Three Poisonous Spiders

Black widow spiders have the most dangerous bite of any spider in North America. Their venom is 15 times stronger than a rattlesnake’s, ounce for ounce.

Funnel-web spiders (Atrax robustus) are feared in Australia because of their potent venom. A bite from one of these spiders may cause pain throughout the body, emesis, respiratory failure, and delirium. Click the Poisonous Spiders In Kentucky to learn more.

Black widows are among the most recognizable spiders due to their distinctive red hourglass marks on their abdomens. Although the females are the most dangerous, the males can also be harmful. These spiders live in dark, secluded areas and bite to protect their eggs and young.

The initial symptoms of a Black Widow bite might feel like a pinprick, but the pain quickly spreads beyond the bite area. The victim might develop a fever, sweating, and nausea. Symptoms might last for about 8 to 12 hours, but can continue for several days.

In severe cases, a bite can lead to muscle cramping and breathing problems. The alpha latrotoxin in a Black Widow’s venom disrupts calcium ion channels in the membrane of nerve cells, leading to “misfiring” in the muscles and other organs. This venom causes the muscles to tighten, which leads to chest pain and abdominal pain. It can even cause the diaphragm to paralyze, making it difficult to breathe.

A person who is bitten by a Black Widow should call a poison control center right away. They will guide the victim in what to do next. While waiting for medical help to arrive, the victim can wash the bite site with soap and water. Then, wrap an ice pack in a cloth and place it over the bite site. The ice should be applied for 10 minutes at a time, with 10-minute breaks in between. They should try to elevate the bite location if possible.

In 2013, people reported about 1,866 Black Widow bites to the American Association of Poison Control Centers. Fortunately, many of the bites resulted in mild or no health complications. But the spider’s bite is still a serious threat because of the toxic alpha latrotoxin protein in the venom, Casem says. Fatalities are rare, but they can occur in children or the elderly. People who are very ill or overweight can also have more severe symptoms and die from a bite.

Brown Widow

While the brown widow has been expanding its range in southern California, many initial reports of bites were actually immature black widows or Steatoda species or orbweavers (Lycopersicon esculentum). However, as brown widow numbers increase in the state, we are seeing more true cases of envenomation. Nevertheless, the bite of this spider is not nearly as dangerous as that of the black widow.

Like the black widow, the brown widow has a distinctive orange to yellow hourglass mark on the underside of its abdomen. It also has a characteristic pattern of light to dark brown to black stripes across its legs.

Unlike the black widow, which can vary greatly in color from light tan to dark brown or even black, the brown widow is typically more of a uniform light to medium tan color with darker bands and markings along its body. Its hourglass mark is more muted and less distinct than the red of the black widow. The lateral diagonal stripe on the abdomen is more of a “finger” than the straight line of the immature black widow, and it may be flattened slightly at the top.

The female brown widow’s retreat area is usually a sheltered place such as the corners of storage closets, buckets, or entryway corners. When disturbed, she usually withdraws into the web and feigns death by pulling her legs close to her body and bending them down over her back (a behavior known as thanatosis). This is how she protects herself from predators.

Female brown widows are prolific breeders and can produce multiple egg sacs over the course of a lifetime. The average number of eggs is 120-150 per clutch. The fertilized eggs are then placed in the spider’s burrow to develop into larvae.

It is thought that the brown widow’s success in displacing the native black widow is due to its ability to survive and thrive in fragmented desert habitats that lack predators of the native spiders. In fact, one study found that none of the invasive brown widows’ egg sacs in a transplant experiment fell prey to local desert predators. The authors speculated that this is due to the spiky surface of the egg sacs, which may confuse the predators into thinking they are prey items.

Brown Recluse

A frightfully venomous species, the brown recluse has been known to cause serious and even fatal reactions in some people. Unlike some spiders, the brown recluse does not spin webs and is most often found in dark, sheltered areas where it hides during the day. Typically, it has a round body and six eyes arranged in three pairs or dyads. The bite of the brown recluse is not painful at first, and some people may feel nothing at all. However, within several hours, pain begins to develop. The venom is very dangerous because it attacks blood vessels, causing cell death and a slow hemorrhage at the bitten area. Over time, a lesion develops that becomes increasingly darker and is often referred to as a “bull’s eye.”

The venom can also kill platelets and destroy red blood cells which results in a severe blood disorder called loxoscelism. Symptoms of this condition include fever, chills, sweating and a general feeling of illness. If left untreated, the venom can cause other serious symptoms including a coma.

While the majority of brown recluse bites do not produce a full-blown necrotic ulcer, some do. The bite initially appears as a small, red and itchy wound. Over the course of a few days, the bite grows larger and more painful, becoming darker in color. In some cases, the bite expands and forms a blister that ruptures in 8 to 36 hours. The ulcer then progresses to a dark, infected and non-healing wound.

The best way to prevent a severe reaction to a brown recluse bite is to deny them access to their hiding places. In homes, this includes garages, attics and crawl spaces. It is important to look for egg sacs, shed skins and other signs in these areas, along with joists, sills, rafters, cracks around fireplaces, wall voids, baseboards, woodwork, storage boxes, and other long-neglected and undisturbed areas.

Yellow Recluse

Cheiracanthium inclusum, also known as the yellow sac spider, is found throughout Kansas. It is one of the few spiders that resembles a brown recluse but doesn’t cause necrotic symptoms. Its front legs are longer than its body, and it is a light yellow color with an orange-brown stripe down its abdomen. It spins small retreats called silk sacs in out-of-the-way places. They are commonly found indoors, often in corners or behind pictures. They are nocturnal and hunt at night.

Like other clubionid spiders, yellow sac spider venom can pierce the skin, causing mild pain. They also release a substance that can destroy the skin and cause ulcers around the bite site. If the wound becomes infected, it can cause a serious reaction. This is more common in children and people with certain medical conditions.

Symptoms of a bite can begin within 24-48 hours and may start with a local lesion or a red, itchy rash that develops into an open sore with a bull’s-eye appearance. The venom can penetrate the tissue and damage blood vessels, nerves and cells. In a small percentage of victims, the effects can progress to a systemic reaction, including fever, headache, muscle aches, nausea, vomiting and a generalized pruritic rash. In severe cases, hemolytic anemia and disseminated intravascular coagulation (DIC) can occur.

The best way to prevent a spider bite is to protect yourself by wearing long-sleeved shirts, hats, and gloves when outdoors and using insect repellent with DEET. When working in the yard, move piles of rocks and firewood away from your home. When bringing in outdoor items, shake them out to eliminate any hiding spiders.

If you do get bitten, clean the wound with soap and water to avoid infection, and apply an ice pack to reduce swelling and numb pain. Over-the-counter pain relievers can help manage the discomfort. If symptoms continue to get worse, contact your doctor. They may need to inject you with an antidote to reverse the effects of the venom. In some cases, a patient may need to be transferred to a hospital for more aggressive treatment.