Tularaemia in Europe: An Epidemiological Overview

Abstract

Tularaemia exists endemically in most European countries. In some areas, such as Finland and Sweden, outbreaks comprising hundreds of cases are recorded at least once a decade. In other areas, outbreaks of such a magnitude occur only occasionally, except in times of war. Between outbreaks, the natural reservoir of the causative agent, Francisella tularensis, is unknown. The organism replicates intracellularly in protozoans. An association of tularaemia to natural water may be of significance in locating the reservoir. Epidemiological work has to date been slow, but is now facilitated by the development of new molecular methods. Due to a variation in numbers of short sequence-tandem repeats in the bacterial genome, individual strains of F. tularensis can today be distinguished.

Tularemia in Deer Mice (Peromyscus Maniculatus) During a Population Irruption in Saskatchewan, Canada

“…Deer mice are nocturnal and secretive, so mortality caused by tularemia is unlikely to be observed in populations at low density. The epidemiology of the disease is extremely diverse (Bell, 1980) and the reservoir for the bacterium is unclear (Tä rnvik et al, 1996). Francisella tularensis is believed to be an obligate host-dependent bacterium (Larsson et al, 2005) and although it is associated with rodents and lagomorphs, it is unclear if these mammals are true reservoirs of the bacterium (Ellis et al, 2002).…”

“…Humans have been infected with type B tularemia through contact with dead animals, contaminated food and water, ticks and biting insects, inhalation, and bite wounds (Bell, 1980;Ellis et al, 2002). Respiratory infection as a result of inhalation of dust occurred in buildings contaminated by rodent carcasses in Sweden (Dahlstrand et al, 1971;Tä rnvik et al, 2004) and in association with haying and threshing in Finland (Syrjä lä et al, 1985). During the investigation, several individuals volunteered that their dogs and cats caught many deer mice.…”

Tularemia in Denmark: Identification of a Francisella tularensis subsp. holarctica Strain by Real-Time PCR and High-Resolution Typing by Multiple-Locus Variable-Number Tandem Repeat Analysis

“…Similarity using the categorical coefficient is indicated on the scale bar. (20). According to the literature, Denmark was long considered devoid of the disease (3,12).…”

Putting the Jigsaw Together - A Brief Insight Into the Tularemia

“…While in the western USA both biting flies and ticks are considered important vectors, in the eastern USA only ticks seem to be significant vectors [139]. In northern European countries, such as Sweden, Finland, and the northern part of Russia, mosquitoes are the dominant vector transmitting tularemia to humans [139,140]. By contrast, mosquitoes in Central Europe probably do not carry F. tularensis in natural foci of tularemia; contact with infected animals, ingestion of contaminated food or water, along with possible infection caused by tick vectors are the dominant modes of transmission in this region [129,138].…”