Tarantulas are among the largest spiders in the world and likely the most feared. Emergency physicians are increasingly likely to encounter patients who have had tarantula contact as the popularity of tarantulas as pets is increasing.
Tarantulas belong to the suborder Orthognatha and the family Theraphosidae. These large (2.5-7.5 cm) arachnids are slow moving. Females can live as long as 35 years, while the male life span is generally 5-7 years. They have poor eyesight and sense their prey through vibrations. The largest species, Theraphosa blondi, which is found in South America, can have fangs 1 inch long and a leg span up to 12 inches.
Tarantulas generally can be found in tropical and subtropical areas of the world. The largest tarantulas are found in South America. In the United States, great numbers are found in the southwestern states. Most tarantulas sold in pet stores in the United States are imported species of Aphonopelma.
Although tarantulas often evoke panic and anxiety on sight, these hairy long-legged spiders generally are nonaggressive and rarely bite. Tarantulas usually retreat as their main line of defense.
Because of the tarantula's forms of defense, human injury is limited mainly to skin and ocular involvement, with occasional respiratory symptoms.
Tarantula venom is rarely toxic to humans; bites from tarantula species in the United States can be painful but are not considered dangerous. The typical effects are no more serious than those of Hymenoptera stings. The most common reaction is a low-grade histamine response.
Hairs discharged from the tarantula can penetrate several layers of skin or ocular tissue and cause mechanical irritation. Urticating hair morphology ranges from type I to type IV. Only type I hairs are found in US tarantulas, and these do not penetrate the skin as deeply as other types. Type III hairs can penetrate up to 2 mm, causing inflammation and local reaction. Although not common, inhalation of urticating hairs may cause significant allergic rhinitis. Exposure to hairs of certain species in South America (Grammastola) can suffocate small mammals within 2 hours.
So don't worry Wenchy, although Nick should tread carefully. We have far worse in this country...
