A patient awaits routine check-up as he lies under a mosquito net inside a dengue ward of a government hospital in New Delhi, India, September 18, 2015.

Thousands of people in Asia have been struck by dengue fever in recent months, putting medical services under strain and highlighting the need for a long-term strategy to fight the potentially lethal disease.

The Philippines, Myanmar, Malaysia, Taiwan, Thailand and Vietnam are among countries that have seen significant spikes in the mosquito-borne disease, while India's capital New Delhi is in the grip of its worst dengue outbreak in almost 20 years.

Hospitals are overwhelmed as thousands of people with symptoms such as high fever, vomiting and joint pains seek treatment, health experts said.

Dengue is the world's fastest-spreading tropical disease, according to the World Health Organization (WHO).

There is no dedicated treatment for the virus, and sufferers are generally asked to rest, drink plenty of fluids and take medication to bring down fever and reduce joint pains.

"Outbreaks like the current dengue cases can have significant impacts on health systems," said Martin Hibberd, professor of emerging infectious diseases at the London School of Hygiene and Tropical Medicine.

"These patients are acutely ill with severe symptoms and need to be treated fast to avoid complications."

The size of the outbreak has forced some hospitals to make tough choices.

In Delhi, a couple jumped to their deaths when their 7-year-old son died of dengue after being refused treatment at a number of city hospitals which said all their beds were filled with dengue patients.

News reports followed of other families with acutely ill children and elderly relatives being turned away from one hospital after another due to a lack of beds or other facilities.

Explosive growth

Dengue affected only a handful of countries in the 1950s but is now present in more than 125 - more than malaria, historically the most notorious mosquito-borne disease.

The WHO estimates that about 50 million new cases of dengue fever occur each year, but a recent study said the number could be four times as high due to underreporting.

In the Asia-Pacific region the hot and humid climate and frequent flooding linked to climate change create ideal breeding conditions for dengue mosquitoes.

In the Philippines concern is growing that flooding caused by Typhoon Koppu this week will cause a spike in the number of dengue cases, already up 32 percent year on year to 108,263 so far this year, according to the WHO.

In Myanmar, much of which was flooded in July and August, authorities recorded almost 36,000 cases from January to September, 200 percent more than in the same period last year and the highest figure since counting began in 1965, the Myanmar Times reported.

More than 96,000 cases have been registered so far this year in Malaysia, up more than 19 percent, according to the WHO.

Health experts say this explosion in dengue cases is closely linked to a rise in urban living as well as increased movement of people and goods.

"For dengue to occur you need concentrated areas of people - it's a city-based disease and a tricky one to eradicate because the dengue mosquito bites during the day, unlike the malaria mosquito," said Hibberd.

The dengue mosquito usually lives inside houses or in courtyards and typically lays its eggs in flower pots or other places with a water source.

Health experts said that while much attention had focused on eradicating malaria, which has higher mortality rates, the fight against dengue lacked a long-term plan and focused on controlling outbreaks instead.

"It requires a shift in approach from responding to isolated outbreaks to investment in strategies that cover effective vector control, access to health services and early clinical management," said Xavier Castellanos, Asia Pacific regional director of the International Federation of the Red Cross.

There is no vaccine for dengue yet, but some are undergoing clinical trials. French drugmaker Sanofi SA hopes to win approval for the world's first dengue vaccine soon.