The Significance of Wild Birds (in Particular, Larus spp.) in the Epidemiology of Campylobacter Infections in Scotland

Whelan, Cheryl Denise (1986) The Significance of Wild Birds (in Particular, Larus spp.) in the Epidemiology of Campylobacter Infections in Scotland. MSc(R) thesis, University of Glasgow.

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A total of 650 human Campylobacter spp. isolates were obtained from 4 localities in Scotland. Approximately 3% of these were designated to be C. coli; the remaining isolates were C. jejuni. With a panel of 29 antisera prepared in rabbits to Penner reference strains, 492 (75.7%) were able to be assigned a serotype using passive haemagglutination for the detection of heat stable antigens. The four most common serotypes were Penner 2, 4, 1 and 31, accounting for 38.3% of the isolates examined, and 50.6% of those which were typable. Cloacal swabs from herring gulls were cultured for Campylobacter spp. throughout the year. Gulls were sampled from refuse tips in the Glasgow area as well as Aberdeen. Unfledged chicks from the breeding colonies at Inchmarnock and Flanders Moss were also sampled. The breeding colony on Horse Island, off the west coast of Scotland, provided Campylobacter spp. isolates from lesser black backed gulls and herring gulls. There was no consistent age or sex effect in the carriage of Campylobacter spp., laridis or jejuni/coli. Geographical location was a factor in the number of gulls that cultured positive for Campylobacter spp., with the refuse tip birds in the Glasgow area having a higher proportion of C. jejuni/coli than the Aberdeen tip birds and the gulls caught in Thurso and Bowmore (from previous data). A seasonal effect was exhibited in the refuse tip birds from the Glasgow area, with C. jejuni/coli responsible for the majority of Campylobacter spp. isolated from the gulls in the November-December period. In January-February, there was a large increase in the proportion of gulls carrying Campylobacter spp., mainly due to an increase in the number of gulls with C. laridis. Feeding ecology plays an important role in the carriage of Campylobacter spp. in gulls. Tip birds had a higher proportion of both C. jejuni/coli and C. laridis when compared with the birds from a breeding colony. The proportion of unfledged chicks with Campylobacter spp. was less than that of the adult gulls, although the difference in the proportion of C. jejuni/coli in both populations was not statistically significant. Twenty-nine percent of the C. jejuni/coli strains isolated from the gulls were able to be serotyped. The percentage of C. jejuni/coli that serotyped in the unfledged chicks was significantly higher than that of the fledged gulls. Serotypes obtained from the chicks were similar to those most commonly found in humans. There was an increased amount of Campylobacter spp. found in reservoirs used by gulls as nocturnal roosting sites. The levels of Campylobacter spp. were shown to increase with the increase in the number of nocturnally roosting gulls. C. laridis was isolated from bodies of water during periods of medium (August-September) and high (November-December) gull usage, but was not found in reservoirs not utilised by gulls as nocturnal roosts. These latter reservoirs had numbers of Campylobacter spp. that followed a different monthly pattern from the utilised reservoirs. The role of gulls in the epidemiology of human Campylobacter infections in Scotland is discussed.

Item Type: Thesis (MSc(R))
Qualification Level: Masters
Keywords: Epidemiology, Microbiology
Date of Award: 1986
Depositing User: Enlighten Team
Unique ID: glathesis:1986-77467
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 14 Jan 2020 11:53
Last Modified: 14 Jan 2020 11:53

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