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In addition to the Hymenoptera, less common arthropods, such as spiders and reduviids, can inflict injuries of medical importance. Identification of the source of the bite or sting may be difficult but is essential to proper treatment. Part 1 of this article describes recognition and treatment of the bites of various spiders; part 2, beginning on page 107, considers bites and stings of other arthropods.
Histologic specimens from 41 rabbits were studied for changes resulting from the manual injection of brown recluse spider venom. Major findings included a mixed inflammatory cell infiltrate, coagulative tissue necrosis, and vasculitis. All specimens demonstrated a well-delineated zone of eosinophilic staining recognizable as "mummified" coagulative necrosis of the epidermis and dermis. A dense band of neutrophils bordered the zone of necrosis. Immediately adjacent to the neutrophilic band, small vessel vasculitis was a universal finding. Degranulated eosinophils and neutrophils and macrophages filled with eosinophilic granules were common. Inflammatory foci were often centered on groups of lipocytes within the dermis. Large vessel vasculitis resembling that seen in polyarteritis nodosa was present deep to 7 of the 40 eschars. Large vessel vasculitis may contribute to the large zones of necrosis seen after some brown recluse spider bites. Eosinophils may play a role in tissue damage after envenomation.
The authors developed a rabbit model of the brown recluse (BR) spider envenomation of the human eyelid. The spider bite causes cutaneous necrosis and systemic toxicity in human eyelids, possibly leading to disseminated intravascular coagulation, hemolysis, and death. The treatment has been controversial. The animal model evaluated the effects of single- and combined-agent therapy in four phases: venom dose response, time course, therapeutic effectiveness (steroid vs. dapsone vs. antivenom), and optimal therapy (steroid and dapsone; steroid and antivenom; and dapsone and antivenom combination groups). The combination dapsone and antivenom treatment group was the optimal animal regimen, although not completely effective in eliminating microscopic necrosis. The authors also report dramatic clinical improvement in human inflammatory response with dapsone therapy and recommend immediate dapsone therapy combined with specific BR venom, if available, in humans.
A model to study the dermonecrotic effects of a crude fraction of venom from the brown recluse spider (Loxosceles reclusa) was developed using female New Zealand white rabbits. In the rabbit model, surgical excision of the sites of intradermally injected crude venom did not always prevent subsequent necrosis or wound dehiscence despite the use of fluorescein to determine the surgical margin. Heparin and steroids did not prevent the venom-induced necrosis and were much less effective than surgical excision or injecting a specific antivenom. When given within 24 hours, the specific antivenom raised against the brown recluse spider venom blocked or markedly attenuated the toxic effects of the venom in the rabbit model system.
Twenty-five patients with definite bites by Badumna spp. spiders were recruited prospectively. Bites occurred across Australia, 92% from October to March, and most during daylight. Pain occurred in all cases, was severe in seven cases, with a median duration of 5 min. Other effects included: puncture marks (24%), swelling (12%) and erythema (68%). Minor systemic effects occurred in 4 bites. No patient had a necrotic ulcer (0%; 97.5% confidence interval 0-14%). Black house spiders (Badumna spp.) are unlikely to cause necrosis, contrary to reports of suspected bites. Patients can be reassured and do not require any further investigation or treatment.
Black widow spider envenomation (BWSE) is commonly associated with severe abdominal pain, muscle cramping, and hypertension. Treatment is primarily symptomatic with the use of opiates and benzodiazepines. Priapism is a complication of BWSE that has only rarely been reported. We describe a 17-month-old male who developed priapism after known BWSE. His priapism did not respond to opiates or benzodiazepines, and he was treated with black widow spider antivenin. Complete detumescence followed within several hours. The patient required no additional opiates for pain and was discharged from the hospital the following day. The patient's rapid improvement after antivenin suggests its efficacy in treating BWSE-associated priapism.
Hyperbaric oxygen (HBO) has been reported by some to be therapeutic for necrotic lesions induced by the venom of the brown recluse spider, Loxosceles reclusa. Others have reported no efficacy for this treatment. In this study, the effect of high pressure oxygen on an enzymatic activity of the toxin of this venom is reported. The time course for the hydrolysis of the phosphocholine ester bond of chicken egg yolk sphingomyelin, as catalyzed by brown recluse spider venom (BRSV) and venom treated with extended HBO (12 hr at 10 atmospheres), was followed by phosphorus-31 nuclear magnetic resonance spectroscopy. The venom and HBO-pretreated venom demonstrated sphingomyelinase D activity. Phospholipase C activity was not detected. The sphingomyelinase D activity of BRSV in three separate experiments was not altered by HBO. The HBO-pretreated venom, in all cases, did not exhibit an altered time course in the overall hydrolysis of the D linkage of sphingomyelin.
An analysis has been made of 2144 consecutive cases of latrodectism (envenomation by the red-back spider, Latrodectus mactans hasselti) reported to the Commonwealth Serum Laboratories. In the last eight years, notifications have averaged 240 cases per annum. Bites, usually on the extremities (74%), occurred most frequently in the summer months, and in the afternoon or evening. Most victims (79%) were aged between 18 and 50 years and 64.4% of them were males. Males are still often bitten on the genitals or buttocks (9.7% of cases). Local pain, redness and swelling were the most common symptoms, although significant pain was felt at other sites in 39% of the cases. The regional lymph nodes often became swollen and tender within 30 minutes. General effects included nausea, vomiting and sweating, but coma and respiratory failure were very uncommon, probably because of use of specific antivenom. This was administered within 24 hours of the bite in 92% of cases, and within two hours in 70%. Although 11 anaphylactic reactions (0.54%) were reported, no deaths resulted either from the venom or from reactions to the antivenom. Few delayed serum reactions (1.7%) were recorded. The action of the venom is described and the management of red-back spider bite is outlined.
Venom of the male Sydney funnel-web spider was injected subcutaneously into the limbs of monkeys (Macaca fascicularis), and the central movement of venom was delayed by first-aid treatment. This treatment consisted of the application of firm pressure over the site of injection and immobilization of the limb. It was found that quantities of venom as high as 2 mg were inactivated when the first-aid procedures were maintained for 24 hours. Over a six-hour period, 0.5 mg of venom could be inactivated. Since the amount of venom injected by the spider into a human victim is unlikely to exceed 0.2 mg, these findings have immediate application both to the first aid and to actual medical management of human victims.
A case of red-back spider (Latrodectus mactans hasselti) envenomation in a neonate is presented. The signs of envenomation in a neonate are discussed, together with the dose of antivenom necessary for the successful treatment of envenomation. In episodes of untractable crying in neonates, the possibility that the baby has been bitten by a red-back spider should be considered.
Latrodectism, produced by the bite of Latrodectus spiders, is worldwide distributed, occurs in hot seasons, and affects mostly men when carrying out agricultural activities. The main symptoms are muscular pain and tremors, profuse perspiration, increased lacrimal, nasal and salival secretions, and hypertension. Symptoms last one week. Neostigmine is a very efficient drug in the treatment of this condition. Loxoscelism, caused by the bite of Loxosceles spiders, is worldwide distributed, affects individuals of all ages. It may present two clinical forms: cutaneous loxoscelism (CL) and viscerocutaneous loxoscelism (VCL). Both forms have been registered in all seasons, with a higher incidence in hot periods, and in bedrooms, when the person is sleeping or dressing. The cutaneous surface of limbs and face are most frequently affected. Local clinical manifestations are pain, edema and livedoid plaque, most of which evolve into a necrotic scar in CL, whereas hematuria, hemoglobinuria, jaundice, fever and sensorial involvement characterize VCL. If visceral involvement does not appear within 24 hours, it is probable that the diagnosis corresponds to CL, with a good prognosis. If a VCL patient survives 48 hours, the possibilities of recovery are high. The patients are successfully treated with parenteral antihistamines or corticosteroids in CL and corticosteroids in VCL.
A population of 2,366 primary care physicians in South Carolina was surveyed by mail to estimate the number of cases of insect morbidity treated in 1990. A response rate of 42.3 percent was obtained. Cases reported totaled 414 for Rocky Mountain spotted fever, 334 for Lyme disease, 143 black widow and 478 brown recluse spider bites and 4,975 fire ant stings. These are counts of cases from a mail survey, not from a research-based study. Five deaths were also reported; two for Rocky Mountain spotted fever, two due to black widow spider bites and one fire ant anaphylaxis.
The history of araneidism is long and confusing. The superstition seems to be inexterminatable that tropical mygalomorphs and mediterranean tarantulas are dangerous for humans. It can be looked up even in the most recent edition of the widespread clinical dictionary of Pschyrembel. In contrast to this certain ctenids, the most dangerous spiders up to now known, are mentioned not at all in medical publications. Exaggerated spider-fear is out of place because about 0.1% of all species are dangerous for man only and many of the venomous species live as hidden as they scarcely come in contact with humans.
Latrodectism-envenomation by the black widow spider, Latrodectus mactans-has been reported in virtually every state. The spider is particularly prevalent in the Southwest, Southeast and California, and symptoms from its bite are painful and may be confusing to clinicians. Prompt improvement can be expected in most cases with administration of calcium and muscle relaxant, but some patients may require treatment with antivenin. No deaths occurred in our series of 11 patients, although one case was complicated by serum sickness.
A patient was bitten on the hand by a spider and subsequently hemorrhagic herpes zoster developed at the site of the bite as well as over most of the area distal to the elbow (innervated by cutaneous nerves C5-C8). Mild systemic symptoms of nausea, abdominal cramping, and visual disturbances responded to the intravenous administration of calcium gluconate. There was residual paresthesia of the C5-C8 dermatome but no atrophy. This is the first reported case of herpes zoster precipitated by a spider bite.
Retinal projections and the degree of ocular segregation in the striate cortex were examined by transneuronal autoradiography following unilateral intraocular injections of 3H-proline in a New World primate, the spider monkey (Ateles ater). The results show that, within the lateral geniculate nucleus (LGN), retinal fibers terminate in six principal layers and within the interlaminar spaces adjacent to the magnocellular layers, as well as the S layers ventral to the magnocellular layers. Projections to the superior colliculus, both ipsilateral and contralateral to the injected eye, were patchy and restricted to the superficial gray layer. Our main result shows that, in the striate cortex, LGN projections terminate in well-defined ocular dominance columns in layer IV. Labelled columns were most clearly delimited in layer IVb, where they averaged 373 + 42 micron in width in both the ipsilateral and contralateral hemispheres, slightly smaller than those reported originally from electrophysiological studies of striate cortex in spider monkeys (Hubel and Wiesel, '68). Unlabelled intercolumns were significantly narrower than labelled columns, which suggests that there may be overlap between input from the two eyes between columns. Quantitative measures showed above-background label also in cortical layers IIIb, V, and VI. Our results support the idea that among primates, ocular dominance columns are not limited to Old World species. At the same time, it is apparent that spider monkeys are exceptional among New World primates in having sharply delimited columns. The functional significance of the variation in the degree of ocular segregation in the cortex and its relation to primate evolution are discussed.
Steady-state projection imaging with dynamic echo-train readout (SPIDER) is a multiecho radial k-space trajectory TrueFISP sequence developed for real-time cine imaging of the heart. This new pulse sequence combines the superior SNR and blood-to-myocardium contrast of TrueFISP with the increased scan time efficiency of EPI and undersampled projection reconstruction. SPIDER sequence RF repetition time (TR) was minimized by limiting the echo-train to a length of three while acquiring the first and third echoes asymmetrically. A temporal resolution of 45 ms was achieved with TR/TE1/TE2/TE3 of 3.24/0.6/1.6/2.6 ms and a factor of 2 view sharing scheme. Phantom experiments showed little difference between the weighting of the signals acquired at each of the echo times but did show considerable off-resonance modulation between them. In vivo experiments demonstrated the feasibility of using the SPIDER sequence for real-time imaging in the cardiac short axis orientation.
We surveyed 12 populations of the wolf spider Schizocosa crassipes (Walckenaer) and S. nr. crassipes in Tennessee, Mississippi, Louisiana and Florida, in the U.S. to determine the extent of variation in male courtship behaviour when observed in standard laboratory conditions. We observed variation in both the frequency of occurrence and the sequence of the four principal male courtship behaviours and, when compared statistically, most of these behaviours differed between populations. Although there was no clinal pattern in the frequency of courtship behaviour, we observed geographically consistent patterns in the sequence in which male courtship behaviours are displayed. We conducted two subsequent studies to determine whether sexual isolation among selected populations existed. In the first study, we performed male-female reciprocal crosses of brush-legged spiders (S. nr. crassipes) between two populations from the Yazoo-Mississippi Delta physiographical region and one population from the Loess Bluff region of Mississippi and measured mating success, number of matings that produced egg sacs, and the number of egg sacs that hatched young. The results of that experiment suggest that sexual isolation occurs among populations in different physiographical regions but not between populations within regions of the state. In a second crossing study, we paired the brush-legged spiders from one of the Mississippi physiographical regions (Yazoo-Mississippi Delta) with Schizocosa ocreata (Hentz) from Ohio. The results of that cross suggest that the Mississippi Delta population is more similar to the northern S. ocreata populations than to S. crassipes. We discuss the results of the crossing experiments in terms of what was revealed about geographical patterns in male courtship behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.