(RA), previously referred to as Pasteurella anatipestifer
, is a highly contagious disease that causes acute or chronic septicemia in domestic ducks. The disease is mainly a problem in young, White Pekin ducks grown for commercial purposes. Outbreaks have been documented in the United States and throughout several countries in Asia. R. anatipestifer
infection occurs in acute or chronic form.
- Acute form: The acute form is primarily a concern for young ducks, between 2 and 8 weeks of age. Affected ducks usually develop a blood infection, resulting in a combination of respiratory, neurological, and gastrointestinal signs and high mortality rate. Signs most often observed include greenish diarrhea, head and neck tremors, listlessness, and various respiratory signs.
is a gram-negative, non-motile, non-spore-forming rod. Over 21 different serotypes have been identified worldwide. R. anatipestifer
infection was first reported in 1932. In the early 1980s a commercial antibiotic was developed against the disease, using a combination of R. anatipestifer
serotypes and a particular strain of Escherichia coli
. The overuse of antibiotics has contributed to the emergence of drug-resistant bacterial strains of R. anatipestifer
. Currently, various vaccines have been developed as an alternative method of controlling the disease in farmed commercial ducks.
RA is spread to ducks horizontally from inhalation by the respiratory tract or through skin wounds. It may be transmitted vertically, from breeder ducks to their eggs.