The World Health Organization (WHO) Friday called for stepping up measures in Angola to halt the further spread of the deadly Marburg virus, which has killed 174 people mainly in the north of the country.

The United Nations agency said a first case of the incurable disease had been found in Kuanza Sul, the sixth province in the northwest to be hit, while a suspect death was also under investigation in neighboring Democratic Republic of Congo.

There was an unusually high death rate among the 200 cases identified since October, mainly in the northern town of Uige, with an overwhelming number of initial cases striking children under 5 years old, the WHO said in a statement.

“The situation right now in Angola is not under control yet…This is still a health crisis at the national level and requires a profound commitment both from national authorities and the international community in order to contain this disease,” Mike Ryan, director of WHO’s alert and response operations, told a news briefing.

Some 50 international experts have been deployed in Angola, where 27 years of civil war have left weakened health systems and staff untrained for coping with a major epidemic, he said.

By isolating victims and tracing their contacts, officials were “breaking the chain of transmission” in Uige, he said.

Two deaths have been confirmed from Marburg in Luanda, a teeming capital of 4 million people, where six more cases are being investigated, Ryan said.

There was no evidence of transmission within Luanda, where the two deaths have been a 15-year-old boy and a nurse, he said.

But Ryan noted the densely populated city saw “movement and exchange of people between all areas of Angola,” adding: “Therefore it is crucially important that the surveillance systems and isolation units have to be fully established in Luanda, both to maintain confidence in travel to Angola and also to protect that population. That is ongoing.”

Separately, the United Nations issued an emergency appeal to donors for $3.5 million to combat the virus, one of the most virulent pathogens known, over the next three months.

The rare haemorrhagic fever, related to the deadly Ebola virus, is characterized by headaches, nausea, vomiting and bloody diarrhea. It is spread through close contact with bodily fluids including blood, saliva and semen.

The outbreak has surpassed the previous record of 123 deaths in a 1998-2000 epidemic in the Democratic Republic of Congo.

The hospital itself in Uige, a town of 500,000, may have contributed to spreading the virus, according to Pierre Formenty, a WHO expert on haemorrhagic fevers.

“There is a possibility ... that the hospital served to infect children who came to be treated there. It is not confirmed, but it is a hypothesis,” Formenty told reporters.

Twelve health care workers were among the total 200 cases.

Medical anthropologists were enlisting tribal leaders to inform the often illiterate population about the dangers of contracting the disease while caring for the sick or preparing bodies for burial, Formenty said.

“Our simple message is very clear: don’t touch sick patients and don’t touch bodies,” he said.