Q fever is a world-wide zoonosis, produced by Coxiella burnetti, a microorganism belonging to the Riskettsiaceae family. Q fever can appear as a non localized feverish disease, as a feverish syndrome with hepatic impairment or as an atypic pneumonia [1, 2]. The form of presentation varies between different geografic areas, thus, feverish form is more prevalent in Australia [3], while the hepatic one is prevalent in France [4] and the pneumonic one in Nova Scotia (Canada) [5]. In order to know which is the most common presentation pattern of Q fever in our area, we have checked all cases diagnosed between 1 January, 1984 and 31 December, 1996, in the province of Soria, situated in northern Spain. A suggestive clinical feature plus antibody detection against Coxiella burnetti were used as diagnostic criteria. The techniques used for serum diagnosis were complement fixation and/or indirect immunofluorescence. Two samples of sera were obtained in all cases, one during the acute phase of the disease, another 2-4 weeks after. Those cases in which seroconversion or a 4-fold antibody titer rise were found, were considered positive. Thirteen cases of Q fever were diagnosed. Patient age at the time of diagnosis ranged from 10 to 41 years old, with a mean age of 26.72 ? 8.05. Of all the Q fever cases, eleven were men and two women. Pneumonia was the most common presentation pattern, counting 10 cases. Another three were a feverish syndrome without any focus and with an intense headache, a feverish form with hepatitis, and a chronic endocarditis. Like in other areas of northern Spain, pneumonia was the most common form of Q fever. Thus, in a group of 60 patients, 75% were pneumonia [6], in a family outbreak of 5 cases, 3 (60%) presented pneumonia [7] and of 492 Q fever cases diagnosed between 1984 and 1991, 265 (54%) had pneumonia [8]. On the other hand, in central and southern regions of Spain, relative prevalence of pneumonia went down, the hepatic form being the most frequent [9, 10]. All our cases presented as an atypical pneumonia with alveolar infiltrate, with cough in four cases and headache in three. Four patients also had chest pain and none had hemoptysis. Only in two cases, contact with animals or derived products could be found as epidemiologic data explaining how the disease was transmitted. Animals infected with C. burnetti are usually the most important source of infection. Man can be infected by aerosol inhalation, or milk or fresh contaminated cheese ingestion [1, 2, 11]. This variability in the form of clinical presentation of Q fever has been related with the presence of different strains of C. burnetti in the different geographic areas and with plasmids that would regulate the virulence of the strains [2]. It has also been postulated that different clinical patterns would be related to different ways of disease transmission. So, in those cases in which C. burnetii is transmitted by milk or dairy products ingestion, both hepatitis and pneumonia can occur, and in those cases in which the organism is acquired by air inhalation, only pneumonia would occur [12].
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Jun 1, 2004
A Liptakova + 5
Open Access
