Swine Enzootic Pneumonia

Swine Enzootic Pneumonia or ‘Mycoplasma hyopneumoniae’

Swine Enzootic Pneumonia is caused by the bacteria Mycoplasma hyopneumoniae and is one of the biggest contributors to respiratory diseases in pigs.

On its own, in a controlled environment, the bacteria would not cause severe disease. However, Mycoplasma hyopneumoniae interacts with other bacteria and/or viruses (for example the PRRS virus) to aggravate the pneumonia and cause severe damage to the lining of the lungs.

Transmission of Mycoplasma hyopneumoniae occurs via direct nose-to-nose contact with affected pigs. It is transferred from sow to piglet and it typically affects growers and finishers.

Signs of Mycoplasma hyopneumoniae infection
The severity of the infection depends on whether there are other infections present. In uncomplicated infections, Mycoplasma hyopneumoniae causes:

• Mild, reoccurring pneumonia with a dry cough
• Rough hair coat
• Reduced growth rate and feed efficiency

With secondary infections clinical signs are more severe:

• Increased coughing
• Laboured breathing
• Elevated temperatures
• Prostration
• Death

Diagnosing a Mycoplasma hyopneumoniae infection
Diagnosis is usually based on the following:

• A chronic dry cough
• PCR testing on lung tissue or lung flushes
• ELISA testing – however antibodies may only be present six weeks after infection, so this test is limited
• Historical examination of lung tissue to show inflammation
• Lung lesions at autopsy: lungs are meat-like and purple-grey in colour with lesions, though the Swine Influenza virus can cause similar lesions

Treatment and prevention of Mycoplasma hyopneumoniae infections

Preventing Mycoplasma hyopneumoniae depends on good management. The optimal conditions for pig health should be prioritised, paying attention to: air quality, ventilation, temperature and stocking density. Age segregation and a strict all-in, all-out policy are also very important.

MSD Animal Health offer a flexible range of M Hyo vaccines:

Antibiotics can be used in the treatment of Mycoplasma hyopneumoniae infections, but timing is difficult. Treating too late or too early is ineffective, so it often needs to be continued over an extended period. 

Understanding the bacteria

The Mycoplasma hyopneumoniae bacteria attach to the cilia (protective lining) in the airways. This causes clumping of cilia, loss of cilia and excessive production of mucus. This damage makes the respiratory tract more susceptible to infection. This is why a Mycoplasma hyopneumoniae infection is often seen in conjunction with other viral infections (frequently PRRS , SIV and PCV2) and bacterial infections (Pasteurella multocida, Bordetella bronchiseptica, Streptococcus suis, Glaesserella parasuis/Glassers disease and Trueperella pyogenes) as part of the wider Porcine Respiratory Disease Complex.
Mycoplasma hyopneumoniae also affects the immune response of the pig. It is both immunosuppressive and stimulatory to lymphocytes. The bacteria induce the production of pro-inflammatory cytokines, including IL-1 TNF and IL-6, which are responsible for much of the inflammation and chronic nature of Mycoplasma hyopneumoniae infections.

Porcilis^® PCV M Hyo Porcine circovirus type 2 (PCV2) ORF2 subunit antigen and Mycoplasma hyopneumoniae J strain inactivated. POM-V
Porcilis^® M Hyo ID ONCE contains inactivated whole cell concentrate of Mycoplasma hyopneumoniae strain 11. POM-V
Further information is available from the SPC, datasheet or package leaflet. 
Advice should be sought from the medicine prescriber. 
Prescription decisions are for the person issuing the prescription alone. 
Use Medicines Responsibly. 
 
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