By Christina Baum, Program Analyst, Infectious Disease, NACCHO
Avian influenza has been a popular topic in the media this past year, and the attention on the topic boils down to two primary points of interest: 1) it has affected millions of birds and 2) the disease is similar to ones which have affected humans in the past. The outbreak began in 2014 and by early summer of 2015 had spread to birds in 21 states. Avian influenza represents just one of many potential public health threats that may be on the radar for local health departments (LHDs) and there are several key points to remember while avian influenza remains a concern.
There are many strains of avian influenza worldwide, and they can be classified as either highly pathogenic (HPAI) or low pathogenic (LPAI) based on the severity of the illness they cause in birds. These viruses are named for the types of proteins found in them. The current outbreak in the United States are all H5 viruses (named for the fifth known type of hemagglutinin protein) and include H5N8, H5N2, and H5N1 which are distinguished by the type of neuraminidase protein they contain. All of the strains are classified as highly pathogenic because of the severe illness they cause in birds. Further, viruses with these combinations of genes had not previously been detected in the United States and they have spread primarily along the Pacific and Central flyways—routes traveled by wild migratory birds. When these viruses are detected, particularly among large flocks of agricultural birds, the animals are often culled to prevent the spread of the disease. Since December 2014, over 48 million birds have been affected and many of them have been eliminated. Prior to this outbreak, the 2004 HPAI outbreak in Texas was the only one in over 20 years and that outbreak affected only 7,000 birds.
The risk of human infection is low, even with the highly pathogenic strains but some genetically similar HPAI viruses have infected people in the past. Most human infections with avian influenza viruses—including Asian HPAI H5 viruses and LPAI H7N9 in China, which were both widely publicized—occurred in people who had direct contact with either infected birds or the excretions/secretions of infected birds.
To see how LHDs have been affected and what they are doing to track avian influenza, NACCHO reached out to members of its Epidemiology, Infectious Disease Prevention and Control, and Immunization workgroups, as well as the Preparedness Policy Advisory Group. Through these conversations, several themes and important lessons emerged:
- The degree of response and concern is highly variable, but most LHDs are monitoring the situation. NACCHO is aware and mindful of the diversity of LHDs—in geographic area, population, programs, and more, and this diversity allows them to address the unique needs of each community. Thus, the response to HPAI in the U.S. is no exception, and varies depending on capacity, perceived threat levels, and community interest.
- Building and maintaining relationships with veterinary public health teams and agricultural partners early on is valuable if and when a response is needed.
- It is important to be mindful about messaging. In communities where animals are affected or the public expresses concern, working with partners to develop accurate and consistent messaging is necessary, as with any emerging threat.
- Maintaining partnerships with state and federal level public health is also integral. LHDs will be relied upon as a resource if response to this threat is necessary, and having good communication across these levels can make preparedness and action more effective.
Even while the avian influenza threat diminishes as the virus is beat back by the summer heat, the topic is just another example of the ways that LHDs are on the frontline of protecting public health and the lessons applied here are often echoed in response to new emerging threats.
For more information about avian influenza:
- CDC webpage about Avian Influenza: http://www.cdc.gov/flu/avianflu/
- List of confirmed U.S. H5 infections in poultry
- List of confirmed U.S. H5 infections in wild birds
About Christina Baum
Christina Baum is a program analyst for NACCHO’s Infectious Disease team. She works with local health departments on such topics as biosurveillance, epidemiology, and informatics.