Initial findings of genomic analysis indicates that the Marburg virus, which caused an outbreak in Rwanda, has "a single zoonotic origin," meaning it jumped from an animal to a human only once and had not passed through multiple hosts, according to health authorities.
Minister of State for Health Dr Yvan Butera shared the results of the initial genomic sequencing of the Marburg virus in Rwanda in a post on X on Sunday, October 20, following a press briefing held by Minister of Health Dr Sabin Nsanzimana and the Director-General of World Health Organization (WHO) Dr Tedros Adhanom Ghebreyesus.
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The Marburg virus transmitted to humans from fruit bats and is spread by human-to-human contact through bodily fluids.
Minister Butera explained that a phylogenetic analysis -- the study of evolutionary relationships among biological entities, often species, individuals or genes -- shows the viral sequences are closely related, with four being identical, indicating rapid spread within a short timeframe.
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"While we found some mutations, none suggests the virus is spreading more easily or becoming more severe," he said.
"Using genomic tools, we found that all sequences share a single zoonotic origin, meaning the virus jumped from animal to human just once."
Identifying the index case
Minister of Health Dr. Sabin Nsanzimana elaborated on the findings, saying that a thorough investigation, which combined sequencing research, epidemiological investigation, diagnostic analysis, clinical information, and One Health insights, led to the identification of the index case.
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"We have a very high probability and high precision that this is our index case, which is very closely linked to a zoonotic quality," he said.
Dr Nsanzimana noted the significance of these findings for public health strategies.
"This is something we confirmed recently after all this testing combined. This will help us adjust and enhance our surveillance capabilities moving forward, not only for this outbreak but also for preventing potential future outbreaks.
"It's crucial information for us and our partners who have been working to make this transmission change precise, allowing us to assert our understanding of the index case and its strong linkage to the zoonotic origin," he added.
He further noted that the sequencing data from their laboratory, in collaboration with various partners, indicates that the virus in Rwanda is referred to as the "October strain," which closely resembles other strains reported in the region since 2014.
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"The integration of five points of information leading to our sequencing results positions us to assert that this virus has a zoonotic origin. It is very similar to strains we've seen in the region before, indicating minimal change over the last decade," Dr Nsanzimana said.
"The transformations appear very small, suggesting it didn't pass through different hosts to acquire mutations. This is critical information for those working in this field," he said.
