Bats are common across Ohio, often seen hunting insects in the twilight sky. They are a beneficial part of the local ecosystem, consuming enormous quantities of pests, such as mosquitoes, every night. While their presence is helpful, residents often worry about potential danger. The risk bats pose to human health is tied directly to physical contact or the long-term accumulation of their waste. When left alone, bats pose virtually no threat, but precautions are necessary when they roost inside a human dwelling.
The Primary Health Threat: Rabies
The most significant health concern associated with Ohio bats is the potential transmission of the rabies virus. Rabies is a viral disease that attacks the central nervous system and is almost always fatal once symptoms appear. Bat strains of rabies have been responsible for most human cases acquired within the United States in recent decades. The danger is that their small teeth mean a bite may go unnoticed, especially if it occurs while a person is sleeping or involves a small child or pet.
From 2019 to 2023, bats accounted for 127 of the 186 confirmed rabies cases in animals throughout Ohio, making them the most common vector in the state. Although the actual incidence of rabies in the wild bat population is estimated to be less than one percent, any encounter must be taken seriously due to the disease’s lethality.
If potential exposure occurs, such as finding a bat in a room with a sleeping person, post-exposure prophylaxis (PEP) is the standard medical response. This treatment involves a series of vaccinations and one dose of human rabies immune globulin. Testing the bat for the virus is the only way to definitively rule out exposure. Prompt medical consultation is necessary to determine the need for PEP.
Histoplasmosis and Guano Risks
A secondary, non-bite-related health risk comes from microscopic fungal spores found in bat droppings, known as guano. The fungus, Histoplasma capsulatum, thrives in the nitrogen-rich soil and accumulated droppings of birds and bats, particularly throughout the Ohio River Valley. Disturbing large piles of guano, such as during cleanup in an attic or abandoned building, can release these spores into the air.
Inhaling these airborne spores can lead to a respiratory infection called histoplasmosis. Most people who inhale the spores do not develop symptoms or experience only mild, flu-like illness, including fever, cough, and fatigue. However, the infection can become severe or chronic, especially in infants, the elderly, or individuals with weakened immune systems. Contracting the disease primarily occurs through the disruption of large guano deposits, not through the mere presence of a single bat.
Safe Procedures for Bat Encounters
When a bat is discovered inside a home, the primary goal is to prevent physical contact and determine if exposure has occurred. If the bat is found in a room with a child, a pet, or someone sleeping or mentally impaired, immediate action is required due to the potential for an unnoticed bite. In this situation, the bat must be safely captured for rabies testing, and you should contact your local health department or animal control for guidance.
If you are certain no contact has occurred, you can try to guide the bat outside while wearing thick gloves. Seal the bat into a single room by closing interior doors and opening windows or exterior doors to allow it to escape. Prevention is the most effective strategy, which involves examining your home for potential entry points. Bats can squeeze through openings as small as a half-inch by a quarter-inch, so sealing gaps with caulk or pest-exclusion materials is recommended.
Understanding Ohio Bat Species and Protection
Ohio is home to several insectivorous bat species that play a role in pest control. The Big Brown Bat (Eptesicus fuscus) and the Little Brown Bat (Myotis lucifugus) are the most commonly encountered species that may roost in buildings. These bats, along with the Indiana Bat and the Northern Long-eared Bat, are protected by state and federal laws.
Harming bats is illegal, and any removal must be conducted humanely following specific guidelines. Due to severe population decline caused by White-Nose Syndrome, conservation efforts are important. Professional wildlife services are often necessary to exclude bats from a structure, ensuring the process is legal and safe for the animals, especially during the maternity season when young are present.