Researchers in Japan have found a link between the measles virus and subacute sclerosing panencephalitis, or SSPE. SSPE is rare but a severe neurological illness that can appear years after a measles infection.

Even though the typical form of the measles virus cannot infect the brain system, the researchers found that viruses that linger in the body can generate changes in a critical protein that controls how they infect cells. It can infect the brain because its regular form can interact with the changed proteins. The findings were published in the journal Science Advances.

When the scientists examined the measles viral genome from SSPE patients, they discovered that their F protein had developed several mutations. It is interesting to note that some mutations increased infection activity while others decreased it. According to the study, a neuron is infected by the virus by a process known as "en bloc transmission," in which multiple copies of the viral genome enter the cell. In this instance, the genomes encoding the mutant and normal F proteins are delivered concurrently, increasing the likelihood that both proteins would coexist in the infected cell.

In another instance, the scientists discovered that a separate collection of F protein mutations causes a decrease in fusion activity. To their astonishment, this mutation can work in conjunction with regular F proteins to boost fusion activity. As a result, even mutant F proteins that dont seem to be able to infect neurons can nonetheless spread to the brain.

The team anticipates that their findings may aid in developing therapies for SSPE and shed light on the evolutionary processes among viruses causing measles that have a similar pattern of infection, such as new coronaviruses and herpesviruses.

(Source: https://theprint.in/health/measles-virus-cooperates-with-itself-to-cause-fatal-encephalitis-research/1339514/)