The name Q fever (coxiellosis) designates infections with the bacterium Coxiella burnetii. As a rule, clinical signs in animals are mild. The pathogen is mainly important as causative agent of infertility and abortions in ruminants and as zoonotic agent. In humans, the causative agent of Q fever causes flu-like symptoms. Therefore it is likely that not all cases are detected. The annual number of human Q fever cases varies. The main reservoir for Coxiellae are ruminants. Here, the pathogen mainly causes abortions. During birth, large amounts of Coxiellae are excreted. Furthermore, the pathogen is excreted via milk, feces and urine. Coxiellae are transmitted aerogenically via aerosols or infected dust. Another reservoir for C. burnetii are infected ticks (natural foci). Farmers, shepherds, shearers and veterinarians are particularly at risk. Infections can also occur along sheep trails. Q fever is suspected in a holding, when serological or milk serological test results, particularly in combination with clinical signs, indicate the presence of the pathogen.
The tasks of the National Reference Laboratory for Q Fever include:
- Participation in national and international workgroups and research projects
- Research for improvement and standardization of Q fever diagnostics as well as on pathogenesis, immunization and epidemiology
- Collection and analysis of epidemiological data
- Training in diagnostic methods
- Coordination of scientific studies with other laboratories
- Publication and spread of information
Strengthen of the co-operation with Egypt in the field of bio-security
Neubauer, H., Parvizi, O., Mayada Gwida, Mertens, K., Henning, K.
in cooperation with the Department of Hygiene and Zoonoses, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt.
The aim of the project is to enable Egypt by implementation of modern animal disease programs to diagnose and control zoonoses in humans and animals. The modus operandi is based on
- education of experts,
- seroprevalence studies,
- typing of isolates to identify infection chains,
- elaboration of a catalogue of measures.
Inactivation of Coxiella burnetii during the short-time heating of milk
Henning, K., Wittwer, M., Mertens, K., and Hammer, P.
The gram negative obligate intracellular bacterium Coxiella burnetii, is the causative agent of Q fever, a well-known zoonosis. The source of human infection is often unknown, although sheep and goats are frequently related to outbreaks of human Q fever. Ruminants shed C. burnetii in urine, feces, birth products, and milk. Investigations have shown sero-prevalences in cattle up to 79 %. Coxiella can be shed via milk over months. The regulations for the pasteurization of milk were developed during the 50ties and 60ties of the last century. According the Codex Alimentarius heating of milk has to lead to a reduction of C. burnetii of 5 log-steps (99,999 %). The aim of the study is to investigate if this regulation is still up-to-date. Differences in the heat resistance of different Coxiella strains will be investigated by sequencing.
Q fever - GermAn Interdisciplinary Program for reSearch (Q-GAPS) – Modelling uptake and organ distribution of the Q fever agent Coxiella burnetii by ticks and possible effects on virulence
Mertens, K. and Henning, K.
Transmission of Coxiella burnetii occurs primarily through the aerosolic route and is strongly associated with infected herds of sheep and goats in close proximity to urban areas. This route might not be exclusive for Coxiella, since the prevalence of Coxiella-positive tick species in the field is comparably high to other vector-borne pathogens and several tick species show vector competence in experimental settings. To clarify the role of ticks as vectors, an artificial tick feeding model will be adapted and vector competence determined as the ability to acquire and to transmit the pathogen. Furthermore, organ distribution of Coxiella over time within the tick will be monitored to determine main excretion routes and the possibility of the salivary cycle. To test the hypothesis that genetic differences of Coxiella are associated with isolate-specific virulence and pathogenic potential, field isolates originating from various hosts will be categorized by using MLVA-typing/whole genome sequencing and plasmid content.
Joint research project: Better diagnostics as countermeasure against zoonotic pathogens. Acronym BruCox
Mertens, K. und Melzer, F.
The main goal of the project is the development of highly specific and sensitive pen-side-tests/point of care tests as mobile used diagnostic test systems for direct detection of zoonotic pathogens. Test systems will be developed for the etiological agents of Q fever and Brucellosis, two zoonotic diseases of high public health and economic relevance. Annually occurring small outbreaks of Q fever in sheep and goat herds as well as several suspicious cases of Brucellosis in wild and domestic pigs cause high economic losses and negatively affect global trading. The economic costs of human infections with these two pathogens needing long-term treatments are hard to calculate. Therefore, mobile diagnostic test systems, applied locally and directly at the target animal will contribute to the elimination of reservoirs and inhibit further spreading. Monoclonal antibodies (mAbs) specific for bacterial proteins (ORFeome) which play a role during host-pathogen interaction (transcriptome) will be used for the development of mobile lateral flow test systems. These tests systems will contribute to a better surveillance and implementation of counter measures against zoonotic pathogens.
Project: „Identification of C. burnetii immunodominant proteins and epitopes for development of new Q fever diagnostitics in ruminants“
Gerlach C., Mertens K.
Veterinary Q fever diagnostics have some deficits leading, along with the asymptomatic shedding, to frequent human epidemics. A major problem in diagnostics is the occurrence of serological negative shedders. Current serology is based on whole cell antigens and thus includes plenty of conserved proteins, but lacks well defined and reproducible epitopes, which together impair sensitivity and specificity.
The aim of this study is to develop an epitope peptide array for more sensitive and specific serological Q fever detection in ruminants. Therefore C. burnetii immunodominant proteins are selected from literature based on number of publications and analyzed sera. On the other hand antigens are identified by proteomics with collected field sera from Q fever infected animals. From these immunogenic proteins B cell epitopes are predicted in silico and selected for amino acid sequence identity within the species and sufficient polymorphism to related pathogens. Selected peptides will be evaluated by ELISAs with ruminant field sera for sensitive Q fever detection in the absence of cross-reactions.