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About Influenza A in Animals

At a glance

  • In addition to people, influenza A viruses can infect many animals.
  • These animals include, but are not limited to ducks, chickens, pigs, whales, horses, seals, cats, goats, and cows.
  • Influenza B viruses are only found in people.
A picture of ducks and a turkey on a farm

Overview

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.

Many different animals can carry or be infected with influenza A viruses. All but two known subtypes of influenza A viruses have been found in birds. Subtypes H17N10 and H18N11 have only been found in bats.

It is uncommon for people to get influenza virus infections directly from animals. However, sporadic human infections and outbreaks caused by certain avian and swine (variant) influenza A viruses have been reported.

Keep Reading: Avian Influenza (Bird Flu)
Keep Reading: Information on Swine / Variant Influenza

Table 1

Influenza A in people and animals by hemagglutinin subtype

Table. Different hemagglutinin subtypes and the species in which they have been detected.
Subtype People Poultry Swine Bats Cats Dogs Horses Cows Other*
H1 people chicken swine X
H2 people chicken swine
H3 people chicken swine dog horse X
H4 chicken swine X
H5 people chicken swine*** cat dog cow X
H6 people chicken swine dog
H7 people chicken swine cat horse X
H8 chicken
H9 people chicken swine
H10 people chicken swine X
H11 chicken
H12 chicken
H13 chicken
H14 chicken
H15 chicken
H16 chicken
H17 bat
H18 bat

Table 2

Influenza A in people and animals by neuraminidase subtype

Subtype People Poultry Swine Bats Cats Dogs Horses Cows Other*
N1 people chicken swine cat dog cow X
N2 people chicken swine cat dog X
N3 chicken
N4 chicken
N5 people chicken swine X
N6 people chicken swine
N7 people chicken horse X
N8 people chicken dog horse X
N9 people chicken
N10 bat
N11 bat

Other flu websites and resources

Zoonotic Influenza Reference Guide

Workers sitting around a desk holding a meeting with paperwork and a computer.
This resource has guidance on animal and zoonotic influenza viruses.

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.

Generalizable One Health Framework

A mother with her small daughter feeding chickens.
A One Health approach can help prevent and control zoonotic diseases.

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.

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Content Source:
National Center for Immunization and Respiratory Diseases