The announcement comes after two unrelated patients from the southern Ashanti region of Ghana, both of whom later died, tested positive for the virus.
The patients had shown symptoms including diarrhea, fever, nausea, and vomiting, WHO said, adding that more than 90 contacts are being monitored.
Marburg is a highly infectious viral hemorrhagic fever in the same family as the better known Ebola virus disease and has a fatality ratio of up to 88%, according to WHO. “Illness begins abruptly, with high fever, severe headache, and malaise,” it stated.
The virus is transmitted to humans from fruit bats and can then be spread human-to-human through direct contact with the bodily fluids of infected people or surfaces and materials contaminated with these fluids, WHO explained.
The global health body said containment measures were being put in place and that more resources would be deployed in response to the outbreak in Ghana. WHO also warned that “without immediate and decisive action, Marburg can easily get out of hand.”
There are no approved vaccines or antiviral treatments for the Marburg virus. However, a patient’s chances of survival can be improved with care including oral or intravenous rehydration and treatment of specific symptoms, WHO said.
The Ghana Health Service has urged the Ghanaian public to avoid mines and caves occupied by fruit bats and to thoroughly cook all meat products before consumption, to help reduce the risk of spreading the virus. Fruit bats are natural hosts of Marburg virus, the health service said.
The Ghana outbreak is only the second in West Africa after Guinea detected the virus last year. The patient in the Guinea outbreak also died from the virus. No further cases were confirmed by Guinean health authorities.
In other parts of Africa, previous outbreaks have been reported in Uganda, Kenya, Angola, South Africa and the Democratic Republic of Congo. The Angola outbreak in 2005 was the most deadly with more than 200 people killed.
According to WHO, countries at higher risk of a resurgence of the virus have been contacted “and they are on alert.”