Indonesia is trying to contain an outbreak of dengue fever which has killed 91 people in six provinces since the start of the year.
Workers in Jakarta have been spraying the streets with insecticide
Health officials say around 4,500 people have been taken to hospital with the disease - twice as many as in last year's outbreak.
They said heavy rains could be responsible for the increase.
Dengue fever is carried by mosquitoes and infects about 100m people worldwide each year, of which about 5% die.
Java island has been the worst hit, with at least 38 people reported dead in East Java province and 17 others in the capital Jakarta.
"The situation is dire and needs immediate handling," said Health Ministry spokeswoman Mariani Reksoprojo.
She said that the figures could rise once more statistics were in from Indonesia's 31 provinces.
Officials in Jakarta have said that the increased number of cases could be to do with heavy rains and pools of stagnant water in the city which serve as a breeding ground for mosquitoes.
Workers in Jakarta have been spraying neighbourhoods with insecticide to try and prevent the disease from spreading.
Other officials have suggested a new strain of dengue fever could account for the high number of cases, but the World Health Organisation (WHO) said it may be to do with the cyclical nature of the virus.
"Dengue fever tends to have a higher incident (of death) on a five year to six year cycle," said the WHO's Steven Bjorge in Jakarta.
"It seems that it takes about five years for non-immune populations to build up, mostly children born after the outbreak," he said.
Symptoms of the disease include fever, body ache and in the most serious cases, internal bleeding.