Respiratory Diseases
Swine Disease

Disease description

The Porcine Respiratory Disease Complex (PRDC) is a term used to describe several diseases that can affect pigs from birth through finishing, with the primary impact usually seen around week 18 to 20. The disease complex includes two primary viruses – PRRS (porcine reproductive and respiratory syndrome) virus and SIV (swine influenza virus) as well as Mycoplasma hyopneumoniae bacteria. Several secondary bacteria are also found in PRDC: Actinobacillus pleuropneumoniae (APP), H. parasuis, A. suis, Strep. suis and salmonella.

A key to PRDC is mycoplasmal pneumonia, also called enzootic pneumonia, which is caused by Mycoplasma hyopneumoniae. The disease is extremely common, especially in commingled groups of pigs. Disease is spread by direct contact from sows to piglets, and then among piglets once they are commingled. The disease has a slow onset with a long incubation, so symptoms may not show up until pigs are 3 to 6 months of age.

Almost all mycoplasmal pneumonia infections are complicated by secondary pneumonias, which can result in high death losses. Severe disease is often due to a complex interaction between mycoplasma bacteria, a poor environment (including changes in weather), and secondary infections from other bacteria, viruses and parasites.

Rhinitis and pneumonia
Atrophic rhinitis (AR) is caused by Bordetella bronchiseptica. These bacteria can act as the primary invader, or may set the animal up for a secondary infection with bacteria such as Pasteurella multocida. Nasal passages damaged by AR are not able to do an effective job of filtering the air the pig breathes, allowing more bacteria access to the lungs. This, in turn, makes it more likely that the pig will develop severe pneumonia.

B. bronchiseptica also causes bronchopneumonia, a more severe disease that can occur in piglets as young as 3 to 5 days.

Pasteurella multocida is another important cause of pneumonia. It has two primary types – Type A and Type D. Type A is a secondary invader that takes advantage of previous lung damage and causes severe pneumonia. Type D colonizes in the nasal passages and releases a toxin that damages tissues. It can cause atrophic rhinitis in older pigs.

Severe cases of pneumonia in growing pigs can be caused by Actinobacillus pleuropneumoniae (APP). Onset is sudden and can be very contagious with high morbidity and mortality. Some pigs may be found dead without having shown clinical signs, which include heavy respiratory distress. Once established in a herd, the disease may be evident only as a cause of reduced growth rate and persistent coughs.

Salmonellosis
Swine salmonellosis is the fourth most costly disease of swine, with annual losses estimated at $20-100 million. It is a systemic disease characterized by pneumonia, as well as liver abscesses and enteritis.

Clinical signs

PRDC, mycoplasmal pneumonia: chronic, non-productive cough and an unthrifty appearance; decreased rate of gain and decreased feed conversion ratio.

Rhinitis: Sneezing, snuffling, rubbing the nose, black tear streaks from the eye and excessive nasal discharge.

Bronchopneumonia: Coughing and labored breathing.

APP: Open-mouth breathing with bloodstained frothy nasal and oral discharge, and high fever, anorexia and reluctance to move.

Disease treatment

Denagard® Liquid Concentrate is a proven, broad-spectrum antibiotic effective in treating swine pneumonia caused by Actinobacillus pleuropneumoniae (APP). It also treats swine dysentery associated with Brachyspira (Serpulina) hyodysenteriae. The water-soluble medication can quickly and conveniently be administered with response usually evident within 24 to 48 hours. It is readily absorbed from the gut and can be found in the blood within 30 minutes after dosing.

Disease prevention

Myco Shield™ is a convenient 1-mL vaccine that can be given to any pig 2 weeks of age or older. Revaccination with a booster dose in 2 weeks produces elevated and extended immunity to help prevent the potentially devastating effects of mycoplasmal pneumonia.

PneumoSTAR® SIV is the only vaccine that provides swine influenza virus (SIV) protection in just one dose. It has broad cross-reactivity among various SIV strains, which means more effective immunity. It is labeled for intramuscular administration, with a 1-mL dose at three weeks of age or older.

Rhinicell® FD is a single-dose, intranasal vaccine that can be given to piglets at one day of age to prevent atrophic rhinitis caused by B. bronchiseptica. It can also be given as an intramuscular injection to gilts and sows prior to farrowing. Also available is Rhinicell + E, the only intranasal erysipelas/Bordetella vaccine approved for use in newborn piglets.

Rhini Shield™ TX4 provides convenient four-way protection, helping prevent atrophic rhinitis caused by B. bronchiseptica and P. multocida Types A and D, pneumonia caused by P. multocida Type A, and erysipelas. It includes a toxoid against the Type D toxin.

Salmo Shield Live offers one-dose protection against both the septicemic and respiratory forms of salmonellosis caused by Salmonella choleraesuis. It should be given to herds where salmonella has been a chronic, ongoing problem or in commingling feeder operations where carrier animals are common.

Caution: Do not feed Denagard 10 undiluted. Do not use in feeds for animals other than swine. Contraindications: Swine being treated with Denagard (tiamulin) should not have access to feeds containing polyether ionophores (e.g., lasalocid, monensin, narasin, salinomycin and semduramicin) as adverse reactions may occur. See product label for directions for use and additional information.

Caution: Do not use Denagard Liquid Concentrate undiluted. Contraindications: Swine being treated with Denagard (tiamulin) should not have access to feeds containing polyether ionophores (e.g., lasalocid, monensin, narasin, salinomycin and semduramicin) as adverse reactions may occur. See product label for directions for use and additional information.