SINGAPORE — In the midst of anecdotal reports of a growing rat infestation problem in Singapore, the Ministry of Sustainability and the Environment (MSE) has announced that it is trialling the use of thermal imaging cameras for rat surveillance in outdoor back-lane areas. 

Mr Baey Yam Keng, Senior Parliamentary Secretary for Sustainability and the Environment, said in Parliament on Monday (March 4) that the National Environment Agency (NEA) will share relevant footage and data with premises operators so that they can conduct “targeted interventions to eliminate potential rat nesting grounds”. 

This was during a debate on the budget for MSE for its spending on vouchers for households, as well as efforts to maintain cleanliness around the island.

Singapore’s new initiative to tackle rat infestations mirrors that of other cities where there are similar problems.

News reports in cities such as New York, Rome and London point towards record-high rat populations, with the authorities scrambling to find solutions. 

So why is it happening here, what can be done about it, and what problems can rats bring? TODAY speaks to pest control firms, sociologists and infectious disease experts to find out more. 

WHY ARE RAT INFESTATION CASES GROWING?

Pest control firms contacted by TODAY said that they have seen a 15 to 20 per cent increase in rat infestation cases over the past year.

There have been several reports of rats being found in public spaces recently.

Last November, the authorities were investigating the case of a squashed rat in a food delivery bag, and in the same month, a twitching rat was filmed on a food tray at Tangs Market food court on Orchard Road. 

Ms Chloe Chee, assistant manager of quality assurance at PestBusters, said that the increasing rat infestations could be due to a higher prevalence of exposed food waste left in public spaces, as well as the monsoon season that runs from December to early March. 

“Heavy rain will cause rodent burrows and low lying areas to flood, forcing rats out of their burrows for food and shelter,” she said. 

Sociologist Tan Ern Ser from the National University of Singapore (NUS) said that with the returning of trays at coffee shops and hawker centres becoming mandatory, it has resulted in more food waste being deposited or unintentionally littered around tray return areas. 

“If the floor and tray return areas are not frequently and thoroughly cleaned, it would result in a greater abundance of food accessible to rats,” he added. 

“While cleaners are expected to wipe tables and wash dishes frequently, there is likely less emphasis on cleaning the floor and areas surrounding the tray return station regularly.” 

There are also macro factors affecting Singapore, such as global warming. 

Mr Hadi Hanafi, technical director of Innovative Pest Management, said that with increasingly hot weather in Singapore, rats’ metabolism would also increase, meaning that they will need more food, leading to more sightings of rats. 

Their numbers are also set to grow in hotter climates. 

“They like to breed in hot weather as their sexual drive will be higher,” Mr Hadi added. “When it is cold weather, they tend to hibernate and don’t move around much.” 

HOW HAVE SINGAPORE AND OTHER CITIES BEEN DEALING WITH IT? 

Responding to queries from TODAY, NEA said that it uses various technological tools such as video scopes, Wi-Fi cameras attached to boom poles, infrared cameras and smart traps to detect the presence of rats.

Pest control firms have their own methods to deal with the infestations, such as putting cameras in ceilings to detect roof rats and placing rat poison in burrows.

NEA said that for the new thermal imaging trial, a site survey will be done to establish the optimum site for the deployment of the thermal surveillance systems.

The agency will also be reviewing related activities that may contribute to rat activities, such as poor housekeeping, littering and improper waste management. 

This is not the first time that thermal imaging has been used to track rodent populations. The Hong Kong authorities said last month that it has deployed thermal imaging and artificial intelligence (AI) technology to more accurately measure the rodent population in the city. 

The thermal imaging would track any animals in an area, while AI will determine whether the heat signatures are those of rats. 

Pest control companies said that more collaboration between different extermination firms could be forged with the help of the Government, because their view is that the current approach to exterminating rats is too “decentralised” and ineffective. 

This will mean that even if some rats are exterminated at a food store, for instance, the main source of the infestation, which could be a burrow outside of the store, cannot be destroyed since it is not under the purview of the store, they explained.

WHAT WILL HAPPEN IF RAT INFESTATIONS ARE LEFT UNCHECKED? 

Should rat infestations be left unchecked or if people try to catch and dispose of rats without professional help, it could spark the spread of several diseases. 

Dr Paul Tambyah, who is president of the International Society for Infectious Diseases, said that rats in Singapore can carry diseases such as murine typhus, leptospirosis and hantaviruses that can be spread to humans if they come in contact.

However, these diseases are generally not life-threatening and are curable. 

“Many of these diseases are not diagnosed clinically in humans as they can respond to antibiotics prescribed by general practitioners.” 

Increasing rat infestations also affect people’s social lives, Dr Tan from NUS said. 

“If rats overrun food-and-beverage outlets, it is possible that, in the extreme case, the food places would cease to be the social space for social interactions and a large part of everyday, community life for people.”