INFECTIOUS-BURSAL- a diseases of avians.pptx

Infectious Bursal Disease (IBD), also known as Gumboro disease, is a highly contagious viral infection that affects poultry, primarily chickens. The disease is caused by the Infectious Bursal Disease Virus (IBDV), a member of the Birnaviridae family. IBD is of significant concern in the poultry industry due to its impact on the immune system of chickens, leading to increased susceptibility to other diseases, reduced productivity, and economic losses.

Etiology and Pathogenesis
IBDV is a non-enveloped, double-stranded RNA virus. There are two serotypes of the virus: Serotype 1, which is pathogenic and causes disease in chickens, and Serotype 2, which is non-pathogenic and found in turkeys. The virus primarily targets the bursa of Fabricius, an important organ in the immune system of birds responsible for the maturation of B lymphocytes.

Once the virus enters the host, typically through the oral route, it is transported to the bursa of Fabricius via the bloodstream. The virus replicates in the lymphoid tissue of the bursa, leading to inflammation, necrosis, and depletion of B lymphocytes. The peak of viral replication occurs around 3-4 days post-infection, and the damage to the bursa is most severe between 5-7 days post-infection. The destruction of the bursa impairs the bird's immune system, making it vulnerable to secondary infections.

Clinical Signs and Symptoms
The clinical presentation of IBD can vary depending on the age of the birds, the virulence of the virus strain, and the presence of maternal antibodies. The disease manifests in two forms: acute and subclinical.

Acute Form: This form is typically seen in chickens between 3 to 6 weeks of age. Clinical signs include:

Sudden onset of disease
Ruffled feathers
Depression and reluctance to move
Diarrhea, often with watery and whitish feces
Anorexia and dehydration
Vent picking
Trembling and unsteady gait in severe cases
Increased mortality, which can range from 20% to over 60% depending on the virulence of the strain and the immune status of the flock
Subclinical Form: This form occurs in younger chickens, typically less than 3 weeks old, especially if they possess maternal antibodies. Birds may not show overt clinical signs, but the virus still causes significant immunosuppression, leading to:

Poor growth and feed conversion
Increased susceptibility to other infections such as Escherichia coli (colibacillosis), Marek's disease, and Newcastle disease
Reduced effectiveness of vaccines due to impaired immune response
Diagnosis
Diagnosis of IBD is based on a combination of clinical signs, pathological findings, and laboratory tests. Key diagnostic methods include:

Clinical Observation: Noting the rapid onset of disease, high morbidity, and characteristic signs such as diarrhea and vent picking in young chickens.

Pathological Examination: Necropsy findings are crucial for diagnosis. The bursa of Fabricius is typically swollen, edematous, and hemorrhagic. In later stages, it may become atrop

1. INFECTIOUS BURSAL DISEASE

2. Infectious bursal disease- also known as Gumboro disease highly contagious viral disease that affect young chicken. Characterized by immunosuppression, it weakens the chickens immune system, making them more susceptible to other infection. The virus infects and d estroy be lymphocytes in the bursa, leading to a decrease in antibody production and compromised immune response.

3. Etiology: The infectious bursal disease virus (IBDV) which belong to the avibirnavirus gumborose species in the family Birnaviridae . IBDV is a double stranded RNA virus and its virions are nonenveloped with an icosahedral single-shelled geometry. Occurrence and economic significant: The disease is highly contagious and immunosuppressive, primarily affecting the young chicken. It has been responsible for major economic losses in the insustry . The economic significance of IBD is challenging to assess due to the complex nature of losses associated with the disease. In addition to direct losses, IBDV infectious-induced immunodeficiency in chicken can make them more susceptible to other viral, bacterial, and parasitic infectious, leading to further economic losses.

4. Transmission The transmission of IBD occurs when chickens or other susceptible birds consume feed or water contaminated with the virus. The virus can be shed in the feces of infected birds, and if the proper hygiene measures are not in place, the virus can be contaminate the environment, including feed and water source. Birds that consume the contaminated feed or water can become infected with IBDV.

5. Clinical sign of infectious bursal disease (IBD) in chicken include: Listlessness Watery diarrhea Ruffled feathers Dehydration Bursal lesions and atrophy

6. Pathology of infectious bursal disease (IBD) involved specific changes in the bursa of fabricius , an important lymploid organ in birds. Bursal lesions Bursal artrophy Immunopathology Transmission routes

7. Diagnosis and confirmation of infectious bursal disease can be done through virus methods: Clinical sign and post-mortem lesions Serological test Detection of viral antigens or viral genome Histological examination

8. Prevention of infectious bursal disease focuses on control measure as there is no treatments the disease once birds are affected: Biosecurity measure Vaccination Good management practices Monitoring and surveillance Control of other infectious