Updated Interim Guidance from Maine DHHS for Laboratory Testing of Persons with Suspected Infection with Avian Influenza A (H5N1) Virus
October 19, 2006
This update provides revised interim guidance for testing of suspected human cases of avian influenza A (H5N1) in Maine and is based on the current state of knowledge regarding human infection with H5N1 viruses. As of 10/16/06 there were 256 cases confirmed with the death of 59%. The epidemiology of H5N1 human infections has not changed significantly since February 2004. Therefore, federal CDC recommends that H5N1 surveillance in the United States remain at the enhanced level first established at that time. However, this revised interim guidance provides an updated case definition of a suspected H5N1 human case for the purpose of determining when testing should be undertaken and also provides more detailed information on laboratory testing. Effective surveillance will continue to rely on health care providers obtaining information regarding international travel and other exposure risks from persons with specified respiratory symptoms as detailed in the recommendations below. This guidance will be updated as the epidemiology of H5N1 changes. Note: Federal CDC is revising its interim guidance for infection control precautions for avian influenza A (H5N1). These will be issued as soon as they are available.
Background: The avian influenza A (H5N1) epizootic (animal outbreak) in Asia has expanded to wild birds and/or poultry in parts of Europe, the Near East and Africa. Sporadic human infections with H5N1 continue to be reported and have most recently occurred in China, Egypt, Indonesia, Azerbaijan, Cambodia, and Djibouti. In addition, rare instances of probable human-to-human transmission associated with H5N1 viruses have occurred, most recently in a family cluster in Indonesia. So far, however, the spread of H5N1 virus from person to person has been rare, inefficient, and unsustained. The total number of confirmed human cases of H5N1 reported as of October 16, 2006 has reached 256. The case fatality rate for these reported cases is approximately 59 percent. As of this date, H5N1 has not been identified among animals or humans in the United States.
The epizootic in Asia and parts of Europe, the Near East and Africa is not expected to diminish significantly in the short term and it is likely that H5N1 infection among birds has become enzootic in certain areas. It is expected that human infections resulting from direct contact with infected poultry will continue to occur in affected countries. Since no sustained human-to-human transmission of influenza H5N1 has been documented anywhere in the world, the current phase of alert, based on the World Health Organization (WHO) global influenza preparedness plan, remains at Phase 3 (Pandemic Alert).* In addition, no evidence for genetic reassortment between human and avian influenza A virus genes has been found. Nevertheless, this expanding epizootic continues to pose an important and growing public health threat. CDC is in communication with WHO and other national and international agencies and continues to monitor the situation closely.
Recommendations: Federal CDC recommends maintaining the enhanced surveillance efforts practiced currently by Maine CDC, hospitals, and clinicians to identify patients at increased risk for avian influenza A (H5N1). Guidance for enhanced surveillance was first described in a federal CDC HAN update issued on February 3, 2004 and most recently updated on February 4, 2005. Enhanced surveillance guidance is detailed in the attached algorithm adapted from the federal CDC recommendations released on June 7, 2006. Report suspect cases to the 24-hour disease reporting and consultation line at the Maine CDC at 1-800-821-5821.
Travel Health Notice
Federal CDC has not recommended that the general public avoid travel to any of the countries affected by H5N1. However, CDC does recommend that travelers to these countries avoid poultry farms and bird markets or other places where live poultry are raised or kept. For details about other ways to reduce the risk of infection