The New York metro pest library

Mice contaminate food surfaces, spread salmonella and hantavirus, and chew electrical insulation — a documented fire risk. A single pair can produce dozens of offspring in a season.

Rats carry leptospirosis, salmonella and fleas, damage structures and utilities, and reproduce fast enough that a small colony becomes a large one within weeks.

Cockroach allergens are a leading asthma trigger in children, particularly in urban apartments. They also carry bacteria across food-prep surfaces.

Bed bugs are not known disease vectors, but the sleep loss, anxiety and cost of repeated failed DIY treatment are significant. They spread between apartment units quickly.

Termites cause billions in structural damage annually and are excluded from most homeowners policies. Colonies feed continuously and silently for years before visible damage appears.

Carpenter ants excavate structural wood to nest, weakening framing over time. Pavement and odorous house ants are primarily a contamination and nuisance problem.

Mosquitoes in New York transmit West Nile virus and, less commonly, Eastern equine encephalitis. Both are monitored annually by state health authorities.

Long Island is a high-incidence region for Lyme disease, babesiosis and anaplasmosis. Suffolk County consistently reports some of the highest tick-borne illness rates in New York State.

Most local spiders are harmless and beneficial. A sudden spider increase usually signals a larger insect population feeding them, which is the real problem to solve.