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Letter
Q Fever in Como, Northern
Italy
Domenico Santoro,* Raffaele Giura,* Maria Chiara Colombo,* Paola Antonelli,*
Maria Gramegna,† Oscar Gandola,† and Giulio Gridavilla†
*St. Anna Hospital, Como, Italy; and †Department of Prevention, Azienda
Sanitaria Locale, Como, Italy
Suggested citation
for this article:
Santoro D, Giura R, Colombo MC, Antonelli P, Gramegna M, Gandola O,
et al. Q fever in Como, northern Italy. Emerg Infect Dis [serial online]
2004 Jan [date cited]. Available from: URL: http://www.cdc.gov/ncidod/EID/vol10no1/03-0467.htm
To the Editor: Q fever is a widespread zoonosis caused by the
intracellular gram-negative bacterium Coxiella burnetii Infection
in humans usually occurs through inhalation of contaminated aerosols from
parturient fluids of infected animals or contaminated wool (1).
C. burnetii also forms spores that may survive for months in the
environment in an area where animals have been present, representing a
source of infection for persons without any evident contact with animals
(2). A self-limited febrile illness, Q fever has the
major signs and symptoms of atypical pneumonia and hepatitis. Diagnosis
is based on serologic test results. Recently, outbreaks of Q fever have
been described in urban areas (3,4), affecting people
without any evident risk factor. We describe an outbreak of Q fever in
Como, northern Italy, which affected 133 persons.
From January 2003 to February 2003, over a 5-week period, 16 men and
1 woman from the prison in Como were admitted to the local hospital with
acute pneumonia. At the same time, a 26-year-old man and a 79-year-old
woman living in the same area were admitted with the same diagnosis. On
admission, all the patients had a high-grade fever and reported a dry
cough; 80.0% of patients had a headache, and 70.0% of patients complained
of fatigue and weakness. In a few patients, nausea and abdominal pain
developed after they were hospitalized. Physical examination of the lungs
showed minimal auscultatory abnormalities. Hemoptysis was observed in
four patients. Routine blood examinations were performed. In all patients,
the leukocyte count was normal, with an increase in the erythrocyte sedimentation
rate and elevated C-reactive protein levels. The transaminase levels were
elevated in eight (47.0%) patients, usually two to three times normal
values. Radiographic findings were nonspecific and differed greatly among
the patients, who exhibited single and multiple opacities, diffuse interstitial
pneumonia, and pleural effusion (in one patient). Bilateral involvement
was seen in five (29.4%) patients. All patients received empirical antimicrobial
therapy with a β-lactam antimicrobial drug in association with a
macrolide or an advanced fluoroquinolone, following the guidelines for
community-acquired pneumonia. Patients improved clinically in 48 to 72
hours after antimicrobial drug therapy was started: the fevers resolved
and the inflammatory indexes and liver enzyme levels returned to normal.
An epidemiologic investigation was started by the Department of Prevention,
Azienda Sanitaria Locale, of Como, after it was notified that six patients
with acute pneumonia of unknown cause had been admitted to St. Anna Hospital
during a 6-day period (January 11–17, 2003); all six patients were men
from the Como prison. Investigation showed that the case-patients resided
in different sections of the prison in different rooms; thus, human-to-human
transmission was excluded. After exclusion of Streptococcus pneumoniae,
Legionella spp., Mycoplasma pneumoniae, and Chlamydia
pneumoniae as etiologic agents, the diagnosis of Q fever was made
on the basis of positive serologic results for C. burnetii from
immunofluorescence assay. Further investigation was directed to determine
the source of the epidemic, with a focus on animals in the area surrounding
the prison. We identified two flocks of sheep and other animals that grazed
in the meadows next to the prison from December 2002 to January 2003,
in an annual migration pattern, and a colony of pigeons nesting in the
prison. The first flock of animals was composed of 950 sheep; 50 goats
and 4 dogs accompanied them. The Laboratory of the Zooprofilattico Institute,
Brescia, tested 80 animals from this flock, including both males and females,
chosen randomly. All four dogs were tested. All the animals tested (sheep,
goats, and dogs) were negative for C. burnetii. The second flock
included 748 animals (sheep and goats) and 4 dogs. All these animals were
tested because the biological specimens, collected for another purpose,
were available. In this flock, 255 of 748 animals were positive for C.
burnetii and 2 of the 4 dogs were positive, for a prevalence rate
of 34.2%. We know that a parturient sheep died on December 31, 2002. The
source of the epidemic was declared extinct on March 5, 2003, on the basis
of a negative result of DNA amplification by polymerase chain reaction
assay conducted on animals’ milk, urine, and feces after antimicrobial
drug treatment of the infected animals.
At the same time, in collaboration with physicians of general medicine
in the area, we actively sought patients with pneumonia of unknown etiology
living in the urban area close to the meadows where the flock grazed.
Since the beginning of the epidemic, 133 cases of acute Q fever, defined
as clinical symptoms (high grade fever, dry cough, auscultatory abnormalities,
arthromyalgia, fatigue) plus positive serologic results (immunoglobulin
[Ig] G phase II >1:64; values were included between 1:64 and 1:1024),
were reported to the Department of Prevention, ASL, in Como. Of these,
59 were prisoners, 37 were prison officers, 33 were persons living in
the area in which the flock traveled, and 4 were personnel of the Veterinarian
Service, who participated in performing the autopsy on the sheep. Analysis
of the data showed a prevalence of disease in the prisoners of 10.8% (59/547),
comparable to the prevalence obtained in the guards, 16.5% (37/224) and
significantly lower than that for the residents, 3.2% (33/1,025). These
differences could be ascribed to the prison’s being situated in a natural
setting, with the flock grazing for 1 month in the meadows nearby.
C. burnetii is an infrequent cause of community-acquired pneumonia
in our region. These data suggest that the infected sheep were the source
of this large outbreak. None of the patients had any contact with animals,
except for the Veterinarian Service personnel, which suggests airborne
transmission of infected dust particles from contaminated soil, favored
by the dry weather recorded in that period. To our knowledge, this is
the second outbreak of Q fever reported in northern Italy (5).
Since 1999, neither the Department of Prevention nor the Veterinary Service
had received any reports of Q fever in Como. In Italy, the total number
of cases of rickettsial diseases, which includes Q fever, reported to
the Ministry of Health was 769 in 2002 and 739 in 2001, with 5 and 13
cases, respectively, from Lombardia, which includes Como. This Q fever
epidemic in Como is thus an exceptional event in our area.
The collaboration between epidemiologists and veterinarians of the Department
of Prevention and staff from Saint Anna Hospital allowed us to share epidemiologic
and medical information, which proved useful in diagnosing the outbreak
and treating patients. Our experience emphasizes the necessity of a greater
awareness of this occupational zoonosis in areas with a high rate of urbanization.
Acknowledgments
We thank Alfonso
Panuccio and Piero Marone for testing serology for Coxiella burnetii.
References
- Maurin M, Raoult D. Q
fever. Clin Microbiol Rev 1999;12:518–33.
- Dupont Tissot H, Torres S, Nezri M, Raoult D. A
hyperendemic focus of Q fever related to sheep and wind. Am J Epidemiol
1999;150:67–74.
- Schulze K, Schwalen A, Klein RM, Thomas L, Leschke M, Strauer BE.
Eine Q-fieber
pneumonie epidemie in Dusseldorf. Pneumologie 1996;50:469–73.
- Armengaud A, Kessalis N, Desenclos JC, Maillot E, Brousse P, Brouqui
P, et al. Urban
outbreak of Q fever, Briancon, France, March to June 1996. Euro
Surveill 1997;2:12–3.
- Selvaggi TM, Rezza G, Scagnelli M, Rigoli R, Massu M, De Lalla F,
et al. Investigation
of a Q-fever outbreak in Northern Italy. Eur J Epidemiol 1996;12
403–8.
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