Бразилия сергелдең бұлғарларының туысы

Genus of spiders

Automatic taxobox
| image = Aranha armadeira(Phoneutria nigriventer) por Rodrigo Tetsuo Argenton (4). jpg
| image caption = Phoneutria nigriventer
| taxon = Phoneutria
| authority = Perty, 1833 Members of the genus are commonly referred to as Brazilian wandering spiders. Other English names include armed spiders (armadeiras in Brazilian Portuguese) and banana spiders (a name shared with several others).

Wandering spiders are so called because they wander the jungle floor at night, rather than residing in a lair or maintaining a web. During the day they hide inside termite mounds, under fallen logs and rocks, and in banana plants (hence the "banana spider" nickname) and bromeliads. P. nigriventer is known to hide in dark and moist places in or near human dwellings. P. nigriventer mates during the dry season from April to June, which leads to frequent observations of the species during this time.

Phoneutria are found in forests from Costa Rica southwards throughout South America east of the Andes including Colombia, Venezuela, the Guianas, Ecuador, Peru, Bolivia, Brazil, Paraguay, and into northern Argentina. Three species (P. reidyi, P. boliviensis and P. fera) are found in the Amazon region, one species (P. fera) is restricted to the Amazon, and one (P. depilata) ranges into Central America in Panama and Costa Rica. The remaining species are restricted to Atlantic Forest of Argentina, Paraguay and Brazil, including forest fragments in the Cerrado savanna. In Brazil, Phoneutria is only absent in the northeastern region north of Salvador, Bahia. Cases continue to be reported but without evidence of expert identification. In 2005, a man was bitten in Bridgwater, England by a spider in a shipment of bananas and, in 2014, a south London family photographed a spider that they claim was in a bunch of bananas delivered to their home.

The genus Phoneutria includes some of the relatively few species of spiders known to present a threat to humans. Danger to humans does not only comprise toxicity, but also factors such as the spider's capacity to deliver a sufficient dose of venom, a disposition that makes a bite likely, and proximity to human habitation. These spiders' wandering nature is another reason they are considered so dangerous. In densely populated areas, Phoneutria species usually search for cover and dark places to hide during daytime, leading them to hide in houses, clothes, cars, boots, boxes and log piles, where they may bite if accidentally disturbed. Spider mouthparts are adapted to envenomate very small prey; they are not well adapted to attacking large mammals such as humans. Some believe that various spiders like Phoneutria, that use venom mainly to kill prey, can deliver a "dry" bite in defense to purposely conserve their venom, as opposed to a more primitive spider like Atrax that usually delivers a full load. A study in March 2009 suggests that Phoneutria inject venom in approximately one third of their bites, and only a small quantity in one third of those cases. Another study similarly suggested that only 2.3% of bites (mainly in children) were serious enough to require antivenom. Research in this area is hindered by the difficulty of identifying particular species. Nevertheless, there are a few well attested instances of death. In one case, a single spider killed two children in São Sebastião. The spider was positively identified as a Phoneutria by Wolfgang Bücherl. The severity of the cases can be related to the sex of the spider, since the male produces less venom and is less lethal than the females, except for P. boliviensis, where the male is more toxic. Symptoms may appear within 10 to 20 minutes after the bite, and death within two to six hours, where severe pain radiates to the rest of the limb, systemic effects include tachycardia, increased blood pressure, vertigo, fever, sweating, visual disturbances, nausea, vomiting, difficulty breathing and paralysis. Death is usually caused by respiratory arrest. These spiders seem to produce a smaller amount of venom during cold months (June to September) a minimum amount of 0.03 mg, an average of 0.44 mg and a maximum of 1.84 mg, during the summer months. The maximum amount among individuals was 3.10 mg (October 26), 4 mg (November 3), 5 mg (November 4) and 8 mg (October 31); 7 mg of dried venom is enough to kill 500 mice subcutaneously and 1,000 intravenously. P. nigriventer is the species responsible for most cases of envenomation in Brazil because it is commonly found in highly populated areas of southeastern Brazil, such as the states of São Paulo, Minas Gerais, Rio de Janeiro and Espírito Santo.

A 45 year old man, with no nervous background, employed in the agricultural section of the Butantan Institute, working barefoot, was bitten at 10:40 AM on the small toe of his left foot by a medium sized Phoneutria. Immediately he felt intense pain that radiated to his foot and leg. He also reported visual disturbances, and when he tried to enter the building, he fell. Without strength, he was supported by two men to the laboratory, where he was examined. He could not stand, had difficulty seeing, difficulty talking (he could not answer questions), and complained of severe general pain and intense cold. He was sweating profusely, there was hyper nasal secretion and salivation, which made him blow his nose and spit constantly. He was agitated, with generalized tremors and continuous cramps in his left foot and leg, and an irregular pulse with 112 beats per minute. An hour after the accident, the serum was injected into the left buttock. During the next hour, the pulse became faster, thready, almost uncountable, and the temperature decreased, with a worsening of the general condition. At noon the victim received a new injection of serum and by 1:00 pm there was improvement. A 23 year old market worker moving a bunch of bananas was bitten on his hand by P. nigriventer in São Paulo, Brazil. The specimen measured 3.5 cm long and 6 cm with its legs. It was reported that the wound was extremely painful, with the victim noticing that the bite area was sweating and the hair on his skin stood on end. He also reported that the pain radiated to his chest, and that his heart began to race. The victim was dizzy and nauseated, felt cold, began to drool and vomit, and exhibited priapism. He was later treated with anesthetics, tetanus prophylaxis and anti venom, and recovered 36 hours after the bite. Another case occurred with a 52 year old man, bitten by an adult female P. nigriventer. Immediately after the bite he experienced severe local pain, blurred vision, profuse sweating and vomiting. From one to two hours after the bite he presented agitation and high blood pressure; at four hours after the heart rate was high at 150 beats per minute, mild tachypnea, cold extremities, profuse sweating, generalized tremors and priapism. He was treated with anesthetics, anti venom and fluid replacement. In 2005, an English man was bitten twice by a spider identified as a Phoneutria, which was hidden in a box of bananas. It was reported that his hand became swollen, he felt dizzy, and that when he got home he collapsed. He was taken to the hospital and received treatment, but his condition continued to deteriorate. He reported chest tightness, difficulty breathing, and both his blood pressure and heart rate were high. He was treated with increased saline to release toxins from the body, and was discharged the next day. He took almost a week to recover. A 70 year old man, bitten by a spider with a legspan of 5 to 6 cm, he was cutting sugarcane at the residence of São Pedro de Alcantara, in the countryside, when a spider jumped on his shoulder, and came "walking" by the right arm to the back where it bit his hand (bled at the time), he felt intense pain at the time. The spider had several young in the abdomen. The patient evolved with agitation, anxiety, blood pressure 200x110 mmHg, heart rate with 62 beats per minute, respiratory rate 36 breathing movements per minute, respiratory distress, hyperemia, edema and radiating pain. After 50 minutes, the patient was admitted to the emergency department of the HU with blood pressure 150x90 (after captopril), mild dyspnea (patient pneumectomized by TU), with paresthesias and local condition as previously reported. He received anesthetic infiltration, dipyrone and two vials of serum, the right hand remained red and swollen, with improvement in anxiety symptoms and controlled blood pressure. Another case occurred in Minas Gerais, Brazil, where a man bitten by a Phoneutria developed numbness in his legs, redness, headache and loss of sense of time and space.

In a case that occurred in Itanhaém, São Paulo, a 40 year old man bitten in the foot, presented significant pain and generalized contractures, dying six hours after the accident.