Big jump in dengue cases last week
THE number of dengue cases spiked by more than 40 per cent last week, raising fears that the virus could reach record levels this year.
After three consecutive weeks of decline, there were 594 reported cases between Feb 14 and 20, 175 more than in the previous week.
The National Environment Agency (NEA), which released the figures yesterday, stressed the need for vigilance and urged the public to "continue taking action to stem the transmission of dengue".
Last week, it warned that the total number of cases this year could surpass 30,000, exceeding the record 22,170 cases in 2013, as a result of warmer temperatures due to the El Nino weather phenomenon and a switch in the predominant virus serotype to DEN-2 from DEN-1.
El Nino, which causes warmer than usual temperatures, promotes faster breeding and shorter incubation times for the dengue virus.
The switch in serotype is historically followed by a spike in dengue cases due to the lower immunity to the new strain.
Dengue clusters often die out spontaneously, according to Professor Annelies Wilder-Smith from Lee Kong Chian School of Medicine at Nanyang Technological University. "The reason is that a certain level of herd immunity builds up in an outbreak-affected community."
But doing nothing to allow for the development of the herd immunity risks the spread of the virus to other areas, resulting in the formation of new clusters, according to Associate Professor Ooi Eng Eong, deputy director of the Emerging Infectious Diseases Programme at Duke-NUS Medical School.
However, the NEA said with good control of the virus, fewer people get infected.
It will step up efforts to eradicate dengue, including the launch of its Mozzie Wipeout Campaign this Sunday which teaches residents to prevent mosquito breeding in their homes.
Meanwhile the country's largest active dengue cluster in Tampines West - which has seen 280 cases at blocks in Tampines Avenue 1, 3, 4, 5 and 8 since last November - has been declared "closed" by the NEA.
A cluster is closed when it has fewer than two cases over two weeks.