CONTENT
Viral Diseases of Poultry: Symptoms, Prevention, Vaccination & Control
Viral diseases are among the most important infectious diseases affecting poultry, causing significant morbidity, mortality, production losses, and immunosuppression. Common viral diseases include Newcastle disease, infectious bronchitis, infectious anemia, infectious bursal disease, Marek’s disease, infectious laryngotracheitis, inclusion body hepatitis, and fowl pox.
Early recognition of clinical signs, appropriate vaccination programs, biosecurity, and effective flock management are essential for prevention and control.
Newcastle Disease
It is one of the most severe diseases of poultry. A high mortality rate can occur in all age groups. Respiratory distress, paralysis of the legs and wings, greenish diarrhea, and twisting of the neck may be observed.
Control Infectious Bursal Disease (IBD) and provide toxin-free feed. Multiple vaccinations should be administered as recommended. Routine screening of serum samples on larger farms is advisable.
Infectious Bronchitis (IB)
Respiratory distress, rales, and gurgling sounds may be evident. Prevent the disease through vaccination.
Infectious Anemia
Young chicks are affected. Mortality of up to 20 percent may occur, and the disease predisposes adults to other diseases. Vaccination of the parent stock is required.
Infectious Bursal Disease (IBD or Gumboro)
Young birds are affected. Listlessness, huddling, whitish, pasty diarrhea, and pecking at the vents are some of the clinical signs. The consequences of this disease include a 10–60 percent mortality rate and immunosuppression, leading to outbreaks of other diseases.
Vaccinate young birds at the recommended age. Include immunostimulants such as vitamin E in the feed. Provide toxin-free feed.
Marek’s Disease
This disease is characterized by poor growth and paralysis of one leg, which is stretched backward. Birds younger than 16 weeks are affected. An inability to consume feed follows, and death may ensue. Ensure that protective vaccination is administered at one day of age in the hatchery.
Infectious Laryngotracheitis (ILT)
Clinical signs such as respiratory distress, rales, extension of the neck during inhalation, nasal discharge, decreased egg production, and mortality of up to 30 percent may be observed. Secondary infections can be controlled with antibiotics.
Inclusion Body Hepatitis (Hydropericardium Syndrome or Leechi Disease)
This condition affects broilers at four to five weeks of age, and a 30–60 percent mortality rate may occur. Straw-colored fluid around the heart may be observed. IBD vaccines are available for the control of this disease.
Fowl Pox
Raised skin lesions appear at the corners of the beak, as well as on the comb and wattles. The mortality rate is low, but recovered birds may have poor performance. Vaccination at the appropriate age is recommended.
