SINGAPORE - More than 35,000 rodent burrows were found and treated from January to November last year by the National Environment Agency (NEA) to get rid of rats.

The agency has also deployed more enforcement officers to make sure food establishments follow good hygiene practices and do not leave food out, said Second Minister of State for the Environment and Water Resources Grace Fu in Parliament on Tuesday.

Her remarks came in the wake of several rat infestations in Singapore recently. In one case, more than 300 rats were killed in a two-week operation at an area near the Bukit Batok MRT station, after videos and pictures of the rodents were posted online.

Ms Fu said the key to reducing the rodents' numbers was to eliminate their food sources.

"We need all stakeholders from food stall and restaurant operators to companies that are in charge of cleaning to really step up and ensure we have a hygienic and clean environment," she said.

She also gave an update on the dengue situation.

Between January and November last year, more than 16,000 mosquito breeding sites were found, a decrease of 19 per cent from the same period in 2013.

The NEA's gravitrap mosquito traps has also caught some 32,000 mosquitoes since the agency's surveillance programme was piloted last year.

The agency is also looking into reducing the population of local dengue-carrying Aedes aegypti mosquito by infecting the male Aedes mosquitoes with a type of bacteria that results in female mosquitoes producing eggs that do not hatch.