Marburg virus death toll hits 180
205 cases have been reported
(CNN) -- The World Health Organization is investigating an outbreak of hemorrhagic fever in northwestern Angola, it said Friday.
As of Thursday, 205 cases of Marburg hemorrhagic fever had been reported in the country, and 180 of those affected had died. Seven provinces have been affected, the latest being Zaire province, where six cases have been reported, the WHO said in its most recent update.
"It is a very, very dangerous and lethal virus in human beings," Mike Ryan, director of alert and response operations for WHO, told CNN. The virus -- in the same family as the Ebola virus -- spreads through blood and body fluid contact.
In this case -- only the second natural outbreak of the virus -- there is evidence it has been amplified through ineffective containment in hospitals, Ryan said.
According to WHO, the first large outbreak under natural conditions occurred from 1998-2000 in the Democratic Republic of Congo.
Some Angolans have taken their anxiety out on health workers.
Mobile surveillance teams in Uige were forced to suspend operations Thursday when vehicles were attacked and damaged by residents, the WHO said Friday. "As the situation has not improved, no surveillance teams were operational today in the province."
In addition, organization staff in Uige were notified Friday of several workers' fatalities, but teams were unable to investigate the causes of death or collect the bodies for burial. Discussions "to find urgent solutions" were under way with provincial authorities, the WHO said.
A WHO worker in Angola told CNN that health workers had been killed by residents who erroneously believed the workers were exposing them to the virus.
"The dramatic symptoms of Marburg hemorrhagic fever and its frequent fatality are resulting in a high level of fear, which is further aggravated by a lack of public understanding about the disease," the organization said. "Moreover, because the disease has no cure, hospitalization is not associated with a favorable outcome, and confidence in the medical care system has been eroded."
WHO said it has seen similar reactions during outbreaks of the Ebola virus. Two medical anthropologists are in Uige and will be joined by experts in social mobilization from Angola, the Democratic Republic of Congo and Mozambique.
Through the United Nations, WHO launched an appeal Friday for $2.4 million to support the emergency response to the outbreak. In addition, the organization has established an international network of laboratories to help in the investigation of this and other viral hemorrhagic fevers. They include two portable field laboratories in Angola.
"Sophisticated laboratory studies of the virus may help shed some light on certain unusual features of the outbreak, including the high fatality rate and the overwhelming concentration of initial cases in children under the age of five years," said a WHO statement.
A longer-term objective, the organization said, is to determine where the Marburg virus hides in nature between outbreaks. Studies of the Angolan virus may offer some clues.