Full text of DOI:10.1111/j.1467-842X.2001.tb00595.x

Infectious Diseases
Abattoir-associated Q fever: a Q fever outbreak
during a Q fever vaccination program
Abstract
Nicole Gilroy, Neil Formica, Mary Beers
National Centre for Epidemiology and Population Health, Australian National
University, Australian Capital Territory
Objectives: To investigate an abattoir
outbreak of Q fever in southern New South
Wales with reference to the protective effect
and safety of the formalin-inactivated Q
fever vaccine (Q Vax) administered before
and during the outbreak.
Andrew Egan
General Practice, Cooma, New South Wales
Methods: In September 1998, after
Stephen Conaty
notification of four Q fever cases in the
abattoir, a cohort investigation of 103 workers
was undertaken. Data on age, sex, immune
status, vaccination status and main work area
were obtained from the medical officer
administering the vaccination program and
abattoir records. Symptoms and occupational
risk factors for illness were obtained from
interview of 63 (61%) employees.
Southern New South Wales Public Health Unit
Barrie Marmion
Institute of Medical and Veterinary Science, South Australia
errick first described acute primary broad spectrum of clinical outcomes.5,6 Infec-
Q fever in 1935. He studied fevers tion may be asymptomatic or present as an
D
in Queensland abattoir and agri- acute febrile illness characterised by fever,
Results: Of 103 abattoir employees, 16
cultural workers and also isolated the causa- sweats, myalgias, arthralgias, headache and
(16%) had immunity from previous Q fever
1
tive organism in guinea pigs. Burnet and weight loss. Acute complications such as
exposure and 19 (18 %) had been
vaccinated at least six weeks before the
first case of Q fever exposure in the
abattoir. Of the remaining 68 workers who
were susceptible to primary infection, 29
Freeman subsequently identified the isolates atypical pneumonia, hepatitis, aseptic men-
2
as rickettsia-like. They now constitute a ingitis and encephalitis may occur. In most
separate genus, Coxiella burnetii, unrelated
cases the symptoms of Q fever are self-
to rickettsiae and are phylogenetically closer limited, though endocarditis, osteitis, hepati-
3
(
43%) had laboratory confirmed acute
to Legionella sp. C. burnetii is an intracel-
tis and chronic fatigue may develop as chronic
sequelae.5,7-9 Reactivation of Q fever occurs
primary Q fever and eight were suspected
cases. No workers vaccinated before the
likely period of exposure developed Q fever.
Of 32 workers vaccinated post-exposure,
four developed laboratory-confirmed Q
fever within eight days of vaccination.
lular bacterium. It has a complex intracellu-
lar replication cycle in macrophages and in animals and humans during pregnancy, and
other cells, which results in the liberation of aerosols from the products of conception in
a small, compact, highly resistant cell with animals are highly infectious by the respira-
a fine structure resembling that of an entero- tory route. The slaughtering of pregnant, in-
bacterium.3,4
fected animals therefore places abattoir
Vaccination administered 10 or more days
after the likely period of exposure showed
no significant protective effect (RR=0.57;
Q fever is endemic in most countries. In workers at high risk of infection.
brief, cattle, sheep and goats are the most
important zoonotic sources of human infec-
tion. Milk, urine, excreta and the products
The stimulus to vaccinate against Q fever
followed outbreaks of disease in laboratory
workers in the 1940s. The first effective
9
5% CI 0.13-2.57; p=0.60).
Conclusions: Q-Vax was highly effective
when administered in advance of the likely
period of Q fever exposure. Post exposure
vaccination was not shown to be protective.
Implications: This study reinforces meat
industry vaccination guidelines for abattoir
employees. The optimal time to vaccinate
workers is before they are put at
of conception from infected animals are vaccines to be developed were formalin-in-
another source of infection and environmen-
tal contamination. Occupational groups
activated whole cell vaccines.10 Subse-
quently, more highly purified vaccines
with direct animal contact such as farmers, strictly in the Phase I antigenic state were
abattoir workers, veterinarians, animal trans- used together with prevaccination testing for
porters and other animal handlers, such as immunity.These proved to be safe and highly
1
1
shearers, are particularly at risk of contract-
ing the disease.
protective. Other vaccines comprising sol-
vent extracted complexes of protein and li-
occupational risk.
(
Aust N Z J Public Health 2001; 25: 362-7)
Exposure to C. burnetii may result in a popolysaccharide or extracted cell residues,
Submitted: August 2000
Revision requested: March 2001
Accepted: May 2001
Correspondence to:
Dr Nicole Gilroy, 62 Fox Valley Road, Wahroonga NSW 2076. E-mail: wyndham@zip.com.au
3
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Infectious Diseases
A Q fever outbreak during a vaccination program
although immunogenic and protective in laboratory animals have
not been field tested in humans on a scale that allows a compara-
tive evaluation of their reactogenicity or duration of protection.11
An effective whole cell, formalin inactivated Phase I antigen
vaccine against Q fever (Q-Vax, CSL Ltd) was licensed for mar-
keting in 1989.12-15 In the same year, a Ministerial Working Party
on zoonoses in the meat industry recommended vaccinating
Q fever in the district for the year. The abattoir had commenced
operations in early April, 1998. Adult cattle, including old dairy
cows, were the only livestock to be slaughtered on the premises.
The abattoir had started a vaccination program inApril 1998 when
19 of the total 103 workforce were vaccinated without adverse
effects. A second phase of the vaccine program for 1998 was in
progress at the time of notification of the four Q fever cases. As
these cases happened to be related in time to pretesting and vac-
cination, the abattoir management raised concerns about the safety
of the skin test reagents and vaccine. This investigation aimed to
describe the outbreak of Q fever in time and to determine the
safety and effectiveness of Q fever vaccination when given be-
fore and after the likely period of Q fever exposure.
1
6
against Q fever. These recommendations were conveyed to the
meat industry and later reinforced by meat industry guidelines.17
The standard protocol for Q fever vaccination includes pretest-
ing by serological examination and skin test. This avoids the
administration of Q fever vaccine to subjects previously infected
clinically or subclinically with C. burnetii. Once sensitised to
C.burnetii, these subjects are at increased risk of adverse reac-
tion to Q fever vaccination (for details see CSL Ltd booklet Q
fever, Your Questions Answered).
Methods
During the clinical trials of Q Vax in the 1980s, which in-
volved approximately 2,500 abattoir workers,14 there were no
confirmed Q fever cases in the vaccinees once sufficient time
Outbreak investigation
To determine the date of onset of symptoms for cases and the
timing and nature of possible exposures to C burnetii, a list of all
employees, their telephone numbers and main work areas were
obtained from the abattoir. Abattoir management were informed
that this was a public health investigation to ascertain extent of
morbidity in affected workers, to describe vaccine safety and ef-
fectiveness and to prevent further cases from occurring.
Employees were interviewed by telephone with a detailed ques-
tionnaire that sought additional information on possible expo-
sure to C. burnetii. Verbal consent for interview was obtained
and the aims of the outbreak investigation explained to each in-
terviewee.
(
more than 20 days) had elapsed after vaccination for cellular
immunity to develop. Since then, with vaccination of a much
larger number (more than 65,000) of subjects, a few cases –
around 14 – of primary Q fever or Q fever-like illness have been
detected in vaccinees within a year or two after inoculation (B.
Marmion, unpublished data). Serological analysis suggests that
about half of the patients had not responded to the vaccine anti-
gen and developed a primary infection. The remainder had been
primed by the vaccine but (presumably) not protected against a
heavy exposure.
In both the 1980s clinical trials, and during the 12 years since
marketing approval, coincidences of occupationally acquired Q
fever and vaccine inoculation have been observed.11 The onset
of Q fever in these instances ranged from a day or so before
inoculation up to 15 days afterwards but not subsequently, re-
flecting the time at which cell-mediated immunity is fully de-
veloped after vaccination. In some circumstances the temporal
association between skin testing (i.e. intradermal inoculation of
Adverse events were explored, including post Q fever fatigue
syndrome, which may have resulted from vaccination.
Active surveillance
The regional public health unit instituted active surveillance
for determination of further cases. Local general practitioners were
encouraged to consider Q fever in any patient who presented with
symptoms of a Q fever-like illness and to obtain laboratory con-
firmation. They were asked to notify any cases that were sus-
pected or confirmed as required by the NSW Public Health Act
1991.
0
.02ug of vaccine on to the volar surface of the forearm), or
vaccination on the one hand and the development of primary Q
fever infection on the other, has been misinterpreted as infec-
tion from the vaccine. This is particularly so when there are no
cases of Q fever in untested or unvaccinated individuals in the
abattoir.
Case definitions for acute primary Q fever
Confirmed case
In the present outbreak, the timing and prolonged nature of
the vaccine program and of the introduction of Q fever into the
abattoir offered a unique opportunity to define the interaction
of the two processes.
A serologically confirmed case of Q fever was one with a
fourfold or greater increase in antibody titre to phase II antigen
by Complement Fixation Test (CFT) or a positive IgM titre (≥80)
to phase II antigen by Immunofluorescence (IF)Test. These crite-
ria were applied to persons in the abattoir or local community
after June 1998.
Background
In early September 1998, four cases of laboratory-confirmed
Q fever were notified to the Southern New South Wales (NSW)
Public Health Unit (PHU). The cases were employees of an abat-
toir in southern NSW. These were the first notifications of
Suspected case
A suspected case was defined as one in which at least four of
the following symptoms were reported, after June 1998, in an
abattoir or local community member: fever, sweats, rigours,
2001 VOL. 25 NO. 4
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363

Gilroy et al.
Practice Note
fatigue, headache, myalgia, arthralgia, or cough but for whom
serological tests were negative or not available.
• Positive screening serology defined as a baseline Complement
Fixation antibody Titre (CFT) to Phase II antigen of ≥1 in 2.5.
Additionally, we considered that a clinical history of Q fever
prior to June 1998 with or without screening test results probably
indicated post-infection immunity, provided that work history
included high-risk exposures including animal husbandry and
slaughtering.
Vaccination and pretesting for immune hypersensitivity
Pre-vaccination skin testing had been done in conformity with
the Q Vax product information. The skin test is a an intradermal
injection of 0.1 mL of diluted Q fever vaccine containing 0.02µg
of purified organisms on the volar aspect of the forearm. Sub-
jects who tested negative on skin test after seven days and who
were non-immune on Q fever specific serology, were vaccinated
Analysis
We calculated Vaccine Efficacy (VE) for the abattoir cohort
comparing the attack rate in those vaccinated in April, pre-out-
break, with the attack rate in those determined to be susceptible
to primary infection prior to the outbreak. Analysis of results was
performed using Epi-info version 6.04.18
with Q-Vax, a whole-cell formalin inactivated Henzerling strain
of C burnetii phase I.13
To determine the safety of the vaccine, we obtained all avail-
able vaccination records for abattoir workers from the local
medical officer responsible for the abattoir Q fever vaccina-
tion program. We requested dates and results for pre-vaccina-
tion skin testing and serology, and dates of vaccination for
both the pre-outbreak program in April and the September pro-
gram conducted during the outbreak. Results of serological
tests were obtained from the reference laboratory to which all
specimens had been sent. Additional demographic informa-
tion regarding age and sex was obtained if available.
Results
The outbreak
Of 103 employees employed at the abattoir since it started
operations in April 1998, 82 (80%) were male and 21 (20%) were
female. Age was determined in 82 (80%) workers. The median
age was 33.5 years (range: 17-62 years). Twenty-nine (28%) of
1
03 employees met the case definition of confirmed Q fever and
(8%) had suspected Q fever. Active surveillance did not iden-
Immunity
8
Workers susceptible to primary Q fever infection in this out-
break were defined as having either no evidence of post-infection
immunity from a previous Q fever exposure, or had not been vac-
cinated at least two weeks before the period during which Q fever
exposure was likely to have occurred. Onset of exposure in this
outbreak was the two-to-four-week period prior to symptom on-
set in the index case.
tify any cases outside the abattoir. The date of onset for the first
confirmed case of Q fever was 18 July 1998, eight weeks after
the first vaccination campaign had ended (see Figure 1). The epi-
demic peaked in the first week of September 1998.This was coin-
cident with the commencement of the second screening and
vaccination campaign. Date of onset of illness was not available
for one case.
Post-infection immunity was shown by the following parameters:
Sixteen workers (16%) had post-infection immunity on the basis
of skin or serological tests and 19 (18%) had received vaccine at
least two weeks in advance of the estimated exposure period of the
•
A positive skin test defined as any erythema or induration at
the site of injection after five to seven days. (i.e. post-infection
immunity secondary to past Q fever exposure); and/or
Figure 1: Date of onset of illness
6
5
4
3
2
1
0
Screening and
vaccination program 1
Screening and
vaccination program 2
in laboratory-confirmed and
suspected cases of Q fever,
southern NSW, 1998
CONFIRMED CASE
SUSPECTED CASE
Date of onset
3
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Infectious Diseases
A Q fever outbreak during a vaccination program
Table 1: Symptoms reported by 24 laboratory-confirmed
Q fever cases and eight cases of suspected Q fever.
four suspected cases provided only one serum sample for testing
and IF tests for Q fever antibody were negative.
Sixty-three employees (61%) were interviewed by telephone:
32 Q fever cases and 31 non-cases. Of the remaining 40 workers,
19 had no contact phone number, 19 could not be contacted after
at least three attempts at calling their number, and two refused
interview. Of the 40 not interviewed, five had Q fever-like illness
as determined from GP records.
Symptom
Number of
confirmed and
suspected cases
interviewed with
symptoms
% with symptoms
out of 32 cases
interviewed
n=32 (interviewed)
Headache
Sweats
32
30
29
29
29
28
25
22
21
15
10
4
100
94
91
91
91
88
78
69
66
47
31
13
13
Impact of Q fever-like illness
Fever
The most common symptoms reported by cases in this out-
break are given in Table 1. One confirmed case was admitted to
hospital for a period of four days. Twenty-three (96%) confirmed
cases reported taking time off work on account of illness as com-
pared with five (62%) suspected cases. The median number of
sick days for ill workers was seven (range 1-23).
Fatigue
Myalgia
Arthralgia
Rigors
Cough
Photophobia
Shortness of breath
Chest pain
Jaundice
Weight loss
Exposure period
Although the onset date of the index case was mid-July, we
estimated from the epidemic curve that the likely period of
intense exposure for most cases in this outbreak wasAugust 1998.
This encompassed the known two-to-four-week incubation
period for C. burnetii and was based on date of symptom onset
for most (97%) cases (see Figure 2). Two cases of Q fever (one
confirmed and one suspected) had a likely period of exposure in
June, eight weeks after the abattoir started operations and eight
weeks after the initial vaccination program. Another case had ill-
ness onset in October, and could have been exposed after the month
of August, or had a longer than usual incubation period.
4
index case. Post-infection immunity was confirmed in only 10 (26%)
of those with previous abattoir experience. Sixty-eight (66%) em-
ployees were considered susceptible to primary infection.
The attack rate in the susceptible workforce of 68 was 43%
(
29) for confirmed cases and 54% (37) for confirmed and
suspected cases combined. The eight suspected cases reported
symptoms resembling Q fever-like illness. Four of the cases re-
mained negative for IgG and IgM antibodies to C. burnetii Phase
I and II antigens and were also negative on serological tests for
other respiratory pathogens (Legionella, influenza A and B,
adenovirus, parainfluenza, chlamydia and mycoplasma).The other
Nature of exposures
High-risk exposures were defined as those that involved the
handling of stock (stockyard) or processing of meat (slaughter-
line, by-product/condemned areas, boning and packing rooms).
Figure 2: Estimated dates of
exposure for cases of Q fever
(confirmed and suspected)
based on a two-to-four-week
incubation period.
40
35
30
25
20
15
10
5
0
Limit of 4 week
incubation period
Limit of 2 week
incubation period
Date of Exposure
2001 VOL. 25 NO. 4
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Gilroy et al.
Practice Note
Table 2:Vaccination and illness in vaccinated and
unvaccinated workers before Q fever exposure.
Table 3: Illness in relation to timing of skin testing and
vaccination.
Ill
Not ill
Total
Skin test and illness onset
Vaccinated pre-exposure
0
19
31
50
19
68
87
Ill after skin test
19/25
Ill < 10 days post skin test
Ill 10-13 days post skin test
Ill ≥14 days post skin test
15
2
Not vaccinated pre-exposure
37
Total
37
2
Notes:
Relative risk (RR) of illness in vaccinated (0/19) versus non vaccinated
37/68) =0
VE= (1-RR)*100= (1-0)*100=100%
Ill before skin test
6/25
0
(
Ill ≤48 hours before skin test
Ill >48 hours before skin test
6
Vaccination and illness onset
The freezer/load-out area was also considered high risk as staff
from this area took delivery of packaged meat that was held in a
carton room that was contiguous with the boning room. Mainte-
nance workers and cleaners were a less well-defined group, as
their allocated work areas were not known. On the basis of these
workers having no regular direct contact with livestock or meat
processing they, together with administration staff, were catego-
rised as being at low risk.
Ill after vaccination
4/7
4
Ill < 10 days post vaccination
Ill 10-14 days post vaccination
0
Ill >14 days post vaccination
Ill before vaccination
0
3/7
1
Ill ≤48 hours before vaccination
Ill >48 hours before vaccination
2
Vaccine efficacy
before. In only two skin-tested subjects did illness develop after a
period of 14 days. Of the seven vaccinated cases, three developed
suspected Q fever before vaccination. The four remaining cases
developed Q fever after skin testing and vaccination. Symptoms
developed in these cases at two, four, six and eight days after
vaccination.
From Figure 2, the estimated period of exposure for most cases
of Q fever-like illness was the month of August. Vaccination and
screening had taken place in two phases: 19 workers were vacci-
nated before and 32 after the likely period of Q fever exposure.
There was no significant difference between exposure poten-
tial for the 19 employees vaccinated in April/May 1998 before
the outbreak and the 68 susceptible employees who were eligible
for vaccination at the time of the outbreak. Twelve of 19 workers
in this vaccinated group (63%) versus 50 of 68 (73%) susceptible
were categorised as working in high-risk areas (RR=0.89; 95%
CI 0.59-1.25, p=0.55). There were no cases of Q fever in this
vaccinated group and 37 cases in the susceptible workers. There-
fore the calculated VE for this group is 100% (see Table 2).
Discussion
We did not find any evidence that this abattoir-related outbreak
of Q fever in southern New South Wales resulted from a Q-Vax
skin testing or vaccination program. It is clear that unscreened,
unvaccinated, non-immune workers developed Q fever after expo-
sure to C. burnetii in the abattoir. Workers vaccinated prior to the
exposure remained well. At the time of the outbreak two-thirds of
the workforce were susceptible to primary infection. The high
attack rate (54%) in susceptible workers suggested a significant
exposure to C.burnetii.The nature of the contaminating event is
unknown but it is possible that the source of the outbreak was in-
fected pregnant cattle that originated from a Q fever endemic area.
Q fever infection is known to occur in 30% to 70% of suscep-
tible exposed persons,19 although between 33% to 54% of sero-
logically diagnosed cases in the outbreak setting may be
asymptomatic.20,21 In this outbreak investigation, only workers
with symptoms were tested for disease and therefore no asympto-
matic infections were identified.
Vaccine safety
No adverse reactions occurred in the 19 workers vaccinated
prior to the outbreak. Between 4 September and 6 October 1998,
3
2 susceptible employees who had been potentially exposed to Q
fever in the abattoir were vaccinated. Q fever-like illness was
reported in seven (22%) vaccinated employees compared with 30
(83%) of 36 non-vaccinated workers.Thirty-one (97%) of all vac-
cinated workers were inoculated on or after 10 September.Twenty-
eight of these had no symptoms before vaccination whereas three
reported illness onset prior to the date of vaccination. Only two
mild local reactions following vaccination were reported.
The relative risk of Q fever-like illness in workers, who were
vaccinated on or after 10 September, assuming all were exposed,
was not significantly different to those who remained unvacci-
nated after this time (RR= 0.57; 95% CI 0.13-2.57; p=0.60).
The timing of skin testing and vaccination in relation to symp-
tom onset in skin tested and vaccinated workers is shown in Table
The effectiveness, safety and longevity of Q fever vaccination
have been assessed in several vaccination challenge trials of
abattoir workers1 and a retrospective cohort survey of employ-
5,12
1
4
ees at three abattoirs over a five-year period. The few cases of
Q fever in vaccinated workers reported in any of these studies
occurred when the dose of vaccine was given during the incuba-
tion period of a natural infection, with no cases occurring after
13 days of vaccination. This same observation occurred in this
3. In the 25 subjects who were skin tested and who were ill, symp-
tom onset in 19 occurred after skin testing, and in six cases
3
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2001 VOL. 25 NO. 4

Infectious Diseases
A Q fever outbreak during a vaccination program
outbreak investigation, with all four cases of Q fever occurring
within eight days of vaccination. Moreover, of 19 workers who
developed illness after skin testing, 17 did so within 14 days of
References
1. Derrick EH. ‘Q’ fever, new fever entity: clinical features, diagnosis and labo-
ratory investigations. Med J Aust 1937;2:281-99.
2
.
Burnet FM, Freeman M. Experimental studies on the virus of ‘Q’ fever. Med
J Aust 1937;2:299-305.
inoculation. In vitro measures of cell mediated and antibody in-
duced immunity are positive after two weeks of vaccination22
3.
Weiss E, Williams JC, Thompson HA. The Place of Coxiella burnetii in the
Microbial World. In: Williams JC, Thompson HA, editors. Q fever: The Biol-
ogy of Coxiella burnetii. Florida: CRC Press, 1991. p. 1-19.
McCaul TF. The Development Cycle of Coxiella burnetii. In: Williams JC,
Thompson HA, editors. Q fever: The Biology of Coxiella burnetii. Florida:
CRC Press, 1991. p. 223-58.
Marrie T. Coxiella burnetii (Q fever). In: Mandell GL, Bennett JE, Dolin R,
editors. Principles and Practice of Infectious Diseases. New York: Churchill
Livingstone, 1995. p. 1727-35.
which supports the observation that the vaccine is clinically
effective after this period of time and not protective against natu-
ral infection beforehand. Only two workers reported mild self-
limiting local reactions to the vaccine. In larger published
vaccination series,11 where subjects were screened for immunity
before vaccination, mild reactions such as tenderness and ery-
thema at the injection site occurred in 48% and 33% of vaccinees
respectively, with symptoms enduring from one to three days.
Severe reactions consisting of sterile abscesses have been reported
in only two of 5,000 subjects vaccinated in the years 1981 to
4
5
6
.
.
.
Benenson AS. Q fever (query fever). In: Benenson AS, editor. Control of
Communicable Diseases Manual. Washington(DC): American Public Health
Association, 1995. p. 379-83.
7
8
.
.
.
Penttila IA, Harris RJ, Storm P, et al. Cytokine dysregulation in post-Q fever
fatigue syndrome. Q J Med 1998;91:549-60.
Marmion BP, Shannon M, Maddocks I, et al. Protracted debility and fatigue
after Q fever. Lancet 1996;347:977-8.
9
1
Raoult D, Marrie T. Q fever. Clin Infect Dis 1995;20:489-96.
1
989. One of these subjects had equivocal pre-vaccine immunity.
The optimal time to vaccinate workers is at least two weeks in
0. Smadel JE, Snyder MJ, Robbins FC. Vaccination against Q fever. Am J Hyg
1948;47:71-81.
1
1
1. Ormsbee RA, Marmion BP. Prevention of Coxiella burnetii Infection. Vaccines
and Guidelines for Those at Risk. In: Marrie T, editor. Q fever: The Disease.
Vol 1. Florida: CRC Press, 1990. p. 225-48.
2. Marmion BP, Ormsbee RA, Kyrkou M, et al. Vaccine prophylaxis of abattoir-
associated Q fever: eight years’ experience in Australian abattoirs. Epidemiol
Infect 1990;104:275-87.
advance of occupational exposure. In this outbreak the vaccine
was highly effective when given in advance of exposure, with no
illness reported in vaccinated subjects. By contrast, post-expo-
sure vaccination did not confer any significant protection. Post-
exposure vaccination was instituted late in the natural history of
this outbreak (at least 10 days after the likely period of exposure)
when most cases had already progressed to illness or were in the
late stages of their incubation period.
1
1
3. Q Vax. In: Caswell A, editor. MIMS. Singapore: Chris Wills, 1998.
4. Ackland JR, Worswick DA, Marmion BP. Vaccine prophylaxis of Q fever: A
follow-up study of the efficacy of Q-Vax (CSL) 1985-1990. Med J Aust
1
994;160:704-8.
1
1
5. Marmion BP, Ormsbee RA, Kyrkou M, et al. Vaccine prophylaxis of abattoir
associated Q fever. Lancet 1984;ii:1411-4.
6. Marmion B. Q fever. Zoonotic Diseases in the Meat Industry. Report to the
Minister for Resources by the Zoonotic Diseases Working Party: Canberra:
Department of Primary Industries and Energy, 1989. p. 14-6.
Increased efforts to promote vaccine utilisation in the work place
need to be considered. Discounts on insurance premiums paid by
industries that vaccinate their workforce could alleviate the costs
to industry of vaccination. Maintaining vaccination standards by
regular audits, streamlining screening and vaccination by the
maintenance of a central register, and making Q fever vaccina-
tion protocols a part of standard occupational health and safety
manuals would serve to lift the profile of vaccination in at-risk
occupational groups.
1
1
7. Q Fever. Information Kit for the Australian Meat Industry. Prepared for the
Meat Research Corporation by Julie O’Neill, Inverell, NSW, 1997.
8. Epi-info: word processing, database and statistics program for Public Health
[computer program]. Version 6.04b. Atlanta(GA): Centre for Disease Control
and Prevention, 1997.
1
9. Aitken ID, Bogel K, Cracea E, et al. Q fever in Europe: Current aspects of
aetiology, epidemiology, human infection, diagnosis and therapy. Infection
1
987;5:323-7.
2
2
2
0. Lopez E, Ascher M, Roberto R, et al. Q fever among slaughterhouse workers
– California. MMWR 1986;35:223-36.
1. Dupuis G, Petite J, Peter O, et al. An important outbreak of human Q fever in
a Swiss alpine valley. Int J Epidemiol 1987;16:282-7.
2. Izzo AA, Marmion BP, Worswick DA. Markers of cell-mediated immunity
after vaccination with an inactivated, whole-cell Q fever vaccine. J Infect Dis
1
988;157:781-9.
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