The National Poultry Improvement Plan (NPIP)

was started in the early 1930s to coordinate

State programs aimed at eliminating pullorum

from commercial poultry. In those days, many poultry

breeders served the needs of thousands of small

flock owners. Today, there are only a very few

breeders of commercial poultry to serve the commercial poultry industry, which produces billions of

chickens and millions of turkeys annually. Today, the

NPIP concerns itself with certifying that flocks are

free of the following diseases:

• Pullorum—An egg-transmitted disease of poultry,

caused by Salmonella pullorum, that kills a high

proportion (60–80 percent) of baby poultry

• Fowl typhoid—An egg-transmitted disease of

poultry, caused by Salmonella gallinarum, that

may result in significant mortality in both baby

poultry and adult birds

• Avian mycoplasmas—The species of Mycoplasma that are most pathogenic to poultry are the

ones covered by the testing program in the NPIP:

Mycoplasma gallisepticum (MG), Mycoplasma

synoviae (MS), or Mycoplasma meleagridis (MM).

• Salmonella enteritidis—An egg-transmitted

disease of poultry, caused by the organism of the

same name, that may also have human health

implications through consumption of contaminated table eggs

• Avian influenza—A worldwide viral infection of

several species of poultry

Pullorum disease, discovered in 1899, is a

worldwide disease of chickens. The main reservoirs

of infection are the egg-producing organs of the

infected hen. Chicks from diseased hens are infected

at conception inside the egg.

Pullorum disease will also affect turkeys, ducks,

guinea fowl, pheasants, sparrows, quail, bittern,

geese, pigeons, doves, parakeets, and canaries. The

causative organism, Salmonella pullorum, rarely

affects mammals.

Once called bacillary white diarrhea of chicks,

pullorum has been a devastating disease of poultry

for more than 50 years. It causes heavy losses in

chicks and poultry and reduces the productivity

of adult birds. Young birds die during their first

3 weeks. Losses may be as high as 80–90 percent

of the brood. Death from pullorum rarely occurs after

4 weeks of age. Infected adult birds normally show

no outward evidence of infection, but they are

disease carriers for life.

The infection may spread by breathing contaminated dust or coming into contact with down from

infected poultry or with other material in the incubator, shipping box, brooder, or pen that has been

touched by infected birds. Infected feces in litter and

feed or water can transmit the disease to other

brood-mates. One chick might infect an entire hatch

of birds. If young birds have other diseases, pullorum

tends to spread faster.

Carrier hens lay infected eggs, and the

hatchlings are infected. Hens can be infected by

eating contaminated feed, infected eggs, or manure

from other infected chickens.

Blood-testing adult breeding birds, biosecurity,

and sanitation have all but eliminated the disease in

the United States. Pullorum–typhoid testing is

available through State agencies as a free service or

at a nominal charge. Individual poultry raisers may

be certified by these State agencies as testing agents

in some States.

Pullorum can be controlled and eradicated by

eliminating infected carrier birds and thus breaking

the disease cycle. Blood-testing potential breeding

animals and culling infected birds are the steps

needed to eliminate the eggborne disease. Breeders

that have tested negative produce noninfected eggs

and thus noninfected chicks.

The official blood tests of the NPIP for pullorum–

typhoid are the rapid whole-blood plate agglutination

test, the rapid serum plate test, the standard tube

agglutination test, and the microagglutination test.

These tests use whole blood or serum of infected

birds which contain antibodies that will clump (stick

together, agglutinate) when mixed with stained

pullorum organisms.

MG, MS, and MM are the species of Mycoplasma that are pathogenic to poultry.

MG is commonly called chronic respiratory

disease in chickens and infectious sinusitis in

turkeys. Producers with MG-affected flocks suffer

economic losses from downgraded carcasses,

lowered egg-production efficiency, and increased

medication costs. MS can become systemic and

cause acute synovitis of chickens and turkeys. MM’s

primary lesion is airsacculitis in baby turkeys.

Avian influenza is a worldwide viral infection of

poultry. An influenza virus has the ability to mutate,

or change its genetic character, so that it can infect a

host animal in one of several ways. The host

responses from influenza infection can range from no

apparent signs to mild and moderate illness to death.

Because of the different symptoms of influenza, three

levels of host disease are described: nonpathogenic,

low pathogenic, and highly pathogenic avian

influenza.

The agar gel immunodiffusion test is the official

test for avian influenza under the NPIP. The test must

be conducted only in laboratories authorized under

the NPIP, and tissues from all suspects are subtyped

at the National Veterinary Services Laboratories,

Ames, IA.

Figure 1—Results of the rapid whole-blood

plate agglutination test for pullorum are

negative (top left), suspect (top right), and

positive (bottom).
Fowl typhoid is a salmonella infection similar to

pullorum but caused by Salmonella gallinarum. Both

diseases elicit common antigenic reactions. The

same blood test works for both diseases. Since

1954, breeders are considered negative for both

diseases on the results of the same test.

Salmonella enteritidis-infected chickens often

display no symptoms at all. But because this disease

is egg-transmitted, like pullorum, it can be passed in

the intact egg. Because Salmonella enteritidis is a

human pathogen, it must be eliminated from

breeding chickens.

For more information, visit

http://www.aphis.usda.gov/vs/npip.

The U.S. Department of Agriculture (USDA) prohibits

discrimination in all its programs and activities on the

basis of race, color, national origin, sex, religion, age,

disability, political beliefs, sexual orientation, or

marital or family status. (Not all prohibited bases

apply to all programs.) Persons with disabilities who

require alternative means for communication of

program information (Braille, large print, audiotape,

etc.) should contact USDA’s TARGET Center at

(202) 720–2600 (voice and TDD).

To file a complaint of discrimination, write USDA,

Director, Office of Civil Rights, Room 326–W, Whitten

Building, 1400 Independence Avenue, SW, Washington, DC 20250–9410 or call (202) 720–5964 (voice

and TDD). USDA is an equal opportunity provider

and employer.

Issued November 2001

National Poultry Improvement Plan

1498 Klondike Road, Suite 200

Conyers, GA 30094

Phone: (770) 922–3496

Fax: (770) 922–3498

United States Department of Agriculture

Animal and Plant Health Inspection Service

Program Aid No. 1708

Helping You,

the Poultry Breeder,

Prevent Disease

NATIONAL POULTRY IMPROVEMENT PLAN