Sudden Fly Swarms Indoors: Could There Be a Dead Animal?

A burst of large flies in a room, especially with an odour, can mean something has died nearby.

The short answer

Sudden swarms of blowflies indoors can come from a dead rodent, bird or other animal in a wall, ceiling, attic or duct. Follow the flies and the smell, check vents, lofts and behind furniture, and wear gloves and a mask when removing. If you can't reach it, call a professional. Afterwards, clean and disinfect, and seal entry points to stop animals getting in.

Signs

• Many large flies suddenly appearing.
• A strong odour.
• Maggots or flies near vents, ceilings or walls.

What to do

1. Look near the flies' source and smell.
2. Check lofts, ducts and behind furniture.
3. Wear gloves and a mask when removing.
4. Seal the carcass and dispose of it.
5. Clean and disinfect and ventilate.

Prevention

• Seal entry points.
• Control rodents.
• Inspect lofts and voids.

When to call a professional

If you cannot find or reach the source, call a professional.

Frequently asked questions

Is it always a dead animal?

Not always, check bins and drains too.

How long do flies last?

Until the source is removed.

Is it hazardous?

Use protection and hygiene.

Can I do it myself?

If reachable. Otherwise call a professional.

This guide is part of IPest's complete resource on fly control. For identification help, prevention and treatment options, see our full fly control guide for Bangalore.