PETALING JAYA: Malaysia may not only have to brace for drier weather, but also a heightened risk of dengue.
The Malaysian Meteorological Department (MetMalaysia) recently projected that the El Nino phenomenon would intensify from April to June and become increasingly dominant by August.
Prof Datuk Dr Azizan Abu Samah, a senior research fellow at the Institute of Ocean and Earth Sciences, said there is a 60% probability that the country would experience El Nino by year-end due to the north-east monsoon.
“Normally, the risk of Aedes breeding increases with higher temperatures. So during El Nino, especially around April, we will see a spike in Aedes mosquitoes,” he said.
He added that puddles and higher temperatures create conducive conditions for mosquito breeding.
Prof Dr Mohd Hasni Jaafar, a medical lecturer at Universiti Kebangsaan Malaysia’s Department of Community Health Medicine, said reduced rainfall during El Nino could lower dam and river water levels, contributing to water supply disruptions and shortages.
“As a result, many households may store water in containers, drums and buckets. Without proper care and attention, these stored water containers can become ideal breeding sites for mosquitoes.
“In addition, although El Nino generally causes drier weather conditions, occasional short periods of heavy rainfall may still occur,” he said.
Dr Mohd Hasni, who specialises in environmental toxicology, said rainwater is often collected in discarded containers, clogged drains and unused items around homes.
“These can create stagnant water sites that favour mosquito breeding, particularly Aedes,” he said.
He added that reduced rainfall also decreases the natural “wash away” effect of rainwater, which normally helps remove mosquito breeding habitats such as gutters and drains.
He said the risk of dengue outbreaks is heightened by higher temperatures, which may accelerate the mosquito life cycle, causing eggs to hatch faster and larvae to develop more rapidly into adult mosquitoes.
“Adult mosquitoes may bite more frequently in hot conditions. Higher temperatures may also shorten the incubation period of the dengue virus inside the mosquito, allowing the mosquito to become infectious sooner and increasing the risk of disease transmission,” he said.
He urged the public to take precautions, including emptying and scrubbing water containers regularly, covering water storage tanks and drums tightly, cleaning roof gutters and drains, and ensuring there is no stagnant water around homes and workplaces.
“Proper disposal of unused containers and rubbish that can collect rainwater is also important.
“Aedes mosquitoes are most active during the early morning and late afternoon.
“Wearing long-sleeved clothing, using mosquito repellents, installing window or door screens and using mosquito electric repellents appropriately may help reduce exposure to mosquito bites,” he said.
He said early medical attention is also important to reduce the risk of severe dengue complications.
