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 Parrish[15] 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.