Piecing together the progression of deadly diseases from autopsy samples is a challenge often met by biomedical scientists. This brain tissue – from a rhesus monkey – is infected with the Japanese encephalitis virus (JEV), the cause of over 10,000 human deaths per year. On the left, JEV (stained in orange) has infected several neurons [nerve cells]. The neurons look healthy, but JEV is a slow-acting and devious virus. It hijacks the neurons’ chemical signals, sending out cytokines that turn inflammation, the brain’s natural protective process, against itself. On the right, the brain’s own immune defenders, microglial cells, have swarmed to attack infected neurons, leaving them shrivelled. There is currently no treatment for JEV, which, aside from many deaths, causes brain damage in many thousands of patients. Cultural constraints on autopsies in the Western Pacific, where Japanese encephalitis predominantly occurs, make this evidence for the timeline of JEV both rare and valuable.
Written by John Ankers
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