ADVISORY – Important Information

2006PHADV015

TO: Hospitals, Infection Control Practitioners, ME Primary Care, ME Laboratories, Public Health Nurses, Public Health, State and Federal Agencies

FROM: Dora Anne Mills, M.D., M.P.H., Public Health Director

SUBJECT: Guidance for Laboratory Testing of Persons with Suspected Infection with Avian Influenza A (H5N1) Virus in the United States

DATE: July 20, 2006

TIME: 7:00 AM

PAGES: 4

PRIORITY: Review

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Updated Interim Guidance for Laboratory Testing of Persons with Suspected Infection with Avian Influenza A (H5N1) Virus in the United States

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. 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 July 14, 2006 has reached 230. The case fatality rate for these reported cases continues to be approximately 50 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 releases 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.

Reports of dead birds suspected of avian influenza should be directed to the Maine CDC dead bird hotline at 1-888-697-5846. These reports will be forwarded to partner agencies involved in testing birds for avian influenza.

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, see http://www.cdc.gov/travel/other/avian_influenza_se_asia_2005.htm.

For More Information:

Maine CDC at www.maineflu.org U.S. Department of Health and Human Services at www.pandemicflu.gov

World Health Organization at World Organization for Animal Health (OIE) at http://www.oie.int/eng/en_index.htm

*For the current WHO Pandemic Phase, see http://www.who.int/csr/disease/avian_influenza/phase/en/index.html.

Figure 1: Case detection and clinical management of suspect or confirmed human cases of novel influenza virus (Who Phases 3 & 4)

Situation: No human cases of novel influenza are present in the community. Human cases might be present in another country or another region of the United States.

Footnotes (HHS Pandemic Influenza Plan and Supplements are available at www.hhs.gov/pandemicflu/plan/)

1. Testing for avian influenza (H5N1) virus infection can be considered on a case-by-case basis in consultation with Maine CDC (1-800-821-5821) for:

· A patient (hospitalized or ambulatory) with mild or atypical disease (for example a patient with respiratory illness and fever who does not require hospitalization, or a patient with significant neurologic or gastrointestinal symptoms in the absence of respiratory disease) who has one of the exposures listed as epidemiologic criteria; OR

· A patient with severe or fatal respiratory disease whose epidemiological information is uncertain, unavailable, or otherwise suspicious but does not meet the epidemiological criteria (examples include a returned traveler from an influenza H5N1-affected country whose exposures are unclear or suspicious, a person who had contact with sick or well-appearing poultry, etc.)

· Further evaluation and diagnostic testing should also be considered for outpatients with strong epidemiologic risk factors and mild or moderate illness: Consult with Maine CDC at 1-800-821-5821.

2. Updated information on areas where novel influenza virus transmission is suspected or documented is available at the CDC website at www.cdc.gov/flu/avian/outbreaks/current.htm; the OIE website at www.oie.int/eng/en_index.htm; and the WHO website at www.who.int/csr/disease/avian_influenza/en/

3. Standard and Droplet Precautions should be used when caring for patients with novel influenza or seasonal influenza. Information on infection precautions that should be implemented for all respiratory illnesses is provided at: www.cdc.gov/flu/professionals/infectioncontrol/resphygiene.htm

4. Hospitalization should be based on all clinical factors, including the potential for infectiousness and the ability to practice adequate infection control. If hospitalization is not clinically warranted, and treatment and infection control is feasible in the home, the patient may be managed as an outpatient: Consult with Maine CDC. The patient and his or her household should be provided with information on infection control procedures to follow at home. The patient and close contacts should be monitored for illness by Maine CDC staff.

5. The general work-up should be guided by clinical indications. Depending on the clinical presentation and the patient’s underlying health status, initial diagnostic testing might include: Pulse oximetry; Chest radiograph; Complete blood count (CBC) with differential; Blood cultures; Sputum (in adults), tracheal aspirate, pleural effusion aspirate (if pleural effusion is present) Gram stain and culture; Antibiotic susceptibility testing (encouraged for all bacterial isolates); Multivalent immunofluorescent antibody testing or PCR of nasopharyngeal aspirates or swabs for common viral respiratory pathogens, such as influenza A and B, adenovirus, parainfluenza viruses, and respiratory syncytial virus, particularly in children; In adults with radiographic evidence of pneumonia, Legionella and pneumococcal urinary antigen testing; If clinicians have access to rapid and reliable testing (e.g., PCR) for M. pneumoniae and C. pneumoniae, adults and children <5 yrs with radiographic pneumonia should be tested; Comprehensive serum chemistry panel, if metabolic derangement or other end-organ involvement, such as liver or renal failure, is suspected.

6. Guidelines for novel influenza virus testing can be found in HHS Plan Supplement 2. Oropharyngeal swab specimens and lower respiratory specimens (e.g. bronchoalveolar lavage or tracheal aspirate [for intubated patients]) should be collected for novel influenza virus testing.

· These specimens are preferred because they appear to contain the highest quantity of virus for influenza H5N1 detection, as determined on the basis of available data. Nasal or nasopharyngeal swab specimens are acceptable, but may contain less virus and therefore not be optimal specimens for virus detection.

· Detection of influenza H5N1 is more likely from specimens collected within the first 3 days of illness onset. If possible serial specimens should be obtained over several days from the same patient.

· Bronchoalveolar lavage is considered to be a high-risk aerosol-generative procedure. Infection control precautions should include the use of gloves, gown, goggles or face shield, and a fit-tested respirator with an N-95 or higher rated filter. A loose fitting powered air-purifying respirator (PAPR) may be used if fit-testing is not possible (for example, if the person has a beard). Detailed guidance on infection control precautions for health care workers care for suspected influenza H5N1 patients is available at www.cdc.gov/flu/avian/professional/infect-control.htm

· Swabs used for specimen collection should have a Dacron tip and an aluminum or plastic shaft. Swabs with calcium alginate or cotton tip and wooden shafts are not recommended. Specimens should be placed at 4’C immediately after collection.

· Laboratory personnel should contact Maine CDC (1-800-821-5821) Epidemiology and HETL for advice on specimen preparation and transportation.

7. Strategies for the use of antiviral drugs are provided in HHS Plan Supplement 7.

8. Guidelines for the management of contacts in a healthcare setting are provided in HHS Plan Supplement 3.

9. Given the unknown sensitivity of tests for novel influenza viruses, interpretation of negative results should be tailored to the individual patient in consultation with the local health department. Novel influenza directed management may need to be continued, depending on the strength of clinical and epidemiologic suspicion. Antiviral therapy and isolation precautions for novel influenza may be discontinued on the basis of an alternative diagnosis. The following criteria may be considered for this evaluation: Absence of strong epidemiologic link to known cases of novel influenza; Alternative diagnosis confirmed using a test with a high positive-predictive value; Clinical manifestations explained by the alternative diagnosis

10. Guidance on the evaluation and treatment of suspected post-influenza community-associated pneumonia is provided in HHS Plan Appendix 3.

**ADVISORY – Important Information**

Updated Interim Guidance for Laboratory Testing of Persons with Suspected Infection with Avian Influenza A (H5N1) Virus in the United States

Figure 1: Case detection and clinical management of suspect or confirmed human cases of novel influenza virus (Who Phases 3 & 4)

ADVISORY – Important Information