Information For Health Professionals on Variant Influenza A: Influenza A Variant Viruses H3N2v and H1N2v - Minnesota Dept. of Health

Information for Health Professionals on Influenza A Variant Viruses
(H3N2v, H1N2v, H1N1v)

Specimen Collection and Testing

  • Commercially available rapid influenza diagnostic tests may not detect H3N2v, H1N2v, or H1N1v in respiratory specimens.
  • MDH is very interested in conducting RT-PCR testing for surveillance purposes on outpatients with illness compatible with influenza* who meet any of the following criteria:
    • Recent (7 days or less) direct or in-direct contact with swine
    • Recent attendance at an agricultural fair where swine were present
    • Recent contact with a confirmed case of variant or swine influenza A infection (such as H3N2v, H1N2v, or H1N1v).

* Illness compatible with influenza may present as influenza-like illness (ILI):
fever ≥ 100°F plus cough and sore throat.
Note that influenza may not cause fever in all patients (especially in patients < 5 years of age, ≥ 65 years of age, or patients with suppression of their immune system).

For patients admitted with ILI or clinical suspicion of influenza without evidence of pneumonia or other lower respiratory disease – submit one upper respiratory specimen per patient.

  • Nasopharyngeal swab is the preferred specimen
  • Other acceptable specimens include; nasal swab, nasal wash/aspirate, throat swab, or combined nasal swab with an oropharyngeal swab, and viral culture
  • Place respiratory specimens into viral transport media (VTM; e.g., M4, M5, Universal Transport Media) for transport to MDH-PHL. Washes and aspirates may be collected in saline and placed into 1-3 milliliters viral transport media.
      • Store and ship at refrigeration temperature.
      • Freeze specimen, and ship frozen, if it will not reach MDH-PHL within 7 days.
  • Swabs collected and/or transported in non-sterile containers, baggies, or without transport media (dry) will not be accepted.
  • Ship at refrigeration temperature.

  • Collection of Nasopharyngeal Specimens with the Swab Technique. (Video-New England Journal of Medicine)

Please indicate "swine exposure" as appropriate.

Only a single Clinical Testing and Submission Form is required; however, you must use the correct version of the form, which is dependent on whether the patient is hospitalized or not.
NOTE: There is NO fee sticker required for influenza testing.

Non-Hospitalized Influenza Testing (Project #493)
Use this form for submitting specimens for influenza testing from non-hospitalized patients. Write project #493 in the upper right hand corner of the form and indicate "swine exposure" as appropriate.

Hospitalized Patients Only (Project #1492)
Use this form for all specimens submitted from persons hospitalized with ILI or clinical suspicion of influenza. In order to allow for prompt testing of submitted specimens for project #1492, please be sure to fill out the form completely, especially information regarding hospitalization (date of admission, hospital of admission, and outcome) found on the lower right hand corner of the form, and indicate "swine exposure" as appropriate.

Shipping to MDH-PHL

  • Ship at refrigeration temperature.
    • Use cold packs to keep specimens at 4 degrees C.
  • Ship specimens to MDH-PHL by an overnight delivery service.
    • NOTE: It is the responsibility of the submitting laboratory to determine the appropriate packaging and shipping for patient specimens and culture isolates.
    • DOT HAZMAT regulations: PHMSA Regulations
  • Ship to:
    Minnesota Department of Health
    Public Health Laboratory
    Attn: Biological Accessioning
    601 Robert St. N
    St. Paul, Minnesota 55155-2531


  • For an MDH epidemiologist, call 651-201-5414 or 1-877-676-5414.
  • During business hours you can call the Virology Supervisor at 651-201-5035.
Commercially available rapid influenza diagnostic tests may not detect H3N2v, H1N2v, or H1N1v in respiratory specimens.

Surveillance and Reporting

  • Reporting Influenza
    In Minnesota, influenza is a reportable disease.
  • MDH is also conducting enhanced surveillance through established sentinel influenza surveillance sites.
More about seasonal and novel influenza A for Health professionals:


  • Clinicians should consider antiviral treatment with oral oseltamivir or inhaled zanamivir in patients with suspected or confirmed variant or swine influenza virus infection.
  • Antiviral treatment is most effective when started as soon as possible after influenza illness onset.
  • Testing at the Minnesota Department of Health may take several days and the decision to treat should be based on clinical judgment.

Further information on diagnosis and treatment

Updated Tuesday, 06-Jul-2021 16:38:32 CDT