KUALA LUMPUR—Dengue fever has killed 33 Malaysians this year and sickened more than 12,000, a health official said Friday, a dramatic increase that is defying intense efforts by the government to curb infections.

Dengue infections through March 16 this year had spiraled from the 8,212 cases recorded in the same period last year, while fatalities more than doubled from the 14 deaths in 2008, said Health Minister Liow Tiong Lai.

“The epidemic must be stopped and calls for the cooperation of all quarters,” Liow told a news conference in northern Malaysia, according to the national news agency Bernama.

Liow’s aide, Lim Chau Leng, confirmed the minister’s comments.

A long rainy season, unsanitary conditions and stagnant water collected in items like flower pots, cans and litter had created fertile breeding grounds for mosquitos that transmit the disease, Liow said.

He blamed “the apathetic attitude of the people of not taking care of the cleanliness of their homes.”

The ministry launched a massive campaign in January to advise people to rid their homes of items that attract the insects and to quickly seek medical treatment if they have symptoms of the disease, which include high fever, joint pains and nausea.

In severe cases, the dengue virus can lead to internal bleeding, liver enlargement, circulatory shutdown and death. There is no known cure or vaccine. AP