Skip to main content

Influenza A Virus Biological Agent Reference Sheet (BARS)

This BARS covers Influenza A viruses excluding 1918 Influenza A (H1N1), human H2N2, and other highly pathogenic influenza H5N1 strains.


Agent Type Risk Group Biosafety Level Animal Housing Biosafety Level
Virus  RG-2 BSL-2 ABSL-2

Agent Characteristics 

Risk Group: RG-2 associated with human disease, rarely serious; preventive, or therapeutic interventions often available.

Agent Type: Virus 

Description: Influenza A viruses are segmented, negative sense, single stranded RNA viruses in the Orthomyxoviridae family. Influenza A viruses are divided based on the nature of the glycoproteins present on the  envelope, haemagglutinin (HA) and neuraminidase (NA). Variation in the surface antigens allows Influenza A viruses to have a broad host range including humans, and other animals. Only three of the 16 HA subtypes (H1, H2, and H3) and two of the 9 NA subtypes (N1 and N2) have established stable lineages in humans since the 1918 pandemic. Pandemics, epidemics, localized outbreaks, and sporadic cases have been caused by influenza A viruses and while many strains produce mild symptoms such as headache, sore throat, cough, and sneezing, at risk populations can experience pulmonary complications, myocarditis and pericarditis. Secondary bacterial pneumonia after influenza is one of the leading causes of mortality in the world.  

Host Range: Includes avian, swine, and primates, including humans, and can be broader depending on strain

Host Shedding: Blood, saliva, feces

Route of Exposure to Humans: aerosol/inhalation, animal bites, contaminated items, direct contact, mucous membranes, and broken skin

Infectious Dose: 100-1000 viral particles for humans, varies by strain 

Incubation Period: 1-7 days

Health Hazards 

Signs and symptoms of infection may include:

  • Flu-like symptoms (i.e. fever, headache, dehydration, weight loss, lethargy)
  • Gastrointestinal symptoms (i.e. loss of appetite, nausea, vomiting, diarrhea)
  • Respiratory symptoms (i.e. coughing, sneezing)

Immunizations: Available                             Prophylaxis*: Antiviral drugs available

*Formal medical advice is obtained during medical consultations with Cornell Health or primary healthcare provider as needed.

Agent Viability 

Survival Outside Host Disinfection Inactivation

24 to 48 hours on nonporous surfaces

8 to 12 hours on porous materials

1:10 Bleach Dilution 

70% ethanol

Providone iodine 

Quarternary ammonia 

Boil for 10 minutes

For more guidance on disinfection see: disinfectant selection.

Laboratory Hazards 

  • High energy-creating activities (centrifugation, sonication, high pressure systems, vortexing, tube cap popping)
  • Handling of sharps (needles, scalpels, microtome blades, broken glass, etc.)
  • Splash/droplet-creating activities (shaking incubators, liquid culturing, mechanical pipetting)
  • Equipment contamination
  • Exposed skin/uncovered wounds

Laboratory Acquired Infection (LAI) History: Research published in 1997 describes a case in which two people showed signs of infection after exposure to experimentally infected pigs. 

Laboratory Handling Guidelines 

Laboratory Biosafety Level (BSL): BSL-2


Lab Engineering Controls Personal Protective Equipment
  • Eye Protection
  • Single gloves
  • Additional gloves (recommended)
  • Snap-front lab coat with cinch cuffs

Waste Management: Regulated Medical Waste (RMW)

Shipping Guidance: Refer to EHS Biological Materials Shipping 

Animal Vivarium Guidance

Animal Housing Biosafety Level (ABSL): ABSL-2

Animal Biosecurity: Experimental animals are housed separately       

Perform Inoculations: In a Biosafety Cabinet

Change Cages: In a Biosafety Cabinet

Exposure and Spill Procedures 

Mucous Membranes: Flush eyes, mouth, or nose for 15 minutes at an eyewash station. See: responding to exposures.

Other Exposures: Wash with soap and water for 15 minutes (open wounds, sores, etc.) or a minimum of 20 seconds for areas with intact skin. See: responding to exposures.

Small Spills: Notify others working in the lab. Evacuate area and allow 30 minutes for aerosols to settle. Don appropriate PPE. Cover area of the spill with paper towels and apply disinfectant, working from the perimeter toward the center. Allow 30 minutes of contact time before disposal and cleanup of spill materials. See:  spill cleanup

Large Spills: Request assistance from the EHS Spill Team by calling CUPD dispatch. Call 911 from a campus phone or 607-255-1111 from a mobile phone.

Incident Reporting: Immediately report the incident to supervisor and complete the EHS online injury/illness report as soon as possible.

Medical Follow-Up:

  • For students, seek medical attention at Cornell Health or local primary care provider. Call Cornell Health at 607-255-5155 (24-hour phone consultation line) or a local urgent care. 
  • For faculty and staff, seek medical evaluation with a local primary care provider or urgent care. Cornell Health does not see employees for post-exposure care. 
  • Emergencies: Call 911 from a campus phone or 607-255-1111 from a mobile phone. 
Cornell EHS would like to thank Emory University for the use of their Biological Agent Reference Sheet (BARS) format and some content. 

More Information


  1. David E. Wentworth, Martha W. McGregor, Michael D. Macklin, Veronica Neumann, Virginia S. Hinshaw. Transmission of Swine Influenza Virus to Humans after Exposure to Experimentally Infected Pigs. The Journal of Infectious Diseases,,1997;  175 (1).
  2. Influenza A/H1N1. Biological Agent Reference Sheets.  Pathogen Safety Data Sheets: Infections Substances - Influenza virus type A.
  3. CDC. 2009. Biosafety in Microbiological and Biomedical Laboratories. Center for Disease Control and Prevention.
  4. Influenza virus type A. Pathogen Safety Data Sheet. Public Health Agency of Canada.
  5. Department of Health and Human Services, National Institutes of Health. 2019. NIH Guidelines for Research Involving Recombinant or Synthetic Nucleic Acid Molecules (NIH Guidelines). NIH Office of Science Policy