FIGURE 1. Location of confirmed cases of human infection (n = 126) with avian influenza A(H7N9) virus and deaths (n = 24) — China, February 19–April 29, 2013
# 7218
Playing a little catch-up after having been away from my desk for much of yesterday, we’ve an Early Release MMWR on the avian H7N8 virus outbreak in China.
It’s a fairly lengthy report, so I’ll just include a few excerpts (reparagraphed for readability) and invite you to follow the link to read it in its entirety.
Emergence of Avian Influenza A(H7N9) Virus Causing Severe Human Illness — China, February–April 2013
Early Release
May 1, 2013 / 62(Early Release);1-6On March 29, 2013, the Chinese Center for Disease Control and Prevention completed laboratory confirmation of three human infections with an avian influenza A(H7N9) virus not previously reported in humans (1). These infections were reported to the World Health Organization (WHO) on March 31, 2013, in accordance with International Health Regulations.
The cases involved two adults in Shanghai and one in Anhui Province. All three patients had severe pneumonia, developed acute respiratory distress syndrome (ARDS), and died from their illness (2). The cases were not epidemiologically linked. The detection of these cases initiated a cascade of activities in China, including diagnostic test development, enhanced surveillance for new cases, and investigations to identify the source(s) of infection.
No evidence of sustained human-to-human transmission has been found, and no human cases of H7N9 virus infection have been detected outside China, including the United States. This report summarizes recent findings and recommendations for preparing and responding to potential H7N9 cases in the United States. Clinicians should consider the diagnosis of avian influenza A(H7N9) virus infection in persons with acute respiratory illness and relevant exposure history and should contact their state health departments regarding specimen collection and facilitation of confirmatory testing.
Epidemiologic Investigation
As of April 29, 2013, China had reported 126 confirmed H7N9 infections in humans, among whom 24 (19%) died (1). Cases have been confirmed in eight contiguous provinces in eastern China (Anhui, Fujian, Henan, Hunan, Jiangsu, Jiangxi, Shandong, and Zhejiang), two municipalities (Beijing and Shanghai), and Taiwan (Figure 1). Illness onset of confirmed cases occurred during February 19–April 29 (Figure 2). The source of the human infections remains under investigation.
Almost all confirmed cases have been sporadic, with no epidemiologic link to other human cases, and are presumed to have resulted from exposure to infected birds (3,4). Among 82 confirmed cases for which exposure information is available, 63 (77%) involved reported exposure to live animals, primarily chickens (76%) and ducks (20%) (3). However, at least three family clusters of two or three confirmed cases have been reported where limited human-to-human transmission might have occurred (3).
The MMWR summarizes their findings thusly:
What is already known on this topic?
Human infections with a new avian influenza A(H7N9) virus were first reported to the World Health Organization on March 31, 2013. Available information suggests that poultry is the source of infection in most cases. Although no evidence of sustained (ongoing) human-to-human spread of this virus has been identified; small family clusters have occurred where human-to-human spread cannot be conclusively ruled out.
What is added by this report?
By April 29, a total of 126 H7N9 human infections (including 24 deaths) had been confirmed. Although a number of travelers returning to the United States from affected areas of China have developed influenza-like symptoms and been tested for H7N9 infection, no cases have been detected in the United States. Laboratory and epidemiologic evidence suggest that this H7N9 virus is more easily transmitted from birds to humans than other avian influenza viruses. Candidate vaccine viruses are being evaluated and human clinical vaccine trials are forthcoming, but no decision has been made regarding a U.S. H7N9 vaccination program.
What are the implications for public health practice?
State and local health authorities are encouraged to review pandemic influenza preparedness plans to ensure response readiness. Clinicians in the United States should consider H7N9 virus infection in recent travelers from China who exhibit signs and symptoms consistent with influenza. Patients with H7N9 virus infection (laboratory-confirmed, probable, or under investigation) should receive antiviral treatment with oral oseltamivir or inhaled zanamivir as early as possible.
The entire release is well worthreading, but I'll call particular attention to the conclusions presented at the end the Editorial notes section, pertaining to preparedness.
Given the number and severity of human H7N9 illnesses in China, CDC and its partners are taking steps to develop a H7N9 candidate vaccine virus. Past serologic studies evaluating immune response to H7 subtypes of influenza viruses have shown no existing cross-reactive antibodies in human sera.
In addition, CDC has activated its Emergency Operations Center to coordinate efforts. In the United States, planning for H7N9 vaccine clinical trials is under way. Although no decision has been made to initiate an H7N9 vaccination program in the United States, CDC recommends that local authorities and preparedness programs take time to review and update their pandemic influenza vaccine preparedness plans because it could take several months to ready a vaccination program, if one becomes necessary.
CDC also recommends that public health agencies review their overall pandemic influenza plans to identify operational gaps and to ensure administrative readiness for an influenza pandemic. Continued collaboration between the human and animal health sectors is essential to better understand the epidemiology and ecology of H7N9 infections among humans and animals and target control measures for preventing further transmission.
With the opening of hurricane season just 30 days away, the spring flood and storm season upon us, and the fact that earthquakes know no season, there are plenty of good reasons – beyond worrying about a possible pandemic - for all of us to be looking at and updating our emergency plans.
The best disaster and preparedness plans are designed around dealing with `all hazards’, as opposed to focusing on any one particular threat.
For information on preparedness, I would invite you to visit:
FEMA http://www.fema.gov/index.shtm
READY.GOV http://www.ready.gov/
AMERICAN RED CROSS http://www.redcross.org/
And lastly, you may wish to revisit some of my earlier preparedness essays, including:
In An Emergency, Who Has Your Back?
