Duck adenovirus A (CAV)

Test code: S0271 - Ultrasensitive qualitative detection of duck adenovirus A by real time polymerase chain reaction

Duck Adenovirus A, also known as Duck Adenovirus 1 (DAdV-1) or adenovirus 127, is a double-stranded DNA virus of the genus Atadenovirus within the Adenoviridae family. It commonly infects wild and domestic waterfowl like ducks and geese. The infections are often asymptomatic or mild, but it can lead to egg drop syndrome’76 (EDS’76) in laying ducks and geese, causing significant economic losses through decreased egg production, thin-shelled or shell-less eggs, and other reproductive issues. The virus can also infect other birds, including chickens, quail, swans, and gulls. The EDS’76 should be distinguished from flaviviral disease of ducks, which has been called "egg drop syndrome in ducks," or "duck egg drop syndrome."

DAdV-1 can be transmitted vertically via infected eggs and horizontally via fecal-oral routes or contaminated environments. Young birds under three weeks old are most often affected. Outbreaks have been reported in ducks, and while typically not causing severe symptoms, can include tracheobronchitis in ducklings and egg drop syndrome in laying ducks.

Because the virus is often asymptomatic in its natural hosts (ducks and geese), prevention of the spread of the virus must involve a combination of vaccination, biosecurity measures, and hygiene practices. Chickens and other susceptible poultry should be kept away from waterfowl (ducks and geese), as they are natural reservoirs. Contact with wild birds should be avoided by fencing bird areas so that no interactions with wild or migratory birds can occur. Proper disposal of affected or contaminated eggs to avoid spreading the virus through fecal material or egg contents is important.

Diagnosis of the viral infection via seroconversion takes time. Because birds may have been exposed to the virus in the past, serology testing does not reliably differentiate active infection. Virus isolation has low sensitivity and is not useful for environmental surveillance. Polymerase chain reaction is now used to detect the infection and to monitor the environment due to its high sensitivity and specificity (Hurst-Proctor et al., 2024; Kumar et al., 2003; Schybli et al., 2014).

Utilities:

• Help confirm the disease causing agent
• Environmental monitoring
• Help ensure that bird populations are free of this virus
• Early prevention of spread of this virus among bird populations
• Minimize human exposure to this virus
• Safety monitoring of biological products and vaccines that derive from birds

References:

Hurst-Proctor S, Fulton RM, Gaydos T. Egg Drop Syndrome 76 in a U.S. Broiler Breeder Flock. Avian Dis. 2024 Sep;68(3):282-286.

Kumar NS, Kataria JM, Koti M, Dhama K, Toroghi R. Detection of egg drop syndrome 1976 virus by polymerase chain reaction and study of its persistence in experimentally infected layer birds. Acta Virol. 2003;47(3):179-84.

Specimen requirements: 0.2 ml feces, or cloacal swab, or 0.2 ml whole blood in EDTA (purple top) tube, or 0.2 ml fresh or frozen tissue, or 0.2 ml cell culture, or environmental swab or swipe.

Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix to confirm specimen acceptability and shipping instructions.

For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround time: 2 business days

Methodology: Qualitative real time PCR

Normal range: Nondetected