A woman in Italy recently died as a result of being bit by a spider related to the notorious brown recluse spider, according to a recent report of her case.

The death, which occured in November 2015, is the first fatal case reported in Europe of a bite from a spider of the genus Loxosceles, said Dr. Mario Pezzi, an intensive-care doctor at the Pugliese-Ciaccio General Hospital in Italy who treated the woman and was the lead author of the case report.

A Mediterranean recluse spider (Loxosceles rufescens) bit the 65-year-old woman on the middle finger of her right hand while she was cleaning her cellar one evening, according to the report, published in August in the journal Case Reports in Emergency Medicine.

Although she was aware of the bite, she initially didn't give it much thought, Pezzi told Live Science. By the next morning, however, a painful lesion had formed on her finger, and she had a fever of 100.8 degrees Fahrenheit (38.2 degrees Celsius), according to the report. [Spider-Man: 5 Weird Effects of Real Spider Bites]

The patient went to her local emergency room but was eventually transferred to the intensive-care unit because she was getting sicker: She was breathing quickly, her blood pressure was very low and her heart rate was high, according to the report.

The doctors contacted Italy's National Poison Control Center, which confirmed that the woman was suffering from a spider bite, according to the report. In addition, a local health service confirmed that there had been a Loxosceles infestation in the houses neighboring the woman's home, they wrote.

There is no anti-venom available in Europe to treat a Loxosceles bite, Pezzi told Live Science. The anti-venom is likely only available in Brazil, where the spiders are more common, he added. Therefore, the only way to treat someone who has been bit by a Loxosceles spider is through supportive care, he said.

But the woman died about 12 hours after being admitted to the hospital, according to the report.

Brown recluse bites

Anti-venom for a Loxosceles bite isn't available in the United States, either, said Dr. Jon Dumitru, an emergency-medicine doctor at Baptist Health in Jacksonville, Florida, who was not involved with the case but has treated people bit by recluse spiders.

Dumitru noted that the spider described in the case report is not found in the United States but that the symptoms appear very similar to those of a brown recluse spider (Loxosceles reclusa) bite. Both spider species are members of the same genus.

Loxosceles venom contains an enzyme called phospholipase D, which has many effects throughout the body, Dumitru told Live Science. In less severe cases, the venom can kill tissue, causing a necrotic lesion at the site of the bite, he said. Less often, it can cause a toxic reaction throughout the person's whole body, he said.

Such a reaction can happen after Loxosceles venom gets into the blood, because the enzyme in the venom is toxic to red blood cells, which are responsible for carrying oxygen in the blood, he said. When red blood cells are destroyed, the organs in the body don't get enough oxygen, he said. [3 Scariest Spiders: Which 8-Legged Beasts to Watch Out For!]

In addition, the venom can impair the blood's ability to clot, meaning that a person is more likely to bleed, Dumitru said.

As described in the report, the only way to treat a person who has been bit by a Loxosceles spider who can't be given anti-venom is through supportive care, Dumitru said. In other words, doctors try to treat the symptoms and keep the patient alive until the body can rid itself of the venom. Patients may be treated with blood transfusions or medications to keep their blood pressure up, for example, Dumitru said.

It's unclear why some people have more severe reactions to spider bites than others, Dumitru said. It may be that the amount of venom delivered by the bite plays a role, he said.

In addition, it seems that very young and very old people are more vulnerable to the severe effects of bites, Dumitru said. People with other health problems may also be at higher risk for a severe reaction, he said; for example, the Italian woman had an autoimmune condition called myasthenia gravis, which can cause muscle weakness throughout the body.

Editor's Note: This article was updated on Oct. 13, 2016 to include information about when the case took place.

Originally published on Live Science.