Many professionals in the biological remediation industry deal with the threat of histoplasmosis very seriously. Guidance documents from the CDC outline the conditions where materials and waste are potentially contaminated with Histoplasma capsulatum. So where does that leave the remediation industry and how do we protect the home owner or business who’s attics are contaminated with bat guano.

Histoplasma capsulatum/CDC
Histoplasma capsulatum/CDC

Bats are protected animals. It is illegal to remove or re-locate them during their breeding season which enables them to fly around, roost and eliminate anywhere for extended periods of time. Home or business owners might want to peek into the attic every once in a while to see if there is evidence of bats. Generally bats are “quiet” animals and their presence can be difficult to detect. Most in our region are tiny and can fit in the smallest of holes. It is always good to bat proof your house. I’ve noticed that homes or buildings where they have a street light or a bright light source close seem to have the most risk of bat invasion. This is because the light ends up being a flying insect attractant and thus an easy food source for the bats at night. One of the good things about bats is that they help keep the flying insect population in check. The bad thing is we do not want them in our homes.

The general public is largely unaware of the risks presented by bat infestations and the fungus spores of H.capsulatum that can be in their waste. Hiring a contractor who is highly knowledgeable in biological remediation is of paramount concern. Bats have also been known to carry a wide variety of viruses that can be easily transmit easily to humans. Ebola, Marburg, rabies and a couple other Biosafety level 4 pathogens to just name a few. Similar to mold, once you disturb the waste, the spores of H.capsulatum can become airborne and can cause an active infection, particularly for those with compromised immune systems.

Brown Bat
Myotis lucifugus, or Little Brown Bat/CDC

Remediating a bat related contamination event must be accomplished with extreme care. As biological remediation contracting professionals, we must do everything we can to prevent cross-contamination and risk to our workers and building occupants. Some of the basics to follow are:

1.   If bats are present call a Certified Wildlife Control Professional to remove them.

2.   Use only a third-party certified biological remediation contractor. These companies and individuals are bound by a code of ethics and have documented training and certification to handle these remediation events. You can refer to the American Bio-Recovery Association (ABRA) or the Institute of Inspection Cleaning and Restoration Certification (IICRC). If its is a healthcare related building, you will want to follow the Infection Control Risk Assessment guidelines and have a Certified Environmental Infection Control Professional run the project.

3.   Negative Pressure Containment – Protect the path of extraction and set up an exclusion zone along with the area of concern utilizing negative containment and be sure that you have a .01 pressure drop to prevent a breach. Set up a staged decontamination or anteroom where an attendant can help decontaminate and remove PPE.

4.   Follow the PPE guidance for remediation projects as contained in the CDC Document link above. We tend to use hooded Powered Air Purifying Respirators with HEPA cartridges as they offer the workers the highest level of protection for biological remediation projects. You are also going to want your technicians to wear a booted poly coverall and inner and outer gloves as they are easier to decontaminate.   Alternate levels of PPE included fitted full face PAPRs and full face APRs with HEPA cartridges.

5.   Remove all porous insulation in the impacted area. Remove and bag the gross filth and HEPA or ULPA vacuum the ceiling and the joists, starting from the most contaminated area to the least being highly detailed. Be sure to clean and disinfect any contents that may be contaminated. Soft contents should be discarded.

6.   Set up disinfection and validation – We use a 6-Log sporicide for H. capsulatum. This means it is EPA-registered and has shown to kill 99.9999% of test spores. Disinfection can be validated by setting up biological indicators inoculated with 6-log of Geobacillus stearothermophilus. They can be hung in a variety of places throughout the space. The biological indicators should be incubated by a third-party laboratory to show that the area was properly decontaminated. This will give the building occupants a level of confidence that the disinfection was successful. Many may want to subcontract this to a specialty disinfection firm. Chemical indicators can be used but they only offer a visual indication that the disinfectant had reached the surface. You may want a third party such as a Certified Industrial Hygienist handle the placing of the test strips and the laboratory analysis so there is no bias. They may also want to test surfaces for the existence of viable  H. capsulatum.

7.   Clean and disinfect the path of extraction on your way out and decontaminate your equipment prior to leaving the site.

8.   Be sure to dispose of the bat waste according to your state and federal laws. States may consider bat guano or other waste generated by wildlife to be Infectious waste or what is considered Other Potentially Infectious Materials (OPIM). Please see your state’s Department of Environment for regulatory requirements for handling and transporting medical and infectious waste.

Author: Thomas Licker, CEICR, CBRM, Infection Control Technologies