Rats are well-known to be carriers of diseases, some of which can be fatal to humans. The three widespread species of commensal rodents in mainland Singapore that can present a danger to public health, and cause considerable damage to foodstuffs are the Norway or brown rat, the roof rat, and the house mouse. Rodents also chew on other materials (lead, aluminium alloys, plastics, etc.), thereby damaging piping and the sheaths of electric cables. The stripping of wires is a particular hazard because it may cause short-circuits, which can lead to fires.
A combination of proactive (seeking out and removing rodents before they start causing problems) and reactive (treating infestations only when they are reported or start causing problems) approaches will be adopted.
Management of commensal rodent will be a two-part activity.
1) Hygiene and proofing
This is to make the environment as unsuitable as possible for rodent infestations to develop. Rodents need three things to survive: food, water and shelter. Environment in which rodents live or might live will be made as inhospitable as possible by reducing the availability of food, water and shelter and by restricting the access that the rodents have to these necessities.
2) Rodent Control
Visual inspection is carried out to identify sites of rodent activity by looking for tell-tale signs such as presence of droppings, urine smell and stain, squeaking noise, runways, rub or smear marks, burrows, gnawing and rodent track/foot print marks. If activity is noted, identity of species involved is established so that appropriate control techniques could be deployed. Attempts will also be made to locate harbourage/nesting sites within the vicinity of control area and destroy it.
Rodent infestation is generally brought under control by employing a number of techniques and devices such as use of:
- Rodent Glue boards
- Drop-door Cages
- Snap Traps
- Poisoned Baits (used in Bait Station Boxes, placed in rat burrows and in drains),
- Poisoned Powders
Poisoned powders are also used as a means of tracking rodent movement. When employing poisoned baits and powders and snap traps, great care and caution is exercised so that they are not made accessible to non-target species.