Health Update
AVIAN INFLUENZA A (H5N1) UPDATE

The Centers for Disease Control and Prevention (CDC) has provided an update on the Avian Influenza A (N5H1) situation, including travel precautions. Avian Influenza in Asia is of concern because it can potentially lead to an influenza pandemic. The Delaware Division of Public Health (DPH) is forwarding CDC's update to assure that Delaware health care providers are informed of appropriate reporting and infection control procedures.

Summary

Thirteen human cases of influenza A (H5N1) infection (with 12 deaths) have been reported by Vietnam since mid-December 2004; WHO has reported that 10 of these cases (with 9 deaths) have been confirmed. One instance of probable limited human-to-human transmission of influenza A (H5N1) virus was reported in Thailand between a child and her mother and aunt in September 2004. See the CDC update below for further information.

Surveillance in Delaware

There is no evidence of avian influenza in humans or birds in Delaware at this time. DPH is maintaining surveillance systems to detect the occurrence of unusual influenza activity in Delaware, and is requesting that health care providers report suspect cases as detailed below. Specifically:

• Enhanced influenza surveillance and reporting procedures - Selected colleges, businesses, long-term care facilities and assisted living facilities already report unusual numbers of influenza-like illnesses weekly. In addition, health care providers and hospitals in Delaware are requested to review the guidance from CDC below and report suspect cases of human avian influenza to DPH immediately. Note that in the absence of laboratory evidence, a travel history to Asia should be used to raise suspicions about human illness that may be caused by avian strains of influenza, as distinguished from human strains now circulating. Such reports, as well as requests to arrange laboratory testing, can be made by calling the telephone immediately below.
• Active syndromic surveillance - In response to Severe Acute Respiratory Syndrome (SARS) and general concerns about bioterrorism, Delaware hospitals are reporting daily the number of patients treated for specific symptoms. This system was established several years ago, and includes symptoms consistent with human avian influenza. Significant increases in the number of patients with such symptoms are investigated by DPH epidemiologists.
• Sentinel influenza surveillance - DPH has a network of physicians in the sentinel influenza surveillance program. Currently, four physician-practices (1 in New Castle, 2 in Kent and 1 in Sussex counties) submit nasopharyngeal swabs from patients with influenza-like symptoms to the DPH laboratory for viral testing. Influenza, when identified, is typed by the DPH laboratory. The DPH laboratory analysis is provided at no cost to the physician and patient. Physician-practices interested in participating in this program, especially from New Castle and Sussex Counties, should contact Dr. Leroy Hathcock, State Epidemiologist at (302) 744-4541 or at Leroy.Hathcock@delaware.gov for further information.

Questions about this Health Update, requests for laboratory testing, and reports of suspected cases can be directed to DPH at 1-888-295-5156. This number is operational all the time. During non-business hours, it is available for emergencies.

This is an official
CDC Health Update
Update on Avian Influenza A (H5N1)

Distributed via Health Alert Network

Current Situation

Outbreaks of avian influenza A (H5N1) among poultry are ongoing in several countries in Asia, including Thailand, Vietnam, and Cambodia. Reports of sporadically occurring human cases of influenza A (H5N1) continued through January 2005. Thailand reported five human cases of influenza H5N1 (with four deaths) in September and October 2004, but no additional cases to date. Thirteen human cases of influenza A (H5N1) infection (with 12 deaths) have been reported by Vietnam since mid-December 2004; WHO has reported that 10 of these cases (with 9 deaths) have been confirmed.

One instance of probable limited human-to-human transmission of influenza A (H5N1) virus was reported in Thailand between a child and her mother and aunt in September 2004. Health authorities in Vietnam are investigating two possible instances of limited human-to-human transmission in family clusters. One instance involves two brothers in Vietnam with confirmed influenza A (H5N1) infections; a third brother was hospitalized for observation only and did not become ill. In the second instance, a daughter developed symptoms within 6 days of her mother’s onset of illness, which was confirmed as influenza A (H5N1). Investigations are exploring possible sources of exposure and looking for other signs of illness in family members, other close contacts, and the general community.

In addition, the first human case of influenza H5 infection in Cambodia has been confirmed in a woman who was hospitalized in Vietnam and died. A joint mission between the Cambodian Ministries of Health and Agriculture and WHO is in Cambodia investigating the circumstances surrounding this case.

As of February 4, 2005, the cumulative number of confirmed human cases of influenza A (H5N1) reported in Asia since January 28, 2004, is 55 cases (with 42 deaths), according to WHO. This total includes the case from Cambodia.

The avian influenza A (H5N1) epizootic in Asia poses an important public health threat, and CDC is in communication with WHO and will continue to monitor the situation. The epizootic in Asia is not expected to diminish substantially in the short term, and it is likely that influenza A (H5N1) infection among birds has become endemic to the region and that human infections will continue to occur. So far, no sustained human-to-human transmission of the influenza A (H5N1) virus has been identified, and no influenza A (H5N1) viruses containing both human and avian influenza virus genes, indicative of gene reassortment, have been detected.

Travel Health Precaution

It is expected that the number of people traveling between the United States and certain parts of Asia will increase around the Lunar New Year, which occurs on February 9 this year. Chinese, Vietnamese, Cambodian, and Korean people celebrate the start of the lunar calendar year. Lunar New Year celebrations last for approximately 15 days in China, 3 days in Vietnam, and typically only 1 day in Cambodia and Korea.

On January 26, 2005, CDC issued a Travel Health Precaution notice about avian influenza A (H5N1): http://www.cdc.gov/travel/other/avian_flu_vietnam_2005.htm  . This notice is directed at travelers who may be returning from Vietnam to visit family and friends, especially during the upcoming holiday, and who may be at greater risk for exposure to poultry through food preparation or at farms and bird markets where infected poultry may not be readily detected. The notice outlines specific measures for travelers to take before, during, and after travel to Vietnam. CDC has not recommended that the general public avoid travel to any countries affected by influenza A (H5N1). For more information, see CDC’s’ Travelers Health website at: http://www.cdc.gov/travel/index.htm .

Enhanced U.S. Surveillance, Diagnostic Evaluation, and Infection Control Precautions for Avian Influenza A (H5N1)

CDC recommends maintaining the enhanced surveillance efforts by state and local health departments, hospitals, and clinicians to identify patients at increased risk for avian influenza A (H5N1) as described in HAN notices that were issued on:

• February 3, 2004 http://www.cdc.gov/flu/avian/professional/han020302.htm
• August 12, 2004 http://www.cdc.gov/flu/avian/professional/han081304.htm

Guidelines for enhanced surveillance are as follows.

Testing for avian influenza A (H5N1) is indicated for hospitalized patients with:

• radiographically confirmed pneumonia, acute respiratory distress syndrome (ARDS), or other severe respiratory illness for which an alternate diagnosis has not been established, AND
• history of travel within 10 days of symptom onset to a country with documented H5N1 avian influenza in poultry and/or humans (for a regularly updated listing of H5N1-affected countries, see the OIE website at: http://www.oie.int/eng/en_index.htm and the WHO website at: http://www.who.int/en/ ).

Testing for avian influenza A (H5N1) should be considered on a case-by-case basis in consultation with state and local health departments for hospitalized or ambulatory patients with:

• documented temperature of >38°C (>100.4°F), AND
• one or more of the following: cough, sore throat, shortness of breath, AND
• history of contact with poultry (e.g., visited a poultry farm, a household raising poultry, or a bird market) or a known or suspected human case of influenza A (H5N1) in an H5N1-affected country within 10 days of symptom onset.

Laboratory Testing Procedures

Virus Culture

Highly pathogenic avian influenza A (H5N1) is classified as a select agent, and culturing of clinical specimens for influenza A (H5N1) virus must be conducted under laboratory conditions that meet the requirements for Biosafety Level (BSL) 3 with enhancements. These enhancements include controlled access double-door entry with change room and shower, use of respirators, decontamination of all wastes, and showering out of all personnel. Laboratories working on these viruses must be certified by the U.S. Department of Agriculture. CDC recommends that virus isolation studies be conducted on respiratory specimens from patients who meet the above criteria only if requirements for BSL 3 with enhancements can be met.

Polymerase Chain Reaction (PCR) and Commercial Antigen Testing

Clinical specimens from suspect influenza A (H5N1) cases may be tested by PCR assays under standard BSL 2 conditions in a Class II biological safety cabinet. In addition, commercial antigen detection testing can be conducted under standard BSL 2 conditions used to test for influenza.

Specimens That Should Be Sent to CDC

Specimens from persons meeting the above clinical and epidemiologic criteria should be sent to CDC if

• The specimen tests positive for influenza A virus by PCR or by antigen detection testing, OR
• PCR assays for influenza are not available at the state public health laboratory.

CDC also will accept specimens from persons meeting the above clinical criteria even if they test negative by influenza rapid diagnostic testing if PCR assays are not available at the state laboratory. This is because the sensitivity of commercially available rapid diagnostic tests for influenza may not always be optimal.

Requests for testing should come through the state and local health departments, which should contact (404) 639-3747 or (404) 639-3591 and ask for the epidemiologist on call before sending specimens to CDC for influenza A (H5N1) testing.

Interim Recommendations: Infection Control Precautions for Influenza A (H5N1)

Infection control precautions for H5N1 remain unchanged from the CDC interim recommendations issued on February 3, 2004 and can be found at:http://www.cdc.gov/flu/avian/professional/han020302.htm. All patients who present to a health-care setting with fever and respiratory symptoms should be managed according to recommendations for Respiratory Hygiene and Cough Etiquette found at: http://www.cdc.gov/flu/professionals/infectioncontrol/resphygiene.htm and questioned regarding their recent travel history. Isolation precautions identical to those recommended for SARS should be implemented for all hospitalized patients diagnosed with or under evaluation for influenza A (H5N1) as follows:

• Standard Precautions
• Pay careful attention to hand hygiene before and after all patient contact
• Contact Precautions
• Use gloves and gown for all patient contact
• Eye protection
• Wear when within 3 feet of the patient
• Airborne Precautions
• Place the patient in an airborne isolation room (i.e., monitored negative air pressure in relation to the surrounding areas with 6 to 12 air changes per hour).
• Use a fit-tested respirator, at least as protective as a NIOSH-approved N-95 filtering facepiece respirator, when entering the room.

For additional information regarding these and other health-care isolation precautions, see the Guidelines for Isolation Precautions in Hospitals found at:http://www.cdc.gov/ncidod/hip/ISOLAT/Isolat.htm. These precautions should be continued for 14 days after onset of symptoms until an alternative diagnosis is established or until diagnostic test results indicate that the patient is not infected with influenza A virus (see Laboratory Testing Procedures below). Patients managed as outpatients or hospitalized patients discharged before 14 days should be isolated in the home setting on the basis of principles outlined for the home isolation of SARS patients (see http://www.cdc.gov/ncidod/sars/guidance/i/pdf/i.pdf).

Additional Avian Influenza A (H5N1) Information

• For information about reported outbreaks of avian influenza A (H5N1) among poultry:
  • see the website of the World Organization of Animal Health (OIE) at:http://www.oie.int/eng/AVIAN_INFLUENZA/home.htm
• For information about human influenza A (H5N1) cases:
  • see the WHO website at:http://www.who.int/en/
• For clinical information about human influenza A (H5N1) cases:
  • see CDC Cases of influenza A (H5N1) - Thailand, 2004 at:http://www.cdc.gov/flu/avian/professional/han081304.htm MMWR 2004;53:100-103
  • see Hien TT, Liem AT, Dung NT, et al. Avian influenza A (H5N1) in 10 patients in Vietnam. New England Journal of Medicine 2004;350:1179-1188
• For information about travel and avian H5N1 influenza
  • see the CDC Travelers Health website at:http://www.cdc.gov/travel/index.htm

  Some of the files offered on this page are in Adobe Acrobat (PDF) format which requires Adobe Acrobat Reader. A free copy of Adobe Acrobat Reader can be downloaded directly from Adobe. If you are using an assistive technology unable to read Adobe PDF, visit Adobe's Accessibility Tools page.