Guangdong province reported 1,431 new cases of dengue fever on Sunday, bringing the total to 21,527, local health authorities said on Monday.

The number was rising quickly, with more than 1,000 new cases found each day last week. One fatality was reported by the provincial health and family planning commission on Sunday, bringing the death toll in the province to six.

Dengue is a mosquito-borne, potentially fatal disease that affects between 50 and 100 million people in tropical and subtropical regions every year, causing fevers combined with muscle and joint aches.

The disease has been detected in 20 out of 21 prefecture-level cities in Guangdong.

The latest case was found in the Liwan District in western Guangzhou, which has seen five deaths caused by dengue so far this year. With 18,192 cases confirmed, Guangzhou is the worst hit city in the southern province.

One fatality was reported in Foshan, a city adjacent to Liwan, with a total of 1,997 cases, according to the commission.

Chen Jianhua, the mayor of Guangzhou, urged at a seminar on Sunday that efforts to kill mosquitoes be stepped up. He also called for early detection, early medical treatment and early quarantine so as to check the spread of dengue fever.

On Monday, the sixth day of China's weeklong National Day holiday, Xinhua reporters saw vehicles spraying pesticide in the streets of Guangzhou. People were also disinfecting sewers, garages, channels and greenbelts in a bid to eradicate mosquitoes. Residents were offered free mosquito repellent in local communities.

As the holiday draws to an end, Guangzhou will launch a cleanup campaign on Tuesday, especially in schools and construction sites that remained unoccupied during the long holiday.

The recent outbreak of dengue fever is believed to be the worst in 20 years.

Health authorities attribute the surge to high temperatures and wet weather in Guangdong, where the mosquito population is five times the normal level.

Apart from Guangdong, some other southern provinces and regions also reported dengue cases lately, including Fujian, Hunan and Guangxi.