Recommendations for Monitoring and Testing of Individuals Exposed to A(H5N1) Viruses

Recommendations for Health Departments

State, local and jurisdictional health department officials should investigate potential human cases of HPAI A(H5N1) virus infection as described below and should notify CDC within 24 hours of identifying a case under investigation.

Rapid detection and characterization of novel influenza A viruses in humans remain critical components of national efforts to prevent further cases, to allow for evaluation of clinical illness associated with them, and to assess the ability of these viruses to spread from human to human. State, local, and jurisdictional health department officials, including the State Public Health Veterinarian, should collaborate with State Department of Agriculture and State Wildlife officials using a One Health approach when relevant to investigate suspected HPAI A(H5N1) virus infections in people linked with animals.

Recommendations for Monitoring and Testing

People exposed to HPAI A(H5N1) virus-infected birds, dairy cows, or other animals (including people wearing recommended PPE) should be monitored for signs and symptoms of acute respiratory illness and conjunctivitis (e.g., eye irritation, redness, or discharge) beginning after their first exposure and for 10 days after their last exposure.

Patients who meet Epidemiologic criteria AND either Clinical OR Public Health Response criteria below should be tested for HPAI A(H5N1) virus infection by reverse-transcription polymerase chain reaction (RT-PCR) assay using H5-specific primers and probes at a state or local public health department.

Epidemiological Criteria

Persons with recent exposure (within 10 days) to HPAI A(H5N1) virus through one of the following:

• Exposure to HPAI A(H5N1) virus-infected birds or other animals defined as follows:
  • Close exposure (within six feet) to birds, dairy cows, or other animals, with confirmed HPAI A(H5N1) virus infection. Bird or other animal exposures can include, but are not limited to handling, slaughtering, defeathering, butchering, culling, or preparing birds or other animals for consumption, or consuming uncooked or undercooked food or related uncooked food products, including unpasteurized (raw) milk, OR
  • Direct contact with surfaces contaminated with feces, unpasteurized (raw) milk or other unpasteurized dairy products, or bird or animal parts (e.g., carcasses, internal organs) from infected birds or other animals, OR
  • Visiting a live bird market with confirmed HPAI A(H5N1) virus infections in birds or associated with a case of human infection with HPAI A(H5N1) virus.
• Exposure to an HPAI A(H5N1) virus-infected person – Close (within six feet) unprotected (without use of respiratory and eye protection) exposure to a person who is a confirmed, probable, or symptomatic suspected case of human infection with HPAI A(H5N1) virus (e.g., in a household or healthcare facility).
• Laboratory exposure (unprotected exposure to HPAI A(H5N1) virus in a laboratory)

Clinical Criteria

Persons with signs and symptoms consistent with acute upper or lower respiratory tract infection, conjunctivitis or complications of acute respiratory illness without an identified cause. In addition, gastrointestinal symptoms such as diarrhea can occur with HPAI A(H5N1) virus infection. Examples include but are not limited to:

• Mild illness (e.g., cough, sore throat, eye redness or eye discharge such as conjunctivitis, fever or feeling feverish, rhinorrhea, fatigue, myalgia, arthralgia, headache)
• Moderate to severe illness: (e.g., shortness of breath or difficulty breathing, altered mental status, seizures)
• Complications: pneumonia, respiratory failure, acute respiratory distress syndrome, multi-organ failure (respiratory and kidney failure), sepsis, meningoencephalitis

Public Health Response Criteria

Testing of asymptomatic persons for influenza A(H5) virus is not routinely recommended. However, for the purpose of public health investigations as part of the response to the ongoing HPAI A(H5N1) situation, in consultation with state and local health departments, when feasible, offer to collect a nasal/ oropharyngeal (OP) (+/- conjunctival) swab specimen to test for influenza A(H5) virus at a public health laboratory using the CDC Influenza A/H5 subtyping kit to asymptomatic workers with high risk of exposure to HPAI A(H5N1) virus [e.g., exposed to animals infected with HPAI A(H5N1) virus and who reported not wearing recommended PPE or who experienced a breach in recommended PPE], or asymptomatic close contacts of a confirmed case of HPAI A(H5N1) virus infection.

Exposed persons should be actively monitored for signs and symptoms of acute respiratory illness or conjunctivitis for 10 days after the last known exposure to HPAI A(H5N1) virus. Any person who develops signs or symptoms of acute respiratory illness or conjunctivitis after high risk of exposure to HPAI A(H5N1) virus, including persons who previously tested negative for influenza A(H5) virus, persons who previously tested positive for influenza A(H5) virus while asymptomatic, and those receiving oseltamivir post-exposure prophylaxis, should be isolated, and tested for influenza A(H5) virus.

Key resources

Interim Guidance on the Use of Antiviral Medications for Treatment of Human Infections with Novel Influenza A Viruses Associated with Severe Human Disease | Bird Flu | CDC

Interim Guidance on Influenza Antiviral Post-exposure Prophylaxis of Persons Exposed to Birds or Other Animals with Novel Influenza A Viruses Associated with Severe Human Disease or with the Potential to Cause Severe Human Disease | Bird Flu | CDC

Interim Risk Categories by Exposure