Influenza in Animals

Tables of Influenza A Subtypes and Species Affected

CDC has compiled two tables that showing the different hemagglutinin and neuraminidase subtypes and the species in which they have been detected.

Influenza A viruses are found in many different animals, including ducks, chickens, pigs, whales, horses, seals and cats.

Influenza B viruses circulate widely only among humans.

Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus: the hemagglutinin (H) and the neuraminidase (N). There are 18 different hemagglutinin subtypes and 11 different neuraminidase subtypes. All known subtypes of influenza A viruses have been found among birds, except subtype H17N10 and H18N11 which have only been found in bats.

While it is unusual for people to get influenza infections directly from animals, sporadic human infections and outbreaks caused by certain avian influenza A viruses have been reported.

Other Flu Websites and Resources
workers having a meeting with charts and a computer

This Zoonotic Influenza Reference Guide provides federal, state, and local animal health and public health officials, and other organizations and academia, with an accessible, easy-to-use online resource for understanding and managing existing and emerging situations involving animal and zoonotic influenza viruses and diseases.

H3N2v virus

Influenza viruses that normally circulate in pigs are called “variant” viruses when they are found in people.

Mom and her daughter feed chickens in chicken coop in backyard of country house

The Generalizable One Health Framework provides a structure for all health sectors to use the One Health approach for reducing the spread of zoonotic diseases, including certain types of flu. The framework includes recommendations for zoonotic disease prevention and control and for enhancing One Health capacity to respond to and control zoonotic disease threats.

Pandemic Flu Monitoring

An influenza pandemic can occur when a non-human (novel) influenza virus gains the ability for efficient and sustained human-to-human transmission and then spreads globally.

A child washing his hands

Actions, apart from getting vaccinated and taking medicine, that people and communities can take to help slow the spread of illnesses like pandemic influenza (flu).

Business/Employers Influenza Toolkit

Archived content developed during the 2009-2010 H1N1 pandemic. The content on this webpage is available for historic and reference purposes only.

healthcare professional using tablet

CDC works with state and local health departments to investigate human outbreaks with novel flu viruses and animal outbreaks caused by unusual or concerning flu viruses.