Toxigenic Corynebacterium diphtheriae associated with an equine wound infection.

In the United States, swine salmonellosis is most often attributed to infections by Salmonellaserovar choleraesuis. As a host-adapted pathogen rarely found in nonswine sources, S. choleraesuis is thoughtto be spread primarily via horizontal transmission, with carrier animals playing an important role. Little hasbeen reported regarding infection of neonatal piglets, particularly regarding their potential to become carriers.Evidence reported herein demonstrates that piglets experimentally infected by S. choleraesuis at 2 days of agewere capable of shedding the pathogen for up to 85 days postinfection, at which time the study was concluded.This study also presents findings supporting the use of GN-Hajna as a preenrichment medium for the isolationof S. choleraesuis. Salmonella choleraesuis infections account for more than90% of the US cases of swine salmonellosis.12 Salmonellosiscaused by S. choleraesuis typically occurs as a postweaningsepticemia or enterocolitis and often occurs in operationsthat commingle pigs of different ages.12 Spread of this hostFrom the USDA/ARS Food Animal Protection Research Laboratory, College Station, TX 77845 (Anderson, Genovese, Harvey, Stanker, Nisbet), Department of Veterinary Pathobiology, Texas A&M; University, College Station, TX 77843 (Genovese), and MS BioScience, Inc., Madison, WI 53704 (DeLoach). Received for publication May 3, 1999.adapted serotype throughout modern pig production systemsis thought to occur primarily via horizontal transmission,which suggests an important role for asymptomatic carri-ers.5–7,12 Salmonella choleraesuis can recur in pigs previously infected, thus further implicating an important role for latentcarriers.12 The development of a S. choleraesuis carrier statehas been investigated experimentally with weaned piglets,5–7 but little is known regarding infection of neonatal piglets and their potential to shed the pathogen. Even though neonatal piglets can be infected, they rarely exhibit clinical salmo-nellosis.12 The primary objective of this study was to experimentally infect suckling piglets with S. choleraesuis and by guest on March 8, 2013vdi.sagepub.comDownloaded from