MANILA — The Philippines declared a national dengue epidemic on Tuesday, saying that the mosquito-borne disease had killed at least 622 people in the country so far this year.

More than 146,000 dengue cases were reported in the first seven months of the year, almost twice as many as in the same period last year, according to the country’s health department.

“This is really staggering,” said Francisco Duque, the health secretary. He said the declaration of an epidemic was needed so that local governments in badly hit places could use “quick response funds” to fight the disease.

Officials said the Western Visayas region of the Philippines had the most cases, at more than 23,000, followed by the suburbs south of Manila, the capital, which had more than 16,500 cases. Parts of the southern island of Mindanao also reported a high number of infections.