With the exception of two spider families, all spider species possess venom glands, but luckily, very few species can inflict a bite that is dangerous to humans. Spiders like the southern black widow, the brown recluse, the brown widow and even the common house spider can inflict medically significant bites to humans. All of these species are common in the state of Louisiana. The southern black widow and the brown recluse have each been documented as inflicting fatal bites to humans, but these two species each produce a very different type of venom. Most spider species produce a type of  venom known as “neurotoxic venom.” Neurotoxic venom attacks the nervous system, causing pronounced and highly unpleasant systemic symptoms. Neurotoxic venom is produced by all five widow spider species in the United States, including the southern black widow and the brown widow. A smaller number of medically significant spider species produce “necrotic venom.” Necrotic venom is produced only by spiders from the Sicariidae family, which includes all 13 recluse species found in the US, most notably the brown recluse. Therefore, Louisiana is one of only a few states that is home to spider species that produce two distinct, and sometimes deadly types of venom.

Other spider species in Louisiana are only dangerous due to causing allergic reactions in sensitive people. For example, a Florida man was once hospitalized after a common house spider bite to his arm resulted in a severe allergic reaction. Suffering a life-threatening bout of anaphylactic shock due to spider venom is very rare, and the common house spider is of no danger to the vast majority of people, even those who have common allergies. However, the southern black widow’s neurotoxic venom causes muscles to spasm and airways to constrict due to a dangerous component in their venom known as a “latrotoxin.” The recluse spider species that produces necrotic venom inflicts bites that cause victims to sometimes develop gangrenous infections that cause tissue-necrosis. Necrotic venom also produces systemic effects, such as kidney failure and vomiting. Although the brown widow produces neurotoxic venom, it is less potent than southern black widow venom. However, the bite of a brown widow can also produce systemic reactions in rare cases.

Have you ever experienced a spider bite that caused pain that lasted for more than a day?