Protecting Employees From Rodent-Related Hazards

With each passing year, we are becoming a more litigious society. Pest control operators might become the target of lawsuits by any of a number of individuals or constituencies with whom they interact, including customers and employees. Ask any PCO how many discrimination cases or frivolous lawsuits he has had to contend with in the last 10 years; the answer may astound you. The subject of worker safety used to mean simply avoiding pesticide exposure and driving safely. Now we must contend with disease exposure, slips, trips, falls, and a host of other potential hazards. This article will address some of the rodent-related health hazards that pest control personnel are most likely to come into contact with and how to avoid them.

HANTAVIRUS. By now, most avid readers of newspapers, pest control trade magazines, and a variety of other publications have probably heard about hantavirus. The disease has various strains that may induce symptoms as minor as high blood pressure or as deadly as pulmonary collapse due to fluid buildup and the overwhelming of the body's defenses. The hantavirus strain know as hantavirus pulmonary syndrome (HPS; also sometimes referred to as Muerto Canyon hantavirus or Four Corners hantavirus) was first identified in 1993 in New Mexico and is one of the deadliest known strains of the disease. It produces pneumonia-like symptoms that can quickly become severe; 40% of the more than 100 cases of HPS that have been documented in the U.S. since 1993 have been fatal.

 

When working in a suburban area where dried mouse feces are present, it is best to err on the side of caution.

The various strains of hantavirus occur in different rodents, primarily mice. The Four Corners strain is known to occur in field mice or deer mice and is transmitted to humans through dried fecal material. This mouse is commonly found in rural areas and occasionally suburban areas, but rarely in urban settings. Most urban cases of hantavirus are likely due to the victim visiting a rural area and contracting the disease there, then return ing home. It should be noted that none of the three most common urban rodent pests — the house mouse, the Norway rat, or the roof rat — have been found to carry hantavirus. When in a suburban setting, where dried mouse feces are present, it is best to err on the side of safety and assume the worst.

SALMONELLA. Associated with exposure to rotting food, salmonellosis may occur after contact with infested droppings of either rats or mice. The salmonella bacteria can enter victims via the mouth, by inhalation, or through direct contact with open cuts or sores. The disease is also commonly associated with bird infestations.

PLAGUE. Plague is rarely taken into account when dealing with rodents. The more rural or mountainous the setting, the more concern there should be when collecting dead rodents from traps. Fleas from rodents can infest humans and domestic animals as well. When infected with plague, rodents harbor the organism for up to a few weeks, infecting any fleas that feed on them. If the rodent is killed, the fleas will vacate the host in search of a fresh one. This next host could easily be a human being. In areas near forests and other wild areas, plague should be of as much concern as hantavirus. Often it is not, however, because less media attention is devoted to it.

HISTOPLASMOSIS. Histoplasmosis is a fungal disease associated with dust generated from pigeon and rodent droppings. The disease affects many humans without requiring hospitalization; it usually causes no more serious symptoms than a drawn-out cold or cough, although it can become more severe and can affect the lungs, liver, spleen, and central nervous system. For the pest control technician, adequate respiratory protection is required to prevent inhalation of the spores of any fungal disease. Many other fungal disease spores are found in bird droppings, so similar precautions should be taken when performing bird control services.

MAN-MADE BIOHAZARDS. While we have enough health hazards from rodent and bird infestations alone, humans create their own biological hazards that can be many times more acutely dangerous.

A crack in a sewer pipe in a crawl space that has enabled raw sewage to seep into the crawl space may be teeming with microorganisms that can produce anything from a cold to hepatitis. These areas should be viewed as highly hazardous.

Another area of concern is waste cans containing red plastic bags labeled Biological Hazardous Waste. These cans should not be touched except with special surgical gloves, and the gloves should be disposed of immediately after use. Dental offices, medical offices, laboratories, and hospitals all generate quantities of biological waste ranging from a bag or two to several hundred bags per day. These materials may constitute an attractive dinner snack for rodents, and can provide a potent biological punch in terms of germs and other organisms. Old blood test materials, soiled garments, surgical materials soaked in blood, and body fluids all pose a potential threat to the pest control professional's health. Proper training in the recognition of these hazards is essential.

GENERAL CONCERNS. It's the middle of the summer, hot and humid. A technician calls in at noon complaining that he is tired and dizzy. The secretary who takes the call dismisses it as no big deal. At 3 p.m. you learn that the technician has passed out from heat exhaustion and is in the hospital. This is a serious matter. It could have been avoided if the secretary had not missed the early clues. During the summer, plenty of liquid should be ingested. This prevents technicians from becoming ill, which results in more headaches.

Every termite inspector and pest control salesperson is instructed to wear a respirator or dust mask when he or she enters an attic or crawl space. Not many do so. Even though there may be no rodent infestation and thus no danger from hantavirus or other health hazards, the dust that is inhaled during the inspection can cause as much lung damage as a fungal material. As dust enters breathing tubes, nose hairs and mucous membranes trap much of it, and then the mucous and hairs in the throat trap more of the materials. In very dusty areas, a significant amount can still enter the lungs. Once in the lungs, the dust particles are encased in fibrous material; at the same time they reduce the capacity of the lungs to move air through the passageways. In time, entire tracheal tubes may become blocked.

SAFE WORK HABITS. Because all the diseases discussed here are a hindrance at best and some may be potentially life-threatening, some basic steps to prevent exposure are necessary.

When dealing with any rodent service, all technicians should be instructed emphatically to wear an approved respirator or dust mask. This will ensure that no particulates enter their bodies.

Dermal protection is a must. Long sleeves, trousers and gloves should always be worn whenever conducting any type of rodent work.

Feces and dead mouse removal is a necessary part of rodent control. In practice it can be very profitable. Prior to removal of any rodent feces or dead mouse bodies, wet down the area with Lysol or a similar product, then sweep up the feces and remove the traps. Old live-capture traps such as Tin Cats or MouseMasters should be immersed in a bleach-and-water bath for at least five minutes and then rinsed with water. Before they are cleaned, these traps should be stored in a sealed plastic bag.

If there is any suspicion of the presence of potentially deadly rodent feces or of field mouse infestations, react with the highest level of safety precautions.

SAFETY PROGRAMS. Each company is required to provide some type of safety training with respect to pesticides and pesticide applications. Your automobile insurance may be reduced with the establishment of a routine driver safety program. In this age of litigation over even the most seemingly insignificant matters, the health and welfare of employees should be of utmost priority to any PCO. A small investment in health safety training and the provision of proper personal protection devices will go a long way toward showing a company's interest in its employees' welfare, and may help prevent costly lawsuits.

SENTENCING RODENTS TO DEATH BY ELECTROCUTION

Someone once said that the only thing that remains constant is change. That is certainly true in our industry, where regulation and public perceptions frequently dictate new practices, technologies and techniques.

It is difficult to determine whether the EPA is led by consumer worries about health threats or vice versa; it is probably closer to the truth to say that the two drive each other along. Among the results of this are that we're being peppered with trivial requirements for the use of bait stations; the Department of Defense is sworn to decrease pesticide use by 50% by 1999; and more of our private customers want alternative — i.e. mechanical — control methods used if at all possible.

OK, take a deep breath. The customer is always right. In fact, the restaurant owner who has been carving dead rats out of his dining room walls and the farmer whose dog died from ingesting improperly placed rodenticides both have valid complaints. So how do we satisfy this growing market's needs?

Of the nonpoisonous control tools, we can eliminate the ultrasonic devices right away. At best, they scare the critters into the next room — not exactly what customers are paying for.

Of those devices that deliver a body, snap traps and glue boards are the favorites. Not only must they be checked for each kill, but a common customer complaint is that such devices are found scattered around a site long after the PCO has forgotten about them. It is important with these methods to utilize good mapping and inspection procedures, both to ensure the best kill rate and to avoid customer irritation.

Some new alternatives are becoming available. The "zapper" rodent electrocution devices are apparently quite good at delivering a body; time will tell whether they're good enough to justify their high initial cost. The manufacturer, Agrizap Inc., has overcome some of the maintenance headaches, however. These units can be purchased with radio transmitters that indicate to a central panel that they've been activated. This "tracker" system then enables the pest control professional to service only those units that actually contain kills.

Hopefully, some other new developments to satisfy pesticide-sensitive customers are on the horizon. "Tin Cat" traps work well for mice. Perhaps some ingenious soul will come up with a repeatable mechanical trap for rats. New products to tackle new and growing markets would be a nice change. Remember: Change is the only thing that remains constant. — Bill Luther

Bill Luther is technical advisor for Agrizap Inc., Ventura, Calif.

Jim Harmon is manager of Urban Entomology Associates, a department of A Perfect Pest Control, San Gabriel, Calif.

August 1996
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