Coxiella burnetii seroprevalence of shepherds and their flocks in the lower Saint-Lawrence River region of Quebec, Canada.
OBJECTIVE
To determine the seroprevalence of Coxiella burnetii among the shepherds and their sheep in the lower Saint-Lawrence River region (LSLRR) of Quebec, Canada.


METHODS
A prospective human-animal comparative study was conducted with 81 shepherds from 46 farms and a control group matched for sex and age. All participants answered a standardized questionnaire to evaluate their risk factors for Q fever, including a specific section on the work practices of the shepherds. All human subjects had a blood sample taken for serology to phase I and phase II antigens of C burnetii performed by indirect immunofluorescence assay. At each participating farm, seven to nine sheep had blood samples taken for C burnetii serology to be assessed by the complement fixation test.


RESULTS
The seroprevalence to C burnetii was higher in the group of shepherds (28.4%) than the control group (1.2%) (P<0.005). Among the group of shepherds, spending more than 5 h/week in the sheep barn (P=0.06) and buying and/or trading sheep within the past six months (P=0.004) were associated with positive C burnetii serology. A total of 137 of 334 sheep (41%) were seropositive for C burnetii. These positive sheep were distributed in 41 of the 46 flocks (89%). No correlation could be demonstrated between a serology for C burnetii in the herds and the shepherds.


CONCLUSIONS
Q fever is highly prevalent in the LSLRR of Quebec, affecting 89% of the flocks and 28% of the shepherds. Shepherds in this region are at increased risk for C burnetii infection in comparison to the general population.
Dolcé
Patrick
P
Department of Medical Microbiology and Infectious Diseases, Centre Hospitalier Régional de Rimouski, Rimouski.
Bélanger
Marie-Joële
MJ
Tumanowicz
Krzysztof
K
Gauthier
Claude P
CP
Jutras
Philippe
P
Massé
Richard
R
Montpetit
Claude
C
Bernatchez
Harold
H
McColl
Dorothy
D
Artsob
Harvey
H