Centipedes are common arthropods often encountered in Ohio homes and gardens. The answer to whether they are dangerous is nuanced, starting with a clarification of terminology. Centipedes are venomous, meaning they inject toxins, rather than poisonous, which means toxins are absorbed or ingested. While equipped with venom, the centipedes found in Ohio rarely pose a serious medical threat to humans.
Identifying Common Centipede Species in Ohio
The most frequently encountered species inside Ohio homes is the House Centipede (Scutigera coleoptrata). This arthropod is easily recognized by its yellowish-gray body, which features three distinct dark stripes running down its back. It has 15 pairs of extremely long, banded legs that increase in length toward the rear. This makes the centipede appear much larger and faster than its actual body length of about one to two inches. House centipedes are nocturnal hunters that move with surprising speed, often alarming homeowners.
Other species are more common outdoors, such as the Stone Centipedes (Lithobiomorpha) and Soil Centipedes (Geophilomorpha). Stone centipedes are generally smaller, reddish-brown, and found under rocks. Slender Soil Centipedes are rarely seen as they live deep within the soil. The House Centipede is the primary species of concern for indoor encounters, though larger centipedes may occasionally be found in southern Ohio forests.
Understanding Centipede Venom Delivery
Centipedes deliver venom through a specialized pair of modified front legs called forcipules. These pincer-like appendages are positioned beneath the head and contain the venom glands. When attacking prey or defending itself, the forcipules pierce the skin, creating a distinct V-shaped puncture wound.
The venom is a complex mixture of proteins and small molecules that act as neurotoxins and cytotoxins, designed to rapidly subdue small arthropod prey. While effective against insects like spiders and cockroaches, the small amount injected is too weak to cause severe systemic harm in humans. A centipede typically only uses this defensive mechanism if it is physically handled or feels trapped against the skin.
Immediate Symptoms and First Aid
A centipede bite, though rare, feels similar to a mild bee or wasp sting, resulting in localized pain. Common symptoms include immediate, sometimes intense, localized pain, mild swelling, redness, and a temporary burning sensation at the bite site. Some people may also experience temporary numbness or tingling around the V-shaped puncture marks.
The primary treatment for an uncomplicated bite is immediate first aid. The wound should be thoroughly cleaned with soap and water to minimize secondary infection. Applying a cold compress or ice pack to the affected area helps reduce pain and inflammation. Over-the-counter pain relievers, such as acetaminophen or ibuprofen, can be used to manage discomfort.
If pain persists beyond 48 hours, or if localized redness and swelling expand, seek medical attention to check for infection. Watch for signs of a severe allergic reaction, which is a rare but serious possibility with any venom. Symptoms such as facial swelling, widespread hives, difficulty breathing, or dizziness require immediate emergency medical care.
Centipede Habitats and Exclusion Strategies
Centipedes require environments that are dark, cool, and damp because their exoskeletons lack the waxy coating that prevents water loss in most insects. Outdoors, they thrive in areas with abundant moisture and cover, such as under leaf litter, wood piles, and rocks near the foundation. Indoors, they seek out places that mimic this environment, including basements, crawl spaces, utility closets, and bathrooms.
To effectively exclude centipedes, homeowners should focus on reducing both moisture and entry points. This involves using dehumidifiers in damp areas like basements to lower the ambient humidity, and ensuring proper ventilation in bathrooms and crawl spaces. Sealing cracks and gaps in the foundation, around doors, and utility entry points prevents them from entering the structure. Removing outdoor attractants, such as clearing leaf litter, mulch, and wood piles away from the home’s perimeter, also makes the area less inviting.