Farmer's lung primary prevention

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Primary Prevention

There is no simple method to prevent conditions that lead to Farmer's Lung. Steps must be taken to avoid crop spoilage and production of bacterial or mold spores that cause the allergic reaction. Workers must also take precautions to avoid breathing in spores from moldy crops.

The following measures are recommended to prevent the growth of mold spores or limit the damage they can cause:

• Buildings with large amounts of dusty material should be properly ventilated.
• Consider ventilation rates to remove particles without high heat cost. In heated buildings air-to-air heat exchangers may increase the minimum winter ventilation rate without higher energy bills.
• Improve air circulation. Make sure that the distribution inlets are managed and operated properly to avoid dead spots.
• Converting to mechanical or automated feeding or feed handling systems can reduce the amount of airborne mold spores or can reduce human exposure.
• Wet hay, grain, or other crops can be dried at harvest. If possible wet hay should be ensiled. This is the key to stopping mold growth.
• Using mold inhibitors, baling hay, ensiling crops, and harvesting and storing grains at the recommended moisture content, limits mold spore growth. It also maximizes the quality of your feed stuffs.
• Keep the facilities clean. Sweep or power wash occasionally to remove the buildup of dry material on the floor and other surfaces
• During cleaning of barns or stables, dust from moldy crops should be wetted down before being swept to prevent it from becoming airborne.
• Always use a plastic sheet to cap open silos, don't use plant materials. Hold the edges of the sheet down with heavy weights.
• Wet down the top of a silo before uncapping the ensiled material. This prevents moldy dust from becoming air borne. This should be done even if the silage was covered with a plastic sheet, because the top layers still tend to mold.
• Use feed additives. Adding tallow or soybean oil to swine finishing feed to reduce its dustiness makes good sense.
• Move the work outdoors whenever possible. While this is not usually practical in the case of feeding operations, be sure to open bales that you know are moldy outdoors.
• Avoid dusty work in confined areas. When constructing new farm buildings or modifying older structures, keep facilities as open as possible.
• When you have to work with moldy material, try to keep your distance. If you have to break open a moldy bale, do so with a fork, instead of bending over and using your hands.

Respiratory protection is the last line of defense against Farmers Lung. The proper type respirator can protect those who have not contacted the diseases or help prevent the diseases from getting worse. Approved, properly fitted dust respirators (e.g., masks with HEPA, High-Efficiency Particulate Air filters) may protect the lungs from spores of molds or bacteria.

This equipment, however, is seldom viewed as an easy solution. Professional advice is required for selection of the proper mask and filter. Individuals must also receive training on the proper use of the equipment and procedures for maintenance and repair.

To be effective, the respirator should be worn on every occasion that farm dust is encountered. Make sure the mask is comfortable and easy to maintain but does not restrict breathing.

The Toxic dust mask, chemical cartridge respirator and powered air helmet are approved for protection against dust, such as asbestos and they provide inexpensive protection against mold spores. More expensive and sophisticated respiratory devices may be required occasionally.

Commonly available disposable respirators for nuisance dusts are not effective against the tiny mold spores.

In all cases, however, a key protective measure is to investigate any procedure that can reduce or completely prevent the growth of the heat-tolerant bacteria or molds that create the unwanted dust.