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Swine Influenza

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Swine influenza is an upper respiratory disease of pigs caused by type A influenza

viruses (IAV). Symptoms of infection may include difficulty breathing, loss of

appetite, and weight loss, resulting in economic losses to producers. Although most

swine IAVs don't affect humans, sporadic cases have been found in people who have

contact with sick pigs.

Swine influenza is widespread in North and South America, Asia, and Europe. The

most common strains found in the United States are H1N1, H1N2, and H3N2. The

World Organisation for Animal Health does not require reporting for cases of IAV-S,

nor is it a regulated disease in the United States.
What To Look For

Swine influenza usually causes high morbidity but low mortality. In many cases,

swine show no signs of illness. Animals are typically symptomatic 1–3 days after

infection. If you see any of these signs in your swine, contact your veterinarian and

isolate the sick animal(s) from the rest of the herd, if possible.

Here's what to look for:

Coughing (sounds like barking)

Sneezing

High fever

Difficulty breathing

Runny nose

Not eating

Lethargy

Red or inflamed eyes

How To Prevent This Disease

IAV-S is spread mainly through close contact, coughing, and sneezing. Contaminated

objects (such as farm equipment) can indirectly spread the disease. Swine influenza

viruses are not transmitted through food and present no food safety concerns.

Vaccinate your pigs. Vaccinating your herd for influenza A with a commercially

available or autogenous influenza vaccine can reduce clinical signs and virus

shedding (though viruses can change rapidly, and vaccination may not provide full

protection against a modified strain).

Practice good biosecurity and hygiene. Good practices include:

Permit only essential workers and vehicles onto your farm.

Avoid visiting other livestock farms.

Do not share equipment or vehicles with other farms or between healthy and

sick animals.
Clean and disinfect items that may carry the virus from one location to another

(such as shoes, clothes, and vehicles).

Shower in and out.

Purchase animals from reputable sources and document their origin.

Isolate and monitor new animals or animals returning from exhibitions.

Use appropriate cleaning and disinfection products and protocols.

Consider getting a seasonal flu vaccine.

Prevent the spread of IAV-S at fairs and other events. Follow guidelines from

the National Assembly of State Animal Health Officials, the National Association of

State Public Health Veterinarians, and the Centers for Disease Control and

Prevention (CDC) to minimize influenza transmission at swine exhibitions.

Some actions you can take include:

Don't eat or drink or put anything in your mouth in the swine barn or show

area.

Don't take toys, pacifiers, cups, bottles, strollers, or similar items into the pig

barn or show area.

Wash your hands often.

How It Is Treated

Isolate sick animals from the rest of the herd and contact your veterinarian to

provide supportive care.

Report Signs of Animal Disease

Producers or owners who suspect an animal disease should contact their

veterinarian to evaluate the animal or herd. Find an accredited veterinarian.

Animal health professionals (veterinarians; diagnostic laboratories; public health,

zoo, or wildlife personnel; and others) report diagnosed or suspected cases of

nationally listed reportable animal diseases to APHIS District Offices and to the State

animal health official as applicable under State reporting regulations. 
Controlling Swine Flu

Surveillance

APHIS works with animal health and public health officials and the swine industry to

carry out a robust and coordinated Influenza A Swine Surveillance Program. Swine

are susceptible to infection by human, avian, and swine influenza viruses, which can

lead to novel reassortments. The surveillance program aims to identify influenza

viruses circulating in swine, proactively identify reassortment viruses that could

impact public health, and gain knowledge to contribute to improved animal health

diagnostics and vaccines. The USDA provides genetics sequencing from surveillance

samples to GenBank, a publicly available database managed by the U.S. Department

of Health and Human Services' National Institutes of Health. Virus isolates collected

through the program are available to the National Veterinary Services Laboratories

upon request.

APHIS works closely with USDA Agricultural Research Service (ARS) researchers to

better understand the virus and develop methods to prevent or control it. ARS

developed an interactive web tool, ocoFLUshow, to visualize and explore trends in

the genetic and geographic diversity of IAV derived from the APHIS surveillance

system. The tool provides information useful in identifying relevant viruses

circulating in swine herds for further characterization and vaccine strain selection.

Quarterly Reports

FY 2022:

1st Quarter

2nd Quarter

FY 2021

1st Quarter

2nd Quarter

3rd Quarter

4th Quarter

FY 2020:
1st Quarter

2nd Quarter

3rd Quarter

4th Quarter

FY 2019:

1st Quarter

2nd Quarter

3rd Quarter

4th Quarter

FY 2018:

1st Quarter

2nd Quarter

3rd Quarter

4th Quarter

Previous years' reports are available upon request.

Recommended Resources for Swine Producers

APHIS Factsheet: Influenza A Virus in Swine

Producer Guide to Influenza Virus Surveillance in Pigs

Influenza: Pigs, People, and Public Health (National Pork Board)

What People Who Raise Pigs Need To Know About Influenza (Flu) - Centers for

Disease Control and Prevention

Influenza Vaccine Selection for Pigs (The Center for Food Safety and Public

Health)

Recommended Resources for Veterinarians

American Association of Swine Veterinarians

Influenza Virus Surveillance in Swine : Program Overview for Veterinarians

The Center for Food Safety and Public Health

Technical Factsheet: Swine Influenza

Optimal Use of Vaccines for Control of Influenza A Virus in Swine

A Review of Optimal Use of Diagnostics and Vaccines for Control of

Influenza A Virus Infection in Swine