Gert van der Hoek
In Memoriam - Editor, Senior Moderator
It is important to have a right diagnosis for chronic Q-fever patients: they need long-term antibiotic treatment. PCR tests not conclusive .
Clin Infect Dis. 2011 Jun;52(12):1431-6.
Follow-up of 686 Patients With Acute Q Fever and Detection of Chronic Infection.
van der Hoek W, Versteeg B, Meekelenkamp JC, Renders NH, Leenders AC, Weers-Pothoff I, Hermans MH, Zaaijer HL, Wever PC, Schneeberger PM.
Epidemiology and Surveillance Unit, Center for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven.
Abstract
Background. Recent outbreaks in the Netherlands allowed for laboratory follow-up of a large series of patients with acute Q fever and for evaluation of test algorithms to detect chronic Q fever, a condition with considerable morbidity and mortality.
Methods.
For 686 patients with acute Q fever, IgG antibodies to Coxiella burnetii were determined using an immunofluorescence assay at 3, 6, and 12 months of follow-up. Polymerase chain reaction (PCR) was performed after 12 months and on earlier serum samples with an IgG phase I antibody titer ≥1:1024.
Results.
In 43% of patients, the IgG phase II antibody titers remained high (≥1:1024) at 3, 6, and 12 months of follow-up. Three months after acute Q fever, 14% of the patients had an IgG phase I titer ≥1:1024, which became negative later in 81%. IgG phase I antibody titers were rarely higher than phase II titers. Eleven cases of chronic Q fever were identified on the basis of serological profile, PCR results, and clinical presentation. Six of these patients were known to have clinical risk factors at the time of acute Q fever. In a comparison of various serological algorithms, IgG phase I titer ≥1:1024 at 6 months had the most favorable sensitivity and positive predictive value for the detection of chronic Q fever.
Conclusions.
The wide variation of serological and PCR results during the follow-up of acute Q fever implies that the diagnosis of chronic Q fever, necessitating long-term antibiotic treatment, must be based primarily on clinical grounds. Different serological follow-up strategies are needed for patients with and without known risk factors for chronic Q fever.
Pubmed
Clin Infect Dis. 2011 Jun;52(12):1431-6.
Follow-up of 686 Patients With Acute Q Fever and Detection of Chronic Infection.
van der Hoek W, Versteeg B, Meekelenkamp JC, Renders NH, Leenders AC, Weers-Pothoff I, Hermans MH, Zaaijer HL, Wever PC, Schneeberger PM.
Epidemiology and Surveillance Unit, Center for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven.
Abstract
Background. Recent outbreaks in the Netherlands allowed for laboratory follow-up of a large series of patients with acute Q fever and for evaluation of test algorithms to detect chronic Q fever, a condition with considerable morbidity and mortality.
Methods.
For 686 patients with acute Q fever, IgG antibodies to Coxiella burnetii were determined using an immunofluorescence assay at 3, 6, and 12 months of follow-up. Polymerase chain reaction (PCR) was performed after 12 months and on earlier serum samples with an IgG phase I antibody titer ≥1:1024.
Results.
In 43% of patients, the IgG phase II antibody titers remained high (≥1:1024) at 3, 6, and 12 months of follow-up. Three months after acute Q fever, 14% of the patients had an IgG phase I titer ≥1:1024, which became negative later in 81%. IgG phase I antibody titers were rarely higher than phase II titers. Eleven cases of chronic Q fever were identified on the basis of serological profile, PCR results, and clinical presentation. Six of these patients were known to have clinical risk factors at the time of acute Q fever. In a comparison of various serological algorithms, IgG phase I titer ≥1:1024 at 6 months had the most favorable sensitivity and positive predictive value for the detection of chronic Q fever.
Conclusions.
The wide variation of serological and PCR results during the follow-up of acute Q fever implies that the diagnosis of chronic Q fever, necessitating long-term antibiotic treatment, must be based primarily on clinical grounds. Different serological follow-up strategies are needed for patients with and without known risk factors for chronic Q fever.
Pubmed