Ecology ofFrancisella tularensis

Abstract

Tularemia is a Holarctic zoonosis caused by the gamma proteobacterium Francisella tularensis and is considered to be a vector-borne disease. In many regions, human risk is associated with the bites of flies, mosquitoes, or ticks. But the biology of the agent is such that risk may be fomite related, and large outbreaks can occur due to inhalation or ingestion of contaminated materials. Such well-documented human risk factors suggest a role for these risk factors in the enzootic cycle as well. Many arthropods support the growth or survival of the agent, but whether arthropods (ticks in particular) are obligately required for the perpetuation of F. tularensis remains to be demonstrated. As with most zoonoses, our knowledge of the ecology of F. tularensis has been driven with the objective of understanding human risk. In this review, we focus on the role of the arthropod in maintaining F. tularensis, particularly with respect to long-term enzootic persistence.

Francisella novicida and F. philomiragia biofilm features conditionning fitness in spring water and in presence of antibiotics

“…Besides protecting bacteria against antibiotics, the biofilm formation by Francisella spp. was hypothesized to be key mechanism of environmental survival and persistence, specifically in aquatic habitats which constitute an important ecological niche of these microorganisms [13,23,61]. In line with this scheme, we now report that both strains growing in biofilms were far more resistant to harsh water-based conditions than free-living bacteria, an effect particularly pronounced for the clinical strain of F. philomiragia CHUGA-FP47.…”

Tularemia: a re-emerging tick-borne infectious disease

“…Cottontail rabbits ( Sylvilagus spp.) and ticks are the main reservoirs of type A (Telford and Goethert 2020 ). On the other hand, aquatic rodents (muskrats and beavers) are believed to spread type B.…”

The Impact of Tick-Borne Diseases on the Bone

“…Bone marrow is highly vascularized and innervated and is responsible for the production of red blood cells, granulocytes, platelets, monocytes and lymphocytes [26]. [22] One of the most essential structures in vertebrates is bone, which supports the body, protects vital organs and stores minerals [23]. Bone is a mixture of inorganic content (minerals primarily in the form of hydroxyapatite crystals), organic components such as collagen, cells and proteins, and water [24,25].…”