Salmonellosis in the Bovine Animal
Abstract
Salmonella organisms are gram negative rods that are parasitic in man and animals and usually are viewed as enteric organisms.
The first "salmonella" organisms were isolated in 1885 by Smith and Salmon from swine. In 1888, the second isolote of the "salmonella" group was from a man who had eaten raw meat from a diseased cow (1). Salmonella was the name proposed for the group of organisms in honor of D.E. Salmon, the first chief of the United States Bureau of Animal Industry.
It is interesting to note that in 1934, 44 serotypes were recognized. This number gradually increased to 962 in 1966 and has continued to some 1,300 now. However, most salmonella isolated now belong to a small number of serotypes (3). The disease is believed to be worldwide and in cattle it appears to have dramatically increased in the last few years. In fact bovine salmonellosis has been recognized as an important cattle disease only since the late 1950's ( 4). Part of this increase may be more apparent than real because of better isolation techniques, and especially a greater awareness of the disease in cattle. It has, of course, been recognized for a long time as a major disease in swine.
Salmonellosis is a disease of all animal species caused by a variety of different species of salmonella and is manifested usually by an acute septicemia, acute enteritis, or chronic enteritis (2).
The morbidity rate is generally high and in certain cases, such as young calves, malnourished animals or stressed animals due to shipping, calving, weaning too early, or the presence of concurrent infections, it can result in very high mortality rates reaching 30 to 70%. Even those animals that survive the acute form of the disease may suffer long-standing chronic problems.
In order, the most common serotypes in cattle, ac-cording to Doctor E.M. Ellis, Veterinary Services Laboratory, U.S.D.A., A.P.H.I.S., Ames, Iowa, as the result of having serotyped thousands of bovine cultures, are as follows: 1. S. typhimurium; 2. S. typhimurium var. copenhagen; 3. S. dublin; 4. S. newport; 4. S. st. paul; 6. S .anatum.
Salmonellosis has been a problem in human health from infected milk, meat, and poultry products. Often this is occasioned by careless handling or contamination after the milk leaves the cow, or in the case of meat and poultry it may be the result of contamination during slaughter or processing. Most all salmonella species in animals should be considered as a potential source of salmonella infection in man.
