Q fever, caused by the obligate intracellular bacterium Coxiella burnetii, is endemic in Europe and a notifiable animal disease. Ruminants are considered as the main reservoir for infections with C. burnetii in humans (zoonosis). In these animals, an infection is usually clinically inapparent, but can lead to abortions and infertility. In cattle, infections are associated with metritis and infertility. Abortions are rare. In sheep and goats, an infection can result in late abortions and the birth of weak offspring. Comparatively, the abortion rate is higher in goats than in sheep.
In ruminants, pathogen excretion in birth materials (afterbirth, amniotic fluid, lochia) can be very high. The pathogen is also excreted in milk, urine, and feces. C. burnetii exhibits some resistance to desiccation and remains infectious in the environment for an extended period of time. Transmission, including to humans, occurs primarily through inhalation of contaminated aerosols and dusts. Ruminants are important food suppliers and the prevention of zoonoses is a high priority. Only in a One Health approach, which comprehensively considers the interrelationships between animals, humans, environment and health, can zoonoses be contained.
An assessment of antibiotic resistance (AMR) plays only a minor role for C. burnetii. A corresponding classification according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) or the Clinical and Laboratory Standards Institute (CLSI) is not available and standardized criteria for resistance testing are lacking.
Climate change, renaturation, the near-natural design of green spaces, but also a reduced use of insecticides in organic agriculture may influence the occurrence of ticks and their pathogenic cargo. C. burnetii was originally isolated from a Dermacentor andersonii tick, however, which role ticks play in the spread of Q fever is still not fully understood. Despite this, it has been shown that native ticks excrete the pathogen in their feces.
Q fever – GermAn Interdisciplinary Program for reSearch
- Q-GAPS –
Q-GAPS is an interdisciplinary consortium with extraordinary expertise, competence and breadth of expertise. The One Health approach aims to analyze the complex interrelationships between humans, animals, the environment, and health, as well as to promote close collaboration among the professions involved in public health and veterinary medicine. Q-GAPS focusses on questions related to the epidemiology, immunology, pathogenesis, surveillance and control of Coxiella burnetii. All results obtained will be incorporated into a Q-fever guideline to assist the public health service in the detection, surveillance, and control of Coxiella burnetii.
At FLI, questions on vector competence of ticks for C. burnetii as well as work on semi-quantitative proteomic analysis of virulent field isolates to characterize the isolate-specific virulence will be addressed. Isolates from different host species and infection courses are used for this purpose. The uptake and excretion of these selected virulent isolates will be compared to previously obtained data with the avirulent C. burnetii isolate to analyze the vector competence of ticks.
Comparative analysis of bacterial mechanisms essential for intracellular replication will be performed using semi-quantitative proteomic analysis. Macrophages and trophoblasts, which represent the target cells in the host, will be used as infection models. By comparing the bacterial replication, invasion and expression, differences will be identified which will contribute to the understanding of isolate-specific virulence. Furthermore, the applicability of bacterial marker proteins for risk assessment in outbreaks will be determined.
Improved molecular monitoring and assessment of host adaptation and virulence of Coxiella burnetii in Europe.
Our understanding of the extent to which Q fever manifestation depends on C. burnetii genotype is very limited. Due to variable and non-standardized methods, current typing provides little information. Whole genome sequencing offers an alternative to this, as it is more feasible to standardize and provides comprehensive information. Currently, only a few full-genome sequences of Coxiellaceae have been published, most of which are limited to old laboratory isolates. This is due to the often-difficult isolation of the pathogens from field samples. In the consortium assembled here, experts in Q fever bacteriology, diagnostics and surveillance as well as genomics will create a biobank with as variable C. burnetii-positive sample materials as possible from different host species with as accurate metadata as possible. Isolation methods will be optimized within the project to obtain new and archived isolates for whole genome sequencing. Based on phylogenetic analyses, prototypes will be selected and phenotypically characterized in cell culture, Galleria mellonella larvae and whole blood models. The combination of geno- and phenotypic data should allow the identification of molecular determinants of host range and virulence. The totality of the project results obtained will be translated into recommendations for molecular surveillance of C. burnetii.
Contact person outside the FLI
Konsiliarlabor Q-Fieber
Regierungspräsidium Stuttgart, Abt. 9
Landesgesundheitsamt
Referatsleitung 93, Allgemeine Hygiene und Infektionsschutz
https://www.gesundheitsamt-bw.de/lga/de/kompetenzzentren-netzwerke/qfieber/