Related Experiment Video
Updated: Jun 19, 2026
A Murine Model of Dengue Virus-induced Acute Viral Encephalitis-like Disease
Published on: April 28, 2019
STUDIES ON EASTERN EQUINE ENCEPHALOMYELITIS : IV. INFECTION IN THE MOUSE WITH FRESH AND FIXED VIRUS
1Department of Animal and Plant Pathology of The Rockefeller Institute for Medical Research, Princeton, New Jersey.
Abstract:
A fresh strain of equine encephalomyelitis virus is infectious for adult mice in high dilutions by all modes of peripheral inoculation. A fixed strain has very limited invasive power when injected peripherally unless virus is placed in fairly close contact with nerve cell bodies, as in the intranasal or intraocular routes. For fixed virus the effectiveness of the mode of inoculation may be graded in the following descending order: intracerebral, intraocular and intranasal, intravenous, intraperitoneal, intramuscular, subcutaneous. Fixed virus has a very limited power of invading the central nervous system along the axones of peripheral nerves even when injected directly into the nerve. Infants are more susceptible to infection than are adults. But even for infants, intraperitoneal inoculation with fixed virus is significantly less effective than similar inoculations with fresh virus. Brain trauma does not increase the effective titer of fresh or fixed viruses but may shorten the incubation period for fresh virus. With fixed virus injected intramuscularly, a pronounced facilitating effect may be produced by the simultaneous intraperitoneal injection of 0.20 to 0.25 cc. of 50 per cent glycerine. Other irritants tried are without effect.
Insights
Fresh equine encephalomyelitis virus infects mice easily via peripheral routes. Fixed strains require direct nerve contact for invasion, with varying effectiveness based on inoculation method.
Area of Science:
- Virology
- Neuroscience
- Infectious Diseases
Background:
- Equine encephalomyelitis virus (EEV) presents varying infectious potentials.
- Understanding viral neuroinvasion is crucial for disease control.
Purpose of the Study:
- To investigate the infectivity and neuroinvasive capabilities of fresh and fixed strains of EEV in mice.
- To determine the influence of inoculation routes and host factors on EEV infection.
Main Methods:
- Mice (adult and infant) were inoculated via various peripheral routes (intracerebral, intraocular, intranasal, intravenous, intraperitoneal, intramuscular, subcutaneous).
- Infectivity and central nervous system invasion were assessed for fresh and fixed EEV strains.
- The effect of brain trauma and co-administered substances (glycerin) was evaluated.
Main Results:
- Fresh EEV was infectious in high dilutions via all peripheral routes in adult mice.
- Fixed EEV demonstrated limited peripheral invasiveness, requiring direct nerve contact (intraocular, intranasal) for effective central nervous system entry.
- Inoculation effectiveness for fixed EEV decreased in the order: intracerebral > intraocular/intranasal > intravenous > intraperitoneal > intramuscular > subcutaneous.
- Infants were more susceptible than adults, but fixed EEV intraperitoneal inoculation was less effective than fresh EEV.
- Brain trauma did not alter viral titers but could shorten incubation periods for fresh EEV.
- Simultaneous intraperitoneal glycerin injection facilitated intramuscular fixed EEV inoculation.
Conclusions:
- The strain of EEV significantly impacts its neuroinvasive potential and infectivity.
- Route of inoculation is a critical determinant for fixed EEV neuroinvasion.
- Age influences susceptibility, with infants being more vulnerable.
- Glycerin can enhance the infectivity of fixed EEV via specific inoculation routes.
