01 February 1997
In order to give a European overview, members of the editorial
board of Eurosurveillance were asked a few questions about
the surveillance of Q fever in the countries they represent and
the possible occurrence of similar outbreaks in recent years.
We received reports from Belgium, Denmark, England and Wales,
France, Germany, Ireland, Italy, the Netherlands, Portugal, Scotland,
and Spain. Four representatives gave additional comments.
Belgium and the Netherlands have two surveillance systems: mandatory
notification by physicians and a laboratory reporting system.
In Belgium, cases of Q fever are included in notifications of
rickettsiosis. England and Wales, Scotland, and Spain collect
data on Q fever only through laboratory reports of Coxiella
burnetii infections. Germany has a specific mandatory notification
system for Q fever. Italy and Portugal have a mandatory notification
system for all rickettsial infections including Q fever (in Italy
thyphus exanthematicus and in Portugal Boutonneuse fever are notified
separately). Ireland, Denmark, and France have no reporting scheme
for Q fever. In Denmark, however, requests for serological tests
are collated at a national laboratory and in France they are centralised
at a national reference centre for rickettsiosis.
Only a few cases of Q fever occurred each year in Belgium, Denmark,
Ireland, the Netherlands, Portugal, and Scotland, and no outbreaks
similar to those described in this issue were identified in recent
years. In England and Wales, four outbreaks were reported (June
to August 1981, 29 cases in Gwent (1); April to June 1983, 25
cases in Oxfordshire (2); Spring 1989, 147 cases in the West Midlands
(3); March 1992, 4 cases (4)). In Spain, between 1990 to 1996,
ten outbreaks were reported among which three were quite large
(14, 11, and 48 cases). In Italy, an outbreak occurred in the
Veneto region (summer and autumn 1993, 58 cases (5)). In Germany
since 1990, 27 to 100 cases are reported each year and two outbreaks
occurred in recent years (1992, 80 cases in Berlin; 1993, 121
cases in Hessen).
Some additional information was received about possible modes
of transmission. Two Q fever outbreaks in England and Wales and
one in Italy were investigated using case control studies (1,3,5).
In Gwent, Wales, the likeliest explanation was that farm vehicles
spread contaminated straw, manure, or dust, and residents
of the affected area became infected by inhaling infected dust
particles. In the West Midlands, the geographical distribution
of cases in an urban area close to many farms where lambs and
calves were being born suggested that infected aerosols from parturient
sheep were spread by the wind. In the Veneto region, Italy, the
case control study showed a significant association with exposure
to flocks of sheep. Three flocks of sheep, which passed through
the outbreak area between late May and early June in the annual
transmigration, were shown to be infected. Birth products were
not incriminated since this outbreak began months after the birthing
season. Contamination of soil through infected urine and faeces
and dry season may have played a role in airborne transmission.
In Spain, cases in most outbreaks were suspected to have been
infected by contact with contaminated livestock: in 1990, 14 cases
were found among workers in a slaughterhouse, and in 1992, 48
cases were found in a military community that camped in a cowshed.
In Germany, two outbreaks were investigated; in 1992 one occurred
in a Berlin research facility where sheep were kept and the other
in 1993 in a rural area in Hessen. In both outbreaks infected
sheep were suspected to be the source of the outbreaks.
K de Schrijver (Gezondheidsinspectie, Antwerpen, Belgium): Four
cases were identified by the laboratory system in 1995. The low
level of reporting may be explained by the fact that symptoms
of Q fever are quite non specific and clinicians rarely request
serological tests for this illness.
R Pebody (writing for England and Wales, EPIET fellow currently
based at the National Public Health Institute, Helsinki, Finland):
Large outbreaks of Q fever have rarely been detected. The source
of infection often remains speculative. Although both of the outbreaks
detected in England and Wales were thought to be related to the
inhalation of infected particles from nearby areas, the evidence
was inconclusive. In the German outbreak reported here the combination
of the descriptive epidemiology and a cohort study, positive coxiella
serology in the sheep flock, and appropriate weather conditions
provided strong evidence that the outbreak was related to airborne
transmission of sheep birth products from a neighbouring farm.
This article is an important addition to documenting the epidemiology
of Coxiella burnetii infection. Coxiellosis is often asymptomatic
in farm animals, but can cause considerable morbidity in humans.
Control and eradication measures require a multidisciplinary approach
from farmers, veterinarians, and public and environmental health
M Esveld (Infectieziekten Bulletin, The Netherlands): In
some human cases no relation with classical sources
can be found and possible new sources must be sought. In a serological
study of dogs and cats, 13.2% (91/688) of dogs and 10.4% (46/441)
of cats were found to be positive for specific antibodies against
C. burnetii (7). This implies that cats and dogs may be
a source of infection. Special attention to hygiene during parturition
may be needed.
G Salamina (Istituto Superiore di Sanità, Italy): In Italy
the case definition for rickettsiosis used for surveillance purposes
specifies both clinical symptoms and serological confirmation.
Therefore, it would be possible, in theory, to identify cases
of Q fever among notifications of rickettsiosis to the Ministry
of Health. However to date this information has not been published.
1. Salmon MM, Howells B, Glencross EJG, Evans AD, Palmer SR. Q
fever in an urban area. Lancet 1982; i: 1002-4.
2. Winner SJ, Eglin RP, Moore VIM, Mayon-White RT. An outbreak
of Q fever affecting postal workers in Oxfordshire. J Infect
3. Smith DL, Ayres JG, Blair I, Burg PS, Carpenter MJ, Caul EO,
et al. A large Q fever outbreak in the West Midlands: clinical
aspects. Resp Med 1993; 87: 509-16.
4. Q fever in the isle of Wight. Commun Dis Rep CDR Wky
5. Manfredi Selvaggi T, Rezza G, Scagnelli M et al. Investigation
of a Q fever outbreak in Northern Italy. European Journal of
Epidemiology. 1996; 12:403-8.
6. Pebody RG, Wall PG, Ryan MJ, Fairley C. Epidemiological features
of Coxiella burnetii infection in England and Wales: 1984 to 1994.
Commun Dis Rep CDR Rev 1996; 6:R128-32.
7. Houwers DJ, Meer van der M, Dijk van AAHM. Prevalence and incidence
of C. burnetii infections in dogs and cats in the Netherlands
and the region Midden-Holland. Utrecht: Rijksuniversiteit Utrecht,
Faculteit Diergeneeskunde, 1992.