High prevalence and genetic diversity of Treponema paraluisleporidarum isolates in European lagomorphs.

IMPORTANCE: Syphilis is an ancient disease of humans and lagomorphs caused by two distinct but genetically closely related bacteria (>98% sequence identity based on the whole genome) of the genus Treponema. While human syphilis is well studied, little is known about the disease in the lagomorph host. Yet, comparative studies are needed to understand mechanisms in host-pathogen coevolution in treponematoses. Importantly, Treponema paraluisleporidarum-infected hare populations provide ample opportunity to study the syphilis-causing pathogen in a naturally infected model population without antibiotic treatment, data that cannot be obtained from syphilis infection in humans. We provide data on genetic diversity and are able to highlight various types of repetitions in one of the two hypervariable regions at the tp0548 locus that have not been described in the human syphilis-causing sister bacterium Treponema pallidum subsp. pallidum.

Vaccination of Zoo Birds against West Nile Virus-A Field Study.

West Nile virus (WNV) is known to cause disease and death in humans and various animals worldwide. WNV has circulated in Germany since 2018. In 2020, four birds tested positive for the WNV genome at Zoopark Erfurt (Thuringia). Moreover, virus neutralization assays detected neutralizing antibodies (nAb) against WNV in 28 birds. In addition, nAb against WNV and Usutu virus (USUV) were found in 14 birds. To protect valuable animals and to reduce the risk of viral transmission from birds to humans, we performed a field study on WNV vaccination at the zoo. To conduct the study, 61 birds from the zoo were categorized into three groups and subjected to a vaccination regimen, where each bird received either 1.0 mL, 0.5 mL, or 0.3 mL of a commercial inactivated WNV vaccine three times. The vaccinations were administered at three-week intervals, or as per modified vaccination schedules. Furthermore, 52 birds served as non-vaccinated controls. Adverse vaccination reactions were absent. The greatest increase in nAb titres was observed in birds that received 1.0 mL of vaccine. However, pre-existing antibodies to WNV and USUV appeared to have a major effect on antibody development in all groups and in all bird species, whereas sex and age had no effect. After vaccination, no death was detected in vaccinated birds for more than 1 year.

Serological screening in wild ruminants in Germany, 2021/2022: No evidence of SARS-CoV-2, bluetongue virus or pestivirus spread but high seroprevalences against Schmallenberg virus.

Wildlife animals may be susceptible to multiple infectious agents of public health or veterinary relevance, thereby potentially forming a reservoir that bears the constant risk of re-introduction into the human or livestock population. Here, we serologically investigated 493 wild ruminant samples collected in the 2021/2022 hunting season in Germany for the presence of antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and four viruses pathogenic to domestic ruminants, namely, the orthobunyavirus Schmallenberg virus (SBV), the reovirus bluetongue virus (BTV) and ruminant pestiviruses like bovine viral diarrhoea virus or border disease virus. The animal species comprised fallow deer, red deer, roe deer, mouflon and wisent. For coronavirus serology, additional 307 fallow, roe and red deer samples collected between 2017 and 2020 at three military training areas were included. While antibodies against SBV could be detected in about 13.6% of the samples collected in 2021/2022, only one fallow deer of unknown age tested positive for anti-BTV antibodies, and all samples reacted negative for antibodies against ruminant pestiviruses. In an ELISA based on the receptor-binding domain (RBD) of SARS-CoV-2, 25 out of 493 (5.1%) samples collected in autumn and winter 2021/2022 scored positive. This sero-reactivity could not be confirmed by the highly specific virus neutralisation test, occurred also in 2017, 2018 and 2019, that is, prior to the human SARS-CoV-2 pandemic, and was likewise observed against the RBD of the related SARS-CoV-1. Therefore, the SARS-CoV-2 sero-reactivity was most likely induced by another hitherto unknown deer virus belonging to the subgenus Sarbecovirus of betacoronaviruses.

Spread of West Nile Virus and Usutu Virus in the German Bird Population, 2019-2020.

West Nile virus (WNV) and Usutu virus (USUV) are important flaviviruses circulating in Germany. While USUV was first reported more than 10 years ago, WNV has only reached the country in 2018. Wild birds are important amplifying hosts for both viruses. Therefore, we have been monitoring the bird population in different regions of Germany by a previously established network for many years. This report summarizes the results of molecular and/or serological methods of 2345 blood samples from birds of 22 different orders and over 2900 bird carcasses from 2019 and 2020. USUV RNA circulation was found in different regions of Germany, with emphasis on USUV lineages Europe 3 and Africa 3. Increased evidence of USUV lineage Europe 2 was detected in eastern Germany. WNV RNA was found only in birds from the eastern part of the country. The seroprevalence for USUV was between 3.11% and 7.20% in all three regions investigated, whereas the WNV seroprevalence spanned from 14.77% to 16.15% in eastern Germany, with a noticeable tendency for a westward and southward expansion in both years. Thus, wild bird monitoring for WNV and USUV can serve as an early warning system for a human exposure risk.

Description, occurrence and significance of Mycoplasma seminis sp. nov. isolated from semen of a gyrfalcon (Falco rusticolus).

The Mycoplasma strain ARNO was isolated from the semen of a clinically healthy gyrfalcon (Falco rusticolus). Colonies of strain ARNO grew in fried-egg shape on Mycoplasma agar plates (SP4). The organism did not ferment glucose or hydrolyze arginine or urea; hence, organic acids are assumed as energy source. Growth was sterol-dependent and optimal growth temperature 42 °C, with a temperature range from 20 to 44 °C. Strain ARNO was not identified as a representative of any of the currently described Mycoplasma species by alignment of the 16S rRNA gene sequence and 16 S-23 S intergenic transcribed spacer region, or immunobinding assay. Hence, strain ARNO represents a novel Mycoplasma species for which the name Mycoplasma seminis sp. nov. is proposed (DSM 27653, NCTC 13927). After developing a species-specific PCR, the prevalence of M. seminis sp. nov. was determined in adult and juvenile falcons in a commercial breeding center for falcons. Semen samples (n = 171) were obtained from 113 male adults, due to repeated sampling of 39 birds. Female adults (n = 26) were sampled once, while 105 of the 152 juvenile birds were sampled twice via choanal swabs. Mycoplasma seminis sp. nov. was found in the semen of clinically healthy adult males (3.5 %) as well as in the respiratory tract of female (34.6 %) and juvenile birds (59.2 %). After comparison of semen samples with (2.9 %) and without M. seminis sp. nov. identification, no indications for a potential influence on the semen quality were demonstrated. Hence, M. seminis sp. nov. seems likely to be of commensal character in falcons.