GUANGZHOU -- The number of dengue fever cases in south China's Guangdong Province rose to 276 on Wednesday, an increase of 29 since Tuesday, said the provincial health department.

The cases include 245 in Guangzhou, the provincial capital, 22 in Yangjiang, six in Foshan and one each in Zhuhai, Jieyang and Chaozhou, said the department.

A dengue case previously reported in Shenzhen has ruled a misdiagnosis, it said.

The number is expected to rise in the near future in Guangdong as symptoms of the disease can take as long as 15 days to appear, said Luo Huiming, director of the epidemic prevention research institute of the Guangdong Disease Prevention and Control Center.

Most of the new cases were contracted before a campaign to eradicate mosquitoes was carried out, said Luo.

Dengue fever is a serious infectious disease transmitted by Aedes mosquitoes, usually seen in tropical and subtropical regions worldwide.

People infected by the dengue fever virus will suffer from headache, fever and vomiting. Dengue fever can sometimes be fatal, experts say.

The local health bureau has called on residents to clean up their local environs, such as sweeping away puddles of standing water where mosquitoes breed. There is no effective vaccine to prevent the disease.

The campaign to eradicate mosquitoes in recent days has been effective as the density of mosquitoes has dropped sharply in many areas in Guangdong, Luo said.

In 2002 more than 1,000 people were infected with dengue fever in Guangdong.

Other Southeast Asia countries are suffering from dengue fever epidemics this year. In Indonesia 30,000 cases of dengue fever were reported by early April, said Luo.