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Hymenopterous Insect Stings

By THOR LEHNERT
Research entomologist, Science and Education Administration, Bioenvironmental Bee Laboratory, Beltsville, Md. 20705.

BEEKEEPING IN THE UNITED STATES
AGRICULTURE HANDBOOK NUMBER 335
Revised October 1980
Pages 141 – 143

The honey bee is the most common single species of stinging insect in the United States. Bees and the related wasps, hornets, yellow jackets, and ants usually do not sting unless stepped on, touched, or molested. They are usually not active at temperatures below 55° F or on rainy days. The highest incidence of stings is in August. Yellow jackets, honey bees, and wasps are the worst offenders, in that order. Yellow jackets cause more moderate and also more severe reactions than bees or wasps.

Bee Venom

The poison gland system of the bee consists of a small alkaline gland and a larger acid gland. The venom comes from these two glands. The stinger is made up of two lancets with sharp barbs pointing backward, similar to a harpoon. When a honey bee stings, its stinger is pulled from its body. Even after the stinger is separated from the bee, its muscular mechanism can continue to force its venom into the wound. Because venom continues to be injected by the stinging mechanism, the stinger should be removed immediately. Most people make the mistake of pulling it out with the thumb and index finger and thereby squeeze more venom into the wound. The stinger should be scraped or scratched out with a fingernail.

Other stinging Hymenoptera, such as yellow jackets, wasps, and hornets, retain their stingers.

Bee venom is a water-clear liquid with a sharp, bitter taste and a distinct acid reaction. The specific gravity is 1.1313. The venom is easily soluble in water and acid, but almost insoluble in alcohol.

The three toxic effects of bee venom are neurotoxic (paralysis of the nervous system), hemorrhagic (increase in the permeability of the blood capillaries), and hemolytic (destruction of red blood cells).

Recent work reveals that bee venom is a very complicated substance with several active biochemical components. At least eight active components plus several biological inactive components have been identified. The substances showing activity are histamine, melittin (a protein), a hyaluronidase, and phospholipase A.

The histamine recovered was shown not to be a major pharmacological factor in bee venom. However, histamine also is released from body cells because of the reaction to the sting in allergic persons.

Melittin, a protein having a molecular weight of 33,000 to 35,000, is thought to be responsible for the general local toxicity of the venom. Melittin in high concentrations also has caused hemolysis of red blood cells.

Bee venom contains at least two enzymes-a hyaluronidase and phospholipase A. The hyaluronidase is believed to be the “spreading” factor. By breaking down the cell-cementing substance, hyaluronidase allows the toxic principles of bee venom to infiltrate the tissues.

Phospholipase A apparently has no general toxicity. However, through indirect action on the unsaturated fatty acids, it causes hemolysis of red blood cells. Phospholipase A also causes inactivation of thrombokinase, inhibits oxidative phosphorylation, and attacks enzymes involved with metabolic dehydrogenation. The pain experienced after being stung may well be the result of these last three actions.

For many years, formic acid erroneously was believed to be the major component of venom produced by the honey bee, and this belief is still held by many. The action of venom is much more complex than the simple concept of direct action on the tissue by formic acid.

Sting Reactions

Usually insect stings cause only a local reaction, with pain lasting for several minutes after penetration of the stinger. A redness and slight swelling at the sting site also may occur. Until recently, some people believed severe symptoms and death from stinging insects were due to venom being introduced directly into a small blood vessel. Severe reactions are now considered to be due to sensitivity to proteins in the venom.

In about 2 percent of persons, a hypersensitivity develops in which each additional sting produces a more severe reaction. Hypersensitivity may appear after a varying number of stings, usually each sting making the reaction progressively worse. Some develop sensitivity after one sting, whereas others after a series of normal reactions. In a few individuals, hypersensitivity appears to be inborn. The first sting has resulted in death.

Symptoms in an allergic person usually appear within a few minutes after the sting, but may not appear for 24 hours. Local swelling may be excessive. A hivelike condition may break out over the body. There is a sensation of choking, difficult breathing, asthma, and the lips turn blue. Shocklike symptoms, vomiting, and loss of consciousness may follow in rapid succession.

Treatment and Precautions

Treatment by a physician is divided into three stages: (1) Immediate treatment for anaphylaxis is epinephrine 1:1,000, 0.3 cc to 0.5 cc, given intramuscularly or by deep subcutaneous injection. (2) Second-stage treatment includes a sympathomimetic agent, such as metaraminol, 100 mg in 500-cc isotonic saline solution given intravenously, antihistamine given intramuscularly, and corticosteroids. (3) Long-term care involves immunization with the appropriate insect antigen.

The long-term treatment undertaken to relieve the allergic condition to stings is known as desensitization. This treatment consists of a graduated series of injections of an extract made from the body of the offending type of insect. If the stinging insect is not identified, the sensitive person should be treated with an antigen composed of honey bee, hornet, paper wasp, and yellow jacket. Many allergists are now getting better desensitizing results with pure venom.

The degree of relief from allergic reactions is not the same for all persons after desensitizing treatments. The frequency of treatment also varies. For some people, one series of treatments is effective. For others, the treatment must be repeated with booster injections once a month.

Another important point is that of cross-protection. The injection of stinging insect extract of one species will protect some persons against all stinging insects. Some will need a combination of extracts to achieve complete protection. This makes the procedure of desensitization an individual process.

Desensitization seems to be helpful to about three-fourths of persons with severe reactions, in that they report lessened reactions to subsequent stings. Desensitization should be considered by persons who have severe reactions.

Such persons should have an emergency kit available at all times. This kit should contain ampules of epinephrine 1:1,000 and an injectable antihistamine. Some doctors now recommend the use of aerosol bronchodilator sprays which contain adrenaline-like compounds for persons sensitive to stings. However, the person who is extremely allergic and becomes faint and lapses into unconsciousness a few minutes after a sting must be taken to a physician or hospital to receive immediate treatment. Instructions on the use of first aid remedies should be obtained from a physician.

A sensitive person should be immunized, since there is no way of completely avoiding stinging insects. However, one can take several precautions to prevent stings. For example, the type of clothing worn affects the probability of being stung. Beekeepers consider clothing color to be one of the most important factors. Light-colored clothing should be worn in preference to dark, rough, or woolly clothing. Bees are attracted to suede or leather materials, particularly horsehide. If around bees, women should wear some type of head covering to keep the bees out of their hair.

The odor of perspiration has little effect on bees. Certain hair oils and perfumes should be avoided because they attract bees, which may sting after being attracted.

Bees will react more quickly to a moving object than to an immobile object. This can be demonstrated easily by making fast, jerky hand movements when working with a hive of bees. Striking, swatting, and swinging at bees will increase the chance of being stung.

No success has been attained in developing an effective repellant against stinging insects. Dimethyl phthalate, which has been effective in repelling mosquitoes and biting flies, is not effective as a repellant against stinging insects.

Only a small percentage of the population suffers serious reactions from hymenopterous insect stings. However, when reactions other than local irritation and swelling do occur, a physician should be called for immediate treatment. He should be consulted for long-range protection with desensitizing shots.

Yellow jacket wasps sting readily and often are confused with honey bees. The wasps build nests in the ground and will sting when people walk or stand near the entrance, which may be difficult to locate. Stings attributed to honey bees are often caused by yellow jackets.

References

AMERICAN MEDICAL ASSOCIATION.
1965. INSECT-STING ALLERGY. American Medical Association Journal 193:115-120.

FRANKLAND, A. W.
1976. BEE STING ALLERGY. Bee World 57:145-150.

HODGSON, N. B.
1955. BEE VENOM: ITS COMPONENTS AND THEIR PROPERTIES. Bee World 36:217-222.

MARSHALL, T. K.
1957. WASP AND BEE STINGS. Practitioner [London] 178:712-722.

MORSE, R. A., and R. L. GHENT.
1959. PROTECTIVE MEASURES AGAINST STINGING INSECTS. N.Y. State Journal of Medicine 59:1546-1548.

PECK, G. A.
1963. INSECT STING ANAPHYLAXIS. California Medicine 99:166-172.

SCHOFIELD, F. W.
1957. PREVENTION OF SEVERE REACTIONS FOLLOWING STINGS OF THE HONEY BEE. Canadian Bee Journal 65:11-13.

SHAFFER, J. H.
1964. HYPOSENSITIZATION WITH INSECT EXTRACTS. American Medical Association Journal 187:968.

STIER, R. A. and R. F. STIER.
1959. THE RESULTS OF DESENSITIZATION IN ALLERGY TO INSECT STINGS. American Academy of General Practitioners 19:103-108.