Germ Warfare

People working in pest control face many hazards during the course of their work. The greatest risk to personal health is found in simply driving a vehicle from one site to the next. Lifting heavy items improperly, falling off ladders and dog bites are the next most important safety risks. The handling of pesticides poses a risk, however the products used today are generally less toxic and are applied at lower concentrations. And with the proper use of personal protective equipment, hazards from handling pesticides can be considered minimal.

In recent years, the specter of environmental pathogens has reared its ugly head within the pest control industry. Hantavirus has become an important headline topic in the news since 1993, and because it is carried by rodents, pest management professionals working in the urban arena have been rightfully deemed “high risk” by the Centers for Disease Control (CDC) for potential contact with this disease.

Other environmental pathogens of risk to pest management professionals that can cause disease in humans include a number of bacteria, rickettsia, fungi and the rabies virus. Even rhinoviruses that cause the common cold can be included due to the contact pest professionals have with numerous customers. One non-disease risk also warrants mention and discussion — insect stings and spider bites.

The risk of contracting disease from any of these pathogens is extremely small, especially the more serious pathogens. Certainly steps can be taken to minimize exposure and possible illness from these pathogens, no matter how small the risk. The purpose of this article is to discuss the risks posed by the environmental pathogens faced by the pest control industry, and the steps that should be taken to minimize these risks.

NATURAL PROTECTION. The world is awash with microorganisms that mankind has been unaware of until the last century. Nature has provided the human body with a series of defenses to protect itself. Our primary defense is our skin, which excludes bacteria from the bloodstream and the inner organs.

Even though potentially pathogenic bacteria, such as Staphylococcus, are always present on the skin’s surface, these organisms are kept outside until a cut or abrasion allows a penetration of the protective layer.

The body has further defenses against airborne pathogens, beginning with the hairs and the mucus layer inside the nasal cavity. Hairs and mucus screen out nearly all dust, bacteria and viruses inhaled while breathing. Should any bacteria or viruses pass this test, they encounter the cilia in the lungs. Should too much dust or other material reach the lungs, the coughing mechanism engages and the vast majority of such material is expelled. Bacteria that enter the body through the mouth or by ingestion are destroyed by stomach acids. Very few bacteria can survive such an encounter.

Any pathogen that is successful in lodging itself in the body must then run the gauntlet of the body’s immune system. This complicated defense is so successful that although our bodies are bombarded by potential pathogens every day, very rarely do any of us become ill. It is extremely rare to succumb to a serious pathogen-caused disease, thus is the beauty of nature’s defenses.

THE ROUTE OF ENTRY. It is important to understand how a disease organism enters the body to understand how best to protect yourself against the various pathogens.

1. Respiration (Inhalation). Most of the viruses entering the body will be airborne and enter the nose or mouth as you breathe. Cold viruses lodge in the nasal cavity while flu viruses that evade the nose’s defenses continue on to the lungs. A few types of bacteria may enter the body in this manner.

2. Ingestion. Food poisoning bacteria are pathogens that enter the body by ingestion. These bacteria or the toxins they produce in food can survive contact with stomach acids and can result in illness.

3. Through the skin. Cuts or abrasions allow bacteria to enter our body past our protective skin layer.

4. Through the eyes. Most of us have experienced a slight infection in our eyes. Bacteria are introduced by rubbing our eyes with our dirty hands. Dust and debris can also carry disease pathogens into our eyes. This route is a possibility with hantavirus.

5. Ectoparasites. Mosquitoes, ticks, fleas and kissing bugs are a few of the arthropods that feed on human blood and can transmit pathogens past the protective skin layer.

THE PATHOGENS. Each pathogen has its own epidemiology that describes its mode of transmission, its requirements for development and the hosts it must have to complete its development. The following briefly discusses a few of those that could be encountered by pest management professionals.

1. Salmonella. These bacteria are present in the surrounding environment, even in the soil. They are especially common where decaying food materials are present. Salmonella bacteria enter the body by ingestion, usually in infected food or off unwashed hands. They cause many types of food poisoning, the slightest effects of which we commonly refer to as the stomach flu. In severe cases, the results may sometimes even be fatal depending on the species of Salmonella involved and lack of treatment.

2. Staphylococcus. Another bacterium that is present in the surrounding environment, Staphylococcus are present even in the soil. Like Salmonella, these bacteria are especially common where decaying food materials are present. They enter the body through breaks in the skin caused by cuts, abrasions and blisters. The results of invasion usually involve infections in cuts and also in the eyes. Severe flesh necrosis (tissue death) can occur and loss of limbs, although rare, is possible. Fatalities are also rare unless the bacteria enters the bloodstream, causing septicemia.

3. E. coli. This bacterium has received considerable mention in the media in recent years due to one strain that causes a serious, often fatal form of food poisoning. E. coli is present in human and animal feces and could be encountered anywhere in the urban environment, especially in areas of poor sanitation. It usually enters the body through poorly cooked meats but could be introduced by ingestion off contaminated hands.

4. Histoplasma capsulatum. This fungus is present in accumulated bird, chicken and bat feces that is in contact with the soil. The bird feces enrich the soil allowing the fungus to proliferate. After the fungus matures, it produces spores that become airborne when feces are disturbed, such as during clean-up of bird or bat roosts. The fungus causes respiratory illness known as histoplasmosis but it may also result in blindness if the spores enter the eyes. Fatalities are rare but are possible.

5. Cryptococcus neoformans. This pathogenic yeast (fungus) is present in accumulated pigeon feces within buildings. Unlike H. capsulatum, this fungus does not need to be in contact with the soil to proliferate. Spores become airborne when feces are disturbed and enter the body by inhalation. It causes a respiratory illness called crypto-coccosis. The disease may develop into cryptococcal meningitis that takes the form of severe headaches, vomiting, vertigo and dizziness. Persons with maladies such as lung disease, diabetes, Hodgekin’s lymphoma and leukemia are most susceptible to the severe forms of the disease.

6. Hantavirus. This serious pathogen is designated by the CDC as one of the most virulent. At least 12 different hantaviruses have been isolated to date, only a few of which are known to cause human disease. Hantavirus is carried by rodents, especially the deer mouse, Peromyscus maniculatus. Disease-causing strains have yet to be isolated from the house mouse populations. Other types of hantaviruses have been isolated from other types of rodents, including the cotton rat and voles. The virus is spread through aerosolized droplets of deer mouse urine and on microscopic particles of dust infected by urine or associated with deer mouse activity. Handling deer mouse carcasses also poses a risk. The virus causes hantavirus pulmonary syndrome (HPS) which causes a victim’s lungs to fill with fluid, sometimes resulting in cardiac arrest.

Through Jan. 5, 1996, 127 confirmed cases have occurred with a 50% mortality rate. Deer mice are found most often in areas bordered by woods and fields. Fortunately, the deer mouse does not readily infest buildings, however the threat is always possible.

7. Rabies. This virus has been widely feared throughout human history It is spread by the bite of an infected animal or by improper handling of infected animal carcasses. In urban areas, skunks, raccoons, coyotes and dogs are the primary reservoirs. The virus affects the central nervous system and is always fatal unless treated prior to the onset of symptoms.

8. Borrelia burgdorferi. This rickettsia causes Lyme disease and is carried and spread by various ticks but especially the black-legged tick, Ixodes scapularis. The reservoir in the wild is the deer mouse. Intermediate hosts are primarily deer but humans often become hosts inadvertently when they pick up infected ticks while in wooded areas. Lyme disease results in a myriad of symptoms depending on which body system is attacked. Attack of the nervous system is the most serious but B. burgdorferi can also cause arthritic-like symptoms. If left untreated, the damage to the body may be irreversible.

9. Insect Stings. No pathogens are involved but a very real health risk exists to persons working in pest control. Bees, wasps, scorpions and some ants can all inject proteinaceous venom that in most people causes only generalized swelling and localized reaction. After one sting, however, sensitive individuals can lapse into anaphylactic shock which can be fatal.

10. Spider Bites. Dangerous spiders, such as the black widow, can be encountered by PCOs in many states. Bites occur when the spider is accidentally trapped against exposed skin. Black widow venom affects the nervous system, causing most muscle systems in the body to cramp. The bite is rarely fatal except in young children and the elderly. The bite of the brown recluse causes collapse of microscopic blood vessels in the area of the bite. Lack of blood and nutrients to the affected area leads to tissue death. Secondary staph infections can lead to more serious necrosis.

OCCUPATIONAL HAZARDS. Walking in and around or crawling beneath a building can bring a PCO into contact with any of these pathogens or with stinging or biting arthro-pods. Rodent, bird and bat feces can be encountered in any attic, crawlspace, garage, cellar or basement. Bird feces can be found accumulated on the ground outside and on rooftops.

Pathogenic bacteria are most likely encountered where animal feces, decaying food, or decaying animal matter is located. Mishandling rodent or animal carcasses also brings individuals in contact with potentially pathogenic bacteria.

Histoplasmosis risk is greatest where bird or bat feces have accumulated in or on top of soil. The risk of developing cryptococcosis is highest for those working in accumulations of pigeon feces indoors in attics, false ceilings and warehouses.

Hantavirus contact is most likely in areas where rodent activity is detected by the presence of large numbers of droppings and/or the smell of urine. Attics, closets, storerooms, cellars, basements, garages and warehouses should all be suspect with regard to the potential for encountering deer mice and other rodents. Hantavirus risk is extremely low. To date no pest management professional has been diagnosed with the disease.

Bee and wasp stings can occur at any time during the summer, especially when accidentally stumbling into a nest of these social insects. Spider bites occur when putting on shoes or clothing in which the spider is hiding or when, during an inspection, moving a board, landscape timber, or other item under which the spider is hiding.

Part 2 of this story, to appear next month, discusses how PCOs can protect themselves from environmental pathogen

PART 2

Last month, Part 1 of this story discussed some of the common pathogens that are regularly encountered by pest management professionals. Part 2 covers how PCOs can and should protect themselves from these pathogens.

Every pest control professional is responsible for his or her own personal hygiene and safety. But even with the proper training, individuals can become lax in following good personal protection practices. And because the risks of disease or illness are rare, we as pest control professionals often overlook common sense and our alertness to potential dangers drops.

PROTECT YOURSELF. The proper personal protection equipment (PPE) needs to be carried by each person who enters such areas as crawlspaces, basements, attics, warehouses, etc. Items that should be available to every professional include the following.

1. High Efficiency Purifying Air (HEPA) Respirator: A HEPA filter will screen out most environmental hazards associated with microorganisms. If a half-face respirator is used, it should be combined with unvented goggles. Of course, proper fit testing should be completed before wearing a respirator.

2. Protective Gloves: To minimize hand contact with potentially contaminated surfaces, latex, rubber or neoprene gloves should be worn. Do not use leather, cloth or lined gloves for protective use. After use, gloves should be washed and decontaminated by soaking in an EPA-registered disinfectant or a weak bleach solution. It is often easier to use disposable gloves for some situations. Heavy leather gloves can be used for work around bee or wasp nests.

3. Unvented Goggles: Unvented goggles protect against entry of pathogens through the eyes. Vented goggles are unacceptable because they allow air — and potentially pathogens — into the eye area.

4. Coveralls/Bee Suit: Disposable Tyvek coveralls are needed when working around hantavirus, histoplasmosis or cryptococcosis situations. The suit can be removed and thrown away in a sealed plastic bag. Heavy coveralls or a bee suit combined with a bee veil is needed for work around bee and wasp nests.

5. Leather Boots/Rubber Overshoes: Canvas and nylon shoes can have dirt and debris rubbed into the fabric. Rubber and leather can be thoroughly cleaned and treated with a certified disinfectant.

6. Disinfectant Soap: This soap is used to regularly wash hands and other body parts that may have been exposed to unsanitary situations.

7. Disinfectant Sprays: EPA-registered disinfectants are necessary to spray animal droppings or areas where hantavirus could be located. A weak bleach solution is also suitable.

8. Insect Repellent: Repellents are needed when working in tick-infested areas.

Bacteria-laden environments, such as this filthy kitchen, pose a serious health risk to the unprepared professional.

PROCEDURES TO FOLLOW. The procedures outlined below should be followed to protect against the most serious environmental pathogens. Common sense and awareness are the best defense in avoiding unnecessary exposure.

1. Hand Washing. Regular washing of hands during the day is the most important personal hygiene practice. Food poisoning bacteria, such as Salmonella and E. coli, are picked up on the hands and transmitted to the mouth while eating or smoking. The hands are the most likely area to be cut or abraded, thus creating a possible entrance for Staphylococcus through the skin. Hands also move bacteria into the eyes.

Hands should be washed at least after every service visit before climbing back into the vehicle and prior to eating, smoking or using the restroom. They should be cleaned as soon as possible after contacting any filthy surface.

2. Look Before You Leap. Recognize areas of potential risk:

• Areas where numerous rodent droppings are present, or where there are bird droppings on soil, on floors, or in attics.

• Excessively dusty conditions.

• Excess decaying food debris or other decaying organic matter.

• Dead rodents, birds or other animals (and the presence of blow flies and fly pupae).

• Areas where raccoons, possums or skunks are believed to be living in the structure.

• Older buildings.

3. Wear Respirator, Eye Protection and Protective Gloves. Personal Protective Equipment is critical in suspect environments. Persons who have facial hair, except for mustaches, will not achieve a tight enough seal with any respirator.

4. Cuts and Abrasions. Keep all cuts carefully bandaged, especially on the hands. Wear gloves for further protection.

5. Use Disinfectants. Spray rodent droppings, rodent nests and dead rodents with an EPA-registered disinfectant spray prior to handling or entering a suspect area. Any other dead animals should also be treated with disinfectant before handling.

6. Don’t Vacuum. Never attempt to sweep up or vacuum animal droppings, as dust will become airborne. Spray such areas with disinfectant, let sit for a short period prior to wiping up with paper towels. Used towels should then be placed into sealed plastic bags for disposal.

7. Immediately Clean Up. Remove and dispose of disposable gloves and Tyvek coveralls immediately after use. Continue to wear a respirator when removing coveralls, as dust on the coveralls could become airborne.

8. Disposal of Contaminated Items. After removing disposable items, immediately place them into a plastic bag, spray additional disinfectant solution into the bag, tightly seal, and dispose.

9. Cleaning Reusable Items. Reusable coveralls; rubber boots; and nitrile, rubber or latex gloves need to be soaked in disinfectant solution, then washed after use in a suspect area. These should be rinsed thoroughly and allowed to dry prior to reuse.

10. Clean the Respirator. Wearing protective gloves, clean the respirator face piece with disinfectant solution and rinse thoroughly. Store respirator in a sealed zip-style bag. It is a good idea to throw the filter cartridges away after working in a clearly unsanitary area, e.g. a bird or bat roost.

11. Use Repellents. When walking or working in areas where ticks could be present (wooded areas, tall grass), tuck pants legs into boots or socks and spray pant legs with insect repellent.

12. Bee Suits are Necessary. Wear a bee veil, heavy coveralls or bee suit, and heavy leather gloves when working in an area where a social bee or wasp nest is located.

13. Look Out for Spiders and Scorpions. Always wear protective gloves when turning over or moving firewood, boards, stones or other items in areas where black widow or brown recluse spiders or scorpions are common. Even in areas where these arthropods are not common, it is a good idea to wear gloves.

14. Avoid Contact with Dogs and Wildlife. Avoid entering any area where a dog or wild mammal may be present. Any animal acting strangely should be avoided. Never enter a crawlspace or attic to inspect if you suspect or know that wild mammals are present. Inspect only after such animals have been removed by a qualified wildlife control specialist.

Stoy Hedges is manager of training for Terminix International, Memphis, Tenn.