Virus sanitation: 5 mistakes and 5 fixes
We are often asked: “What is the best disinfectant to use to prevent XYZ virus?” or “What product(s) should I use for good biosecurity?” It is at this point that the farm manager or veterinarian is at a significant crossroads, as is the ownership and often the purchasing department. In optimal livestock production, the appropriate question to ask should be: “How can I carefully design, implement, and sufficiently execute a biosecurity program that minimizes my risk of a disease event?”
Alternatively, there could be a feeling that: “My biosecurity programs are strong and are in place but, somehow, the virus still entered our system, and I need an aggressive clean-up plan for this virus.” But is it ever a good idea to look for a disinfectant program for just one pathogen or just one pathogen type (i.e., an enveloped virus versus gramnegative bacteria)?
If an admission that biosecurity programs are not in place and/or not being executed, then development of a plan for permanently reducing the population of pathogens or minimizing the risk of them entering a production system will be more challenging.
Five sanitation general mistakes or misconceptions
The biosecurity reality of many facilities might often be summarized by one or more of the following:
Some biosecurity measures are in place, some of the time, with very little contractual or financial incentive to execute beyond infrequent monitoring of compliance or customer/veterinary inspection.
Biosecurity is viewed as a time (labor) and cost burden, with no clear recognition within financial or accounting practices as a “profit” activity (i.e., lower production cost, lower pathogen pressure = improved gains, reduced mortality).
Biosecurity procedures most often focus on the speed in which a checklist can be executed, thus furthering encouragement of shortcuts like mixing chemicals (i.e., insecticides and disinfectants); low water or no soap approaches due to labor shortages or training gaps; thermal fogging to make a “really nice fog that hangs in the air a long time…”; and the use of high odor/low volume products (i.e., a glug of bleach, cresylic “acid,” which is actually not a disinfectant at all).
Selection of chemicals is often based on legacy products or legacy product categories or brands; an EPA label (“my organism of concern is on the label therefore it must be the right product”); and/ or cost per gallon (without considering pre-cleaning with soap, dilution with water, or the selection of the correct chemistry).
Disinfection (foam or spray) is administered using the labeled rate, meaning it is assumed that most often a 5 percent organic load is all that remains on surfaces and that those surfaces are 100 percent dry.
To fix these problems, programs and procedures must be in place to measure the desired performance outcome, not based on convenience (easier, faster, less burdensome) or economics (less labor, less overtime, cheapest products).
Five sanitation fixes
Stop looking for the product to do all of the work — instead, have a process that works. If you review published studies, you will find several disinfectant brands that are “recommended” as effective on certain pathogens.1 This is potentially misleading and suggests that by simply choosing to purchase and then using these products, they will work properly, with little or no regard for pre-cleaning.
A research report from Iowa State University showed that one of those recommended products failed to disinfect 60 percent of power hot-water-washed trailers, leaving PCR-positive enveloped virus samples in the trailer.2 The reason for the lack of success is unclear and may be due to the lack of soap and rinsing in the cleaning step, or improper dilution (or “double dilution”) as very often happens in solid disinfectant use.
The fix: Use a good, high-quality foaming soap. Rinse the soap and viruses down the drain — hot water is best. Set up the disinfectant for success by cleaning film, oils, proteins, chick down, feathers, litter, dried or sticky feces, mucous, etc., prior to disinfection.
Make proper use and care of boot, hand/glove, service truck biosecurity part of the culture. Boot baths, hand wipes/sanitizer, seat and floor mat aerosols, tire disinfection, and veterinary equipment sanitizers must all be used in the right way, in the right sequence. Wash hands prior to (alcohol) sanitizing as the last step before entering and leaving a farm.
Disposable wipes are a useful tool for steering wheels, supplies, and equipment. But do not make assumptions about the active ingredient by the brand name. Clorox® wipes may contain quat instead of bleach, and Lysol® may contain alcohol and quat instead of phenol. Use glutaraldehyde disinfectant for tires, trailers, and trucks; boot bath disinfectant should be changed often and used (not stepped over or around). You can also use Intervention wipes for truck or vehicle interiors versus a simple quat.
Shortcuts, gimmicks, and rushing are no substitute for elbow grease — use the right sequence and you will achieve the desired results. Have employees spend enough time doing a thorough job of cleaning prior to disinfecting — it is not a race, and there are no trophies given out for finishing first. Do a complete job of soaping, rinsing, and drying prior to disinfection. Thermal fogging was introduced to agriculture to place insecticides into the air, to allow very small droplets — sufficient to kill the insect — to land on that bug. Microscopic organisms require full contact of sufficient disinfectant concentration. Viruses are not alive — you can only inactivate them, and you will need to fully contact all surfaces with a wet solution.
Avoid the pitfalls of assumption. Phenols are not effective in or on feces; bleach disinfection requires 8 to 16 times more product to be effective, and trying to translate the organism list on the label to the best and most effective product is an attempt to cover a huge pre-cleaning gap with assumption. There has been too much made of “effectiveness in high organic matter” for aldehyde and phenolic disinfectants. You still cannot disinfect viruses in manure, even with a drying powder that contains a known, effective algaecide.3