High-pressure developments for resonant X-ray scattering experiments at I16.

An experimental setup to perform high-pressure resonant X-ray scattering (RXS) experiments at low temperature on I16 at Diamond Light Source is presented. The setup consists of a membrane-driven diamond anvil cell, a panoramic dome and an optical system that allows pressure to be measured in situ using the ruby fluorescence method. The membrane cell, inspired by the Merrill-Bassett design, presents an asymmetric layout in order to operate in a back-scattering geometry, with a panoramic aperture of 100° in the top and a bottom half dedicated to the regulation and measurement of pressure. It is specially designed to be mounted on the cold finger of a 4 K closed-cycle cryostat and actuated at low-temperature by pumping helium into the gas membrane. The main parts of the body are machined from a CuBe alloy (BERYLCO 25) and, when assembled, it presents an approximate height of 20-21 mm and fits into a 57 mm diameter. This system allows different materials to be probed using RXS in a range of temperatures between 30 and 300 K and has been tested up to 20 GPa using anvils with a culet diameter of 500 µm under quasi-cryogenic conditions. Detailed descriptions of different parts of the setup, operation and the developed methodology are provided here, along with some preliminary experimental results.

Anaplasmataceae in wild ungulates and carnivores in northern Spain.

Wild vertebrates are essential hosts for tick-borne diseases but data on the prevalence and diversity of Anaplasma spp. in wildlife are scarce. In this study, we used real-time PCR to investigate the distribution of Anaplasma species in spleen samples collected from 625 wild animals (137 cervids, 227 wild boar, and 261 carnivores) in two regions in northern Spain. A first generic real-time PCR assay was used to screen for the presence of Anaplasma spp. followed by a second species-specific multiplex real-time PCR or partial sequencing of the 16S rRNA gene for species identification. Anaplasma phagocytophilum was highly prevalent in cervids (64.2%), but it was absent from wild boar and carnivores. Interestingly, Anaplasma marginale and Anaplasma ovis were not detected in cervids, but Anaplasma centrale was identified in 1 roe deer and 1 red deer, A. bovis in 4 roe deer, and a novel Ehrlichia sp. in one badger. These findings were highly associated with the tick burden identified in the different hosts. Thus, Ixodes ricinus, the recognized vector of A. phagocytophilum in Europe, was the main tick species parasitizing cervids (93.5%, 1674/1791), whereas Dermacentor reticulatus was the most abundant in wild boar (76.1%, 35/46) and Ixodes hexagonus in carnivores (58.4%, 265/454). More investigations are needed to assess the impact of the different Anaplasma species in wildlife and the risk of transmission to domestic animals.

Coxiella burnetii shedding and environmental contamination at lambing in two highly naturally-infected dairy sheep flocks after vaccination.

Abortion due to Coxiella burnetii was confirmed in the 2007/08 season in two naturally-infected dairy sheep flocks. Proportion of C. burnetii shedders and bacterial loads in vaginal mucus were high among aborted or lambed ewes, as was within-flock seroprevalence. Before the next reproductive season (2008/09) 75% of ewes and 50% of replacement lambs were vaccinated (Coxevac, CEVA Santé Animale) keeping the remaining as untreated controls. Compared with the previous year results when abortion outbreak started, a great reduction in the percentage of abortions, in the number of shedders and in the bacterial burden excreted by the ewes was found in both flocks. However, seroconversion in non-vaccinated yearlings from both flocks and the presence of C. burnetii DNA in bioaerosols taken at sheep premises at lambing indicated that infection was still active. No differences were observed between vaccinated and control groups in terms of proportion of C. burnetii shedders. These results suggest that optimal results of vaccination in heavily infected flocks may not be obtained in a short-term period.