ABSTRACT
Neurotropic viruses initiate infection in peripheral tissues prior to entry into the central nervous system (CNS). However, mechanisms of dissemination are not completely understood. We used genetically marked viruses to compare dissemination of poliovirus, yellow fever virus 17D (YFV-17D), and reovirus type 3 Dearing in mice from a hind limb intramuscular inoculation site to the sciatic nerve, spinal cord, and brain. While YFV-17D likely entered the CNS via blood, poliovirus and reovirus likely entered the CNS by transport through the sciatic nerve to the spinal cord. We found that dissemination was inefficient in adult immune-competent mice for all three viruses, particularly reovirus. Dissemination of all viruses was more efficient in immune-deficient mice. Although poliovirus and reovirus both accessed the CNS by transit through the sciatic nerve, stimulation of neuronal transport by muscle damage enhanced dissemination only of poliovirus. Our results suggest that these viruses access the CNS using different pathways.
Subject(s)
Central Nervous System/virology , Orthoreovirus, Mammalian/pathogenicity , Peripheral Nerves/virology , Poliovirus/pathogenicity , Yellow fever virus/pathogenicity , Animals , Cell Line , Cricetinae , HeLa Cells , Humans , Interferon Type I/immunology , Mice , Mice, Inbred C57BL , Mice, Knockout , Orthoreovirus, Mammalian/growth & development , Poliomyelitis/pathology , Poliomyelitis/transmission , Poliovirus/growth & development , Receptor, Interferon alpha-beta/genetics , Reoviridae Infections/pathology , Reoviridae Infections/transmission , Sciatic Nerve/virology , Yellow Fever/pathology , Yellow Fever/transmission , Yellow fever virus/growth & developmentABSTRACT
A number of Japanese encephalitis (JE) vaccines have been used for preventing Japanese encephalitis around the world. We here reviewed the immunogenicity and safety of the currently available Japanese encephalitis vaccines. We searched Pubmed, Embase, Web of Science, the Cochrane Library and other online databases up to March 25, 2014 for studies focusing on currently used JE vaccines in any language. The primary outcomes were the seroconversion rate against JEV and adverse events. Meta-analysis was performed for the primary outcome when available. A total of 51 articles were included. Studies were grouped on the basic types of vaccines. This systematic review led to 2 aspects of the conclusions. On one hand, all the currently available JE vaccines are safe and effective. On the other hand, the overall of JE vaccine evaluation is disorganized, the large variation in study designs, vaccine types, schedules, doses, population and few hand-to-hand trails, make direct comparisons difficult. In order to make a more evidence-based decision on optimizing the JE vaccine, it is warranted to standardize the JE vaccine evaluation research.