Scorpionism and dangerous species of venezuela

Abstract

All 54 recognized Tityus species in Venezuela are located at the mountain ranges, from sea level to 2,000 m above sea level, with rain forest as predominant habitat. The species comprised in Tityus genus are considered dangerous to humans, with similar LD50 among their venoms. Scorpionism is endemic coinciding with the rainy season. Its character is regional, being more severe in five country areas. Scorpionism clinical reports in Venezuela agree with an initial cholinergic phase, which can be followed or not by an adrenergic phase. The most serious complications developed by moderate or severe scorpionism in the country are pancreatitis, myocarditis, acute pulmonary edema, or acute lung injury and its final outcome, the respiratory distress syndrome, the most severe, lethal, and usually untreatable. The complication will depend on the scorpion species involved into the accident. The pathology changes in different Venezuelan regions. Scorpionism in the North Central region is predominantly cholinergic with severe gastrointestinal complications and some cases developing acute lung injury or respiratory distress syndrome. In other regions, scorpionism is predominantly adrenergic with severe cardiopulmonary complications developing acute pulmonary edema and myocarditis. Complications after scorpion envenomation would depend on the particular venom involved in the accident, since it varies intra- and interspecies over the year and in some species, even between females and males. Scorpion envenomation in Venezuela is one noninfectious process inducing pro-inflammatory cytokine release, which can lead to a generalized inflammatory process. Venezuelan scorpion antivenoms are also discussed, as well as diverse reports showing their effectiveness against Tityus envenoming. The state of the art of 83 Venezuelan Tityus toxins, with their total or partial sequences and their activities, is discussed in detail.