A pathogen that causes suffering and death

Marburg virus is just one of several pathogens that have had an exceptional few years. In the years 2022 and 2023, humanity also struggled with rare or extreme epidemics of monkeypox, polio, RSV, and bird flu. And then there’s COVID, of course. Epidemiologists blame our new viral age on climate change and deforestation (which disrupts animal populations), as well as global air travel (which spreads a virus) and deepening opposition to science and public health in some communities (which which makes it more difficult to prevent and limit infections). But even among the other viruses on the rise, Marburg is unique. Vaccines are available or in development for all other viruses. But not for Marburg, whose outbreaks start so suddenly, kill so thoroughly and end so quickly that there has never been time to conduct large-scale human trials of a candidate vaccine. ” We don’t have data from human trials,” Brian Garibaldi, director of the Maryland-based Johns Hopkins Biocontamination Unit, told The Daily Beast. And there is no easy way to solve this problem.

Where and when did Marburg Appear?

Marburg virus emerged in the far northeast of Equatorial Guinea in West Africa on February 13, a year after the last outbreak in Ghana. Six weeks later, on March 21, officials detected human Marburg infections in Tanzania, a thousand kilometers to the east. “It does not appear that the two outbreaks are related,” Garibaldi said. It’s just pathogenic bad luck. The two outbreaks are not identical. “In Tanzania, the outbreak appears to be diminishing, while it appears to be expanding in Equatorial Guinea, where more cases have been reported, said Amira Roess, a professor of global health and epidemiology at George Mason University in Virginia. “The situation in Equatorial Guinea is unclear in part due to a lack of surveillance, a fear of reporting, and other political and economic pressures. This worries many of us because, without timely surveillance data and information, this outbreak may spread and cause significant disruption and death.” By Monday, the virus had spread separately to at least 33 people in both countries combined, killing 16 of them. Perhaps most worryingly, Equatorial Guinea’s Ministry of Health has reportedly detected cases in Bata, the country’s main transport hub. If Marburg is to spread to other continents, it may use Bata—its airport and seaport—as a starting point. It is not for nothing that the US Centers for Disease Control and Prevention are asking doctors in the United States to be vigilant. “It is important to systematically evaluate patients for the possibility of viral hemorrhagic fever… through a process of triage and evaluation, including a detailed travel history,” the CDC recommended Thursday. With almost any other virus, local, national, and international health officials would work together to isolate and treat patients while vaccinating everyone at high risk of infection. But with Marburg, officials’ options are limited. Based on Ebola vaccines or by modifying proteins from the Marburg virus, scientists have developed some very rudimentary vaccine prototypes. They can test these vaccines on healthy people to get safety data. They can inoculate rodents or non-human primates, then infect them with Marburg to get theoretical data on efficacy. But they have never been able to carry out large-scale testing on infected people.

By Roberto Caseli