Two deadly Marburg virus outbreaks in Africa alarm global health experts

Two simultaneous outbreaks of the Marburg virus, a close relative of Ebola that can kill 90% of those infected, have important implications for the behavior of this enigmatic bat-borne pathogen and global efforts to prepare for a potential pandemic. I am raising an issue.

Marburg disease, a hemorrhagic fever, is rare. Only a handful of outbreaks have been reported since the virus was identified in 1967.

Marburg disease causes high fever, vomiting, diarrhea and, in the most severe cases, bleeding from orifices. It is spread from person to person through direct contact with the blood or other body fluids of an infected person and with surfaces or materials, such as clothing, that have been contaminated with these fluids.

One of two outbreaks in Tanzania, East Africa, appears to have been brought under control, with only two people isolated. But in Equatorial Guinea on the west coast, where the virus continues to spread, the World Health Organization last week said the country was not transparent in reporting cases.

There is no cure or vaccine for Marburg disease, but there are several promising candidates in phase 1 clinical trials. But these candidates will need to be tested in active outbreaks to prove they work, and so far no vaccine supply has been provided for testing in the current outbreak.

“At the moment an outbreak is detected, a mechanism that rapidly migrates,” said Dr. John Amuasi, head of the Department of Global Health at the Kwame Nkrumah University of Science and Technology in Ghana, who last investigated the Marburg epidemic in the country. There should be,” he said. Year.

He said the WHO and others have excelled at rapid response to control the spread of the virus, but lacked the same rapid response to research. We need a stockpile of vaccine candidates and researchers ready to ship without further straining an already struggling health system. Neither currently exist.

WHO says it drafted Research protocol This can be applied to these outbreaks and other filoviruses (family including Marburg and Ebola virus).

If the outbreak response works well, if infected people can be isolated and contacts traced, the epidemic will be controlled quickly, and Tanzania seems to be the case. A failure to respond (as in Equatorial Guinea) threatens to double widespread outbreaks and the need for vaccination.

When the Ebola epidemic began in Uganda in September 2022, the strains that died quickly were those for which there was no vaccine, but there were likewise strong candidates waiting to be tested. Researchers have announced plans to try it in Uganda.but The outbreak was over by the time the vaccine dose arrived.

Outbreaks in Equatorial Guinea and Tanzania are the first reported cases in either country.outbreak in equatorial guinea I started in January. The government has reported nine deaths with confirmed Marburg disease and another 20 deaths associated with confirmed cases that have not been tested but are considered probable cases.

The government of Equatorial Guinea has released limited information about the outbreak, and the WHO said that there is likely an undetected chain of transmission and that not all known cases are clearly linked to each other. It suggests a wider spread than previously thought.

“WHO is aware of additional cases and has asked the government to officially report these cases to WHO,” WHO Director Dr Tedros Adhanom Ghebreyesus said last week.

An outbreak in Tanzania was first reported in March. Five people with confirmed Marburg infection died there, including a health care worker.

Although Tanzania has reported no new cases for two weeks, the outbreak is considered active in Marburg as the incubation period is 21 days.

Keri Issa, the Tanzanian Red Cross Marburg virus disease control manager, said in a telephone interview from the Kagera region where the disease originated, “This is the hard part, people are being quarantined and waiting for days. I will,” he said.

The WHO said both outbreaks pose regional risks.Equatorial Guinea has a hole in its borders with Cameroon and Gabon, and so far cases have occurred in geographically dispersed parts of the country. The Kagera region of Tanzania shares borders with Uganda, Rwanda and Burundi.

These outbreaks follow outbreaks in Ghana last year and Guinea the year before, and are a marked change from previous sporadic outbreaks. Dr Amuasi said improved tracking likely contributed to the increase in the number of cases. All African countries have improved their PCR testing capacity and infectious disease surveillance as part of their response to the Covid-19 pandemic. This means that Marburg disease is diagnosed more frequently.

However, this suggests that the virus may have been circulating among humans more than historically thought, and how it makes people sick was previously understood. It may differ from the

Dr. Nancy Sullivan, director of the National Institute of Emerging Infectious Diseases at Boston University, believes climate change and the way it is altering human and animal behavior is causing the actual increase in cases. The virus “has more of an impact on the reservoir,” she said.

Dr. Sullivan made the most progress with the Marburg vaccine candidate while working at the National Institute of Allergy and Infectious Diseases. Phase 1 clinical trials have shown safety and immune responses, and Sabin and his Vaccine Institute, a Washington-based nonprofit that drives global vaccine development, continues the testing process.

The Sabin Institute said it has 600 doses of the vaccine in vials, ready to use, and plans to eventually stockpile 8,000 doses by the end of this year. Sullivan said 600 doses would be enough to start ring vaccination trials for at-risk people in Tanzania and Equatorial Guinea.

However, WHO has yet to release operational details on trials of this vaccine candidate or three other vaccine candidates. Trials require a principal investigator from the country of origin, legal agreement with the vaccine manufacturer, and regulatory approval. Equatorial Guinea has a notoriously opaque government that has been under the rule of President Teodoro Obiang Nguema Mbasogo and his family for over 30 years.

Without committed resources and pre-approved clinical trial protocols, filovirus outbreaks will continue to occur and little progress will be made on interventions that can stop them, Dr. Amuasi said.