A yellow fever outbreak in Angola that began late last year has killed 158 people, up from 50 a month ago, as deaths from the disease transmitted by mosquitoes accelerate, a World Health Organisation official said on Friday.

There has also been an increase in malaria, cholera and chronic diarrhoea in Luanda and other cities, partly due to a breakdown in sanitation services and rubbish collection, health officials say.

City authorities have slashed their budget for rubbish collection to cope with a budget crisis, leaving piles of waste building up in poorer suburbs including Viana, where the first case of yellow fever was reported in late December.

“This is an urban pattern of outbreak of Yellow Fever and it is much more complicated to tackle and deal with,” said Hernando Agudelo Ospina, the WHO representative in Luanda.

“The possibility of spreading out to other provinces or even to the all country is much higher than if it had happened in a rural area.”

The disease was mainly confined to Luanda and its suburban areas where the outbreak was first registered, he said.

Angola relies on crude exports for around 95 percent of its foreign exchange earnings and a sharp decline in oil prices since mid-2014 has hobbled Africa’s second biggest oil exporter, sending the kwanza currency plummeting and necessitated deep cuts in public spending.

(Reporting by Herculano Coroado; Writing by TJ Strydom; Editing by James Macharia)