Unraveling female communication through scent marks in the Norway rat.

Chemical communication by females remains poorly understood, with most attention focused on female advertisement of sexual receptivity to males or mother-offspring communication. However, in social species, scents are likely to be important for mediating competition and cooperation between females determining individual reproductive success. Here, we explore chemical signaling by female laboratory rats (Rattus norvegicus) to test i) whether females target their deployment of scent information differentially according to their sexual receptivity and the genetic identity of both female and male conspecifics signaling in the local environment and ii) whether females are attracted to gain the same or different information from female scents compared to males. Consistent with targeting of scent information to colony members of similar genetic background, female rats increased scent marking in response to scents from females of the same strain. Females also suppressed scent marking in response to male scent from a genetically foreign strain while sexually receptive. Proteomic analysis of female scent deposits revealed a complex protein profile, contributed from several sources but dominated by clitoral gland secretion. In particular, female scent marks contained a series of clitoral-derived hydrolases and proteolytically truncated major urinary proteins (MUPs). Manipulated blends of clitoral secretion and urine from estrus females were strongly attractive to both sexes, while voided urine alone stimulated no interest. Our study reveals that information about female receptive status is shared between females as well as with males, while clitoral secretions containing a complex set of truncated MUPs and other proteins play a key role in female communication.

Report of Workshop on Euthanasia for Zebrafish-A Matter of Welfare and Science.

The increasing importance of zebrafish as a biomedical model organism is reflected by the steadily growing number of publications and laboratories working with this species. Regulatory recommendations for euthanasia as issued in Directive 2010/63/EU are, however, based on experience with fish species used for food production and do not take the small size and specific physiology of zebrafish into account. Consequently, the currently recommended methods of euthanasia in the Directive 2010/63/EU are either not applicable or may interfere with research goals. An international workshop was held in Karlsruhe, Germany, March 9, 2017, to discuss and propose alternative methods for euthanasia of zebrafish. The aim was to identify methods that adequately address the physiology of zebrafish and its use as a biomedical research model, follow the principles of the 3Rs (Replacement, Reduction, and Refinement) in animal experimentation and consider animal welfare during anesthesia and euthanasia. The results of the workshop are summarized here in the form of a white paper.

Genome characterisation of two Ljungan virus isolates from wild bank voles (Myodes glareolus) in Sweden.

Ljungan virus (LV) (family Picornaviridae, genus Parechovirus) is a suspected zoonotic pathogen with associations to human disease in Sweden. LV is a single-stranded RNA virus with a positive sense genome. There are five published Ljungan virus strains, three isolated from Sweden and two from America, and are classified into four genotypes. A further two strains described here were isolated from wild bank voles (Myodes glareolus) caught in Västmanlands county, Sweden in 1994. These strains were sequenced using next generation pyrosequencing technology on the GS454flx platform. Genetic and phylogenetic analysis of the obtained genomes confirms isolates LV340 and LV342 as two new putative members of genotype 2 along with LV145SL, with 92% and 99% nucleotide identities respectively. Only two codon sites throughout the entire genome were identified as undergoing positive selection, both situated within the VP3 structural region, in or near to major antigenic sites. Whilst these two strains do not constitute new genotypes they provide evidence, though weakly supported, which suggests the evolution of Ljungan viruses to be relatively slow, a characteristic unlike other picornaviruses. Additional genomic sequences are urgently required for Ljungan virus strains, particularly from different locations or hosts, to fully understand the evolutionary and epidemiological properties of this potentially zoonotic virus.

Detection and genetic characterization of Seoul virus from commensal brown rats in France.

BACKGROUND: Hantaviruses are single-stranded RNA viruses, which are transmitted to humans primarily via inhalation of aerosolised virus in contaminated rodent urine and faeces. Whilst infected reservoir hosts are asymptomatic, human infections can lead to two clinical manifestations, haemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS), with varying degrees of clinical severity. The incidence of rodent and human cases of Seoul virus (SEOV) in Europe has been considered to be low, and speculated to be driven by the sporadic introduction of infected brown rats (Rattus norvegicus) via ports. METHODS: Between October 2010 and March 2012, 128 brown rats were caught at sites across the Lyon region in France. RESULTS: SEOV RNA was detected in the lungs of 14% (95% CI 8.01-20.11) of brown rats tested using a nested pan-hantavirus RT-PCR (polymerase gene). Phylogenetic analysis supports the inclusion of the Lyon SEOV within Lineage 7 with SEOV strains originating from SE Asia and the previously reported French & Belgian SEOV strains. Sequence data obtained from the recent human SEOV case (Replonges) was most similar to that obtained from one brown rat trapped in a public park in Lyon city centre. We obtained significantly improved recovery of virus genome sequence directly from SEOV infected lung material using a simple viral enrichment approach and NGS technology. CONCLUSIONS: The detection of SEOV in two wild caught brown rats in the UK and the multiple detection of SEOV infected brown rats in the Lyon region of France, suggests that SEOV is circulating in European brown rats. Under-reporting and difficulties in identifying the hantaviruses associated with HFRS may mask the public health impact of SEOV in Europe.