Novel Avian Influenza A (H7N9) in China
By CAHAN San DIego
May 2, 2013
On April 1, 2013, the World Health Organization (WHO) reported the first known human infections with a novel avian influenza A (H7N9) virus almost exclusively in China. As of May 2, 128 human cases of influenza A (H7N9) virus infection have been laboratory-confirmed, including 26 deaths.
While investigations are ongoing, there is currently no evidence that the virus has become easily transmissible from person to person. Most cases have been reported in the eastern part of China, with the highest case counts in the provinces of Jiangsu, Shanghai, and Zhejiang. However, new cases continue to be reported, and case counts are likely to increase. Click here for updates.
Reporting Suspect Cases
Healthcare providers in San Diego County should be alert for suspect cases of influenza A (H7N9), especially among recent travelers to China. The Epidemiology Program should be immediately notified at (619) 692-8499 (Monday–Friday, 8:00am–5:00pm) or (858) 565-5255 (after hours) if a patient is suspected to have influenza A (H7N9) or any other novel influenza virus, regardless of rapid influenza test results.
The California Department of Public Health (CDPH) currently considers a suspect case of influenza A (H7N9) to be a patient with influenza-like illness* (ILI) that meets either of the following exposure criteria:
- Recent travel (within ≤ 10 days of illness onset) to China; OR
- Recent contact (within ≤ 10 days of illness onset) with a confirmed or probable case of influenza A (H7N9)
*ILI is defined as fever (temperature of 100°F [37.8°C] or greater) and cough and / or sore throat. Click here for the CDC criteria for confirmed and probable cases.
Laboratory Testing of Suspect Cases
Specimens from patients with suspect influenza A (H7N9) virus infection should be promptly submitted to the San Diego County Public Health Laboratory (SDCPHL) for testing, regardless of rapid influenza test results. Clinicians should obtain a nasopharyngeal swab or aspirate, place the swab or aspirate in viral transport medium, and contact the SDCPHL at (619) 692-8500 to arrange specimen transport.
Infection Control Precautions
The CDC has issued interim guidance for influenza A (H7N9) infection control precautions. Healthcare personnel providing care for patients with confirmed, probable, or suspect influenza A (H7N9) infection should use standard precautions, including eye protection, plus contact and airborne precautions. Aerosol-generating procedures should be performed on such patients only if they are medically necessary and cannot be postponed.
These recommendations are more stringent than the infection control precautions routinely used for seasonal influenza because there is currently no vaccine for influenza A (H7N9), the virus is suspected to have a high rate of morbidity and mortality among infected patients, it has an unknown potential for person-to-person transmission, and there are currently no cases reported in the United States.
Many primary care clinics will not be able to implement all elements of airborne precautions (e.g., placing patient in airborne infection isolation room). However, all possible precautions should be taken to minimize the risk of exposure to staff and patients, including the following:
- Receptionists and phone triage personnel should ask all patients with ILI if they have had travel to China within 10 days of symptom onset.
- Patients with ILI and a history of travel to China should be given a surgical mask to wear upon entering the clinic and immediately placed in a room with a door that closes. They should not remain in waiting areas.
- If possible, these patients should be seen at the end of the day or when fewer people are in the clinic.
Click here for interim guidance on antiviral treatment of human infections with influenza A (H7N9) from the CDC. Because of the potential severity of illness associated with this infection, the CDC recommends that all confirmed, probable, and suspect cases of influenza A (H7N9), including outpatients with uncomplicated illness, be treated with neuraminidase inhibitors as early as possible. Clinicians should not wait for laboratory confirmation of influenza before initiating treatment.