Cocirculation of Leptospira spp. and multiple orthohantaviruses in rodents, Lithuania, Northern Europe.

In Europe, zoonotic Leptospira spp. and orthohantaviruses are mainly associated with specific rodent hosts. These pathogens cause febrile human diseases with similar symptoms and disease progression. In Lithuania, the presence of Dobrava-Belgrade orthohantavirus (DOBV), Tula orthohantavirus (TULV) and Leptospira spp. in rodent reservoirs is still unknown, and Puumala orthohantavirus (PUUV) was detected in bank voles (Clethrionomys glareolus) at only one site. Therefore, we collected and screened 1617 rodents and insectivores from Lithuania for zoonotic (re-)emerging Leptospira and orthohantaviruses. We detected Leptospira DNA in six rodent species, namely striped field mouse (Apodemus agrarius), yellow-necked mouse (Apodemus flavicollis), bank vole, common vole (Microtus arvalis), field vole (Microtus agrestis) and root vole (Microtus oeconomus). Leptospira DNA was detected with an overall mean prevalence of 4.4% (range 3.7%-7.9% per rodent species). We detected DOBV RNA in 5.6% of the striped field mice, PUUV RNA in 1% of bank voles and TULV RNA in 4.6% of common voles, but no Leptospira DNA in shrews and no hantavirus-Leptospira coinfections in rodents. Based on the complete coding sequences of the three genome segments, two distant DOBV phylogenetic lineages in striped field mice, one PUUV strain in bank voles and two TULV strains in common voles were identified. The Leptospira prevalence for striped field mice and yellow-necked mice indicated a significant negative effect of the distance to water points. The detection of (re-)emerging human pathogenic Leptospira and three orthohantaviruses in rodent reservoirs in Lithuania calls for increased awareness of public health institutions and allows the improvement of molecular diagnostics for pathogen identification.

Survival time of Leptospira kirschneri on strawberries.

In the past decade, two leptospirosis outbreaks occurred among strawberry harvesters in Germany, with 13, and 45 reported cases respectively. In both outbreaks, common voles (Microtus arvalis) infected with Leptospira kischneri serovar Grippotyphosa were identified as the most likely outbreak source. In an univariate analysis, eating unwashed strawberries was identified as one of the risk factors associated with Leptospira infection. The aim of this study was to evaluate the survival time of L. kirschneri serovar Grippotyphosa on strawberries under varying conditions. Strawberries were spiked with 5x109 of both a laboratory reference strain (strain Moskva V) and an outbreak field strain (94-6/2007) of L. kirschneri serovar Grippotyphosa sequence type 110. Survival times were investigated in a fully crossed design with three incubation times (2h, 4h, 6h and 8h) and three temperatures (15°C, 21°C and 25°C) with three replicated for each condition. A wash protocol was developed and recovered Leptospira were determined by qPCR, dark field microscopy and culturing. Viable L. kirschneri of both the reference strain and the field strain were identified in all samples at 25°C and an incubation time of 2h, but only 1/9 (11%) and 4/9 (44%) of the samples incubated at 15°C were positive, respectively. Both reference and field strain were viable only in 2/9 (22%) at 25° after 6h. After an 8h incubation, viable Leptospira could not be identified on the surface of the strawberries or within the fruit for any of the tested conditions. Based on these results, the exposure risk of consumers to viable Leptospira spp. through the consumption of strawberries bought at the retail level is most likely very low. However, there is a potential risk of Leptospira infection by consumption of strawberries on pick-your-own farms.