Rat-borne diseases at the horizon. A systematic review on infectious agents carried by rats in Europe 1995-2016

Abstract

To investigate the spectrum of rat-borne pathogens circulating in Europe a systematic review spanning across 55 European countries during the years 1995-2016 was performed. The study surveyed viruses, bacteria, macroparasites and unicellular eukaryotes (protozoa). Fifty-three different infectious agents, all with zoonotic potential, were reported to be carried by commensal rats; 48 by the brown rat (Rattus norvegicus) and 20 by the black rat (R. rattus). There was a tendency for rural areas to harbour more rat-borne microbes than urban areas regarding the brown rat, but the opposite could be observed for the black rat. The study clearly indicated that an improved surveillance on wild rats is needed in Europe, and further indicated the pathogens and geographical areas where the major focus is required. For example, six zoonotic microbes seemed to be clearly more geographically widespread in Europe than others; virulent or resistant E. coli, pathogenic Leptospira spp., Hymenolepis diminuta, H. nana, Capillaria hepatica and Toxoplasma gondii.

Keywords: Capillaria; Europe; Hymenolepis; Leptospira; Rattus; zoonoses.

Figure 1.

Literature screening for systematic review.

Figure 2.

Number of unique pathogens per taxa and rat species. Pathogens combined, regardless of rat species, are also reported.

Figure 3.

Number of different infectious agents per European zone, rat species and taxonomic level. Where a genus is known to include species that cause disease in humans but no species is given, the genus is counted once for each habitat and rat species.

Figure 4.

(a) Number of different zoonotic infectious agents found in the literature search by rat species and habitat (urban/suburban, rural/farm, oceanic islands). Where a genus is known to include species that cause disease in humans but no species is given, the genus is counted once for each habitat and rat species. (b) Number of different zoonotic infectious agents found in the literature search by taxonomic division, rat species and habitat.