2023-01-08 23:00:00
Q fever can be transmitted from animals to humans, in whom it can cause severe flu syndrome with possible hepatic or pulmonary complications. In rare cases, the disease can become persistent and cause, for example, endocarditis or chronic fatigue syndrome. The main reservoirs of this zoonosis are ruminant farms. It is the main source of infection for humans, the transmission of Q fever between humans being exceptional.
A collaboration combining the animal aspect and the human aspect
The study published in November 2022 in the journal Frontiers in Microbiology is the result of a collaboration between the animal Q fever unit of the Anses laboratory in Sophia Antipolis, which is thenational reference laboratory (LNR) and for the World Organization for Animal Health (WHOA), and the national reference center (CNR) on Q fever, hosted by the Mediterranean Infection University Hospital Institute in Marseille. The NRL is responsible for the animal aspect of Q fever, while the CNR takes care of the human aspect.
ANSES provided whole genome sequences of strains of Coxiella burnetii isolated from ruminants. These strains completed the collection of bacteria from patients kept by the CNR. The research work carried out by the two partners constitutes the largest genetic analysis in the world carried out on Coxiella burnetii : 75 genomes have been sequenced, including 65 new ones.
The comparison of the genomes of the bacterial strains made it possible to obtain its pangenome, that is to say the parts of the genome common to all strains. The researchers also deciphered specific parts of certain strains and showed that some were linked to clinical signs or specific geographic areas.
Better understand the risks of transmission and exposure
« These works are the first step of a long-term project on Q feverexplains Elodie Rousset, deputy head of the Animal Q Fever unit and head of the NRL. In 2020, we signed an agreement with the national reference center to strengthen the “one health” approach to work on Q fever. We are looking for new methods to facilitate the isolation and sequencing of Q fever strains. C. burnetii. Indeed, the bacteria has so far been difficult to isolate and cultivate. »
ANSES also works closely with a team from Inrae, the epidemiology of animal and zoonotic diseases joint research unit. The objective of this collaborative work is to continue to increase the collections of strains, in particular to have strains of Coxiella burnetii isolated from patients and from farms in the same geographical area. This will make it possible to better understand transmission scenarios and exposure risks, to quickly detect certain hyper-virulent or hyper-disseminable strains, and if necessary to trace the origin of a possible epidemic.
With this in mind, the Animal Q Fever unit is also participating in the European Q-Net-Assess project, which will start with six other organizations from six different countries. It aims to develop and share harmonized methodologies, from the collection of samples in the field to the genetic analysis of strains. Objective: to constitute a large epidemiological and genetic database strains of Coxiella burnetii on a European scale. Its international OMSA reference mandate allows the Anses Q Fever unit to position itself as a privileged interlocutor in these European and international projects.
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