Biological Hazards for the Construction Industry
Introduction
Biological hazards are hazards from plants, animals, insects and microorganisms, or their waste products that may be infectious, toxic or allergenic. Sources of biological hazards include bacteria, viruses, insects, plants, birds, animals including reptiles and humans. Exposure to these sources can lead to a variety of health effects ranging from skin irritations, to allergies, infections and severe injury.
Plants
The most common exposures to poisonous plants in the United States involve poison ivy, poison oak and poison sumac. There are five types of poison Ivy, sumac & oak in the United States, and all of the plants contain the exact same substance that leads to the rash as a result of contact.
Poison Ivy
A climbing vine with three serrated-edge, pointed leaves grows in the East, Midwest and South. In the northern and western states, poison ivy grows as a non-climbing shrub.Poison Oak
Poison oak also has three leaves. It grows in the sandy soil of the Southeast as a small shrub. In the western United States poison oak is a very large plant, which grows as a standing shrub or climbing vine.Poison Sumac
A shrub or bush with two rows of 7 - 13 leaflets, most common in the peat bogs of the Northern United States and in swampy Southern regions of the country.Biological Risks-Construction[1].doc Page 13 of 13
Symptoms
Signs and symptoms of exposure vary depending on the sensitivity of the individual exposed, the duration of exposure and the season. The first symptom of poisoning is a severe itching of the skin. Later, a red inflammation and a blistering of the skin occurs. In severe cases, oozing sores develop. The rash spreads by the poisonous sap, not as the result of contamination from sores. The rash will continue to spread through repeated contact with the sap which may remain on clothes, shoe laces and other surfaces that have been in contact with the plant. Although extremely irritating, most cases disappear in a week or 10 days.
Treatment
Relief may be found through the application of medication available in most drugstores. A physician should examine severe rashes, especially those covering large areas or accompanied by fever. Medical treatment is most effective if applied before the oozing sores appear.
Wash infected skin as soon as possible with cold water to minimize the severity of the rash and prevent the spread of the sap to uninfected parts of the body. Skin absorbs the active compounds in the sap within the first 3 minutes, and dermatitis cannot be prevented in most cases without medical treatment. Soap and water is more effective than just water in removing the sap, but may temporarily remove a natural protective layer that helps keep the active compounds from being absorbed through the skin.
Clothing can be decontaminated by laundering with soap or detergent. Protective gloves are recommended before handling contaminated clothing.
Microorganisms
Microorganisms include viral, bacterial and fungal exposures. These diseases may be spread through the air in dust or droplet form, through skin contact or by animal vectors such as ticks.
Hanta Virus
Viral hazards are uncommon in the construction industry. The most significant viral exposure in the industry is Hanta Virus. The virus is transmitted through the air when rodent droppings are disturbed, creating dust that is inhaled by the worker, or through exposure to rodent saliva if rodents are handled. The deer mouse and western chipmunk are two species that are known to carry the virus. In the United States, cases have been largely restricted to the Southwestern region of the country, in the Four Corners area.
Exposure
Insufficient information is available at this time to allow general recommendations regarding risks or precautions for persons in the affected areas who work in occupations with unpredictable or incidental contact with rodents. Occupations that may have exposures include:
¨ telephone installers;
¨ maintenance workers;
¨ plumbers;
¨ electricians;
¨ construction workers.
Workers in these jobs may have to enter various buildings, crawl spaces, or other sites that may be rodent infested. Recommendations for such circumstances must be made on a case-by-case basis after the specific working environment has been assessed and state or local health departments have been consulted.
Symptoms
Initial symptoms are flu-like with fever and muscle aches. These symptoms can appear from one to six weeks after exposure, followed by shortness of breath and coughing. The disease can progress rapidly and may require hospitalization.
Histoplasmosis
Histoplasmosis is an infectious disease of the lungs caused by a fungus found in the droppings of chickens, pigeons, starlings, blackbirds, and bats. The infection sometimes can spread to other parts of the body.
This fungus thrives in moderate temperatures and moist environments. Birds are not infected with it because of their high body temperatures, but they do carry it on their feathers. Bats can be infected because they have a lower body temperature than birds and can excrete the organism in their droppings.
When the spores from the fungus are inhaled, they are small enough that they enter the lungs and start an infection. Many of these infections are easily overlooked because they either produce mild symptoms or none at all. However, histoplasmosis can be severe and produce an illness similar to tuberculosis.
Exposure
Workers in occupations that involve contact with the soil, in particular soil enriched with bird and bat droppings are at high risk of acquiring infection. They include:
¨ farmers and poultry keepers, especially when cleaning silos, chicken coops, pigeon roosts and bat-infested lofts;
¨ gardeners and horticulturists using poultry manure as fertilizer;
¨ construction and other workers in earth-moving operations;
¨ workers in road construction, tree-clearing or landscaping;
¨ workers clearing or dismantling contaminated buildings;
¨ construction workers in road and bridge construction activities.
Symptoms
The symptoms of the infection appear within 5 to 18 days after exposure, most commonly in 10 days. Symptoms can range from mild to chronic lung and pulmonary infections.
Workers who will be performing construction activities in areas with noticeable amounts of bird and/or bat droppings should take precautions to avoid breathing in the spores that can become airborne when the waste material is disturbed. Dust suppression techniques such as wetting material before scraping or shoveling can minimize the risk of creating dust and reduce inhalation hazards. Good hygiene practices, including washing hands and storing lunches away from the work area will help to minimize exposure. Respiratory protection may be required in some cases to provide adequate protection for workers.
Lyme Disease
Two species of ticks carry the bacteria that cause Lyme disease. The disease is spread when the tick bites a human, however the disease is not spread from person to person. Since it is a bacterial infection the same person can become infected more than once.
The ticks that carry the disease are the deer tick, found mainly in the eastern regions of the United States, and the California blacklegged tick found in the Western and Pacific regions of the country.
Exposure
Most victims of Lyme disease were in situations where being bitten by a tick could be expected. Many people who develop the disease, however, do not remember seeing ticks or being bitten. Tick bites may cause small red irritations, but they often go unnoticed, especially those from small, immature ticks.
Tick bites commonly occur from May to September, although this varies from year to year and from region to region. Ticks sometimes move around on the body but they usually attach themselves to the skin and stay in one place. Before feeding, ticks look like small, brown scabs or freckles. After feeding, ticks may swell considerably, and, according to some people, look like a raisin or blood blister with legs. Soon after receiving a tick bite, some victims of Lyme disease experience a brief flu-like illness.
Symptoms
Lyme disease is sometimes difficult to recognize, and it has occasionally been confused with other diseases. It is important to consult with a doctor if you think it is possible that you have Lyme disease.
The disease has three major features: a history of tick bites, a slowly expanding rash, and complications from nerve disease, heart disease, or arthritis. The following symptoms have been recorded by the Centers for Disease Control (CDC):
Rash - In about 75 % of reported cases of Lyme disease, the victims develop a rash around or near the tick bite usually within one week. In some cases, a peculiar, bright red, circular rash develops. It soon expands to form a ring-shaped "bull's-eye" that can grow to the size of a dinner plate. Often, however, a more mild, general rash appears anywhere on the body. The rashes fade after several weeks. Some victims, however, never develop a rash, yet experience more advanced symptoms of the disease.
Nerve disease, heart disease, arthritis - About 15 % of untreated victims develop temporary nerve problems from a few weeks to several months after a tick bite. The most common problem is meningitis (inflammation of the covering of the brain) with fever, headache and stiff neck. Some victims experience neuritis (nerve inflammation) with pain and other disturbances such as deafness. These nerve problems are usually temporary and disappear with proper treatment.
Heart disease occurs in about 5 % of untreated victims often with no symptoms of infection. The most common problem is a heart block that affects the rhythm of the heartbeat. This problem is also temporary and disappears permanently with proper treatment.
Lyme disease causes arthritis in about 25 % of studied cases and occurs several months to two years after receiving a tick bite. This arthritis most often affects the knees, although it also occurs in the shoulders, wrists, elbows, hips, and ankles. Prompt treatment usually solves this problem. Without treatment, however, this arthritis can lead to permanent disability.
In rare cases, people who have the disease for several months or years, and do not receive treatment, develop serious changes in the nervous system. These changes result in loss of feeling in the limbs, loss of memory, and extreme tiredness.
Rocky Mountain Spotted Fever
The name Rocky Mountain spotted fever is misleading as this disease is broadly distributed throughout the continental United States, as well as southern Canada, Central America, Mexico, and parts of South America. Between 1981 and 1996, Rocky Mountain Spotted Fever was reported from every U.S. state except Hawaii, Vermont, Maine, and Alaska.
The disease is spread by the wood tick and the dog tick. Wood ticks are found in the Western and Pacific regions of North America, and the dog tick is primarily found in the Eastern U.S. and California.
Symptoms
Rocky Mountain Spotted Fever is caused by a parasite called Rickettsia, which is transmitted to the victim when they are bitten. Symptoms can include fever, headache, muscle pain and a characteristic rash. The rash appears several days after the other symptoms and starts on the wrists and ankles before spreading to the palms and soles of the feet.
In most cases Rickettsia can be treated successfully with antibiotics.
Prevention
With all tick borne diseases prevention consists of checking for ticks when working in an area where they are prevalent. Ticks live in grassy areas, and forested or brushy areas including willows near streams. The tick resides on a branch or grass stalk with the front legs extended. When a host brushes by the tick latches on and finds a place to bite the victim. They prefer protected areas such as creases in the skin, and under the hairline at the nape of the neck. By checking for ticks regularly they can be detected and removed before they bite.
Snakes
There are approximately 20 species of venomous snakes are in the USA. Most are rattlesnakes, cottonmouths (water moccasins), coral snakes and copperheads. All of these snakes with the exception of coral snakes are called "pit vipers" because they have deep pits lined with heat receptors in the cheeks between the eyes and nostrils. These receptors are thought to detect the presence of prey and guide the direction of the strike.
Pit vipers are widely distributed throughout the USA, but most bites occur in southern and southwestern states between the months of April and October. Rattlesnake bites are the most serious; copperhead bites are usually not severe, and cottonmouth bites are usually considered moderately severe.
Coral snakes are found in southern states as far west as Texas. The copperhead is found in most of the eastern and mid-western states. The cottonmouth Moccasin occupies waterways and wetlands throughout the south as far west as Texas. Rattlesnakes are the most widely dispersed with different varieties that can be found throughout most of the US.
Statistics
· 7000 venomous snakebites are reported annually in the United States.
· 85% of the natural bites are below the knee.
· 50% are dry. Squeezing the venom glands to inject is a voluntary reflex. In that strikes against humans are generally defensive actions, it is estimated that no venom is purposely injected about half the time. This holds true with the pit vipers. With the Coral Snake the amount of venom injected is directly related to the size of the snake and the length of time it holds on to the victim.
First Aid Therapy
The stabbing strike of a pit viper can be recognized by one or two definite puncture wounds, and if venom is injected there will be intense, burning pain and swelling around the holes. The following lists some of the Do’s and Don’ts when treating a snakebite injury:
Do
· Remain calm - Remember that there is an excellent chance for survival, and in most cases there is plenty of time.
· Suction – remove as much venom as possible directly from the wound. A snakebite kit generally provides a suction cup for this purpose. Do not attempt to suck venom from the wound by mouth.
· Remove jewelry - Swelling can progress rapidly, so rings, watches and bracelets can be a real problem.
· Mark the time - The progress of symptoms (swelling) is the most obvious indicator of the amount of venom.
· Keep the stricken limb below the heart.