Evaluation of Patients Who Meet Case Definition for Avian H5N1 Influenza
Once you suspect that a patient may have avian H5N1 influenza, notify MDH. The MDH epidemiologist will work with you determine proper testing and treatment, similar to the options listed here. This applies to the current pandemic alert period, WHO phase 3, with no or limited human-to-human transmission of H5N1.
Suspect case? Call MDH anytime at 651-201-5414 or 1-877-676-5414.
On this page:
Testing for the H5N1 virus
Other diagnostic testing
Treatment - antivirals
CDC recommendations
Testing for the H5N1 virus
The MDH Public Health Lab (PHL) can do PCR testing to determine if a patient has H5N1. Further testing, including viral culture, can only be done at a BSL3+ or BSL4 facility, such as the CDC lab. Do not attempt to perform viral culture. Culture for H5N1 should only be done at BSL3+ or BSL4 facility. If the MDH epidemiologist recommends any testing for H5N1, some of these specimens should be collected. Be sure to let your lab know that the patient may have the H5N1 virus.
Preferred specimen (required):
- 2 throat swabs (also called oropharyngeal swabs)
Use a dacron or rayon swab with a plastic or aluminum shaft. Store specimens in viral transport media.
Additional specimens:
- 1 nasopharyngeal (NP) swab or nasal wash or aspirate
Use a dacron or rayon swab with a plastic or aluminum shaft. Store specimens in viral transport media. - Tracheal aspirate (if intubated)
- Other respiratory specimens obtained as part of clinical care may be submitted (BAL, pleural fluid, etc.)
- Other specimens may be requested, depending on clinical presentation
The H5N1 virus replicates well in the lower respiratory track, so throat swabs and lower respiratory specimens (e.g., bronchoalveolar lavage [BAL]or tracheal aspirates) are more suitable specimens than nasal or NP swabs. Note: while lower respiratory tract specimens are recommended, it is recognized that these specimens are more difficult to collect than throat swabs.
Hold specimens at 4°C (39°F) until transport to MDH Laboratory can be arranged.
Specimens will be used for H5N1 evaluation and may be used for evaluation of other respiratory pathogens by PCR at MDH including other influenza, adenovirus, parainfluenza, RSV, human metapneumovirus, Legionella spp., M. pneumoniae, and C. pneumoniae).
Infection control during specimen collection
- Full Barrier Personal Protective Equipment (PPE) with N95 Respirator or
- Full
Barrier Personal Protective Equipment (PPE) with Powered Air Purifying
Respirator (PAPR)
Use full barrier precautions when obtaining respiratory specimens. Consider use of a positive air purifying respirator (PAPR) for procedures that may generate aerosols.
Specimen submission
- Specimen Submission
and Laboratory Testing for Avian Influenza
Work with the MDH epidemiologist to arrange transport and testing of samples to the MDH Public Health Lab.
Other diagnostic testing
Blood work:
- Complete blood count with differential and platelet count
- Blood cultures
- Serum chemistries
- Serum for acute serology (convalescent serology after 3 weeks)
Other tests
- Pulse oximetry
- Chest radiograph
- Sputum culture and gram stain (and/or tracheal aspirate, if intubated, pleural effusion aspirate, if present)
- Antimicrobial susceptibility testing for bacterial isolates
- In adults with radiologically confirmed pneumonia, consider urine antigen testing for Legionella pneumophila and Streptococcus pneumoniae
Treatment - antivirals
If suspicion of H5N1 infection is high, initiate antiviral treatment with oseltamivir (Tamiflu) or zanamivir (Relenza) – the neuraminidase inhibitors - as soon as possible, even if laboratory results are not yet available. Clinical trials have shown that neuraminidase inhibitors can decrease the illness duration due to seasonal influenza by several days when they are initiated within 48 hours of illness onset.
Antiviral Agent 1-6 7-9 10-12 13-64 >65 Oseltamivir
5 days of treatmentZanamivir
5 days of treatment
Antiviral recommendations are evolving. Some clinicians recommend a higher dose and duration of oseltamivir for seriously ill patients. Consultation with ID clinician recommended.
Contact tracing and ongoing monitoring
Document information on contacts of patient, from one to two days prior to illness to present. Also document the healthcare workers who had unprotected close contact with the patient.
CDC recommendations
- Updated
Interim Guidance for Laboratory Testing of Persons with Suspected
Infection with Avian Influenza A (H5N1) Virus in the United States
June 7, 2006 health alert providing an updated case definition for H5N1 in humans. Attention: Non-MDH link
- WHO Rapid Advice Guidelines on pharmacological management of humans
infected with avian influenza A (H5N1) virus (PDF: 138 pages)
WHO guidelines for treatment of avian H5N1 influenza.
