KUALA LUMPUR • The number of dengue fever cases in Malaysia reached an all-time high for the period from January to Aug 3, hitting nearly 80,000 cases and 113 deaths reported.

Deputy Health Minister Lee Boon Chye expects the number of cases to hit 150,000 by the end of the year if efforts are not taken to keep it under control.

The highest number of cases recorded previously was in 2015, when there were 120,836 cases with 336 deaths.

The figures between January and Aug 3 are almost double last year's for the same period - which saw 42,496 cases, with 70 deaths.

There were also 251 hot spots in nine states, with most in flats and apartments. The states are: Selangor, the Federal Territories, Johor, Kelantan, Sabah, Penang, Sarawak, Negeri Sembilan and Pahang.

Dr Lee said the ministry was using various ways to overcome the dengue outbreak in the country, and measures included fogging and the removal of mosquito breeding sites.

He said a new method, the release of Aedes mosquitoes infected with the Wolbachia bacteria to bring down the population of the mosquitoes, was still being monitored. He added that the dengue vaccine was used in the Philippines but it was withdrawn after it led to a higher mortality rate.

The ministry is monitoring the dengue situation continually and receives weekly reports on the number of cases.

With district health offices nationwide keeping an eye on the situation, once dengue cases are reported, measures such as fogging are immediately implemented, said Dr Lee.

When there is a hot spot, the health office also organises a combined community effort with local residents via social mobilisation or through the local council, he added.

Dr Lee also reminded members of the public to play their part in ensuring their living areas are free of Aedes mosquitoes.

"Dengue is increasing in many parts of the world, even in Singapore. Cuba eradicated it once but it has re-emerged. Southern China, southern Taiwan and southern Japan also have reported cases.

"As air travel becomes common, the virus spreads," he said.

The Health Ministry's director-general Noor Hisham Abdullah said that since June, the number of weekly dengue cases has increased and reached 3,557 cases a week, but there was a slight decrease in the first week of this month.

About 70 per cent to 80 per cent of the dengue cases occurred in urban areas, he said.

The World Health Organisation report on the dengue situation, dated July 4, shows that Malaysia was not the only place which experienced an increase in the number of dengue cases, with neighbouring areas, such as Singapore, the Philippines, Taiwan, Vietnam, Cambodia, Laos and China also seeing an increase, he said.

"The major contributing factor is poor environmental cleanliness. Abundant man-made containers provide places for the Aedes mosquito to breed and increase the spread of the dengue virus," Datuk Noor Hisham said, adding that littering contributes to the problem.

The change in serotype - the species of bacteria - called "serotype shift" also triggered the dengue surge.

"It has been observed that dengue cases will increase usually four to six months after a serotype shift due to the lack of immunity in the community towards the new serotype," he said.

"From our surveillance monitoring, there was a shift of dengue serology from dengue virus strain (DEN) 3 to DEN 2 in June last year.

"Theoretically, DEN 2 is associated with more severe manifestation and high fatality rate," added Dr Noor Hisham.

In the same period from January to Aug 3, fewer than 1 per cent of the cases were of severe dengue, also known as dengue haemorrhagic fever.

"There is no specific treatment for dengue or severe dengue, but early detection and prompt medical care will save lives," Dr Noor Hisham said.

He added that the changing rainy and hot seasons resulting in stagnant water collected, people movement and increase in population density in urban areas also facilitated the spread.

Studies have shown an association between the occurrence of dengue cases and outbreak and temperature, rainfall and humidity, he said.

THE STAR/ASIA NEWS NETWORK