Between doses

How fleas get past a closed door

An indoor cat's territory ends at the door, but the door opens dozens of times a day — and that is the entire loophole. Fleas and ticks ride in on trouser cuffs, tote bags, delivery boxes and the dog whose walk went through the tall grass.

Neither pest respects the seasons the way we'd like. Fleas and ticks are active in all fifty states, thrive indoors year-round, and ticks in particular keep working in cooler weather. A radiator in February is, from a flea's perspective, the tropics.

The bite is the dangerous part. Flea bites can trigger flea allergy dermatitis and anemia in small cats, and fleas carry bartonellosis and tapeworm; ticks can transmit Lyme disease, cytauxzoonosis and more. Oral medications only act after that bite happens. Catego kills through contact instead — the pest touches the treated coat and dies with its delivery route unused.

So the closed-door household needs the same calendar as the farmhouse: one drop at the nape each month. The label covers indoor and outdoor cats alike, from 1.5 pounds and 8 weeks up, and the ritual is identical whether the territory is a windowsill or a five-acre fence line.