Retrospective detection of HHV-6 A and HHV-6B viruses in patients suspected of viral infection of the central nervous system in Córdoba, Argentina

Abstract

In recent years, Herpesviruses HHV-6A and HHV-6B have been increasingly associated with infections of the central nervous system. Many investigations have reported these viruses as etiological agents of meningitis, encephalitis or meningoencephalitis in people of different ages and from different parts of the world.

In our country, there is very little knowledge about the epidemiology of these viruses associated with infections of the central nervous system. Moreover, recent need to study the epidemiology of this viruses separately has arisen because until a few years ago they were considered variants of the same virus (HHV-6) and due to their biological, clinical and epidemiological differences they were reclassified as two different Herpesviruses.

In order to make a contribution to the epidemiology of HHV-6A and B associated with central nervous system infections in our environment, we conducted a retrospective study in samples of cephalic spinal fluid (CSF) that were obtained in hospitalized patients suspected of having viral meningoencephalitis.

For the study, 67 CSF samples obtained between January 2007 and March 2008 (age range 1-85 years) were selected. They were sent to the INVIV Institute of Virology for viral diagnosis and then preserved at -80°C. All selected samples were negative for other viruses such as Enterovirus, Herpes simplex, St. Louis encephalitis virus, West Nile virus and Dengue virus.

For the detection of viral DNA, a generic nested PCR was used that detects both viruses (HHV-6). The samples that were positive were then typified as A or B through specific PCR techniques for each of the viruses.

Of the 67 samples processed, 16 (23.9%) were positive for HHV-6, which, in turn, were all classified as HHV-6B.

The present retrospective study allowed us to infer that HHV-6B is a frequent cause of meningoencephalitis in people of differen