Neurotoxic activity and ultrastructural changes in muscles caused by the brown widow spider Latrodectus geometricus venom

Abstract

suMMARyBrown widow spider (Latrodectus geometricus) venom (BrWSV) produces few local lesions and intense systemic reactions such as cramps, harsh muscle pains, nausea, vomiting and hypertension. Approximately 16 protein bands under reducing conditions and ~ 14 bands under non-reducing conditions on a 12.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis were observed. Neurotoxic clinical manifestations were confirmed in vivo, while proteolytic activity was demonstrated on gelatine film. Severe ultrastructural damages in mice skeletal muscles were observed at 3, 6, 12 and 24 h postinjection with at total of 45 µg of venom protein. Infiltration of eosinophils and ruptures of the cellular membranes were observed in the muscles along with swelling of the nuclear cover and interruption of the collagen periodicity. Altered mitochondrias and autophage vacuoles, nuclear indentation and mitochondria without cristae, slight increment of intermyofibrillar and subsarcolemic spaces and myelinic figures formation were also observed. In the capillary, endothelial membrane unfolding into the lumen was noticed; along with myelinic figures compatible with a toxic myopathy. Swollen sarcotubular systems with lysis of membrane, intense mitochondria autophagia and areas without pinocytic vesicles were observed. Swollen mitochondria surrounded by necrotic areas, myofibrillar disorganization and big vacuolas of the sarcotubular system, degenerated mitochondrium with formation of myelinic figure was seen. Glycogenosomes with small particulate, muscle type glycogen was noticed. Autophagic vacuole (autophagolysosomes) and necrotic areas were also noticed. These damages may be due to interactive effects of the multifactorial action of venom components. However, Latrodectus geometricus venom molecules may also be utilized as neuro therapeutic tools, as they affect neuronal activities with high affinity and selectivity. To our knowledge, the present study is the first ultrastructural report in the literature of muscle injuries and neurological and proteolytic activities caused by BrWSV.

Chemical Control of Spiders and Scorpions in Urban Areas

“…Phylogenic work has confirmed that there are two main groupings (mactans clade and geometricus clade) [45]. Members of the genus are notorious for the highly potent neurotoxin alpha-latrotoxin contained in their venom, which triggers a massive neurotransmitter release upon injection in vertebrates [46]. People may suffer eye injuries from contact with the bodily fluids of a widow spider, when the spider is crushed with a tool such as a www.intechopen.com hammer [47].…”

“…The prevalence of scorpions was assessed, both before and after the spraying, through direct searches (40 min/house) and by householder reports of sightings inside the houses. Pyrethroids and residual treatments were evaluated in different sectors of Chalcatzingo, with almost complete coverage indoors and peridomestically, using the following four formulations: bifenthrin 10% wettable powder (WP) applied at 50 mg a.i./ 83,46 and 15% in houses sprayed with cyfluthrin WP, bifenthrin WP or deltamethrin SC, respectively. Householder reports of sighting scorpions indoors were 33-85% below pre-intervention levels.…”

Envenomation by an arachnid (Latrodectus or Steatoda): Case report involving a woman and her female dog

“…(17) The neurotoxicity of this venom is characteristic and may cause the release of norepinephrine and acetylcholine in an exhaustive manner. (18) The secretion of these neurotransmitters seems to be secondary to calcium dependent and independent mechanisms. (19,20) Opioids and muscle relaxants administration is the most recommended therapy for latrodectism (21), whereas antivenin use should be considered only in severe envenomation cases.…”

Primer registro de la viuda café Latrodectus geometricus en Sonora, México

“…Las arañas, grupo conformado por más de 48 mil especies (1), incluyen familias como Ctenidae, Sicariidae, Hexathelidae, Atracidae, Actinopodidae y Theridiidae, en las cuales se encuentran especies de importancia médica, ya que tienen la capacidad de ocasionar la muerte posterior a la mordedura (2). Para la familia Theridiidae, destacan las especies Latrodectus mactans (viuda negra) y L. geometricus (viuda café) por las α-latrotoxinas (α-LTX) que poseen en su veneno, teniendo L. geometricus una dosis letal 50 (DL50) estimada de 0.225 mg/kg, suficiente para comprometer gravemente la salud humana posterior a una mordedura (3,4).…”