An Ixodes minor and Borrelia carolinensis enzootic cycle involving a critically endangered Mojave Desert rodent.

Microtus californicus scirpensis is an endangered, isolated subspecies of California vole. It requires water pools and riparian bulrush (Schoenoplectus americanus) and occupies some of the rarest habitat of any North American mammal. The minimally vegetated, extremely arid desert surrounding the pools is essentially uninhabitable for Ixodes species ticks. We describe an enzootic cycle of Borrelia carolinensis in Ixodes minor ticks at a site 3500 km distant from the region in which I. minor is known to occur in Tecopa Host Springs, Inyo County, eastern Mojave Desert, California. Voles were live-trapped, and ticks and blood samples queried by PCR and DNA sequencing for identification and determination of the presence of Borrelia spp. Between 2011-2013, we found 21 Ixodes minor ticks (prevalence 4-8%) on Amargosa voles and Reithrodontomys megalotis. DNA sequencing of 16S rRNA from ticks yielded 99% identity to I. minor. There was 92% identity with I. minor in the calreticulin gene fragment. Three ticks (23.1%), 15 (24%) voles, three (27%) house mice, and one (7%) harvest mice were PCR positive for Borrelia spp. Sequencing of the 5S-23S intergenic spacer region and flagellin gene assigned Amargosa vole Borrelia strains to B. carolinensis. Ixodes minor, first described in 1902 from a single Guatemalan record, reportedly occurs only in the southeast American on small mammals and birds. The source of this tick in the Mojave Desert and time scale for introduction is not known but likely via migratory birds. Borrelia strains in the Amargosa ecosystem most closely resemble B. carolinensis. B. carolinensis occurs in a rodent-I. minor enzootic cycle in the southeast U.S. although its epidemiological significance for people or rodents is unknown. The presence of a tick and Borrelia spp. only known from southeast U.S. in this extremely isolated habitat on the other side of the continent is of serious concern because it suggests that the animals in the ecosystem could be vulnerable to further incursions of pathogens and parasites.

Interrupting the natural history of diabetes mellitus: lifestyle, pharmacological and surgical strategies targeting disease progression.

In recent decades we have seen a surge in the incidence of diabetes in industrialized nations; a threat which has now extended to the developing world. Type 2 diabetes is associated with significant microvascular and macrovascular disease, with considerable impact on morbidity and mortality. Recent evidence has cast uncertainty on the benefits of very tight glycaemic goals in these individuals. The natural history of disease follows an insidious course from disordered glucose metabolism in a pre-diabetic state, often with metabolic syndrome and obesity, before proceeding to diabetes mellitus. In the research setting, lifestyle, pharmacological and surgical intervention targeted against obesity and glycaemia has shown that metabolic disturbances can be halted and indeed regressed if introduced at an early stage of disease. In addition to traditional anti-diabetic medications such as the glinides, sulphonylureas and the glitazones, novel therapies manipulating the endocannabinoid system, neurotransmitters, intestinal absorption and gut hormones have shown dual benefit in weight loss and glycaemic control normalisation. Whilst these treatments will not and should not replace lifestyle change, they will act as invaluable adjuncts for weight loss and aid in normalising the metabolic profile of individuals at risk of diabetes. Utilizing novel therapies to prevent diabetes should be the focus of future research, with the aim of preventing the challenging microvascular and macrovascular complications, and ultimately cardiovascular death.

Bacterial flora on Cascades frogs in the Klamath mountains of California.

Amphibians are experiencing global declines due in part to the infectious disease chytridiomycosis. Some symbiotic bacteria residents on frog skin have been shown to inhibit the growth of Batrachochytrium dendrobatitis (Bd) but few studies have attempted to fully describe the resident bacterial flora of frog skin. We cultured and sequenced 130 bacterial isolates from frogs collected from the California Klamath Range, recovering predominantly Gram-negative bacteria from 20 higher order taxa and 31 genera. There were also a large number of unclassifiable isolates. Forty-three isolates were assessed for their ability to inhibit the growth of Bd in vitro; of these, two had strong and three had slight anti-Bd activity. We suggest that many bacterial species may play a secondary role in Bd resistance, acting synergistically with inhibitory species. Future research is required in order to characterize these interactions. Understanding the relationships between bacterial strains may be important in predicting and managing the effects of future anti-Bd treatments such as antimicrobial compounds or probiotic bacteria.