Poultry

Common Types of Respiratory Diseases in Poultry

Respiratory diseases in poultry remain a key challenge for farmers globally, especially during the winter months. Addressing these issues is crucial for maintaining the health and well-being of hens. Factors such as poor ventilation, wet litter, dust, and ammonia are common causes that leads to respiratory diseases as well. Moreover, live vaccinations can sometimes trigger chronic respiratory disease. These conditions often result in a morbidity rate of 10-20% and a mortality rate of 5-10%.

Chronic respiratory diseases in poultry are often caused by bacteria like Mycoplasma gallisepticum, which primarily target and damage the respiratory system of birds. M. gallisepticum spreads quickly through eggs, airborne contamination, and indirect or mechanical means, such as introducing healthy birds to infected flocks or transporting birds in contaminated containers. This bacterium can silently persist within a flock, typically showing few symptoms until the birds undergo significant stress, at which point the signs of respiratory disease become apparent.

Symptoms of chronic respiratory disease in poultry

As a farm owner, it’s essential to periodically check on your poultry for better health and productivity. Therefore, it is crucial to understand the early sypmtoms of respiratory diseases in poultry . Here are some signs of chronic respiratory disease in poultry:

Nasal and eye discharge
Sneezing
Coughing
Submandibular swelling
Depression
Loss of appetite
Sinusitis
Wattle swelling
Rattling or congested breathing
Difficulty breathing, such as neck stretching and panting

Post-mortem lesions

Swollen heads and sinuses
Subcutaneous head infection with abnormal fluid or pus in the sinuses
Conjunctivitis
Severe tracheitis with varying exudate (catarrhal, purulent, or bloody)
Air sac infection
Pericarditis

Common types of respiratory diseases in poultry

Avian coronavirus

Coronaviruses are single-stranded RNA viruses causing various respiratory diseases in poultry. Gammacoronaviruses, mainly infecting birds, include the avian infectious bronchitis virus (IBV), which leads to severe respiratory disease in poultry. IBV’s rapid evolution creates new antigenic types and multiple serotypes with limited cross-protection, causing respiratory issues, decreased egg production, and higher mortality in birds.

Aspergillosis

Poultry birds typically acquire aspergillosis from exposure to Aspergillus fungi, which are commonly found in the environment. These fungi can be present in moldy feed, bedding, or litter causes respiratory diseases in poultry.

Aspergillosis manifests as an acute disease in young birds and a chronic one in older birds. Young birds may experience breathing difficulties and gasp for air, but there are no characteristic rales or abnormal respiratory sounds. Feed intake decreases, and fungal toxins may occasionally cause paralysis or convulsions.

Mortality in young birds ranges from 5-20%, potentially reaching 50%. In mature birds, symptoms include respiratory distress, reduced feed consumption, and cyanosis (bluish skin). Nervous disorders like twisted necks may occur in a few cases, with mortality typically under 5%. The disease is caused by a fungus that thrives at room temperature and above. Contaminated litter, nest materials (such as peat moss, peanut hulls, sawdust, peat, bark, straw), feed, and water are common sources of chronic respiratory disease in poultry.

Chicken Pox

Fowl pox affects various poultry—chickens, turkeys, pheasants, quail, ducks, psittacines, and ratites—across all ages. It has two forms: the dry form, with raised, wart-like lesions on unfeathered areas, heals in about 2 weeks but can leave raw, bleeding surfaces if scabs are removed prematurely; it causes unthriftiness and reduced growth, and a temporary decline in egg production in laying hens.

The wet form presents canker-like lesions in the mouth and throat, potentially causing respiratory distress by obstructing airways. Fowl pox spreads through direct contact, mosquitoes, and virus-containing scabs. Mosquitoes, which can carry the virus for life, are the primary transmitters, with outbreaks possible during winter and early spring.

Avian influenza

Avian influenza affects nearly all bird species and comes in two forms: mild and highly pathogenic. The mild form causes listlessness, loss of appetite, respiratory issues, diarrhea, reduced egg production, and low mortality. The highly pathogenic form leads to facial swelling, blue combs and wattles, dehydration, and severe respiratory distress, with possible dark spots on legs and combs, and blood-tinged nasal discharge.

Mortality can range from low to nearly 100%, with reduced egg production and hatchability, and an increase in soft-shelled or shell-less eggs. The virus remains viable at moderate temperatures and indefinitely in frozen conditions, spreading through improper disposal, contaminated equipment, and mechanical carriers like insects and rodents which causes respiratory diseases in poultry.

Newcastle disease

The highly contagious and deadly form of Newcastle disease, known as viscerotropic velogenic Newcastle disease (VVND), affects internal organs but is currently absent from U.S. poultry. Newcastle disease affects birds of all ages and can cause mild conjunctivitis in humans and other mammals. There are three forms: mildly pathogenic (lentogenic), moderately pathogenic (mesogenic), and highly pathogenic (velogenic).

Symptoms include hoarse chirps, nasal discharge, labored breathing, facial swelling, paralysis, trembling, and twisted necks, with mortality ranging from 10% to 80%. In laying birds, it causes reduced feed and water intake and a sharp drop in egg production. The respiratory diseases in poultry spreads via airborne transmission, contaminated equipment, and infected birds, and can be shed in body fluids, secretions, excreta, and breath.

Psittacosis/Parrot Fever

Historically known as psittacosis in psittacine birds and ornithosis in others, the disease is now called chlamydiosis across all species. It affects turkeys, pigeons, ducks, psittacine birds, and other animals, though chickens are rarely affected. Humans, particularly the elderly and immunocompromised, are at risk. Symptoms in birds include nasal discharge, conjunctivitis, diarrhea, and weakness. In turkeys, it also causes respiratory distress and yellow-green droppings. The disease spreads slowly through turkey flocks, primarily via inhalation of fecal dust and respiratory secretions. Recovered birds can remain carriers, shedding the infection intermittently, especially under stress.

Infectious coryza

Coryza primarily affects chickens, pheasants, and guinea fowl, and is common in game chicken flocks. Symptoms include facial swelling, foul-smelling discharge from the nostrils and eyes, labored breathing, and abnormal breathing sounds (rales). The eyelids may stick together, and affected birds might have diarrhea and stunted growth.

While mortality is generally low (usually 20% but can reach 50%), coryza reduces egg production and worsens other diseases. The illness can last from days to months, depending on pathogen virulence and other infections. Coryza spreads through direct bird-to-bird contact, inhalation of respiratory droplets, and contaminated feed or water, often occurring at poultry shows, swaps, and live-bird sales. Recovered birds can remain carriers and spread the disease intermittently.

Infectious Laryngotracheitis (ILT)

Chickens and pheasants, especially those over 14 weeks old, are susceptible to LT, with most outbreaks in mature hens. Recently, LT has also affected broilers over 3 weeks old, mainly in cooler seasons, likely due to vaccine spread. Symptoms start with watery eyes, followed by breathing difficulties, coughing, and head shaking. Birds may wheeze and expel blood-tinged exudates, with some dying from asphyxiation when tracheal plugs dislodge. LT spreads via respiratory routes and contaminated items. Recovered birds remain carriers, and the virus may persist in exhibition birds and game fowl.

Respiratory diseases in poultry treatment

Treatment of chronic respiratory disease in poultry requires a comprehensive approach to ensure effective recovery and minimize complications. Here are key steps to consider:

Natural remedies: Consider natural treatments for less advanced respiratory infections.
Probiotics after antibiotics: Administer a course of probiotics following antibiotic treatment to restore gut health.
Hospitalization for serious cases:
- Provide injectable and aerosolized medications.
- Implement gavage feeding and IV fluids if necessary.
Early diagnosis and appropriate therapy: Prompt and proper treatment is essential for effective management and recovery of respiratory diseases in poultry.

To promote optimal long-term health for your birds, it’s best to avoid using antibiotic growth promoters or antibiotics. To maintain your birds’ health throughout all stages of life and avoid occurrence of respiratory diseases in poultry, it is crucial to provide nutritious feed. Incorporating phytogenic supplements into their diet can help keep your birds strong and better equipped to combat diseases.

How to prevent and reduce stress in poultry

Natural remedies for viral infection in poultry and farm animals