No abstract

We investigated the role of the western gray squirrel (Sciurus griseus) as a reservoir host of the Lyme disease spirochete Borrelia burgdorferi. A survey of 222 western gray squirrels in California showed an overall prevalence of B. burgdorferi infection of 30%, although at a county level, prevalence of infection ranged from 0% to 50% by polymerase chain reaction. Laboratory trials with wild-caught western gray squirrels indicated that squirrels were competent reservoir hosts of the Lyme disease bacterium and infected up to 86% of feeding Ixodes pacificus larvae. Infections were long-lasting (up to 14 months), which demonstrated that western gray squirrels can maintain B. burgdorferi trans-seasonally. Non-native eastern gray squirrels (Sciurus carolinensis) and fox squirrels (Sciurus niger) were infrequently infected with B. burgdorferi.

In the far-western United States, the nymphal stage of the western black-legged tick, Ixodes pacificus, has been implicated as the primary vector to humans of Borrelia burgdorferi sensu stricto (hereinafter referred to as B. burgdorferi), the causative agent of Lyme borreliosis in North America. In the present study, we sought to determine if infection prevalence with B. burgdorferi in I. pacificus nymphs and the density of infected nymphs differ between dense-woodland types within Mendocino County, California, and to develop and evaluate a spatially-explicit model for density of infected nymphs in dense woodlands within this high-incidence area for Lyme borreliosis. In total, 4.9% (264) of 5431 I. pacificus nymphs tested for the presence of B. burgdorferi were infected. Among the 78 sampling sites, infection prevalence ranged from 0 to 22% and density of infected nymphs from 0 to 2.04 per 100 m2. Infection prevalence was highest in woodlands dominated by hardwoods (6.2%) and lowest for redwood (1.9%) and coastal pine (0%). Density of infected nymphs also was higher in hardwood-dominated woodlands than in conifer-dominated ones that included redwood or pine. Our spatial risk model, which yielded an overall accuracy of 85%, indicated that warmer areas with less variation between maximum and minimum monthly water vapor in the air were more likely to include woodlands with elevated acarological risk of exposure to infected nymphs. We found that 37% of dense woodlands in the county were predicted to pose an elevated risk of exposure to infected nymphs, and that 94% of the dense-woodland areas that were predicted to harbor elevated densities of infected nymphs were located on privately-owned land.

ABSTRACT:Overlapping geographic distributions of tick-borne disease agents utilizing the same tick vectors are common, and coinfection of humans, domestic animals, wildlife, and ticks with both Borrelia burgdorferi and Anaplasma phagocytophilum has been frequently reported. This study was undertaken in order to evaluate the prevalence of both B. burgdorferi sensu stricto (hereinafter referred to as B. burgdorferi) and A. phagocytophilum in several species of sciurid rodents from northern California, USA. Rodents were either collected dead as road-kills or live-trapped in four state parks from 13 counties. Thirty-seven western gray squirrels (Sciurus griseus), nine nonnative eastern gray squirrels (S. carolinensis) and an eastern fox squirrel (S. niger), four Douglas squirrels (Tamiasciurus douglasii), and two northern flying squirrels (Glaucomys sabrinus) were tested by polymerase chain reaction (PCR) and serology for evidence of coinfection. Of the 14 individual S. griseus that were PCRpositive for B. burgdorferi, two (14%) also were PCR-positive for A. phagocytophilum and 11 (79%) had serologic evidence of A. phagocytophilum exposure. Two of the four Douglas squirrels were PCR positive for B. burgdorferi and seropositive to A. phagocytophilum. Evidence of coinfection with these zoonotic pathogens in western gray squirrels suggests that both bacteria may be maintained in a similar transmission cycle involving this sciurid and the western black-legged tick Ixodes pacificus, the primary bridging vector to humans in the far-western US.

This study aimed to identify barriers and facilitators of mental health care for patients with trauma histories via qualitative methods with clinicians and administrators from primary care clinics for the underserved. Individual interviews were conducted, followed by a combined focus group with administrators from three jurisdictions; there were three focus groups with clinicians from each clinic system. Common themes were identified, and responses from groups were compared. Administrators and clinicians report extensive trauma histories among patients. Clinician barriers include lack of time, patient resistance, and inadequate referral options; administrators cite reimbursement issues, staff training, and lack of clarity about the term trauma. A key facilitator is doctor-patient relationship. There were differences in perceived barriers and facilitators at the institutional and clinical levels for mental health care for patients with trauma. Importantly, there is agreement about better access to and development of trauma-specific interventions. Findings will aid the development and implementation of trauma-focused interventions embedded in primary care.