CHICKEN INFECTIOUS ANEMIA

🐣CHICKEN INFECTIOUS ANEMIA 🐓

(CIA; Chicken Anemia Virus; Chicken Anemia Agent; Blue Wing Disease)

🔴DEFINITION

Chicken infectious anemia (CIA)is a disease of young chickens characterized by aplastic anemia, generalized lymphoid atrophy,subcutaneous and intramuscular hemorrhage, and immunodepression.

🌍OCCURRENCE 

CIA is ubiquitous in all major chicken-producing countries  

in the world.

⭕️ETIOLOGY

1_CIAV is classified into genus Gyrovirus of the family Circoviridae. 

2_Viral particles are non enveloped and are environmentally very resistant. 

3_They have a diameter of approximately 25 nm and contain a single-stranded circular DNA genome[SSDNA].

4_Although viral isolates may differ at a molecular level antigenic or pathogenicity differences have not been reported.

🌏EPIDEMIOLOGY

1_All ages are susceptible to infection but clinical disease is typically seen only during the first 2 to 4 weeks. However, age resistance may be delayed by simultaneous infection with infectious bursal disease virus. 

2_The virus is spread both vertically and horizontally.

🔻The most important method of transmission is vertical  

from infected hens.

🔻Antibody-negative chicks are most susceptible to clinical disease.

🔻CIA virus also easily spreads via feces among birds in a population.

🟡CLINICAL SIGNS 

1_The only specific sign of CIAV infection is anemia characterized by hematocrit values ranging from 6 to 27 (normal hematocrit values are generally 29-35%).

2_Nonspecific clinical signs include

A_Depression

B_Pale tissues

C_Depressed weight gain

D_Secondary bacterial, mycotic, and viral infections.

3_Morbidity and mortality rates depend on various viral, host and environmental factors and concurrent infection with other agents. Uncomplicated CIA may only cause low mortality and poor performance. When complicated with other factors mortality can be 30% or even higher. 

4_Early infections with CIAV can interfere with vaccination against Marek’s disease or infectious bursal disease.

🟣LESIONS 

1_Marked thymic atrophy is the most consistent lesion.

2_Fatty yellowish bone marrow, particularly in the femur, is characteristic  

3_Bursal atrophy can also be seen in a small number of  

birds. 

4_Hemorrhages in the mucosa of the proventriculus,subcutis, and muscles may also be observed  

5_Secondary bacterial infections may occur and include gangrenous dermatitis or blue wing disease if the wings are affected 

6_Histologically, there is marked thymic lymphoid depletion and marked atrophy of all cell lines in the bone marrow 

🔻The bursal lymphoid follicles  

are mildly to severely depleted and spleen and other tissues with lymphoid aggregates are variably depleted.

🔻There may be histological evidence of secondary bacterial infections including gangrenous dermatitis.

🔬DIAGNOSIS 

1_A presumptive diagnosis is based upon clinical signs and gross lesions.

2_Isolation in cell cultures (MDCC-CU147 or MSB1) and identification of the virus from most tissues, buffy coat cells,and cloacal contents.

3_Serologic assays to detect antibodies such as the ELISA, virus neutralization test, and indirect immunofluorescence. 

4_PCR is the test of choice for identification of CIA virus in cell cultures and chicken tissues.

🔰CONTROL 

✅Best prevention is by immunization of breeder flocks prior to the onset of egg production (between 13-15 weeks of age but no closer to egg production than 4 weeks).

💊TREATMENT 

▪️No treatment is available.

🔄ZOONOTIC POTENTIAL 

🔸None reported.

Dr Abuzar Ghaffari 

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