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Infectious Bursal Disease

Other Names: Gumboro Disease, Infectious Avian Nephrosis

Infectious bursal disease (IBD) is an acute viral infection of young chickens that affects the lymphoid tissue, particularly the bursa of Fabricius. The disease occurs worldwide, and is caused by the infectious bursal disease virus (IBDV).

Chickens are most susceptible to clinical disease when they are between 3 to 6 weeks of age. Chicks less than 3 weeks of age are still susceptible to becoming infected with the virus, but typically don't demonstrate signs of illness. All chicks that are infected with the virus, regardless of whether they demonstrate clinical signs at the time of infection, have lasting impacts. The damage the virus causes to the bird's immune system results in greater susceptibility to infections, including normally nonpathogenic microbes.
Infectious bursal disease
When clinical disease occurs, in chicks 3-6 weeks old it is characterized as follows:
  • Has a sudden onset and rapidly runs through all flock members.
  • One of the first clinical signs is watery or whitish diarrhea that clings to the chick's vent feathers (referred to as 'pasty butt'). Sometimes blood is also present. Affected chicks are often seen picking at their own vents.
  • General, non-specific signs such as lethargy, depression, loss of appetite, reduced water intake, huddling, ruffled feathers, and reluctance to stand soon follow.
  • Diarrhea and reduced water intake leads to dehydration, soon followed by incoordination, trembling and weakness.
  • 20-30% of chicks will usually die within 3 days from when they first developed signs of illness.
  • Remaining flock members will usually undergo a rapid recovery 5-7 days later.


Infectious bursal disease is spread by direct and indirect contact with infected birds, often through exposure to feces. The virus is shed in the feces of infected chicks and can survive in the environment for several months.

Incubation period

The incubation period is very short, with clinical signs becoming apparent within 2-3 days following exposure to the virus.


For live birds, the disease is diagnosed through serology, bursal histopathology or PCR testing. Necropsy results will often reveal bursae filled with pus or blood which are regarded as pathognomonic changes for this condition.


Treatment consists of supportive care. Antibiotics may be indicated to help control secondary bacterial infections.

Clinical Signs

Reduced appetite
Ruffled feathers
Vent pecking behavior
Pasty butt
White, watery diarrhea


  • History
  • Clinical signs
  • Histopathology of bursae
  • Virus isolation
  • Virus detection in the bursa by immunoassays or RT-PCR
  • AGID or ELISA for antibody detection
  • Virus characterization or neutralization

Reported Cases

  • Case 1: Infectious bursal disease in a Chickens Endemic Infectious bursal disease virus (IBDV) was diagnosed in 6-week-old Silkies and 5-week -old brown organic broilers located on the same premises. Approximately 10% of the flock was affected. Extensive hemorrhages were present in the skeletal muscles of the breast and legs. Bursas were hemorrhagic and enlarged with extensive lymphocyte depletion and inflammation. Diagnosis was based on histology, PCR and sequencing of the virus. Ref

  • Case 2: Infectious bursal disease in a Chickens Infectious bursal disease (IBD) was diagnosed in 3.5 to 7-week-old birds from multiple chicken operations experiencing increased mortality. Some of the affected birds had smaller than normal Bursa of Fabricius. Histopathology identfied lesions consistent with IBD in the bursa and birds were positive by PCR. Ref


Supportive careIsolate the bird from the flock and place in a safe, comfortable, warm location (your own chicken "intensive care unit") with easy access to water and food. Limit stress. Call your veterinarian.
Treatment of pasty buttWhen poop hardens it can cause a blockage to the chick's gastrointestinal system, as if the poop has no way to leave the chick's body, the chick will die.
Gather a warm wet facecloth, dry paper towels, and petroleum jelly (Vaseline).
Using the facecloth, gently run it over the hardened poop. The intent is to clean it off completely, but depending on how hard it is this may take repeated attempts and a little time. Once clean, gently dry off the chick's bum with the dry paper towel and apply a small amount of petroleum jelly to the area that was sticky, to try to prevent fresh poop from sticking in the future. Repeatedly check on the chick, as this process is likely to need to be repeated.
Thymulin 5cHDiluted into drinking waterSato C et al., 2012
Calendula officinalis extract0.5 ml added to feed daily for for 7 daysS Marina et al; E Barbour et al
Ashwagandha (Withania somnifera) root powderAdded at 1% in feed ameliorates IBDV-induced hematological, biochemical, and immunological alterations, resulting in lower viral persistence in the host, and also afforded protection against virus-induced stress and histopathological changes.Ganguly, Bhaskar, et al., 2019; Pant, M., T. Ambwani, and V. Umapathi.., 2012
Baicalin (Scutellaria baicalensis) extract100-200 mg/kg of dietYan, Jing, et al. 2014; F Yang et al., 2020; Z Wu et al.,2020; Y Zhou et al., 2019; B Yin et al., 2021; M Bao et al., 2022; Z Hu et al., 2022



  • Vaccination of parent breeders and/or chicks
  • Biosecurity


variable depending on the levels of maternal derived antibody present.

Scientific References

Good Overviews

Age Range

IBD affects chicks between 3-6 weeks of age.

Risk Factors

  • Unvaccinated chicks
  • Overcrowded conditions
  • Unsanitary conditions