Tularemia in Germany—A Re-emerging Zoonosis

Abstract

Tularemia, also known as “rabbit fever,” is a zoonosis caused by the facultative intracellular, gram-negative bacterium Francisella tularensis. Infection occurs through contact with infected animals (often hares), arthropod vectors (such as ticks or deer flies), inhalation of contaminated dust or through contaminated food and water. In this review, we would like to provide an overview of the current epidemiological situation in Germany using published studies and case reports, an analysis of recent surveillance data and our own experience from the laboratory diagnostics, and investigation of cases. While in Germany tularemia is a rarely reported disease, there is evidence of recent re-emergence. We also describe some peculiarities that were observed in Germany, such as a broad genetic diversity, and a recently discovered new genus of Francisella and protracted or severe clinical courses of infections with the subspecies holarctica. Because tularemia is a zoonosis, we also touch upon the situation in the animal reservoir and one-health aspects of this disease. Apparently, many pieces of the puzzle need to be found and put into place before the complex interaction between wildlife, the environment and humans are fully understood. Funding for investigations into rare diseases is scarce. Therefore, combining efforts in several countries in the framework of international projects may be necessary to advance further our understanding of this serious but also scientifically interesting disease.

Francisella tularensis Periprosthetic Joint Infections Diagnosed with Growth in Cultures

“…There are only limited data on the in vitro antibiotic susceptibility of F. tularensis; however, no major changes in susceptibility rates have been reported. The duration of antibiotic therapy of more common manifestations of tularemia usually does not exceed 3 weeks; however, there have been case reports of prolonged clinical courses of tularemia with the need for repeated antibiotic therapy (14). In all four reported cases of tularemia PJI, the antibiotic therapy was prolonged or repeated, and two of the cases appeared not to respond to the initial course of antibiotics.…”

“…Due to the fact that two out of four patients were hunters, the transmission route could also be through exposure to blood or body fluid with contaminated meat (11). In Germany, between 2002 and 2016, 10 outbreaks of tularemia were associated with contact with wild animals in the context of hunting (14). In all four PJI cases, diagnosis was made by culture-based methods in part with longer incubation times than expected in other pathogens more commonly isolated in PJI (1).…”

First European report of Francisella tularensis subsp. holarctica isolation from a domestic cat

“…In Switzerland, the incidence of tularemia in humans has risen from 0.18/100 000 in 2010 to 1.72 in 2019 [14]. A large outbreak was observed in Sweden in 2019 [15] and in Germany tularemia is also considered a re-emerging disease [16]. A higher frequency of tularemia cases can be related to more sensitive diagnostic procedures, increasing surveillance or spread of the pathogen.…”

First Case of Tularemia Reported in Portugal: Probably of Imported Origin

“…holarctica in different tick species, lagomorphs and in one human sample ( 6 , 18 ). In humans tularemia probably represents a re-emerging disease with a high proportion of undiagnosed cases ( 19 ). Our report represents the first imported tularemia case notified in Portugal.…”