Detection and Isolation of Rickettsia tillamookensis (Rickettsiales: Rickettsiaceae) From Ixodes pacificus (Acari: Ixodidae) From Multiple Regions of California.

The western black-legged tick (Ixodes pacificus) is the most frequently identified human-biting tick species in the western United States and the principal vector of at least three recognized bacterial pathogens of humans. A potentially pathogenic Rickettsia species, first described in 1978 and recently characterized as a novel transitional group agent designated as Rickettsia tillamookensis, also exists among populations of I. pacificus, although the distribution and frequency of this agent are poorly known. We evaluated DNA extracts from 348 host-seeking I. pacificus nymphs collected from 9 locations in five California counties, and from 916 I. pacificus adults collected from 24 locations in 13 counties, by using a real-time PCR designed specifically to detect DNA of R. tillamookensis. DNA of R. tillamookensis was detected in 10 (2.9%) nymphs (95% CI: 1.6-5.2%) and 17 (1.9%) adults (95% CI: 1.2-3.0%) from 11 counties of northern California. Although site-specific infection rates varied greatly, frequencies of infection remained consistently low when aggregated by stage, sex, habitat type, or geographical region. Four novel isolates of R. tillamookensis were cultivated in Vero E6 cells from individual adult ticks collected from Alameda, Nevada, and Yolo counties. Four historical isolates, serotyped previously as 'Tillamook-like' strains over 40 yr ago, were revived from long-term storage in liquid nitrogen and confirmed subsequently by molecular methods as isolates of R. tillamookensis. The potential public health impact of R. tillamookensis requires further investigation.

Multimodality and multiterritory vascular imaging in a toddler with acquired, complex, and unusual aortic arch anatomy.

A 20-month-old otherwise well child with no cardiac history presented for evaluation of a recent onset cardiac murmur. His initial examination revealed significant right carotid bruit along with a transthoracic echocardiogram (ECHO) concerning for severe transverse arch hypoplasia with unusual appearance and left ventricular hypertrophy with preserved function. This report demonstrates the utility of various modalities including echo, CT, and MRI to assess vascular structures in different vascular territories in a challenging patient who underwent a satisfactory arch repair with unexpected pathology findings.

Comparative roles of the atrial septal aneurysm versus patent foramen ovale in systemic embolization with inferences from neonatal studies.

Patent foramen ovale (PFO) and atrial septal aneurysm (ASA) have a significant statistical relation to ischemic strokes in adults. We reviewed their prevalence in 106 echocardiograms of neonates. Although all normal neonates have PFO, only 4% had ASA. From fetal and neonatal echocardiograms, we conclude that ASAs are more likely to be caused by inadequate size of the PFO, but the ASA can act as a funnel, enhancing the chances of paradoxic embolization in the presence of a PFO. There is no convincing evidence that an ASA alone causes strokes in adults; the confounder is probably atrial fibrillation.