HOG CHOLERA 



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* SALMONELLA AND ERYSIPELOTHRIX INFECTION IN SWINE SUSPECTED OF HAVING HOG CHOLERA./ n 

 Harrington, R. and Hulse, I). C. (Project Report) 



Summary 



Frequently the diagnosis of hog cholera is complicated by clinical signs which in many ways are similar to 

 those seen in septicemic disease caused by bacteria. Although there are several bacterial diseases that may cause 

 clinical signs somewhat similar to hog cholera, acute swine erysipelas and acute salmonellosis are the two most 

 frequent bacterial diseases that may produce clinical signs indistinguishable from hog cholera. Bacteriologic 

 examination should be performed for differential diagnosis of these diseases. 



A major responsibility of the General Bacteriology Unit of the Diagnostic Bacteriology Section, VSDL, has 

 been the bacteriologic examination of swine tissues from hog cholera negative specimens. Results from these 

 examinations have provided valuable information for differential diagnosis of hog cholera in support of the hog 

 cholera eradication program. 



This report summarizes a study of the occurrence of salmonella and erysipelothrix in tissues of swine from 

 cases where hog cholera was suspected during calendar years 1971 and 1972. 



Materials and Methods 



Tissues were obtained from swine in herds where hog cholera was suspected by State and Federal regulatory 

 veterinarians. The tissues were submitted to the General Bacteriology Unit following examination for hog cholera 

 virus by the Swine Viruses Unit of the Diagnostic Virology Section, VSDL. Approximately 95 percent of the tissues 

 were spleens. 



Culture methods for the isolation of erysipelothrix and the fluorescent antibody technique for the detection 

 of salmonellae have been described (1, 3). 1 



Results and Discussion 



Bacteriologic examinations were conducted on 4,273 swine tissues (table 1). This represents 3,138 animals 

 J from 2,106 herds in 43 States and Puerto Rico. Salmonellae were detected in one or more tissues from 37.6 percent 

 of the animals. Erysipelothrix rhusiopathiae was isolated from one or more tissues from 21.4 percent of the animals. 

 Salmonellae and E. rhusiopathiae were detected in one or more tissues from 8.7 percent of the animals. 



The number of specimens examined from many of the States was not large enough to make analysis of the 

 results meaningful. Nevertheless, a breakdown of the salmonella and erysipelothrix results by State are presented in 

 table 1. The States with the highest percentage of salmonella positives, from 100 or more animals, were Indiana 

 (56.3 percent), Ohio (45.1 percent), Louisiana (27.6 percent), Oklahoma (26.9 percent) and Minnesota (23.8 

 percent). The States with the highest percentage of erysipelothrix positives, from 100 or more animals, were 

 Oklahoma (30.8 percent), Louisiana (28.6 percent), Texas (26.6 percent), Indiana (18.2 percent), Ohio (13.3 

 percent) and Minnesota (10.3 percent). 



The results of this study do not depict the true incidence of salmonella and erysipelothrix infections in swine. 

 Only on rare occasions was the laboratory called upon to perform bacteriologic examinations on tissues from swine 

 other than those suspected of having hog cholera. Nevertheless, as previously reported (2, 4), the data indicate that a 

 large segment of the swine population in the States sampled is infected with salmonella and erysipelothrix. Since 



Numbers in parentheses refer to References at the end of this report. 



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