Health department says there were roughly 146,000 cases of mosquito-borne virus from January to July.

The Philippine government has declared the country’s outbreak of dengue a national epidemic following the death of at least 622 patients since January.

The country’s health department announced late on Tuesday that Francisco Duque III, the health secretary, made the declaration to improve the response to the outbreak by allowing local governments to draw on a special Quick Response Fund.

It said the Philippines recorded 146,062 cases of dengue from January through July 20 this year, 98 percent more than the same period in 2018. That is roughly 5,036 cases every week.

Among the worst-hit areas are central Philippines as well as some regions in the northern island of Luzon and the southern island of Mindanao.

Duque said a campaign is being launched focusing on the destruction of mosquito breeding sites.

Dengue is a mosquito-borne viral infection found in tropical countries worldwide. It can cause joint pain, nausea, vomiting and a rash, and can cause breathing problems, haemorrhaging and organ failure in severe cases.

While there is no specific treatment for the illness, medical care to maintain a person’s fluid levels is seen as critical.

The Department of Health said that starting on Tuesday, it was conducting a campaign to focus on finding and destroying mosquito breeding sites, which is a primary means of containing dengue.

Other government agencies, local government units, schools, offices and communities will join in the effort, it said.

In 2017, the administration of President Rodrigo Duterte banned the dengue vaccine, Dengvaxia, after its French manufacturer reported that it could cause severe effects on patients not previously exposed to the virus.

Some critics have blamed the decision for the current outbreak, but Duque, the health secretary, said that the World Health Organization did not recommend the use of the vaccine as an outbreak response.

Other Southeast Asian countries have also reported an upsurge in dengue cases this year, according to the WHO.

The organisation said Malaysia had registered 62,421 cases through June 29, including 93 deaths, compared with 32,425 cases, including 53 deaths, during the same period last year.

Vietnam over the same period had 81,132 cases, with four deaths reported, compared with 26,201 cases, including six deaths, in 2018.

In South Asia, Bangladesh has been facing its worst-ever dengue fever outbreak, putting a severe strain on the country’s already overwhelmed medical system.