Human Vilyuisk encephalitis

125

161

mentioning

confidence: 99%

Cardioviruses Are Genetically Diverse and Cause Common Enteric Infections in South Asian Children

Blinkova

Kapoor

Victoria

et al. 2009

125

161

“…For over 100 years, a form of human encephalomyelitis called Vilyuisk encephalitis (VE) has been known to affect the Yakut people who inhabit the Vilyuy Valley in Siberia (22,35). Between 1954 and 1957, viral isolates thought to be linked to the disease were recovered from human clinical specimens.…”

Section: Discovery Of a Novel Human Cardiovirusmentioning

confidence: 99%

Saffold Virus, a Novel Human Cardiovirus with Unknown Pathogenicity

Himeda

Ohara

2012

Although cardioviruses have been thought to mainly infect rodents, a novel human cardiovirus, designated Saffold virus (SAFV), was identified in 2007. SAFV is grouped with Theiler-like rat virus and Theiler's murine encephalomyelitis virus (TMEV) in the species Theilovirus of the genus Cardiovirus of the family Picornaviridae. Eight genotypes of SAFV have now been identified. SAFV has been isolated from nasal and stool specimens from infants presenting with respiratory and gastrointestinal symptoms as well as from children with nonpolio acute flaccid paralysis; however, the relationship of SAFV to this symptomatology remains unclear. Of note, the virus has also been isolated from the cerebrospinal fluid specimens of patients with aseptic meningitis. This finding is of interest since TMEV is known to cause a multiple sclerosis-like syndrome in mice. The involvement of SAFV in various diseases (e.g., respiratory illness, gastrointestinal illness, neurological diseases, and type I diabetes) is presently under investigation. In order to clarify the pathogenicity of SAFV, additional epidemiological studies are required. Furthermore, identification of the SAFV cellular receptor will help establish an animal model for SAFV infection and help clarify the pathogenesis of SAFV-related diseases. In addition, investigation of the tissue-specific expression of the receptor may facilitate development of a novel picornavirus vector, which could be a useful tool in gene therapy for humans. The study of viral factors involved in viral pathogenicity using a reverse genetics technique will also be important.

“…This virus was isolated as a putative causative agent of endemic encephalitis episodes occurring in the Yakuts population near the Vilyui river in Siberia (7). VHEV was recovered from a mouse inoculated with cerebrospinal fluid of a patient presenting with chronic encephalitis.…”

mentioning

confidence: 99%

Nonstructural Protein L* Species Specificity Supports a Mouse Origin for Vilyuisk Human Encephalitis Virus

Drappier

Opperdoes

Michiels

2017

Vilyuisk human encephalitis virus (VHEV) is a picornavirus related to Theiler's murine encephalomyelitis virus (TMEV). VHEV was isolated from human material passaged in mice. Whether this VHEV is of human or mouse origin is therefore unclear. We took advantage of the species-specific activity of the nonstructural L* protein of theiloviruses to track the origin of TMEV isolates. TMEV L* inhibits RNase L, the effector enzyme of the interferon pathway. By using coimmunoprecipitation and functional RNase L assays, the species specificity of RNase L antagonism was tested for L* from mouse (DA) and rat (RTV-1) TMEV strains as well as for VHEV. Coimmunoprecipitation and functional assay data confirmed the species specificity of L* activity and showed that L* from rat strain RTV-1 inhibited rat but not mouse or human RNase L. Next, we showed that the VHEV L* protein was phylogenetically related to L* of mouse viruses and that it failed to inhibit human RNase L but readily antagonized mouse RNase L, unambiguously showing the mouse origin of VHEV.IMPORTANCE Defining the natural host of a virus can be a thorny issue, especially when the virus was isolated only once or when the isolation story is complex. The species Theilovirus includes Theiler's murine encephalomyelitis virus (TMEV), infecting mice and rats, and Saffold virus (SAFV), infecting humans. One TMEV strain, Vilyuisk human encephalitis virus (VHEV), however, was isolated from mice that were inoculated with cerebrospinal fluid of a patient presenting with chronic encephalitis. It is therefore unclear whether VHEV was derived from the human sample or from the inoculated mouse. The L* protein encoded by TMEV inhibits RNase L, a cellular enzyme involved in innate immunity, in a species-specific manner. Using binding and functional assays, we show that this species specificity even allows discrimination between TMEV strains of mouse and of rat origins. The VHEV L* protein clearly inhibited mouse but not human RNase L, indicating that this virus originates from mice. KEYWORDS Theiler's murine encephalomyelitis virus, Vilyuisk human encephalitis virus, L* protein, mitochondria, RNase L, species specificity, natural host D efining the natural host species of a virus is often hampered by the fact that an evolutionarily well-adapted virus tends to lose virulence toward its natural host (1, 2). In the process of coevolution, many DNA viruses integrated host genes into their own genome. This feature can provide hints to trace the original host species of a given virus (3). On the other hand, RNA viruses have a limited coding capacity and therefore do not generally integrate host-derived genes. In this case, host prediction can be aided by phylogenic proximity to viruses of known species origin. In addition, species-specific activities of certain viral proteins can help to identify the original host. For instance, Theiler's murine encephalomyelitis virus (TMEV) (or Theiler's virus) encodes the accessory L* protein that inhibits host RNase L, a well-characterized eff...