High Mortality in Commercial Chukar Partridges (Alectoris chukar) Infected with Salmonella arizonae.

Arizonosis is a bacterial septicemic disease caused by Salmonella enterica subspecies arizonae. This case report describes S. arizonae septicemia in commercial chukar partridge (Alectoris chukar) chicks that resulted in a 7-day flock mortality of 30% (2100/7000), with mortality rapidly progressing to 99.3% (6950/7000) by 3 wk of age. To our knowledge, this is the first documented case of S. arizonae acute septicemia in chukars. Gross and histopathologic findings in the chukars included hepatosplenomegaly, omphalitis, and multiorgan inflammation. Salmonella arizonae was isolated from the liver, spleen, and yolk sac cultures, and the isolate was serotyped as Salmonella arizonae serovar 18:z4,z23. Minimum inhibitory concentration antimicrobial susceptibility testing performed on S. arizonae classified the isolate as resistant to erythromycin, gentamicin, neomycin, and sulfadimethoxine and not susceptible to amoxicillin and penicillin; the isolate was classified as susceptible to oxytetracycline, tetracycline, ceftiofur, and spectinomycin. In addition to the arizonosis case report, a retrospective analysis of poultry arizonosis cases diagnosed at the California Animal Health and Food Safety laboratories from January 2005 to December 2024 identified 79 poultry cases of S. arizonae, predominantly in turkeys (69/79). A sharp decline in annual S. arizonae poultry cases was noted after 2009. The most common site of isolation was the yolk sac (45/79 cases), suggesting that vertical transmission plays a significant role in the dissemination of the disease. This case report highlights the susceptibility of chukar partridges to S. arizonae infection and disease and underscores the importance of early diagnosis, antimicrobial susceptibility testing, and stringent biosecurity practices to mitigate transmission and economic loss in commercial game bird operations.