Extensive Recruitment of Plasma Blasts to the Cerebrospinal Fluid in Toscana Virus Encephalitis

An update on Toscana virus distribution, genetics, medical and diagnostic aspects

BACKGROUND

Toscana virus is an arbovirus transmitted by sand flies within the Mediterranean area where it can cause febrile illness and neuroinvasive infections during the seasonal circulation period of the vector. Although it is an important cause of meningitis and encephalitis, it remains a neglected virus with limited published data, as demonstrated by <250 peer-reviewed articles since the 1970s.

OBJECTIVE

The last review article on Toscana virus was published in 2012. The aim was to compile peer-reviewed articles to provide an updated review highlighting recent findings to complement previous review articles.

SOURCES

PubMed database was searched using the 'Toscana virus' keyword from 2010 to present. A total of 152 articles were retrieved and identified studies were assessed for novel information on virus genetics, and geographic and medical aspects compared with existing knowledge reported in previous review articles.

CONTENT

Studies addressing medical, veterinary and entomological aspects have provided evidence that Toscana virus is present in North Africa, in the Balkan Peninsula, and in most of the Mediterranean islands. Besides the two previously recognized genetic lineages, a novel evolutionary lineage has been identified in the Balkan Peninsula. Co-circulation of two genetic lineages has been demonstrated in France, in Turkey and in Croatia. In addition to meningitis and meningo-encephalitis, which have been reported for 40 years, various neuroinvasive forms have been recently reported such as Guillain-Barré syndrome, hydrocephalus, myositis, fasciitis, polymyeloradiculopathy, deafness and facial paralysis.

IMPLICATION

Because it is endemic in countries bordering the Mediterranean, physicians should include Toscana virus in the differential diagnosis of patients presenting with febrile illness and/or neurological manifestations.

Single-Cell High-Throughput Technologies in Cerebrospinal Fluid Research and Diagnostics

High-throughput single-cell technologies have recently emerged as essential tools in biomedical research with great potential for clinical pathology when studying liquid and solid biopsies. We provide an update on current single-cell methods in cerebrospinal fluid research and diagnostics, focusing on high-throughput cell-type specific proteomic and genomic technologies. Proteomic methods comprising flow cytometry and mass cytometry as well as genomic approaches including immune cell repertoire and single-cell transcriptomic studies are critically reviewed and future directions discussed.

The spectrum of aseptic central nervous system infections in southern Germany - demographic, clinical and laboratory findings

BACKGROUND AND PURPOSE

Aseptic infections of the central nervous system (CNS) are frequently observed in Germany. However, no study has systematically addressed the spectrum of aseptic CNS infections in Germany.

METHODS

Data on 191 adult patients diagnosed from January 2007 to December 2014 with aseptic meningitis or encephalitis/meningoencephalitis at our hospital were collected by chart review and analyzed for demographic, clinical and laboratory findings. Patients were stratified according to the causative virus and findings were compared between groups.

RESULTS

In our cohort, meningitis was caused in 36% by enterovirus (EV), 15% by herpes simplex virus (HSV), 12% by varicella zoster virus (VZV) and 5% by tick borne encephalitis (TBE). Encephalitis/meningoencephalitis was caused in 13% by HSV, 13% by VZV, and three out of 11 tested patients were positive for TBE. The highest incidence of EV infections was between 25 and 35 years and of HSV infections between 30 and 60 years. VZV infections had a bimodal distribution peaking below 30 and above 70 years. VZV and EV infections were more frequently observed during summer, whereas HSV infections showed no seasonal preference. Inflammatory changes in cerebrospinal fluid (CSF) were highest in HSV and lowest in EV infections.

CONCLUSIONS

Polymerase chain reaction tests for HSV, VZV and EV in CSF and TBE serology determined the causative virus in over 60% of tested patients. The age of affected patients, seasonal distribution, disease course and inflammatory changes in CSF differ between groups of patients affected by the most common viral infections.