Spotted fever group rickettsiae in ticks collected from wild animals in Israel

We report molecular evidence for the presence of spotted fever group rickettsiae (SFGR) in ticks collected from roe deer, addax, red foxes, and wild boars in Israel. Rickettsia aeschlimannii was detected in Hyalomma marginatum and Hyalomma detritum while Rickettsia massiliae was present in Rhipicephalus turanicus ticks. Furthermore, a novel uncultured SFGR was detected in Haemaphysalis adleri and Haemaphysalis parva ticks from golden jackals. The pathogenicity of the novel SFGR for humans is unknown; however, the presence of multiple SFGR agents should be considered when serological surveillance data from Israel are interpreted because of significant antigenic cross-reactivity among Rickettsia. The epidemiology and ecology of SFGR in Israel appear to be more complicated than was previously believed. Copyright © 2011 by The American Society of Tropical Medicine and Hygiene

The Eco-Epidemiology of Pacific Coast Tick Fever in California

Rickettsia philipii (type strain “Rickettsia 364D”), the etiologic agent of Pacific Coast tick fever (PCTF), is transmitted to people by the Pacific Coast tick, Dermacentor occidentalis. Following the first confirmed human case of PCTF in 2008, 13 additional human cases have been reported in California, more than half of which were pediatric cases. The most common features of PCTF are the presence of at least one necrotic lesion known as an eschar (100%), fever (85%), and headache (79%); four case-patients required hospitalization and four had multiple eschars. Findings presented here implicate the nymphal or larval stages of D. occidentalis as the primary vectors of R. philipii to people. Peak transmission risk from ticks to people occurs in late summer. Rickettsia philipii DNA was detected in D. occidentalis ticks from 15 of 37 California counties. Similarly, non-pathogenic Rickettsia rhipicephali DNA was detected in D. occidentalis in 29 of 38 counties with an average prevalence of 12.0% in adult ticks. In total, 5,601 ticks tested from 2009 through 2015 yielded an overall R. philipii infection prevalence of 2.1% in adults, 0.9% in nymphs and a minimum infection prevalence of 0.4% in larval pools. Although most human cases of PCTF have been reported from northern California, acarological surveillance suggests that R. philipii may occur throughout the distribution range of D. occidentalis

Electrotonic Signals along Intracellular Membranes May Interconnect Dendritic Spines and Nucleus

Synapses on dendritic spines of pyramidal neurons show a remarkable ability to induce phosphorylation of transcription factors at the nuclear level with a short latency, incompatible with a diffusion process from the dendritic spines to the nucleus. To account for these findings, we formulated a novel extension of the classical cable theory by considering the fact that the endoplasmic reticulum (ER) is an effective charge separator, forming an intrinsic compartment that extends from the spine to the nuclear membrane. We use realistic parameters to show that an electrotonic signal may be transmitted along the ER from the dendritic spines to the nucleus. We found that this type of signal transduction can additionally account for the remarkable ability of the cell nucleus to differentiate between depolarizing synaptic signals that originate from the dendritic spines and back-propagating action potentials. This study considers a novel computational role for dendritic spines, and sheds new light on how spines and ER may jointly create an additional level of processing within the single neuron

Genetic Basis of Myocarditis: Myth or Reality?

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