Gert van der Hoek
In Memoriam - Editor, Senior Moderator
Giving personal protection like masks apparently wasn't enough. Vaccination should be considered?
Q Fever among Culling Workers, the Netherlands, 2009?2010
Conclusions
Seroconversion for C. burnetii among 17.5% of culling
workers who were seronegative before culling provides
evidence of high-risk work. Before culling, seroprevalence
was 13%, similar to that among blood donors in a highincidence area in the Netherlands in 2009 (H.L. Zaaijer,
pers. comm.) and in similar high-risk occupational groups
(7). Laboratory testing by using ELISA is an accepted
method in an acute setting (8), and positive results (including
positive IgM only) were confi rmed by immunofl uorescence
assay. Nonparticipants were in the youngest and oldest age
groups; their effect on the proportion of seroconversion is
uncertain. Eighteen workers (excluded for not providing
a follow-up blood sample) completed the questionnaire
in June. Symptom incidence for these 18 workers was the
same as that for included participants.
Symptomatic infection (31% of seroconverters) was
probably underestimated. A diagnosis of Q fever was selfreported (unconfi rmed) to the occupational health service
by 8 workers who did not participate in the study.
During
December?July 2010, the national infectious disease
surveillance system reported 11 culling-related cases of
acute Q fever; 2 of these patients were hospitalized.
A strong association was shown between risk for
seroconversion and total hours worked on the farms and
working inside the stable. In other settings internationally,
a risk gradient has also been shown for close direct and
indirect animal contact over time (9,10). In our study,
half the participants had experience with previous animal
epidemics (avian infl uenza, foot-and-mouth disease,
classical swine fever) and using PPE. Their compliance
with PPE was reportedly high; however, a key problem was
not wearing PPE while taking work breaks but remaining
on the farm.
Given the high risk for infection despite extensive
personal protective measures during culling, additional
preventive measures are needed. The Health Council of the
Netherlands issued guidelines for persons in risk groups
who would benefi t from vaccination against Q fever (11).
Culling workers were not included in these guidelines. The
effi cacy of human Q fever vaccine has been shown to be
high for young and healthy persons in similar occupational
groups (12?14). Vaccination of culling workers could be
considered if further animal culling is advised.
Full article:CDC
Q Fever among Culling Workers, the Netherlands, 2009?2010
Conclusions
Seroconversion for C. burnetii among 17.5% of culling
workers who were seronegative before culling provides
evidence of high-risk work. Before culling, seroprevalence
was 13%, similar to that among blood donors in a highincidence area in the Netherlands in 2009 (H.L. Zaaijer,
pers. comm.) and in similar high-risk occupational groups
(7). Laboratory testing by using ELISA is an accepted
method in an acute setting (8), and positive results (including
positive IgM only) were confi rmed by immunofl uorescence
assay. Nonparticipants were in the youngest and oldest age
groups; their effect on the proportion of seroconversion is
uncertain. Eighteen workers (excluded for not providing
a follow-up blood sample) completed the questionnaire
in June. Symptom incidence for these 18 workers was the
same as that for included participants.
Symptomatic infection (31% of seroconverters) was
probably underestimated. A diagnosis of Q fever was selfreported (unconfi rmed) to the occupational health service
by 8 workers who did not participate in the study.
During
December?July 2010, the national infectious disease
surveillance system reported 11 culling-related cases of
acute Q fever; 2 of these patients were hospitalized.
A strong association was shown between risk for
seroconversion and total hours worked on the farms and
working inside the stable. In other settings internationally,
a risk gradient has also been shown for close direct and
indirect animal contact over time (9,10). In our study,
half the participants had experience with previous animal
epidemics (avian infl uenza, foot-and-mouth disease,
classical swine fever) and using PPE. Their compliance
with PPE was reportedly high; however, a key problem was
not wearing PPE while taking work breaks but remaining
on the farm.
Given the high risk for infection despite extensive
personal protective measures during culling, additional
preventive measures are needed. The Health Council of the
Netherlands issued guidelines for persons in risk groups
who would benefi t from vaccination against Q fever (11).
Culling workers were not included in these guidelines. The
effi cacy of human Q fever vaccine has been shown to be
high for young and healthy persons in similar occupational
groups (12?14). Vaccination of culling workers could be
considered if further animal culling is advised.
Full article:CDC