Researchers from the Mayo Clinic have meticulously traced the mutation and proliferation patterns of the measles virus in the brain of an individual who died from a rare and fatal brain condition. This disease is an uncommon complication arising from measles infection, and its occurrence might increase as measles becomes more prevalent among unvaccinated populations, according to the researchers.
Leveraging advanced genetic sequencing technologies, the Mayo Clinic team recreated the process by which a variety of viral genomes took hold within a human brain. These genomes underwent specific mutations facilitating the virus’s expansion from the frontal cortex to other areas.
Roberto Cattaneo, Ph.D., a leading virologist at Mayo Clinic and co-author of the study published in PLOS Pathogens, emphasized the significance of their findings. He stated that their research offers critical insights into how the viral RNA mutates and disseminates within a major human organ—specifically, the brain. These insights are pivotal for understanding the persistence and adaptation of other viruses within the human brain, potentially leading to disease. Furthermore, this knowledge could aid in the development of potent antiviral medications.
Measles is known for its high contagion levels. It initially infects the upper respiratory system and utilizes the trachea as a launch pad, spreading through droplets emitted during coughs or sneezes by infected individuals.
Dr. Cattaneo has been at the forefront of research on the systemic spread of the measles virus. His fascination with measles began approximately 40 years ago, particularly with subacute sclerosing panencephalitis (SSPE), a lethal brain disease that emerges in roughly 1 out of every 10,000 measles cases. SSPE manifests years after the initial measles infection, leading to severe neurological symptoms such as memory loss, seizures, and paralysis. Dr. Cattaneo dedicated many years to studying SSPE until the disease became rare, thanks to widespread measles vaccination.
However, the resurgence of measles, driven by vaccine scepticism and missed vaccinations, especially during the COVID-19 pandemic, has led to a significant rise in measles cases and deaths globally. The decline in vaccination rates has resulted in an estimated 18% increase in measles cases and a 43% surge in measles-related deaths in 2021 compared to the previous year, as the Centers for Disease Control and Prevention (CDC) reported.
The research team, including Dr. Cattaneo and Iris Yousaf, a Ph.D. candidate at the Mayo Clinic Graduate School of Biomedical Sciences, utilized a unique opportunity to study SSPE through a collaboration with the CDC. They analyzed brain samples from an individual who contracted measles in childhood and later succumbed to SSPE. By conducting genetic sequencing on various brain regions, they pieced together how the measles virus evolved and increased within the brain.
They found that the virus’s genome began mutating in detrimental ways upon entering the brain, creating a diverse population of viral genomes. Two specific genomes possessed characteristics that significantly enhanced the virus’s ability to spread from the frontal cortex, effectively colonizing the entire brain.
The research team plans to explore further how particular mutations facilitate the virus’s spread in the brain. These investigations will involve studies on brain cell cultures and brain-like organoids. The aim is to uncover potential antiviral treatments to prevent virus proliferation within the brain. Despite the challenges in treating advanced stages of diseases like SSPE, vaccination against measles remains the most effective prevention strategy.
More information: Iris Yousaf et al, Brain tropism acquisition: the spatial dynamics and evolution of a measles virus collective infectious unit that drove lethal subacute sclerosing panencephalitis, PLoS Pathogens. DOI: 10.1371/journal.ppat.1011817
Journal information: PLoS Pathogens Provided by Mayo Clinic
