Equatorial Guinea’s first outbreak of Marburg virus—a relative of the Ebola virus that causes similarly deadly hemorrhagic fever—is continuing to grow, spreading over a wide geographic area with potentially undetected chains of transmission, officials for the World Health Organization said.
As of Wednesday morning, officials in Equatorial Guinea had reported nine confirmed cases, with seven confirmed deaths across three provinces since early February.
“However, these three provinces are 150 kilometers apart, suggesting wider transmission of the virus,” WHO’s Director-General Tedros Adhanom Ghebreyesus said in a press conference Wednesday.
In addition, there are 20 probable cases linked to the confirmed cases, all of whom have died.
Officials for WHO noted that while they are working with officials in Equatorial Guinea, the agency also has field workers on the ground helping to respond to the outbreak in affected areas. And through the field workers, WHO knows of additional laboratory-confirmed cases that have not been reported by officials.
“WHO is aware of additional cases, and we have asked the government to report these cases officially to WHO,” Tedros said.
In a Facebook post that appeared later on Wednesday, Equatorial Guinea’s Ministry of Health and Social Welfare stated that, as of March 28, there have now been 13 cases, with nine confirmed deaths. Two cases remain hospitalized with mild symptoms, the ministry said, and officials are tracking 825 contacts. It’s unclear if the new cases include all the unreported cases WHO had previously identified.
In the earlier press briefing, the WHO’s executive director of health emergencies program, Mike Ryan, expressed frustration at the delay in reporting.
“There’s always a slight delay between the case being confirmed on the ground and having an official report—that’s not my concern,” Ryan said. But, reporting, especially in the middle of an outbreak with a dangerous pathogen, needs to be done as quickly as possible so affected people can protect themselves, he emphasized. “Any delay in releasing information related to lab-confirmed cases—especially when it relates to newly affected areas—prevents the process of alerting communities and having them take action to protect themselves and their families,” he said. “So, this is not just a legal requirement in some international law [to report cases to WHO]. This is a sovereign and solemn requirement of all states to inform their own people of what is going on in their country, to the best of their knowledge.”
The outbreak currently spans three of Equatorial Guinea’s five continental provinces: the Litoral province, which stretches the Gulf of Guinea coast; the Centro Sur province, which covers the center of the country from the Cameroon border to the north to the border with Gabon to the south; and Kie-Ntem province at the northeast corner, bordering both Cameroon and part of Gabon to the east. Some of the cases have been identified in Bata, a port city in Litoral, with an estimated population of nearly half a million.
With all affected provinces sharing borders with Cameroon and Gabon, WHO has assessed the risk of a multi-country outbreak as high.
“Cross-border population movements are frequent, and the borders are very porous. Although no [Marburg virus disease] cases have been reported outside Equatorial Guinea, the risk of international spread cannot be ruled out,” WHO reported in a recent outbreak update.
Marburg outbreaks—thought to be sparked when the virus jumps to humans from bats or intermediate animals, such as monkeys—tend to be small and infrequent. Since the virus was first recognized in 1967, there have been 17 or so outbreaks, and most have had confirmed case counts only in the single digits. The largest outbreak, in Angola between 2004 and 2005, reached 252 confirmed cases, with 227 deaths (a 90 percent fatality rate).
This month, Tanzania reported its own first outbreak of Marburg. So far, there have been eight confirmed cases and five deaths, all of which were identified in one region.