INTRODUCTION

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Although most residents of the United States are aware of the pain and discomfort associated with contacting a venomous arthropod, many are not aware that these arthropods (such as ants, bees, wasps, spiders, and scorpions) are responsible for more human deaths in the United States each year than any other group of venomous animals, including snakes. In fact, a study by Parrish15 showed that venomous arthropods accounted for more than 65% of the reported human fatalities caused by venomous animals in the United States from 1950 through 1959. His findings are summarized as follows:

Venomous animal group Human fatalities (1950-59)
Hymenoptera (bees, wasps, and ants) 229/460 or 49.8%
Poisonous snakes 138/460 or 30.0%
Spiders 65/460 or 14.1%
Scorpions 8/460 or 1.7%
Others 20/460 or 4.4%

It would be incorrect, however, to assume from the above information that a high percentage of arthropod envenomizations are fatal. In actuality, the opposite is true. Of the estimated millions of people envenomized by arthropods in the United States each year, about 25,000 have severe reactions; and of these, approximately 30 result in reported deaths.19 Therefore, the high number of fatalities caused by venomous arthropods, relative to other venomous animals, can be attributed to the high incidence of arthropod envenomizations rather than the efficient killing power of their venoms. This high-incidence rate is accounted for by the tremendous abundance of venomous arthropods and their ability to live in close proximity to man.

Air Force personnel stationed in the continental United States face a greater risk of contacting a venomous arthropod than the average United States resident because: (1) a large portion of bases are located in the southern half of the United States, where venomous arthropods are most numerous; (2) many facilities (such as radar, communications, security, and missile sites) are located in remote areas where venomous arthropods are not controlled; (3) numerous Air Force training and work activities must be performed outside; and (4) many military structures (such as older wooden buildings, storage buildings, and field training facilities) provide excellent habitats for venomous arthropods. It is important, therefore, that Air Force medical facilities have current information available concerning the most important venomous arthropods in their areas.

The venomous arthropods discussed in this handbook were selected for inclusion due to the relative severity of their envenomizations and/or the high frequency of their contact with humans. It should be stressed that other arthropods found in the United States are capable of producing envenomization reactions in humans. Regardless, all venomous arthropods found in the United States can be categorized under one of the three types of envenomization methods described in this handbook: (1) biting/piercing, (2) stinging, and (3) urticating/vesicating. The biting/piercing arthropods inject a toxin through an apparatus associated with or near their mouthparts; and the stinging arthropods, through a stinger located at the posterior end of the abdomen. Urticating and vesicating arthropods are grouped together because they both release their toxins on contact. They differ in that the urticating arthropods usually release their toxin through venomous hairs; and vesicating arthropods carry a toxic substance within their system, which is released through small body openings.

To facilitate the utilization of this handbook, each venomous arthropod presentation has been organized into the following information categories:

Identification. Bringing the arthropod causing an envenomization to the medical facility treating the victim is most helpful. In most cases, an identification must be made before the proper form of treatment can be determined. To assist personnel with identification, the key characteristics and representative color photographs are provided for the venomous arthropods discussed.

Distribution. Most arthropod envenomizations occur during the warm plant-growing season when venomous arthropods are most numerous. Since the Southern United States has the longest growing season, venomous arthropods are abundant for a longer period of time in this region. Also, the moderate climate of the Southern States, with fewer weather extremes, permits a greater variety of venomous arthropods to survive, propagate, and produce multiple generations each year. Specific regional occurrences are indicated.

Biology/Behavior. Pertinent biological information is provided to help increase the reader’s awareness and understanding of venomous arthropods. These factors are essential in developing a good avoidance and control program.

Avoidance/Control. To assist in preventing envenomization accidents, several means of avoidance are listed for each venomous arthropod. Since the status of insecticide recommendations is constantly changing, few specific recommendations are included. When insecticide control is necessary, an Air Force, County Extension Service, or United States Department of Agriculture entomologist should be consulted for current recommendations. Any insecticide must be applied according to the instructions on the container label.

In addition to the information presented in the text, a table on envenomization reactions and treatment is included as an appendix. The reactions listed in this table are “typical” and do not necessarily represent the entire range of reactions which might occur.

                                                                                                                                                                                                                                                                                                           

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