Seroepidemiological survey of Q fever in León province, Spain

Comprehensive literature review of the sources of infection and transmission routes of Coxiella burnetii, with particular regard to the criteria of "evidence-based medicine"

The present review aims to compile the currently available literature since 1936 according the sources of infection of the Q fever pathogen (Coxiella (C.) burnetii) as well as the transmission from animal to man and also from human to human. In terms of quality and validity, the existing publications were reviewed systematically. For this purpose, firstly a structured literature search was carried out using various databases and search engines supplemented by a manual literature search. For critical appraisal, 1444 relevant publications were identified for the moment and evaluated. A total of 73 publications describing a transmission of C. burnetii from animals to man or a human-to-human transmission were discovered. The identified publications are 29 case series, two case reports, 21 cohort studies and 21 case-control studies. With regard to the sources of infection, 25 publications describing the transmission of C. burnetii from sheep to humans could be identified.

Waning population immunity prior to a large Q fever epidemic in the south of The Netherlands

Historical survey data suggest that the seroprevalence of antibodies against Coxiella burnetii in the general population of The Netherlands decreased from more than 40% in 1983 to 2·4% in 2007, just before the start of the large 2007-2010 Q fever epidemic. To assess whether the sharp decline in seroprevalence was real, we performed a cross-sectional study using historical samples. We tested samples using a contemporary commercial indirect immunofluorescence assay. In plasma samples from the south of The Netherlands from 1987, we found an age- and sex-standardized seroprevalence of 14·4% (95% confidence interval 11·2-18·3). This was significantly lower than a 1983 estimate from the same area (62·5%), but significantly higher than 2008 (1·0%) and 2010 (2·3%) estimates from the same area. The study suggests that there was a steady and sharp decline in Q fever seroprevalence in the south of The Netherlands from 1987 to 2008. We assume that seroprevalence has decreased in other parts of The Netherlands as well and seroprevalence surveys in other European countries have shown a similar declining trend. Waning population immunity in The Netherlands may have contributed to the scale of the 2007-2010 Q fever epidemic. For a better understanding of the infection dynamics of Q fever, we advocate an international comparative study of the seroprevalence of C. burnetii.

[Seroepidemiology of Coxiella burnetii infection among blood donors in Albacete]

INTRODUCTION

The objectives of this study were to determine the prevalence of antibodies to Coxiella burnetii among blood donors and to examine the epidemiological characteristics of C. burnetii infection in Albacete, Spain.

METHODS

A total of 863 serum samples were collected from blood donors aged 18-65 years. Donor samples were stratified by age, sex, and residence (rural or urban). IgG and IgM titers to the C. burnetii phase II antigen were determined by an indirect immunofluorescence assay.

RESULTS

The prevalence of anti-phase II IgG was 23.1%, and three (0.3%) donors had positive IgM titers. Men were more frequently seropositive than women (29% vs. 18%; OR: 1.85; 95% CI: 1.34-2.56), and this difference was not related to differential occupational exposure to animals. Pet ownership had no impact on seroprevalence. In contrast, occupations involving contact with domestic ungulates were associated with a higher seroprevalence (OR: 2.39; 95% CI: 1.04-5.48). Nevertheless, 90% of seropositive donors reported no contact with farm animals.

CONCLUSION

Our results show that C. burnetii infection is highly endemic in Albacete and that most infections are not linked to specific occupational exposure in this area. The high prevalence of antibodies to C. burnetii among blood donors indicates the advisability of studies to determine the risk of transfusion-transmitted Q fever in endemic areas.

Epidemiological study of Q fever in humans, ruminant animals, and ticks in Cyprus using a geographical information system

A cross-sectional study of Q fever was conducted in a representative sample of the human and animal population in Cyprus in order to assess the seroprevalence of Q fever and the prevalence of related risk factors. A total of 583 human and 974 ruminant animal serum samples were collected and tested for the detection of antibodies against Coxiella burnetii phase II antigen using an indirect immunofluorescent assay. One hundred forty-one ticks were collected from the infested animals examined; the polymerase chain reaction and the shell-vial technique were used to detect and isolate C. burnetii. Standardized questionnaires were used to obtain information concerning inhabitants and their animals. A geographical information system was used to identify high-risk regions. The prevalence of IgG antibodies against C. burnetii phase II antigen was estimated at 52.7% for humans, 48.2% for goats, 18.9% for sheep, and 24% for bovines. C. burnetii was detected in 11 (7.8%) ticks. Using the geographical information system, two villages were identified as high-risk regions on the basis of high seroprevalence rates of IgG antibodies in humans and animals. Risk factors related to Q fever seropositivity were identified by logistic regression analysis and included age, residence, occupation, use of manure in the garden, ownership of animals (especially goats), and the presence of tick-infested or aborting animals. Q fever poses an occupational hazard to humans living in close contact with sheep and/or goats. In parallel, ticks should be considered an important aspect in the epidemiology of Q fever and should be further studied to better elucidate their role.

Coxiella burnetii and milk pasteurization: an early application of the precautionary principle?

Stringency of milk pasteurization has been established on requirements for Coxiella burnetii as being the most heat-resistant organisms of public heath significance. This paper discusses the estimation of the efficiency of pasteurization time/temperature combinations as required in regulations for food safety. Epidemiological studies have been interpreted as C. burnetii being a significant pathogen causing clinical disease through ingestion of milk. The paper examines the evidence and challenges the designation of C. burnetii as a foodborne pathogen. Consequently it questions the need for pasteurization parameters to be established on its heat resistance characteristics.

Colecistitis alitiásica: una forma infrecuente de presentación de fiebre Q

Acute acalculous cholecystitis is a very rare clinical presentation of Q fever. We report the case of a 38-year-old man who presented with fever associated with elevation of liver enzyme levels and thickening of the gallbladder wall on abdominal ultrasonography and who was initially diagnosed with acute acalculous cholecystitis. Due to the persistence of fever and transaminase elevation despite antibiotic treatment, a liver biopsy was performed. Characteristic "doughnut" epithelioid granulomas were observed, suggesting a diagnosis of granulomatous hepatitis caused by Q fever, which was confirmed by serological methods. Treatment with doxycycline was commenced and the patient subsequently showed rapid clinical improvement, with disappearance of fever and normalization of liver enzyme levels. We review 8 cases of acute cholecystitis associated with Q fever published in the literature and stress the importance of liver biopsy in the etiological diagnosis of patients with prolonged fever and abnormal liver function tests.