The term “banana spider” is commonly used, yet it refers to a variety of spiders, not a single species. This broad naming can cause confusion, as some are largely harmless to humans, while others possess potent venom. This article clarifies what happens if a bite occurs, focusing on the distinct types often called “banana spiders” and providing actionable advice for care and prevention.
Common “Banana Spiders” and Their Bites
One common “banana spider” in the Americas is the golden silk orb-weaver (Trichonephila clavipes). These spiders are easily recognized by their large size, featuring a silvery-white cephalothorax, an orange-brown abdomen with white-yellow spots, and yellow-banded legs. They construct extensive, golden-hued orb webs, which can span up to 1.5 meters in diameter.
The venom of golden silk orb-weavers is typically not considered medically significant to humans due to its low toxicity. Bites are rare and usually occur only in defensive situations, such as when the spider is accidentally handled or provoked. If a bite does occur, the pain is generally mild, often compared to a bee sting, and is accompanied by localized redness, slight swelling, or itching at the bite site.
Individuals might experience mild numbness, or, less commonly, nausea or dizziness. These symptoms are typically transient and usually resolve without medical intervention within a few hours to a couple of days. The prognosis for a bite from a common golden silk orb-weaver is generally favorable, with no lasting health concerns.
The Brazilian Wandering Spider: A Different “Banana Spider”
Another spider sometimes referred to as a “banana spider” is the Brazilian Wandering Spider, belonging to the genus Phoneutria. These are large, robust spiders, with impressive leg spans.
Unlike web-dwelling orb-weavers, Phoneutria spiders are ground-dwelling and actively hunt their prey. A distinctive defensive behavior involves raising their two front pairs of legs high, revealing a black and light-banded underside, while swaying from side to side. This display serves as a warning, signaling the presence of a highly venomous spider whose bite can be medically significant and particularly dangerous for children.
A bite from a Brazilian Wandering Spider can cause immediate and intense burning pain at the site, followed by symptoms such as sweating, goosebumps, and muscle twitching, spasms, or cramps. Within 30 minutes, more severe systemic effects can manifest, including fluctuations in blood pressure, changes in heart rate, nausea, vomiting, abdominal cramping, hypothermia, vertigo, blurred vision, and even convulsions. In males, a prolonged and painful erection, known as priapism, is a characteristic symptom.
These spiders are primarily native to South America, found across various regions. They are occasionally encountered outside these regions through accidental transportation in international shipments, particularly with produce like bananas. Immediate medical attention is necessary following a suspected bite from a Brazilian Wandering Spider.
Immediate Care and When to Seek Help
For any spider bite, initial first aid involves cleaning the affected area thoroughly with mild soap and water. Applying a cool cloth or an ice pack to the bite site periodically, for about 15 minutes at a time, can help reduce pain and swelling. Elevating the bitten limb, if possible, can also assist in minimizing swelling.
Over-the-counter pain relievers can be used to manage discomfort, and antihistamines may help alleviate itching. It is important to monitor the bite site closely for any signs of worsening symptoms or the development of an infection.
Seeking immediate medical attention is crucial if a bite from a Brazilian Wandering Spider is suspected. Medical consultation is also advised if symptoms become severe, spread, or worsen, such as intense pain, spreading redness, abdominal cramping, or the formation of a growing wound. Signs of an allergic reaction, including difficulty breathing, a widespread rash, or swelling of the face or mouth, necessitate urgent care.
Medical evaluation is recommended if there are signs of infection like pus, fever, or increasing warmth around the bite. Bites occurring in sensitive areas, or affecting vulnerable individuals such as children, the elderly, or those with compromised immune systems, should also prompt professional medical assessment. If it is safe to do so, taking a clear picture of the spider can significantly aid healthcare providers in identification and treatment.
Preventing Encounters
Minimizing the risk of spider bites often involves understanding their behavior and habitats. Spiders frequently seek shelter in dark, undisturbed locations, including basements, attics, and outdoor clutter like woodpiles. Keeping these areas tidy and free of debris can reduce potential hiding spots.
Wearing protective clothing, such as gloves, when engaging in outdoor activities like gardening or handling firewood, can prevent accidental bites. Shake out shoes and clothing before putting them on, particularly if they have been stored in garages or sheds. When bringing in produce, especially imported items like bananas, a quick inspection can help avoid inadvertently introducing spiders into the home.
Sealing cracks and crevices in the foundation and around windows and doors can prevent spiders from entering living spaces. Utilizing screens on all windows and doors provides an additional barrier against entry. Reducing clutter both inside and outside the home further diminishes areas where spiders might reside.