sp. nov., a novel species of the complex, occupying a basal position to North American species.

species are vector-borne parasitic bacteria with unusual, highly fragmented genomes that include a linear chromosome and linear as well as circular plasmids that differ numerically between and within various species. Strain CA690, which was cultivated from a questing nymph in the San Francisco Bay area, CA, was determined to be genetically distinct from all other described species belonging to the complex. The genome, including plasmids, was assembled using a hybrid assembly of short Illumina reads and long reads obtained via Oxford Nanopore Technology.

Borrelia lanei sp. nov. extends the diversity of Borrelia species in California.

The diversity of Borrelia species discovered in California appears to be particularly high. A divergent group of Borrelia strains collected from Ixodes ticks in California was described by Postic and co-workers and designated 'genomospecies 2' (Postic D, Garnier M, Baranton G. Int J Med Microbiol 2007;297:263-271; Postic D, Ras NM, Lane RS, Hendson M, Baranton G.

Remarkable diversity of tick or mammalian-associated Borreliae in the metropolitan San Francisco Bay Area, California.

The diversity of Lyme disease (LD) and relapsing fever (RF)-group spirochetes in the metropolitan San Francisco Bay area in northern California is poorly understood. We tested Ixodes pacificus, I. spinipalpis, and small mammals for presence of borreliae in Alameda County in the eastern portion of San Francisco Bay between 2009 and 2012.

Eco-epidemiological factors contributing to the low risk of human exposure to ixodid tick-borne borreliae in southern California, USA.

Little is known about the eco-epidemiology of Lyme disease in southern California, a region where the incidence is much lower than it is in northern California. Here, we sought to discover the previously unknown microhabitats of nymphs of the primary vector, the western black-legged tick (Ixodes pacificus), in 3 moderately to heavily-utilized state parks in the Santa Monica Mountains in Los Angeles County; to elucidate the seasonal distribution and abundance of adults of I. pacificus and another human-biter, the Pacific Coast tick (Dermacentor occidentalis); and to determine what Lyme-disease or relapsing-fever group borreliae are present in questing nymphs or adult ticks.

Larval keys to the genera of Ixodidae (Acari) and species of Ixodes (Latreille) ticks established in California.

In California, hard (Ixodidae) ticks transmit at least 8 zoonotic disease agents (1 virus, 6 bacteria, 1 protozoan) to humans or other animals. The correct taxonomic identification of all 3 parasitic stages (larvae, nymphs, adults) of ticks is integral to understanding host-tick associations and disease dynamics, but immature ticks, especially the larvae, can be difficult to identify. Here, we present larval keys to the 4 genera of Ixodidae (DermacentorKoch, 1844; HaemaphysalisKoch, 1844; IxodesLatreille, 1795; RhipicephalusKoch, 1844) and to the 18 species of Ixodes known to be established in California.