The National Environment Agency (NEA) has found 10,000 rat burrows around the island in just the two months of October and November last year.
This is up from 6,400 burrows in the same period in 2013.
It also received 4,106 complaints about rats in 2014, about 35 per cent more than the 3,031 complaints in 2013, the Straits Times reported.
This “apparent explosion in the rat population” in Singapore is a potential threat to public health, as it can “lead to diseases spreading and even fires in older buildings if the rodents gnaw on power cables.”
“If the wires are exposed, people may be electrocuted by live wires during maintenance work, the electricity supply may become unstable and household appliances could catch fire,” Star Pest Control’s general manager, Bernard Chan, said.
According to the Straits Times, the NEA said “close to 90 per cent of the burrows in its October- November inspection were in housing estates.”
“We are concerned about the increase in the number of burrows detected,” said a NEA spokesman.
The number of inquiries to pest-control companies has also increased, with such agencies receiving “up to 60 per cent more rat-related inquiries in the past year.”
“For a small island like Singapore, the rat burrow figures are very alarming, and do not auger well for our reputation as a clean country,” PestBusters’ technical director, Eugene Surendra, told the Straits Times.
The authorities have said that the key to getting rid of rats is removing their food sources and hiding places.
“Food that is left on open ground or improperly disposed of causes the proliferation of rats, cockroaches and other vermin,” Second Minister for the Environment and Water Resources Grace Fu told Parliament on Tuesday.
“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,” Ms Fu said.
Ms Fu’s advice comes amidst recent instances of rat infestation problems reported by members of the public, in particular the ones at an open field near Bukit Batok MRT station in December, and at Punggol Field in January.
Singapore has had similar problems with rats in the past, and other causes, besides the presence of food sources, were highlighted.
In 1988, for example, the Straits Times cited experts as saying that “underground digging for the MRT” could be one such cause of rat infestation.
This came after rats were spotted by residents at the Holland Village area.
“Rentokill area director John Ho, 43, suggested that there may not have been an actual rise in the number, but that rats have become more visible recently because of the digging carried out by construction crews, particularly for the Mass Rapid Transit system,” the Straits Times’ report said.
“This has disturbed the rodents’ natural habitat, forcing them to move to populated areas, Mr Ho said.”
This is similar to what some Marina Square tenants told Yahoo Singapore when they were asked about the rats issue after a rat was found in a dish at the Hotpot Culture restaurant there.
The owner of the restaurant, Lim Choon Kok, Lim told Yahoo Singapore he believed “the rats came from the lower floors at Marina Square, where renovation and construction work is ongoing.”
A quick check with several other tenants at the mall showed that other shops – both retail and food and beverage – have also spotted rats in the mall since construction work started.
“I think he’s just very unlucky that it got into the food. We have been complaining to the management about the rat issue many times before this. It’s out of control,” said a tenant who declined to be named.
Experts say if the rat problem is not contained or eliminated, it could also lead to the spread of infectious diseases.
In 2012, a foreign worker’s death was linked to leptospirosis, a bacterial infection spread from rats to humans, the Straits Times said.
Besides the rats problem, Ms Fu also said Singapore’s dengue situation “continues to be a problem despite the drop in breeding sites found”.
She therefore urged the public and those in authority, such as town councils, to do their part to help curtail these.
“Food that is left on open ground or improperly disposed of causes the proliferation of rats, cockroaches and other vermin,” she said, and reminded the public that containers with stagnant water also allow mosquitoes to breed.
Nonetheless, the authorities are stepping up their effort to eradicate these problems.
“The health and safety of humans must remain paramount,” Ms Fu said. “We hope the public will understand and support these measures.”
Incidentally, Singapore has declared plague-free by the World Health Organisation since 1933.