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Speaker 1: Welcome to BrainStuff, a production of iHeartRadio. Hey, BrainStuff. Lauren Vogelbaum here. In the United States, the brown recluse spider is one of our arachnid boogeymen. It is true that the spider's venom can cause necrotic lesions in some people, and it can potentially be deadly for a small portion of the population. But most stories about brown recluses are cases of mistaken identity. Today, let's separate out some spider facts from spider fiction. The brown recluse, taxonomical name Loxosceles reclusa, is just one species of recluse spiders, along with some 150 others around the world in the same genus. The brown recluse is fairly small. Females can have a body length of up to half an inch, or 15 millimeters, with a leg span of just over an inch, or around 30 millimeters. Males are about half that size. The genus name means crooked legs, and to be fair, those long, segmented legs can look a little like a jumble of coat hangers. The brown recluse is, appropriately, tan to brown in color, and those legs are not hairy or spiny. Brown recluses are sometimes called fiddleback spiders because some, though not all, have a distinctive, darker brown mark on their cephalothorax, which is the animal's fused head and central body. that looks a little bit like a fiddle, with its base at the spider's eyes and neck pointing back towards the spider's rear. Recluses have only six eyes, in three pairs. Most other spiders have eight. They are a hunting spider, meaning they don't sit around in webs waiting for their supper to come to them. They do get around on strands of silk and will make silken retreats or little shelters to hang out in by day, but at night, round recluses hunt their prey down on foot. Their ancestors were cave spiders, so in the wild, they like dry areas beneath rocks, bark, shingles, woodpiles, crawlspaces, cardboard boxes, etc. These days, round recluse spiders are synanthropic, meaning their numbers increase in association with humans. Other synanthropic animals include rats, raccoons, flies, and house sparrows. Humans' homes are actually very much like nice dry caves, and a female brown recluse would love nothing more than to lay her egg sack on the dry underside of the flap of a cardboard box and while away the hours guarding it in the eternal twilight of your attic. They're active in a temperature range from around 45 to 110 degrees Fahrenheit, that's 7 to 43 Celsius, which means that our homes are perfectly cozy for them. But just because brown recluse spiders are happy to use human spaces, that doesn't mean they're absolutely everywhere. Their native range is actually pretty limited, and they don't travel very far. For the article this episode is based on, HowStuffWorks spoke with Richard Vetter, a retired technician in the University of California, Riverside Urban Entomology Department, whose work has changed the way doctors diagnose spider bites. He said, The distribution of brown recluses in the U.S. is a little like a rain cloud over the Midwest. If you're standing in the center of the storm, in Kansas or Oklahoma, you're going to get very wet. A lot of water droplets are going to hit you. If you're standing at the edge of the thundershower, in Georgia, the droplets will be much fewer and farther between. In a paper published in 2009, Vetter and his co-authors reported that at the southeastern edge of the spider's range in the state of Georgia, researchers found only 25 brown recluse spiders over the course of a five-year search. Compare that with one Kansas residence, in which the homeowner collected 2,055 brown recluses over the course of six months. Which, I enjoy creepy crawlies, and I admit that's enough to make me go, But even in areas where they are common, the danger that brown recluse spiders pose is often overestimated. Brown recluses do bite on occasion, and they are venomous. Recluse spider's venom contains a few different toxins that can damage living cells, both at the site of the bite and sometimes throughout the body. But recluse spiders are just what it says on the tin. Recluses. They're not aggressive. They tend to hide when threatened. Brown recluse mouthparts are too small to bite through most fabrics. Their bites usually happen on bare skin, when you accidentally press up against one by reaching a hand into its space, or, say, putting on a garment that's been sitting on the floor for long enough to become a hiding space. Just for example, the owner of that Kansas residence that was harboring a full-blown brown recluse infestation lived there for 11 years before she knowingly sustained a brown recluse spider bite, which ended up being asymptomatic. Vetter said... She reached inside a shirt, felt a pinch, and the spider fell out. She says she took a Benadryl and went on with her day. She was fine. I'm not sure the Benadryl did anything. Research has shown that about 90% of all brown recluse bites result in absolutely no reaction. About 10% of cases result in a necrotic skin lesion, that is, a localized area of rotting flesh surrounding the bite. But even that lesion will usually heal up completely by itself. Some do require a skin graft. In less than 1% of cases, and usually in small children, the reaction to brown recluse venom becomes systemic, destroying red blood cells and causing a toxic backup in the kidneys. In these cases, hemoglobin can pass into the urine, which will then come out black. If this happens, the patient can die within 12 to 30 hours, even before anything shows up on the skin around the site of the bite. So if you notice that your or your child's urine is black, seek medical attention immediately. According to Vetter, dialysis and hydration should clear up the reaction if you catch it in time. Brown recluse bites are rarely fatal. A necrotic skin lesion may take several weeks to heal, but you're not likely to die from it. Vetter said, even though fatal brown recluse bites are unbelievably rare, that's what makes the news. Say you know nothing about car accidents, and all you know about them is what you've seen on the news. The only car accidents anybody reports on are the ones that involve fatalities. So if you don't know better, it's easy to believe that all car accidents kill people. The truth is, most of the time, somebody just gets a fender bent in a parking lot and drives away. Another issue that causes overestimation of the danger posed by brown recluses revolves around misdiagnosis. Many physician-diagnosed spider bites are actually not spider bites at all. Vetter said, Bacterial infections, fungal infections, and all kinds of viruses are misdiagnosed as brown recluse bites. Once I was called by a military base in the Northeast because all the soldiers were coming down with these inflamed skin lesions. They were trying to get a permit to spray for spiders. The description of the lesions didn't sound like necrotic brown recluse bites at all. They were swollen and red, and necrotic recluse bites become sunken and blue. I told them as much, and a few months later, they called back to tell me it was actually MRSA, a bacterial infection, going around the base. But, you know, people are very prejudiced against spiders. Part of the problem is that many people never learn how to properly identify spiders. A vetter said, I did a study where I got people to send me brown recluses they found from all over the country. If you thought it was a brown recluse, you stuck it in an envelope and sent it to me. Over four and a half years later, I was sent 1,800 specimens representing 158 species. Some were pseudoscorpions. I got some granddaddy longlegs. A little of everything. Basically, if it has eight legs, people think it's a brown recluse. About 40 different medical conditions are commonly misdiagnosed as brown recluse bites, from vascular disease to leukemia. A mild reaction to a brown recluse bite might include a burning sensation or pain and a bit of inflammation early on, followed by sunken skin at the site of the bite. You can treat any insect or arachnid bite by cleaning it with mild soap and water and applying an antibiotic ointment, and then applying an ice pack on and off for a few minutes at a time to manage discomfort. If you ever suspect that an area of skin irritation is from a spider bite, it helps enormously to capture the spider in question so that you can identify it. Wear gloves. Squashing it is fine, identification-wise. For brown recluses, you're looking for that brown coloration with no striping and the telltale six eyes, arranged in three tight pairs at the center of its face. If it displays a fiddle marking, the eyes will be in the base of the fiddle. If you wind up seeking medical treatment, bring the specimen with you. Vetter and his colleagues came up with a mnemonic device to help both healthcare providers and laypeople better identify what is not a brown recluse bite. It's the acronym NOT RECLUSE. And if any of these statements apply, the injury in question is not from a brown recluse bite. So we've got NOT RECLUSE. Numerous wounds. Occurrence outside of the spider's normal territory. Timing during the spider's dormant period during the winter. Reddening at the center of the wound. Elevation at the center of the wound. Chronic persistence of the wound for more than three months. Large size of the wound of more than 4 inches or 10 centimeters. ulcerous crustiness around the wound during the first week, swelling of the wound if it's below the neck, and, my favorite, exudative, meaning that the wound is wet with a pus or clear fluid. Remember, these are all signs that what you're looking at is not a brown recluse bite. And that was a big list, so you can look up not recluse if you're interested. Of course, check in with a healthcare professional if you have a question or concern about any injury. One final note. I wanted to mention that Vetter won an Ig Nobel Prize for his work with arachnids back in 2020. The Ig Nobels are sort of a parody of the Nobel Prizes, awarded to research that makes you laugh, but also makes you think. Vetter's winning paper, published in the described a psychological survey that he conducted of his colleagues in bug science that investigated their fear of spiders. It's called arachnophobic entomologists, when two more legs makes a big difference. So if you're a little eked out by spiders, take comfort in knowing that you're far from the only one. But you don't need to be that worried about the brown recluse. Today's episode is based on the article, Don't Fear the Brown Recluse Spider, Seriously, on HowStuffWorks.com, written by Jessalyn Shields. BrainStuff is a production of iHeart Podcasts in partnership with HowStuffWorks.com and is produced by Tyler Klein. For more shows from iHeart Podcasts, visit the iHeart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.
Speaker 1: Welcome to BrainStuff, a production of iHeartRadio. Hey, BrainStuff. Lauren Vogelbaum here. In the United States, the brown recluse spider is one of our arachnid boogeymen. It is true that the spider's venom can cause necrotic lesions in some people, and it can potentially be deadly for a small portion of the population. But most stories about brown recluses are cases of mistaken identity. Today, let's separate out some spider facts from spider fiction. The brown recluse, taxonomical name Loxosceles reclusa, is just one species of recluse spiders, along with some 150 others around the world in the same genus. The brown recluse is fairly small. Females can have a body length of up to half an inch, or 15 millimeters, with a leg span of just over an inch, or around 30 millimeters. Males are about half that size. The genus name means crooked legs, and to be fair, those long, segmented legs can look a little like a jumble of coat hangers. The brown recluse is, appropriately, tan to brown in color, and those legs are not hairy or spiny. Brown recluses are sometimes called fiddleback spiders because some, though not all, have a distinctive, darker brown mark on their cephalothorax, which is the animal's fused head and central body. that looks a little bit like a fiddle, with its base at the spider's eyes and neck pointing back towards the spider's rear. Recluses have only six eyes, in three pairs. Most other spiders have eight. They are a hunting spider, meaning they don't sit around in webs waiting for their supper to come to them. They do get around on strands of silk and will make silken retreats or little shelters to hang out in by day, but at night, round recluses hunt their prey down on foot. Their ancestors were cave spiders, so in the wild, they like dry areas beneath rocks, bark, shingles, woodpiles, crawlspaces, cardboard boxes, etc. These days, round recluse spiders are synanthropic, meaning their numbers increase in association with humans. Other synanthropic animals include rats, raccoons, flies, and house sparrows. Humans' homes are actually very much like nice dry caves, and a female brown recluse would love nothing more than to lay her egg sack on the dry underside of the flap of a cardboard box and while away the hours guarding it in the eternal twilight of your attic. They're active in a temperature range from around 45 to 110 degrees Fahrenheit, that's 7 to 43 Celsius, which means that our homes are perfectly cozy for them. But just because brown recluse spiders are happy to use human spaces, that doesn't mean they're absolutely everywhere. Their native range is actually pretty limited, and they don't travel very far. For the article this episode is based on, HowStuffWorks spoke with Richard Vetter, a retired technician in the University of California, Riverside Urban Entomology Department, whose work has changed the way doctors diagnose spider bites. He said, The distribution of brown recluses in the U.S. is a little like a rain cloud over the Midwest. If you're standing in the center of the storm, in Kansas or Oklahoma, you're going to get very wet. A lot of water droplets are going to hit you. If you're standing at the edge of the thundershower, in Georgia, the droplets will be much fewer and farther between. In a paper published in 2009, Vetter and his co-authors reported that at the southeastern edge of the spider's range in the state of Georgia, researchers found only 25 brown recluse spiders over the course of a five-year search. Compare that with one Kansas residence, in which the homeowner collected 2,055 brown recluses over the course of six months. Which, I enjoy creepy crawlies, and I admit that's enough to make me go, But even in areas where they are common, the danger that brown recluse spiders pose is often overestimated. Brown recluses do bite on occasion, and they are venomous. Recluse spider's venom contains a few different toxins that can damage living cells, both at the site of the bite and sometimes throughout the body. But recluse spiders are just what it says on the tin. Recluses. They're not aggressive. They tend to hide when threatened. Brown recluse mouthparts are too small to bite through most fabrics. Their bites usually happen on bare skin, when you accidentally press up against one by reaching a hand into its space, or, say, putting on a garment that's been sitting on the floor for long enough to become a hiding space. Just for example, the owner of that Kansas residence that was harboring a full-blown brown recluse infestation lived there for 11 years before she knowingly sustained a brown recluse spider bite, which ended up being asymptomatic. Vetter said... She reached inside a shirt, felt a pinch, and the spider fell out. She says she took a Benadryl and went on with her day. She was fine. I'm not sure the Benadryl did anything. Research has shown that about 90% of all brown recluse bites result in absolutely no reaction. About 10% of cases result in a necrotic skin lesion, that is, a localized area of rotting flesh surrounding the bite. But even that lesion will usually heal up completely by itself. Some do require a skin graft. In less than 1% of cases, and usually in small children, the reaction to brown recluse venom becomes systemic, destroying red blood cells and causing a toxic backup in the kidneys. In these cases, hemoglobin can pass into the urine, which will then come out black. If this happens, the patient can die within 12 to 30 hours, even before anything shows up on the skin around the site of the bite. So if you notice that your or your child's urine is black, seek medical attention immediately. According to Vetter, dialysis and hydration should clear up the reaction if you catch it in time. Brown recluse bites are rarely fatal. A necrotic skin lesion may take several weeks to heal, but you're not likely to die from it. Vetter said, even though fatal brown recluse bites are unbelievably rare, that's what makes the news. Say you know nothing about car accidents, and all you know about them is what you've seen on the news. The only car accidents anybody reports on are the ones that involve fatalities. So if you don't know better, it's easy to believe that all car accidents kill people. The truth is, most of the time, somebody just gets a fender bent in a parking lot and drives away. Another issue that causes overestimation of the danger posed by brown recluses revolves around misdiagnosis. Many physician-diagnosed spider bites are actually not spider bites at all. Vetter said, Bacterial infections, fungal infections, and all kinds of viruses are misdiagnosed as brown recluse bites. Once I was called by a military base in the Northeast because all the soldiers were coming down with these inflamed skin lesions. They were trying to get a permit to spray for spiders. The description of the lesions didn't sound like necrotic brown recluse bites at all. They were swollen and red, and necrotic recluse bites become sunken and blue. I told them as much, and a few months later, they called back to tell me it was actually MRSA, a bacterial infection, going around the base. But, you know, people are very prejudiced against spiders. Part of the problem is that many people never learn how to properly identify spiders. A vetter said, I did a study where I got people to send me brown recluses they found from all over the country. If you thought it was a brown recluse, you stuck it in an envelope and sent it to me. Over four and a half years later, I was sent 1,800 specimens representing 158 species. Some were pseudoscorpions. I got some granddaddy longlegs. A little of everything. Basically, if it has eight legs, people think it's a brown recluse. About 40 different medical conditions are commonly misdiagnosed as brown recluse bites, from vascular disease to leukemia. A mild reaction to a brown recluse bite might include a burning sensation or pain and a bit of inflammation early on, followed by sunken skin at the site of the bite. You can treat any insect or arachnid bite by cleaning it with mild soap and water and applying an antibiotic ointment, and then applying an ice pack on and off for a few minutes at a time to manage discomfort. If you ever suspect that an area of skin irritation is from a spider bite, it helps enormously to capture the spider in question so that you can identify it. Wear gloves. Squashing it is fine, identification-wise. For brown recluses, you're looking for that brown coloration with no striping and the telltale six eyes, arranged in three tight pairs at the center of its face. If it displays a fiddle marking, the eyes will be in the base of the fiddle. If you wind up seeking medical treatment, bring the specimen with you. Vetter and his colleagues came up with a mnemonic device to help both healthcare providers and laypeople better identify what is not a brown recluse bite. It's the acronym NOT RECLUSE. And if any of these statements apply, the injury in question is not from a brown recluse bite. So we've got NOT RECLUSE. Numerous wounds. Occurrence outside of the spider's normal territory. Timing during the spider's dormant period during the winter. Reddening at the center of the wound. Elevation at the center of the wound. Chronic persistence of the wound for more than three months. Large size of the wound of more than 4 inches or 10 centimeters. ulcerous crustiness around the wound during the first week, swelling of the wound if it's below the neck, and, my favorite, exudative, meaning that the wound is wet with a pus or clear fluid. Remember, these are all signs that what you're looking at is not a brown recluse bite. And that was a big list, so you can look up not recluse if you're interested. Of course, check in with a healthcare professional if you have a question or concern about any injury. One final note. I wanted to mention that Vetter won an Ig Nobel Prize for his work with arachnids back in 2020. The Ig Nobels are sort of a parody of the Nobel Prizes, awarded to research that makes you laugh, but also makes you think. Vetter's winning paper, published in the described a psychological survey that he conducted of his colleagues in bug science that investigated their fear of spiders. It's called arachnophobic entomologists, when two more legs makes a big difference. So if you're a little eked out by spiders, take comfort in knowing that you're far from the only one. But you don't need to be that worried about the brown recluse. Today's episode is based on the article, Don't Fear the Brown Recluse Spider, Seriously, on HowStuffWorks.com, written by Jessalyn Shields. BrainStuff is a production of iHeart Podcasts in partnership with HowStuffWorks.com and is produced by Tyler Klein. For more shows from iHeart Podcasts, visit the iHeart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.
