MINNEAPOLIS — University of Minnesota researchers have made key discoveries about one of the world’s most lethal pathogens, the Marburg virus, including potential weaknesses that could result in vaccines or drug treatments against it.

Marburg is lesser-known than its close cousin, Ebola, and remains confined so far to Africa. But its severity was apparent last year when an outbreak in Ethiopia killed nine of 14 people with confirmed infections. U researchers discovered that Marburg is 300 times more efficient than Ebola at infiltrating human cells, and mapped out the biological pathways by which the virus spreads.

“Scientists have long suspected that Marburg virus enters human cells more efficiently than Ebola virus, but until now there was no reliable way to compare the two fairly‚" said Fang Li, a lead author and a pharmacology professor at the U of M Medical School in Minneapolis.

The team’s study was published Wednesday in Nature, a prestigious scientific journal, and was based on a novel method that the U developed for comparing the efficiency of viruses. The researchers worked with “pseudoviruses,” or biological material that simulates the behavior of Marburg and Ebola without presenting the danger of live viruses, Li said.

Ebola and Marburg infect human cells using the same biological mechanism, but a microscopic protein on the surface of the Marburg virus allows it to spread faster. The protein binds tightly to human cells and then changes shape in a way that opens them up for infection, the U of M researchers showed.

The virus’ startling efficiency explains why it often causes hemorrhagic fevers, damages blood vessels and leads to organ failure, said Dr. Bin Liu, a coauthor at the U’s Hormel Institute, a biomedical research lab in Austin, Minn. The fatality rate from infection is around 70%.

“There are currently no approved treatments or vaccines,” he said, but the U’s research could be a first step in changing that lack of options.

A protective cap on the Marburg protein helps it avoid detection by the human immune system until its too late. However, U researchers discovered that a key antibody can slip past the cap and block the protein’s ability to lock onto human cells, potentially preventing infection.

To unlock Marburg’s mysteries, the U scientists used technology at the Hormel Institute called cryo-electron microscopy, a method of freezing biological samples below -230 F to gain ultra-clear images that can then be used to develop 3D models.

Marburg originated in a species of African bat, which is one reason why the virus hasn’t presented threats elsewhere in the world. But the virus can spread quickly among people, especially if they touch contaminated surfaces such as bedding or bodily fluids such as blood and then touch their mouths, noses or eyes.

The risk of such deadly viruses was evident in 2014, when the first person diagnosed with an Ebola infection in the U.S. quickly spread it to two nurses in Texas who treated him. The initial patient died while the nurses recovered.

Several false alarm cases were investigated at the time in Minnesota amid hospital preparations for managing Ebola and preventing infections among healthcare workers. Plans by U of M researchers to test an experimental Ebola vaccine were disrupted a year later when an outbreak in Africa subsided. U biostatistician James Neaton contributed to a study in 2022 showing that Ebola vaccines produced an immune response in recipients without causing safety concerns.

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