Mosquitoes, including the dengue-carrying types, are now more active and hungrier, the Department of Health (DOH) said Thursday.

"There are studies that say mosquitoes today are more active, hungrier, and always want to eat. They always need to take a bite," DOH Secretary Francisco Duque told ABS-CBN's Umagang Kay Ganda, as he explained why the number dengue cases is significantly increasing this year.

Duque said mosquitoes are constantly moving and more active because of global warming. He said warm temperature agitates the blood-sucking insects.

Another cause of the spiking number of dengue cases is the "rapid urbanization and congestion," the health secretary said.

Duque said over the weekend that dengue-carrying mosquitoes "don't need to travel far to spread dengue" because of too much congestion in urban areas, particularly Metro Manila.

The DOH said Metro Manila has the highest number of dengue cases recorded nationwide from January to June 14 this year with over 3,065 patients.

The DOH noted increases in dengue cases in Manila (from 327 cases in 2007 to 937 this year) and Quezon City (up 934 from 301 in the same period last year).

The number of cases in Caloocan also went up from 103 to 567; in Navotas, from 52 to 153; and in Malabon, from 102 to 144.

The health department said a total of 15,061 cases of dengue nationwide were recorded during the first six months of the year. It said the number is 43 percent higher compared to the same period in 2007.

Following Metro Manila with the most number of dengue cases are Calabarzon with 2, 008 cases and Central Luzon with 1,647 cases.

Duque said despite the increasing number of dengue cases, the case fatality rate remained low at 1 percent. He said this is because of the health department's awareness program.

He said potential dengue victims are being rushed to hospitals earlier than the previous years.

Climate change

Duque on Wednesday said that the rise in dengue cases may be also be due to global warming.

"The increase in the number of dengue cases may be attributed to the constantly changing climate brought by global warming as well as congestion in urban areas," health secretary Francisco Duque said.

World Health Organization officials earlier this year warned climate change was increasing the incidence of dengue fever and other infectious diseases in the country.

There is no known cure or vaccine for dengue fever, which is transmitted by the white-spotted mosquito. With a report from Agence France-Presse