When hatching eggs/chicks are infected, acute septicemia with reduced hatching rates, hatching of weak chicks, mortality of 10% to 50% in the first weeks of life are predominant, or the chicks show corneal opacities or nonspecific symptoms such as reduced feed intake, movement disorders, diarrhea, and convulsions. Adults, which may be latently infected, show nonspecific symptomatology such as decreased performance, diarrhea, and weakness.
Arizonosis is caused by Salmonella enterica subspecies arizonae (mainly serotype O18:Z4,Z23 and O18:Z4,Z32), gram-negative motile rod bacteria of the Enterobacteriacae family. Susceptible are mainly young turkeys, but infections have also been detected in other bird species (chickens, ducks, canaries, parakeets and wild birds). In arizonosis, vertical transmission from infected parents to hatching eggs results in reduced hatching rates (up to 70%) and hatching of life-weak chicks. Yolk sac regression is delayed, and acute septicemic infections occur in turkey poults up to 3 to 5 weeks of age. Mortality varies from 10% to 50% in the first weeks of life; chicks may become blind as a result of corneal opacity and accumulation of exudate in the eye.
Salmonella arizonae infection can result in permanent intestinal colonization with intermittent shedding in older birds, leading to contamination of hatching eggs and corresponding infections of hatching chicks. Adult turkeys show nonspecific symptoms such as decreased laying performance and reduced feed intake. As infection progresses, Salmonella arizonae can colonize ovaries and oviduct, resulting in the production of infected chicks. Other avian species and reptiles are usually subclinically infected.
In pathology, persistent yolk sacs, cloudy cornea, enlarged pale liver and spleen with pale foci, and fibrinous serositis with a high bacterial load of yolk sac, meninges, eyes, and ears are observed in chicks.
Last updated: 10.10.2023