CASE REPORT: First isolation of Francisella tularensis holartica from a domestic cat in Europe

4 January 2021 – News

Tularemia is a bacterial zoonosis which has been increasingly reported in humans, in Europe. There are four subspecies of Francisella tularensis (its etiological agent) and their isolates generally come from humans, lagomorphs, or rodents. However, there are a few cases including wild carnivore mammals.
In March 2019, the first isolate of Francisella tularensis from a 9-year-old male neutered outdoor cat, living in Switzerland, was reported. The patient was presented to the Small Animal Clinic of the University of Bern for the usual maintenance of his subcutaneous ureteral bypass, placed four years before. Besides the notorious weight loss and the concomitant chronic kidney disease, the clinical exam and anamnesis were satisfactory. A urine sample was taken, and urinalysis parameters were assessed, revealing some important alterations. A routine culture was also performed and, after four days, a confluent growth of F. tularensis was observed. PCR also confirmed the presence of this bacteria.
Doxycycline was prescribed and three months later the urinary cultures were negative. Nevertheless, the treatment took longer than usual due to the persistent positive PCR and the possible zoonotic risk.
Both the cat and geographically related hare isolates were subjected to genome sequencing and single-nucleotide polymorphism analyses, aiming to investigate a possible epidemiological cconnection with wildlife. A close phylogenetic relationship was found, supporting an epidemiological link between these cases.
The unexpected subclinical bacteriuria of this case makes it unique and raises some questions. In fact, cats’ urine is not routinely analyzed for this bacterium, so previous cases might have been missed and the potential risk for owners and veterinary staff needs to be assessed.

Kittl, S. et al. (2020). First European report of Francisella tularensis subsp. holarctica isolation from a domestic cat. Veterinary Research, 51:109. https://doi.org/10.1186/s13567-020-00834-5