Did you know that there is a real danger to bat droppings? Indeed, if your home is infested with bats, it is better to take care of it quickly. Find out how to catch a bat. Exposure to large amounts of guano is the cause of many health problems.
Find out why you need to get rid of bats quickly when this winged visitor decides to make his home within your walls.
A recurring problem in the attic or attic requires a different approach than a simple cleaning. If you spot a bat catching, you must first secure the accesses before thinking about guano. Decontamination comes second, once the colony is removed.
The danger of bat droppings
Bat droppings, also known as bat droppings or guano, can pose dangers to human health. These droppings are sometimes home to microscopic fungi whose spores can be inhaled and cause health problems such as histoplasmosis. Hence the importance of handling these droppings with caution and taking precautions in the presence of bats.
We therefore recommend calling an exterminator as soon as you find bat droppings in your home.
If you go to Google to see what bat droppings look like in photos, you’ll notice that these are similar to the droppings of other rodents. However, the droppings are larger than in mice, however.
The danger of bat droppings does not lie in the size, but in the quantity. During a bat infestation, guano quickly accumulates between your walls. Guano contains microscopic fungal particles that cause respiratory problems in humans.
Also, when the excrement decomposes, it turns into dust. This bat poop dust is toxic and is also a health risk and cannot be removed simply with a sweep or vacuum cleaner. You will need to call in an expert to decontaminate the affected area to ensure that there is no longer any danger.
In addition to respiratory problems, bat droppings are responsible for the disease called histoplasmosis. Histoplasmosis is a lung disease that can have serious consequences. It is better not to neglect bat infestations.
For a colony that is already established, our animal capture service takes care of the complete exclusion with unidirectional devices that respect the maternity period, which is prohibited between mid-May and mid-August in Quebec. Exclusion during this window risks trapping babies in the walls and aggravating contamination.
How to properly decontaminate after a bat infestation?
We can’t say it enough, but in the case of a bat infestation, leave the decontamination to professionals. Especially if the areas to be cleaned are difficult to access and there is a large amount of droppings. The danger of bat droppings is increased tenfold by direct exposure and professionals have the necessary protective equipment to carry out the work.
The tools you’ll need:
- N100 class masks that filter dust to prevent toxic particles from entering your respiratory tract and contaminating it;
- Safety glasses or visors. Dusty droppings can get into your eyes and cause infections;
- Disposable coveralls, as microscopic fungi could cling to your clothes;
- Disposable rubber gloves.
The Danger of Bat Excrement: How to Decontaminate Effectively?
In addition to the equipment, you must also isolate the area to be decontaminated before starting the work. You will need to close windows, ventilation systems and block air hatches to prevent any air circulation.
Never attempt to sweep or vacuum guano that has dried out. You won’t do anything good by sending all those toxic particles flying through the air. To get rid of dry guano, you should first moisten it and then scoop it up with a dustpan. Dispose of wet feces in a lined bag (a bag within a bag).
When this is done, clean the area with a mixture of bleach and water. This is only valid for small amounts of guano. If there are many, do business with specialists.
If you have a bat problem at home, we can help. Do not hesitate to contact our experienced exterminators for you to capture bats and decontaminate your home.
For significant contamination, more than one square meter of guano or a prolonged presence over several months, our decontamination department mobilizes technicians equipped with complete PPE, in accordance with CNESST procedures, to neutralize the risk of histoplasmosis before restoration.
Five health risks associated with bat guano
The accumulation of guano in an attic or attic is never benign. Several pathogens coexist in the faeces, and each has a different route of transmission and severity. The table below summarizes the five risks documented by Public Health Canada.
| Health risk | Pathogen | Route of transmission | Population at risk | Severity |
|---|---|---|---|---|
| Histoplasmosis | Histoplasma capsulatum | Inhalation of spores released from dry guano | Immunocompromised, children, elderly | High to very high |
| Rabies | Virus Lyssavirus | Bite, contact with saliva on wound | Anyone in direct contact | Fatal without post-exposure treatment |
| Salmonellosis | Salmonella spp. | Hand-mouth contact after contaminated surfaces | All, more severe in children | Moderate (severe gastroenteritis) |
| Cryptococcosis | Cryptococcus neoformans | Inhalation, mainly wet guano | Immunocompromised | High |
| Respiratory allergies | Guano antigens | Dust inhalation | Asthmatics, allergic | Low to moderate |
Histoplasmosis remains the main concern because of its mode of transmission by inhalation, which makes simply scanning guano dangerous. Any prolonged exposure, particularly in an immunocompromised person, warrants medical monitoring within 4 to 6 weeks.
Three typical cases and their management
Small accumulation discovered during a renovation
Common case: less than 1 m² of dry guano in a corner of an attic discovered during renovation work, without a confirmed active presence. Home decontamination possible with full PPE (minimum N95 mask, nitrile gloves, waterproof glasses), prior humidification, collection in a double sealable bag, disinfection with diluted bleach 1:10. Structural inspection to identify the access point and seal it. Moderate cost, half day duration.
Active colony in an attic
A more complex situation: 5 to 30 bats that enter and leave daily through a crack under the roof, abundant droppings on the floor of the attic. Surgery is not possible between mid-May and mid-August (period of protected motherhood). Outside this window: installation of a one-way exclusion device for 5 to 7 days, verification of the absence of remaining individuals, permanent closure of all accesses. Complete decontamination after departure. Total duration: 2 to 3 weeks.
Prolonged accumulation over several years
The heaviest case: guano accumulated over more than a square meter and several centimeters thick, sometimes mixed with the insulation. Maximum risk of exposure to histoplasmosis during handling. Intervention by a specialized firm is mandatory: HEPA vacuum cleaners, waterproof suits, forced ventilation during the work, complete removal of contaminated insulation, disinfection of the joists, replacement with new insulation. Significant cost, duration of one to two weeks depending on the surface.
Status of bats and legal framework
Several species of bats in Quebec have a high protection status, which severely restricts intervention methods even when they pose a health problem in a residential building.
Protected species in Quebec
The Little Brown Myotis (Myotis lucifugus), which nests most often in human buildings, has been designated Endangered since 2015 due to White-nose Syndrome. Northern Myotis and Tri-colored Bat share this status. The capture, direct destruction and disturbance of active nests is strictly prohibited by the Act respecting threatened or vulnerable species.
Methods allowed even for protected species
The unidirectional exclusion (which lets the animal out without hurting it and then blocks the return) remains legal outside the maternity period (mid-May to mid-August). This is the standard method for solving a bat problem without contravening regulations. Decontamination of guano after departure is not restricted and can be performed at any time.
What to do with a lone bat in the house
A not uncommon case: a single individual enters through a window or an open fireplace. If no bite is suspected, open the exterior windows, close the interior rooms and dim the light to facilitate its exit. If a bite or contact is suspected (especially during sleep), do not release the animal: the bat must be captured alive (thick gloves, closed container) or killed for rabies analysis. Call Info-Santé 811 immediately for post-exposure medical follow-up.
Questions
Why is bat droppings dangerous?
Bat guano can harbor Histoplasma capsulatum, the fungus responsible for histoplasmosis. The spore is released when the dry guano is disturbed (sweeping, stirring). Inhalation causes a lung infection that can be serious in immunocompromised people, children, and the elderly. Guano can also contain bacteria (E. coli, salmonella) and parasites. Prolonged accumulation in an attic becomes an infectious source that gradually contaminates the insulation and the surrounding air.
When should you intervene against bats?
Exclusion is strictly forbidden between mid-May and mid-August in Quebec: this is the maternity period during which females give birth and nurse only one young per year. An exclusion during this window leaves babies trapped in the structure, where they die and cause long-lasting odors. The best intervention periods are at the end of April (before the arrival of the females) and September to October (young capable of flying, just before hibernation).
How do you clean bat guano safely?
Four mandatory steps for cleaning bat guano:
- Wear full equipment : N95 mask (ideally P100), nitrile gloves, goggles and disposable coveralls.
- Moisten the guano completely with a solution of water and detergent. Never dry brew: spores are released into the air.
- Scoop with a dustpan in a double sealable bag. Seal and label.
- Disinfect the area with diluted bleach 1:10 after it has dried completely.
For accumulations greater than 1 m² or several centimetres thick, call a decontamination service equipped with HEPA vacuum cleaners.
Are bats protected in Quebec?
Yes, many species are protected by the Threatened or Vulnerable Species Act and federal regulations. The Little Brown Myotis (Myotis lucifugus), which frequently nests in buildings, has been designated Endangered since 2015 due to White-nose Syndrome. The capture, destruction or disturbance of active nests is prohibited. Humanitarian exclusion, which allows bats to leave without being able to return, is still allowed outside the maternity period.
How do you prevent bats from coming back?
Three complementary actions: identify all entry points (openings of more than 6 mm to soffits, roof junctions, ventilation ducts, chimney cracks), install a unidirectional exclusion device (cone or one-way net that lets out but blocks the return) for 5 to 7 days, then permanently closes all accesses with welded metal mesh or expanding foam. The annual inspection in early spring prevents new installations.
Should insulation be decontaminated after an infestation?
Yes in the majority of cases. Guano becomes embedded in cellulose or mineral wool and releases spores whenever the insulation is disturbed. The ammonia in the urine corrodes the materials and permanently impregnates the fibers. For a short infestation (a few weeks) with localized deposition, a targeted removal of the contaminated insulation may be sufficient. For a prolonged infestation (several months or years), complete removal of the insulation and disinfection of the joists are strongly recommended.
When to call a bat exterminator?
Four signs call for it: direct observation of a bat inside the house (risk of bite and rabies, especially during sleep), scratching or squeaking noises in the walls at the end of the day, urine or guano stains visible on the soffits, and any human or animal exposure (bite, contact). In the event of a suspected bite or contact, wash the wound for 10 minutes and call Info-Santé 811 immediately: bat-transmitted rabies is rare but fatal without post-exposure treatment.
Areas Served
Our bat specialists operate throughout the South Shore and the Richelieu Valley. We are present in Longueuil (Vieux-Longueuil and Saint-Hubert, where the wooden soffits of old triplexes are particularly exposed) and in Boucherville (especially Vieux-Boucherville, where open-frame heritage buildings encourage the establishment of settlements).
