Document Type

Thesis - Open Access

Award Date

1957

Degree Name

Master of Science (MS)

Department

Bacteriology

Abstract

Organisms of the genus Listeria have stimulated a great deal of interest as a result of their pathogenicity and affinity for the central nervous system. The clinical condition produced by this organism is known as listeriosis, or in ruminants as “circling disease”. The organism was described by Murray, Webb and Swann in 1926 as the causative agent of an eqizootic infection in laboratory rabbits and guinea pigs. Their observations showed that the disease produced emaciation, abundant exudate in serous cavities, necrotic foci in and on various organs, and a marked increase in monocytes circulating in the blood stream. The name Bacerium monocytogenes was used to describe the organism. In 1927 Pirie isolated an organism from gerbilles which he called Listerella heptolytica referring to the numerous necrotic foci found on the liver. The comparative studies of Murray and Pirie showed that the organisms which they had worked with were identical, and the name of the genus was changed to Listeria, its present form. The word “Listeria” was actually derived from the name of the famous English surgeon and bacteriologist, Joseph Lister. While it may be rather precarious to attempt prognostication at this time, it is nevertheless a possibility that listeriosis may exhibit a history similar to Malta fever. When Sir David Bruce discovered Micrococcus melitensis as the causative organism of Brucellosis, there was little evidence to support the occurrence of a new disease in humans. Yet, it is a well-recognized fact that one of the public health problems today is undulant fever. There is reason for contemplating that the genus Listeria now occurring in twenty species of animals in nearly all the Northern States and fifteen foreign countries is adapting itself to man. It does not seem too remote that in the future we may witness many human cases of listeriosis rather than isolated cases as now occur. Recently a culture of Listeria monocytogenes was sent to this laboratory for verification from St. John’s Hospital in Rapid City, South Dakota. The culture was taken from the spinal fluid of a fifty-two year old man, a station agent for the Milwaukee Railroad at Faith, South Dakota. Biochemical and serological tests proved that the bacterium was Listeria monocytogenes. It is believed that this is the first diagnosed case of human listeriosis in South Dakota. From the period between 1951 and 1953 thirteen cases occurred in humans in the State of California. Prior to this time one case had been reported. Linsert reports that during the interval between 1953 and 1956 eighteen human cases were bacteriologically confirmed by the Bezirk Hygienic Laboratory of Germany. Whether or not the sudden appearance of many listeriosis cases in man is a matter of better technique in diagnostic procedure is certainly a factor to consider, but seems rather doubtful since it could hardly account for the large percentage of the total number. It is quite possible that there exists an epidemiological connection between man and animal, although this is strictly a matter of conjecture on the part of the investigator. It is hoped that these studies, directly or indirectly, may contribute to solving this problem. From the standpoint of farm economics the two most important animals involved are sheep and cattle. It is not uncommon that listeriosis in sheep reaches epizootic proportions. An outbreak in flocks of 3,000 may cause losses totaling as high as 200 to 500 animals. Fewer than two percent of the animals showing definite clinical symptoms recover. Listeriosis in cattle has been sporadic and usually involves only a small number of animals, although twenty percent of a large beef or dairy herd may be infected. The exact mode of transmission under field conditions is not understood. Bolin and Osebold report that Listeria cells pass into the urine and feces of rodents, therefore raising the question of food and water contamination of domestic animals. On the other hand, clinical listeriosis is often detected when animals are kept in close quarters. Examples of this are in feed-lot cattle and in sheep at lambing time. Osebold further suggests that the opportunity for consumers’ meat to be infected with Listeria could likely exist since many animals that are involved show no apparent infection, therefore not decreasing their commercial value. Since it appears that many of the infected animals show no symptoms of listeriosis, it would seem advantageous to conduct a systematic study to determine the degree of infestation, hence giving information on the pathogenicity of the organism, its prevalence, and the number of potential carriers resulting from previous infections.

Format

application/pdf

Number of Pages

52

Publisher

South Dakota State University

Rights

No Copyright - Non-Commercial Use Only
http://rightsstatements.org/vocab/NoC-NC/1.0/

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