Airborne Precautions, including eye protection, until more is known about the transmission characteristics of the A (H7N9) virus.
Suspected cases of novel influenza must be immediately reported to the Monterey County Health Department (831-755-4521; after-hours 831-755-5100 and ask for the on-call Health Officer).
For additional information, see the Centers for Disease Control and Prevention’s website: http://www.cdc.gov/flu/avianflu/h7n9-virus.htm.