Leptospira spp. in Small Mammals from Areas with Low and High Human Hantavirus Incidences in South-West Germany.

INTRODUCTION: Leptospirosis is caused by Leptospira spp. and is considered the most widespread zoonotic disease worldwide. It mimics nephropathia epidemica in humans, a disease mainly caused by Puumala hantavirus (PUUV). Small mammals are reservoirs for Leptospira spp. and PUUV. Seewis virus (SWSV) is a shrew-borne hantavirus with unknown pathogenicity. The objective of this study was to estimate the prevalence for Leptospira spp. and the frequency of Leptospira-hantavirus co-infections in small mammals collected at locations with high and low incidences in humans. MATERIALS AND METHODS: In 2012 and 2013, 736 small mammals belonging to seven species (Apodemus flavicollis, Microtus agrestis, Microtus arvalis, Myodes glareolus, Sorex araneus, S. coronatus, and S. minutus) were collected at four high incidence sites (H1-H4) and four low (L1-L4) incidence sites for PUUV infection in humans. Kidney-derived DNA samples were tested for Leptospira spp. by real-time PCR targeting the lipl 32 gene and further analyzed by duplex PCR targeting the flaB and the secY genes. For the detection of Seewis virus, lung-derived DNA was tested via RT-PCR targeting the nucleocapsid gene. RESULTS: Altogether, 42 of the 736 small mammals including 27 of 660 bank voles and 11 of 66 shrews, were positive for Leptospira spp., while Sorex spp. (14.7%) showed significantly higher prevalences compared to bank voles (4.1%). Detected Leptospira spp. were pathogenic species other than L. kirschneri. Significantly more Leptospira-positive bank voles were found at H sites than at L sites. Altogether 22.2% of positive bank voles were infected with PUUV. Double infection of PUUV and Leptospira spp. occurrence in bank voles is 1.86 times (OR = 1.86; 95% CI: 0.72-4.73) more likely than infections with each pathogen separately. DISCUSSION: Leptospira- positive bank voles are focally positively associated with PUUV infection in bank voles and with human hantavirus cases. It should be considered that shrews may serve as Leptospira spp. reservoirs.

The enzootic life-cycle of Borrelia burgdorferi (sensu lato) and tick-borne rickettsiae: an epidemiological study on wild-living small mammals and their ticks from Saxony, Germany.

BACKGROUND: Borrelia burgdorferi (sensu lato) and rickettsiae of the spotted fever group are zoonotic tick-borne pathogens. While small mammals are confirmed reservoirs for certain Borrelia spp., little is known about the reservoirs for tick-borne rickettsiae. Between 2012 and 2014, ticks were collected from the vegetation and small mammals which were trapped in Saxony, Germany. DNA extracted from ticks and the small mammals' skin was analyzed for the presence of Rickettsia spp. and B. burgdorferi (s.l.) by qPCR targeting the gltA and p41 genes, respectively. Partial sequencing of the rickettsial ompB gene and an MLST of B. burgdorferi (s.l.) were conducted for species determination. RESULTS: In total, 673 small mammals belonging to eight species (Apodemus agrarius, n = 7; A. flavicollis, n = 214; Microtus arvalis, n = 8; Microtus agrestis, n = 1; Mustela nivalis, n = 2; Myodes glareolus, n = 435; Sorex araneus, n = 5; and Talpa europaea, n = 1) were collected and examined. In total, 916 questing ticks belonging to three species (Ixodes ricinus, n = 741; Dermacentor reticulatus, n = 174; and I. trianguliceps, n = 1) were collected. Of these, 474 ticks were further investigated. The prevalence for Rickettsia spp. and B. burgdorferi (s.l.) in the investigated small mammals was 25.3 and 31.2%, respectively. The chance of encountering Rickettsia spp. in M. glareolus was seven times higher for specimens infested with D. reticulatus than for those which were free of D. reticulatus (OR: 7.0; 95% CI: 3.3-14.7; P < 0.001). In total, 11.4% of questing I. ricinus and 70.5% of D. reticulatus were positive for Rickettsia spp. DNA of B. burgdorferi (s.l.) was detected only in I. ricinus (5.5%). Sequence analysis revealed 9 R. helvetica, 5 R. raoultii, and 1 R. felis obtained from 15 small mammal samples. CONCLUSION: Small mammals may serve as reservoirs for Rickettsia spp. and B. burgdorferi (s.l.). While the prevalence for Rickettsia spp. in M. glareolus is most likely depending on the abundance of attached D. reticulatus, the prevalence for B. burgdorferi (s.l.) in small mammals is independent of tick abundance. Dermacentor reticulatus may be the main vector of certain Rickettsia spp. but not for Borrelia spp.

Rickettsia spp. in small mammals and their parasitizing ectoparasites from Saxony, Germany.

Rickettsiae are emerging pathogens causing various types of spotted fever and typhus and are mostly transmitted by arthropods to humans and animals. In order to investigate the distribution of Rickettsiae of the spotted fever group (SFG) in small mammals as potential reservoirs and in fleas and ticks from these animals as potential vectors, a total of 91 small mammals (seven species) were captured and their ectoparasites were collected at seven sites around Leipzig, Saxony, Germany, in 2010 and 2011. Altogether, 91 skin samples, 125 fleas (five species) and 363 ticks (four species) were investigated for DNA of Rickettsia spp. with a real-time PCR targeting the gltA gene. A total of 26 (28.6%) rodents, 5 (3.9%) fleas and 151 (41.6%) ticks were positive for Rickettsia spp. by real-time PCR. Altogether 42 positive tick-, and all positive small mammal- and flea-samples were further determined to Rickettsia species level with a conventional PCR targeting the ompB gene followed by sequencing. Sequencing of 14 positive rodent samples revealed R. helvetica (n=12) and R. raoultii (n=2). Three Rickettsia spp. were detected in ticks: Rickettsia raoultii (59.6%), R. monacensis (4.8%) and R. helvetica (33.3%). In total 85.6% of Dermacentor reticulatus ticks and 20.4% of Ixodes ricinus ticks were positive. Rickettsia raoultii was found in 4 of the 5 positive fleas. To our knowledge this is the first detection of R. raoultii in Myodes glareolus and of R. helvetica in Apodemus agrarius from Germany. The high prevalence of R. helvetica in small mammals suggests that they may play an important role as potential natural reservoir hosts. The high prevalence in engorged I. ricinus for R. helvetica and in D. reticulatus ticks for R. raoultii, mostly deriving from uninfected mammals, leads to the conclusion that those tick species may serve as vectors for those Rickettsia spp. Detection of R. raoultii in fleas, parasitizing on their small mammal hosts, may indicate accidental uptake during feeding on hosts with bacteraemia rather than an active involvement of fleas in the transmission cycle of this Rickettsia species.