Top 7 Respiratory Diseases in Swine: Signs, Transmission, and Prevention

Table of contents:

• Mycoplasma Hyopneumoniae: A Chronic Respiratory Disease in Swine

• Swine Influenza Virus (SIV): A Fast-Spreading Respiratory Viral Threat

• Actinobacillus Pleuropneumoniae: A Severe Respiratory Disease in Swine Herds

• Pasteurella Multocida: A Common Secondary Invader in Swine Respiratory Diseases

• Porcine Reproductive and Respiratory Syndrome (PRRS): A Dual-Impact Swine Disease

• Bordetella Bronchiseptica: An Early-Life Swine Respiratory Pathogen

• Ascaris suum: A Parasitic Cause of Swine Respiratory Illness

• Integrated Prevention of Respiratory Diseases in Swine

• Frequently Asked Questions (FAQs)

• Conclusion

Respiratory diseases in swine represent a significant concern for pig producers, veterinarians, and the global pork industry. These illnesses not only affect animal welfare but also lead to substantial economic losses due to reduced performance, increased mortality, and higher treatment costs. A combination of infectious agents, environmental stressors, and inadequate management practices triggers outbreaks of respiratory disease.

Understanding the most common respiratory diseases in pigs, including their clinical signs, modes of transmission, and preventive strategies, is crucial for maintaining herd health and productivity. This article reviews the top seven respiratory diseases in swine, offering practical insights for effective prevention and control.

1. Mycoplasma Hyopneumoniae: A Chronic Respiratory Disease in Swine

Mycoplasma hyopneumoniae is the primary pathogen behind enzootic pneumonia, a widespread and chronic respiratory disease in pigs. This organism compromises the cilia of the respiratory tract, making pigs more susceptible to secondary infections.

Signs: Persistent dry cough, poor feed conversion, slowed growth, and uneven body condition across the herd.

Transmission: Spreads through aerosolized droplets and close pig-to-pig contact. The bacterium persists in infected herds for months, particularly under conditions of poor ventilation and inadequate ventilation.

Prevention: Includes vaccination, all-in/all-out production practices, improved barn airflow, and biosecurity protocols to minimize pathogen load and stress.

2. Swine Influenza Virus (SIV): A Fast-Spreading Respiratory Viral Threat

Swine influenza virus (SIV) is a highly contagious pathogen that causes rapid respiratory outbreaks in pig populations. Often transmitted from humans or other pigs, it contributes significantly to respiratory disease in swine.

Signs: Sudden onset of fever, coughing, nasal discharge, depression, and loss of appetite.

Transmission: Airborne droplets, direct contact, contaminated equipment, and human handlers are key vectors of transmission.

Prevention: Relies on herd vaccination, minimizing human-pig interaction during flu seasons, and enforcing hygiene measures among farm staff and visitors.

3. Actinobacillus Pleuropneumoniae: A Severe Respiratory Disease in Swine Herds

Actinobacillus pleuropneumoniae causes pleuropneumonia, a severe bacterial disease that affects the lungs and pleural cavity. In naïve herds, it causes sudden death with little warning.

Signs: Labored or open-mouth breathing, high fever, lethargy, cyanosis, and, in some cases, sudden death.

Transmission: Direct pig-to-pig contact and aerosol over short distances. Crowding and stress increase the risk of outbreaks.

Prevention: Includes vaccination, early antibiotic intervention during outbreaks, and herd health monitoring. Good ventilation and stress reduction are essential.

4. Pasteurella Multocida: A Common Secondary Invader in Swine Respiratory Diseases 

Pasteurella multocida is frequently a secondary invader in pigs already suffering from other respiratory infections. It worsens the severity and duration of respiratory illness.

Signs: Nasal discharge, difficulty breathing, weight loss, coughing, and, in piglets, signs of progressive atrophic rhinitis.

Transmission: Through direct contact or nasal secretions. Environmental stressors and co-infections promote colonization.

Prevention: Focuses on controlling primary infections, reducing environmental stress, maintaining cleanliness, and using antibiotics judiciously under veterinary guidance.

5. Porcine Reproductive and Respiratory Syndrome (PRRS): A Dual-Impact Swine Disease

PRRS is one of the most economically devastating respiratory diseases in swine, affecting both reproduction and respiratory health. It suppresses the pig’s immune response, making them more vulnerable to other infections.

Signs: Fever, respiratory distress, poor growth in nursery pigs, and reproductive issues such as abortions and stillbirths in sows.

Transmission: Spread via aerosol, contaminated semen, equipment, and direct contact with infected pigs. The virus persists in a herd for long periods.

Prevention: This includes herd stabilization, strategic vaccination, strict biosecurity measures, and isolation of new or returning animals. Continuous monitoring is key to preventing recurrence.

6. Bordetella Bronchiseptica: An Early-Life Swine Respiratory Pathogen

Bordetella bronchiseptica is commonly associated with atrophic rhinitis and respiratory distress in piglets. While not typically fatal, it reduces growth efficiency and increases the risk of more serious infections.

Signs: Sneezing, coughing, and, in some cases, facial deformities resulting from damage to the nasal turbinates.

Transmission: Via direct contact or contaminated environments, especially in overcrowded or unsanitary farrowing areas.

Prevention: Sow vaccination before farrowing, maintaining dry and clean environments, and early piglet immunization support the control of this disease.

7. Ascaris suum: A Parasitic Cause of Swine Respiratory Illness

Although Ascaris suum is a gastrointestinal parasite, it causes respiratory signs during its larval migration through the lungs. It is often overlooked as a cause of respiratory distress in pigs.

Signs: Coughing, labored breathing ("thumps"), decreased feed efficiency, and stunted growth.

Transmission: Pigs ingest infective eggs from contaminated soil, feed, or bedding.

Prevention: Routine deworming, proper manure management, and strict sanitation effectively control Ascaris suum infections and prevent lung migration.

Integrated Prevention of Respiratory Diseases in Swine

Effective control of respiratory diseases in swine requires a comprehensive approach that addresses all risk factors.

• Biosecurity: Limit outside access, isolate new arrivals, and sanitize equipment between uses to prevent the spread of pathogens.

• Vaccination: Implement protocols tailored to the specific pathogens present on the farm.

• Air Quality: Optimize ventilation to reduce humidity and ammonia, improving lung health.

• Nutrition: Support the immune system through balanced diets and consistent feeding.

• Veterinary Guidance: Collaborate with a veterinarian to develop comprehensive diagnostic, vaccination, and treatment plans for sustained respiratory health.

This integrated approach reduces the risk of outbreaks, minimizes antibiotic use, and promotes better animal welfare.

Frequently Asked Questions (FAQs)

What are the early signs of respiratory diseases in swine?

Coughing, sneezing, nasal discharge, labored breathing, and decreased feed intake are common early indicators.

Are any swine respiratory diseases transmissible to humans?

While most are not, swine influenza can be zoonotic. Proper hygiene and regular health monitoring of farmworkers reduce the risk.

How often should pigs be vaccinated for respiratory pathogens?

Vaccination frequency depends on the disease and the farm risk level. Swine veterinarians usually recommend a custom vaccination schedule.

Does air quality affect respiratory disease in pigs?

Absolutely! Poor ventilation increases the risk of airborne pathogens, ammonia buildup, and respiratory stress.

Can pigs suffer from multiple respiratory diseases at once?

Yes. Co-infections are common and complicate treatment, making diagnosis and prevention critical.

What should be done during a respiratory outbreak?

Isolate affected animals, involve a veterinarian immediately, and implement emergency biosecurity and treatment protocols.

Conclusion

Respiratory diseases in swine are complex, multifactorial challenges that require strategic, science-based solutions. By understanding the major pathogens, recognizing early clinical signs, and implementing comprehensive prevention strategies, producers effectively protect herd health, enhance productivity, and minimize losses. Collaboration with veterinarians, commitment to biosecurity, and tailored vaccination programs form the foundation of an effective respiratory health plan in modern pig production.