HERD HEALTH
PIH-50
pork industry handbook
COOPERATIVE EXTENSION SERVICE • PURDUE UNIVERSITY • WEST LAFAYETTE, INDIANA
Atrophic Rhinitis
Authors:
Kurt Wohlgemuth, North Dakota State University
Alex Hogg, University of Nebraska
William P. Switzer, Iowa State University
Reviewers:
David J. Ellis, Michigan State University
Steven C. Henry, Abilene, Kansas
Ralph A. Vinson, Oneida, Illinois
History
Rhinitis is an inflammation of the mucous membranes that line the pig's nose. Atrophic rhinitis (AR) is a transmissible disease of swine that is characterized by both rhinitis and wasting away or lack of growth of the turbinate bones in the nose. The turbinate bones are small, scroll-like, mucous membrane-covered structures in each nostril. They condition the air by warming, moistening, and filtering it during the inspiration phase of respiration.

Other forms of rhinitis include necrotic rhinitis (bull nose) and a virus disease, inclusion body rhinitis. These diseases cause inflammation but not turbinate atrophy. This discussion will be limited to atrophic rhinitis.

There are extensive reports in the veterinary literature regarding atrophic rhinitis. The oldest of these reports is an 1830 German description of atrophic rhinitis. The disease was first described in the United States and Canada in 1942-43. It had undoubtedly existed on this continent prior to that time.
Incidence
Atrophic rhinitis is widespread among the U.S. swine population. Various authors report that 25-75% of all slaughter swine have evidence of atrophic rhinitis. Herd incidence has been estimated at 40-90%.

Cause
A bacterium, Bordetella bronchiseptica, is a widely distributed cause of AR in the U.S. Other bacteria, especially Pasteurella, are involved as secondary invaders that intensify the disease. Irritating gases in the pig s environment and concurrent diseases such as diarrhea or chronic pneumonia have been suggested but not verified as factors intensifying atrophic rhinitis.

Transmission of AR is complicated by the fact that B. bronchiseptica can be carried in respiratory tracts of many mammals such as cats, dogs, mice, rats, and even man.
The following facts explain how B. bronchiseptica bacteria survive and infect pigs:
1.	In a dry area exposed to the sun, most of the organisms will die in 5 or 6 weeks.
2.	In a cool, shaded, moist area, the organisms may survive up to 4 months.
3.	All of the common disinfectants and fumigants are effective against the organism if they come in contact with it.
4.	The organism lives and multiplies almost exclusively in the respiratory tract but is not confined to the respiratory tract of only swine. Control and eradication plans would be much more successful if B. bronchiseptica were exclusively an organism of swine.
5.	It has been recovered from the respiratory tracts of a wide range of mammals including man, cats, dogs, and rodents. It may occur with a much lower frequency in the respiratory tract of birds, but at present birds are not considered to have very much potential for spreading the disease.
6.	The organism has been recovered from flies and ants. The possible insect spread of the infection must receive additional study.
7.	Not all strains of the organism have equal disease-producing ability (virulence) for swine. Laboratory tests are now available to differentiate toxigenic (toxin-producing) strains of Bordetella and Pasteurella from nontoxigenic strains. Toxigenic Bordetella alone causes mild AR, and toxigenic Pasteurella alone can cause moderate AR. However, the combination of both toxigenic strains is associated with development of severe AR.
8.	Baby pigs infected with 8. bronchiseptica at an early age may develop advanced turbinate atrophy within three weeks. These turbinates may undergo regeneration and partial restoration of the atrophied structures if secondary invaders such as toxigenic or nontoxigenic Pasteurella multocida, Hemophilus parasuis, or other secondary bacterial invaders or adverse environmental conditions are not present.
Cooperative Extension work in Agriculture and Home Economics, State of Indiana, Purdue University, and U. S. Department of Agriculture cooperating; H. A. Wadsworth, Director, West Lafayette, IN. Issued in furtherance of the acts of May 8 and June 30, 1914. The Cooperative Extension Service of Purdue University is an affirmative action/equal opportunity institution.