The Tokyo authorities have temporarily closed the sprawling Shinjuku Imperial Gardens, famous for its cherry blossoms, amid the country's first post-war dengue outbreak as the number of confirmed cases rose to 80.
The precautionary move is to allow checks to be carried out at the gardens, where no dengue cases have been reported so far.
Similar checks are taking place at Yoyogi Park - a huge outdoor space where the first dengue cases in 70 years in Japan were reported late last month - and also at other parks in the city.
Japan's latest epidemic comes just as a World Health Organisation conference warned of a potential increase in dengue fever and other infectious diseases like malaria that are sensitive to changes in world climate.
Rising temperatures and humidity mean that mosquitoes can survive longer even in temperate countries like Japan, thereby increasing the risk of outbreaks.
In Tokyo, most of the dengue victims - including the six new cases announced by the health and labour ministry yesterday - were infected after spending time in or around Yoyogi Park. None of the six had been abroad in the past month.
Experts say mosquitoes in the park could have picked up the virus from visitors who had been infected while abroad. Although mosquitoes are said to move only within a radius of about 50m, officials said infection can spread beyond that due to infected people moving from one place to another.
Yoyogi Park, the current dengue hot spot, is often the venue for international food and other events that draw both Japanese and foreigners.
Last month, there were 14 such events featuring South-east Asian and Latin American themes, according to officials.
About 80 per cent of Yoyogi Park has been closed to the public since the outbreak, forcing the cancellation of many events last weekend.
A flea market and an Asian food fair, held at a part of the park that remained open, saw few visitors. Stallholders used mosquito coils to keep the insects at bay.
Some pharmacies near the park reportedly ran out of insect repellent on the weekend.
At Meiji Shrine, a heavily- wooded area adjacent to Yoyogi Park, insect spray was offered to worshippers at entrances to the shrine and exterminators were called in to get rid of mosquitoes.
A shrine official was quoted by the NHK network as saying: "We have heard concerns from worshippers, so we continue to take measures to ensure the infection does not spread."
On Saturday at Jingu Stadium, which is located in a wooded belt not far from Meiji Shrine, 200 cans of insect repellent were made available for spectators to spray themselves before the start of a baseball game. One of the dengue patients said he was probably bitten near the stadium.
Last Friday, Chief Cabinet Secretary Yoshihide Suga appealed for calm.
"Even if one is infected, serious cases are rare. There have been no reports of fatal cases so far," he told a press conference.
The disease is mainly transmitted by the Aedes aegypti mosquito. Symptoms include fever, severe headache, rashes and pain behind the eyes, muscle and joint pain.
No vaccines against dengue fever are currently available.
But Japanese pharmaceutical firm Takeda and France's Sanofi are developing vaccines, with Sanofi hoping to commercialise its product next year.
Singapore saw its worst dengue epidemic last year - 22,170 people were infected and seven died. There have been two dengue deaths so far this year.
This article was first published on September 09, 2014.
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