The epidemiology and control ofSalmonella thompsoninfection of fowls

Abstract

The details are given of the epidemiology ofS. thompsoninfection in a flock of pullets which survived an outbreak of this disease when chicks, and also of a flock of adult birds suspected of being carriers of the organism. The results of blood testing and bacteriological examinations of cloacal swabs, random faecal samples and eggs from both flocks indicated that:(1) Many chicks which survived an outbreak ofS. thompsoncontinued to carry the organism for some months without showing any symptoms. In most cases the organism was harboured in the intestines and was excreted intermittently in the faeces. On one occasionS. thompsoninfected the gall bladder, and the bacilli were excreted in the faeces for at least 18 months after the outbreak had occurred.(2) The common method of egg infection was by the contamination of the shell with infected faeces. Under conditions of incubation the bacilli penetrated the egg shell and infected the yolk. Although there was little penetration of the organism under storage conditions, the bacilli on infected shells remained viable for at least 21 days.(3) The common methods of spreading infection in a hatchery were from:(a) The contact of infected and non-infected egg shells.(b) The handling of eggs before and during incubation.(c) The contact of egg shells with infected incubators.(d) The ingestion and inhalation of infected fluff and incubator debris at hatching time.(e) The ingestion of food and water contaminated with infected faeces from survivor chicks.For the control ofS. thompsoninfection in poultry, the following procedures have been recommended:(1) The production of agglutinins by carrier birds was not a reliable indication of infection. In known infected flocks, however, the detection of carriers by blood testing and by the examination of cloacal swabs is of value. For such a test an alcoholized antigen is preferable to a heat-treated broth antigen, and a titre of 1/20 or more should be regarded as an indication that a bird is infected.(2) Only clean eggs should be used for hatching. Dirty egg shells should be cleaned by scraping or brushing and not by wiping with a damp cloth.(3) Fertile eggs should be stored in a cool, dry atmosphere for as short a period as possible before incubation.(4) Eggs should be fumigated in the incubator with formaldehyde vapour, not later than 24 hr. after they have been set.We wish to record our appreciation of the assistance received from Mrs E. Sidery in the bacteriological examination of eggs and the preparation of agglutination tests.

Salmonella enteritidis phage type 4 from the contents of intact eggs: a study involving naturally infected hens

“…In this respect it differs from S. thompson (10), S. anatum (11) but behaves in a manner similar to S. pullorum (10) and S. menston (12).…”

The influence of age on the response of SPF hens to infection with Salmonella enteritidis PT4

“…Its presence in the former site is presumably as a result of infection of the ovary while contamination of the albumen may result from infection of the upper oviduct. Contamination of egg shells with salmonellas is usually thought to be the result of faecal carriage [10]. While this, or the environment, could clearly have been the source in the study reported here, the apparent lack of relationship between presence of S. enteritidis PT4 in faeces and on egg shells with the SPF-I birds (Table 1) raises other possibilities.…”

Factors associated with the dissemination of Salmonellae in turkey products and processing plants

“…typhi murium over a period of 65 days by naturally infected adult turkeys and up to 15 days in artificially infected adult turkeys. found that poults voided typhimurium in feces up to 96 days after oral admini stration, and they indicated that disease transmission resulted when this fecal material was ingested by susceptible poults, Buxton and Gordon (1947) observed that chickens may remain intestinal carriers of £, thoirpson up to 18 months. Wilson (1948) found that adult chickens may serve as intestinal carriers of typhimurium and thompson for periods up to 9-16 months.…”

“…all strains penetrated the shell membranes and multiplied within the eggs to populations as high as one billion cells per ml of egg meat (Stokes et al 1956), Penetration and growth occurred as rapidly with nonmotile serotypes as with motile serotypes, Williams (1959) stated that Salmonellae are able to gain entrance into the egg, to multiply in the yolk, and to infect the developing embryo which may die or hatch as an infected poult, Buxton and Gordon (1947), Gregory (1948), Lancaster and Crabb (1953), and Banwart and Ayres (1957 have shown that egg albumen has very little inhibitory effect on Salmonellae that penetrate the shell, Wilson (1948) cautioned that mixing contaminated eggs with clean eggs in the incubator is a means of spreading infection. Proper tem perature and moisture has been shown to be important in the rate of penetration through the shell.…”

“…Proper tem perature and moisture has been shown to be important in the rate of penetration through the shell. £, thompson has been shown by Buxton and Gordon (1947) to readily penetrate the shell of chicken eggs stored at 37°C, but penetration was less common in eggs stored at room tem perature, Bigland and Papas (1953) reported shell penetration in 8% of eggs contaminated with S_, typhimurium, 3% with oranienburg, 15% with S, kentucky, and none with 2* bareilly.…”