Several studies reported a high prevalence of SARS-CoV-2 among white-tailed deer in North America. Monitoring cervids in all regions to better understand SARS-CoV-2 infection and circulation in other deer populations has been urged. To evaluate deer exposure and/or infection to/by SARS-CoV-2 in Poland, we sampled 90 red deer shot by hunters in five hunting districts in north-eastern Poland. Serum and nasopharyngeal swabs were collected, and then an immunofluorescent assay (IFA) to detect anti-SARS-CoV-2 antibodies was performed as well as real-time PCR with reverse transcription for direct virus detection. No positive samples were detected. There is no evidence of spillover of SARS-CoV-2 from the human to deer population in Poland.

Small mammals are suspected of contributing to the dissemination of Toxocara canis and helping with the parasite survival during periods when there is a temporary absence of suitable definitive hosts. While the primary aim of the current study was the assessment of seroprevalence of Toxocara spp. infections in wild rodents in Poland, we also explored the role of intrinsic (sex, age) and extrinsic factors (study site) influencing dynamics of this infection to ascertain whether grassland versus forest rodents play a greater role as indicators of environmental contamination with T. canis. We trapped 577 rodents belonging to four species (Myodes glareolus, Microtus arvalis, Microtus agrestis, Alexandromys oeconomus) in north-eastern Poland. Blood was collected during the parasitological examination, and serum was frozen at − 80 °C until further analyses. A bespoke enzyme-linked immunosorbent assay was used to detect antibodies against Toxocara spp. We found Toxocara spp. antibodies in the sera of all four rodent species with an overall seroprevalence of 2.8% [1.9–4.1%]. There was a significant difference in seroprevalence between vole species, with the grassland species (M. arvalis, M. agrestis and A. oeconomus) showing a 16-fold higher seroprevalence (15.7% [8.7–25.9%]) than the forest-dwelling M. glareolus (0.98% [0.5–1.8%]). We hypothesise that the seroprevalence of Toxocara spp. differs between forest and grassland rodents because of the higher contamination of grasslands by domestic dogs and wild canids. Our results underline the need for wide biomonitoring of both types of ecosystems to assess the role of rodents as indicators of environmental contamination with zoonotic pathogens.

We report serological surveillance for exposure to SARS-CoV-2 in 1,237 wild rodents and other small mammals across Europe. All samples were negative with the exception of one. Given the ongoing circulation of this virus in humans and potential host jumps, we suggest such surveillance be continued.

We report results from serologic surveillance for exposure to SARS-CoV-2 among 1,237 wild rodents and small mammals across Europe. All samples were negative, with the possible exception of 1. Despite suspected potential for human-to-rodent spillover, no evidence of widespread SARS-CoV-2 circulation in rodent populations has been reported to date. Esitämme tulokset serologisesta tutkimuksesta, jossa seulottiin SARS-CoV-2 tartuntojen varalta 1,237 luonnonvaraista jyrsijää ja piennisäkästä eri puolilta Eurooppaa. Kaikki näytteet olivat negatiivisia, yhtä näytettä lukuun ottamatta. SARS-CoV-2:n läikkymisen ihmisistä jyrsijöihin on arveltu olevan mahdollista, mutta todisteet viruksen laajamittaisesta leviämisestä jyrsijäpopulaatioissa puuttuvat.

No abstract