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The genotypic diversity of Coxiella burnetii in clinical samples obtained from the Dutch Q fever outbreak episodes of 2007-2010 was determined by using a 6-locus variable-number tandem repeat analysis panel. The results are consistent with the introduction of one founder genotype that is gradually diversifying over time while spreading throughout The Netherlands.

Purpose: In 2007, a large goat-farming-associated Q fever outbreak occurred in the Netherlands. Data on the clinical outcome of Dutch Q fever patients are lacking. The current advocated follow-up strategy includes serological follow-up to detect evolution to chronic disease and cardiac screening at baseline to identify and prophylactically treat Q fever patients in case of valvulopathy. However, serological follow-up using commercially available tests is complicated by the lack of validated cut-off values. Furthermore, cardiac screening in the setting of a large outbreak has not been implemented previously. Therefore, we report here the clinical outcome, serological follow-up and cardiac screening data of the Q fever patients of the current ongoing outbreak., Methods: The implementation of a protocol including clinical and serological follow-up at baseline and 3, 6 and 12 months after acute Q fever and screening echocardiography at baseline., Results: Eighty-five patients with acute Q fever were identified (male 62%, female 38%). An aspecific, flu-like illness was the most common clinical presentation. Persistent symptoms after acute Q fever were reported by 59% of patients at 6 months and 30% at 12 months follow-up. We observed a typical serological response to Coxiella burnetii infection in both anti-phase I and anti-phase II IgG antibodies, with an increase in antibody titres up to 3 months and a subsequent decrease in the following 9 months. Screening echocardiography was available for 66 (78%) out of 85 Q fever patients. Cardiac valvulopathy was present in 39 (59%) patients. None of the 85 patients developed chronic Q fever., Conclusions: Clinical, serological and echocardiographic data of the current ongoing Dutch Q fever outbreak cohort are presented. Screening echocardiography is no longer part of the standard work-up of Q fever patients in the Netherlands.

In the Netherlands, there is an ongoing and unparalleled outbreak of Q fever. Rapid and reliable methods to identify patients infected with Coxiella burnetii, the causative agent of Q fever, are urgently needed. We evaluated the performance of different DNA extraction methods and real-time PCR assays that are in use in seven diagnostic or reference laboratories in the Netherlands. A low degree of variation in the sensitivities of most of the developed real-time PCR assays was observed. However, PCR assays amplifying short DNA fragments yielded better results than those producing large DNA fragments. With regard to DNA extraction, the automated MagNA Pure Compact system and the manual QIAamp DNA mini kit consistently yielded better results than either the MagNA Pure LC system and NucliSens EasyMag (both automated) or the High Pure viral nucleic acid kit (manual). The present study shows that multiple combinations of DNA extraction kits and real-time PCR assays offer equivalent solutions to detect C. burnetii DNA in serum samples from patients suspected to have Q fever.

In the Netherlands an increasing number of laboratories are involved in diagnosing acute Q-fever. More uniformity in diagnostics and interpretation is desirable. To enable this, a working group on diagnostics of acute Q-fever was created on the initiative of the National Institute for Public Health and the Environment (RIVM) and the Dutch Association for Medical Microbiology (NVMM). The diagnostics of acute Q-fever includes a diagnostic flow chart (algorithm) consisting of tests for DNA and for antibodies against the antigens that appear in the successive stages of the disease. Reporting of both confirmed and suspected cases of acute Q-fever is obligatory.

Acute Q-fever is a systemic illness which rarely has a fatal outcome. Fatal cases do occur with the chronic form of the disease and associated with endocarditis. This report presents the case of a fatal, acute Q-fever pneumonia in an 11-year-old patient with chronic granulomatous disease. Complement fixation antibody titer rose to 1:1,024 with positive IgM in immunofluorescence. Giemsa stained lung sections and indirect immunofluorescence demonstrated the microorganisms in the tissues. The Coxiella burnetii infection was probably contracted during a holiday trip to rural France. Despite the fact that the patient received a variety of antimicrobial agents with broad spectrum activity against bacteria and fungi, coverage for Q-fever, i.e. chloramphenicol or tetracyclines, was not included.