A single mouse never stays alone for long. Mus musculus squeezes through a 6 mm opening, gestates for 3 weeks, and produces 5 to 10 litters a year: a presence tolerated for a few months becomes an established colony. Acting at the first sign isn't optional.
Recognising a mouse infestation
Droppings are the first clue: black, cylindrical, 3–6 mm, pointed at both ends. Fresh = shiny, old = dry and grey. Where they concentrate (behind the fridge, under the sink, in cupboards) shows the main runways.
A persistent musky smell, especially in enclosed spaces, signals an established colony: mice mark their territory with urine.
Sounds: scratching in walls, ceilings or floors at night, between 11pm and 4am. Mice are nocturnal and skittish; hearing them during the day points to a high population density.
Mouse vs rat: rat droppings (Rattus norvegicus) measure 12–18 mm, and rats themselves reach 25 cm without the tail. A small dropping means a mouse, a large one means a rat. Treatment differs.
The real risks
Mice contaminate food and surfaces with their urine and droppings: salmonellosis is the most concrete risk in kitchens and storage areas. The hantavirus documented in Belgium (Puumala virus, monitored by Sciensano), on the other hand, has the bank vole as its reservoir, not the house mouse — a common mix-up.
Material damage is often underestimated. A mouse gnaws constantly to keep its incisors at the right length: electrical cables, plastic pipes and insulation all get chewed through. An exposed 230V cable behind a partition wall or in the attic is a potential fire starter — the most serious risk of an infestation left untreated.
Food contamination: a mouse soils far more food than it eats, leaving urine and droppings as it moves. A bag of flour or cereal left accessible should be thrown out if you notice any traces.
Mechanical traps: the only DIY method that works
Pressure traps (the classic snap trap or a modern closed-jaw spring trap) are the only effective tool available to the general public in Belgium. Place them perpendicular to the wall (mice always hug the walls), 1–2 metres apart, in areas with droppings.
Bait: skip the cheese, mice prefer carbohydrates. Peanut butter, chocolate or spread work well. Wear gloves when handling them: mice avoid human scent.
Results within 24–48h if the traps are well placed. If nothing is caught after 3 days, move the traps. Several traps triggered every night means a large colony — professional treatment is needed.
Ultrasonic devices have no proven effectiveness. Cats slow down a light infestation but don't eliminate it.
Sealing entry points: the key to not starting over
Without closing entry points, any elimination is temporary. Mus musculus enters through a 6 mm opening, the width of a pencil. Critical areas: the gap under exterior doors (add a brush door sweep), pipe runs through walls (seal with steel wool + sealant, as rodents can't gnaw through steel wool), cracks in the foundation.
Check under the sink: the gap around pipes is rarely sealed properly. A 1 cm gap between the pipe and the wall is enough. Same goes for behind the fridge and under built-in kitchen units.
In older homes (pre-1960), cellars and crawl spaces often have unpointed breeze-block walls with 10–15 mm gaps, perfectly accessible to mice.
When to call a professional
Calling in a professional is recommended if: several traps trigger every night for more than 5 days (an established colony), droppings appear inside walls or the attic (hard to access), the property is old with many entry points, or you have children or pets (a contraindication for over-the-counter rodenticide baits).
A professional uses professional-use-only products, installs secured bait stations inaccessible to children and pets, and identifies every entry point to seal. A follow-up check confirms the activity has stopped.
Antinox includes a written guarantee: if mice return during the covered period, we come back at no extra charge.
Frequently asked questions
How long does it take to get rid of mice?
With well-placed traps: 1 to 2 weeks for a light infestation (1–5 individuals). Professional treatment shows results faster, with a follow-up check to confirm activity has stopped. Without sealing entry points, the problem returns within weeks.
Can mice live inside walls?
Yes. They nest in cavity wall insulation, gaps between floor slabs and in attics. You'll hear them at night inside partition walls. A technician locates nests using acoustic and thermal infrared inspection in complex cases.
Does seeing one mouse mean there are others?
Almost always. Mice live in family groups of 10 to 50 individuals. Spotting a mouse during the day is particularly telling: food competition within the colony pushes it out of its usual hours.
Can I use poison myself?
The most effective products are restricted to registered professionals in Belgium. Over-the-counter products exist but are less effective and potentially dangerous if placed carelessly (children, pets). Mechanical traps are the safest and most effective DIY solution.