Molecular characterization of viruses associated with encephalitis in São Paulo, Brazil.

The objective of this study was to characterize the prevalence of viral encephalitis due to arbovirus infection of the Togaviridae and Flaviviridae families in São Paulo, Brazil. A total of 500 cerebrospinal fluid (CSF) samples collected between August 2012 and January 2013, from patients with symptoms of acute encephalitis were analyzed. Findings suggestive of viral encephalitis-elevations in cell concentration, glucose and total protein-were observed in 234 (46.8%) samples, designated as Group 1. The remaining 266 samples comprised Group 2. All samples were tested for Flaviviruses (dengue virus 1, 2, 3 and 4, yellow fever virus and West Nile virus), Alphavirus (NS5 region) and enterovirus by RT- PCR and for herpesviruses and enteroviruses using CLART-Entherpex. A presumptive viral etiological agent was detected in 26 samples (5.2%), 18 (8.0%) in Group 1 and 8 (3.0%) in Group 2. In Group 1 human herpesviruses were detected in 9 cases, enteroviruses in 7 cases, dengue viruses (DENV) in 2 CSFs and St. Louis encephalitis virus (SLEV) in one case. In Group 2 there were 3 CSFs positive for human herpesviruses, 2 for enteroviruses, 2 for DENV and 1 for SLEV. Detection of arboviruses, even though present in a minority of infected patients, identifies these viruses as a probable etiological agent of encephalitis. This is of special concern in regions where this class of viruses is endemic and has been linked to other recent epidemics.

Detection of the Epstein-Barr virus (EBV) by in situ hybridization as definitive diagnosis of hairy leukoplakia.

Histopathological findings in cases of hairy leukoplakia (HL) are not exclusive to this lesion. A total of 36 tissue samples from patients previously diagnosed with HL based solely on morphological aspects were used in this study. Our purpose was to confirm the presence of Epstein-Barr virus (EBV) in these tissue samples by in situ hybridization (ISH), and to compare the detection of EBV with specific histopathological findings observed in each case. Among the 36 specimens, 80.55% were EBV positive, confirming the previous clinical and histhophatological diagnosis. None of the histopathological findings analyzed correlated with the presence or absence of EBV. This shows that a definitive diagnosis of HL cannot be established based on histopathological findings alone. Because there are many important implications on the establishment of definitive diagnosis of HL, the detection of EBV by ISH is obligatory.