Epidemiology of Snake, Spider and Scorpion Envenomation in Mashhad, Khorasan Razavi, Iran (2004-2011)

Backgrounds: Envenomation is common in Asia including Iran that induces morbidity and mortality. This study investigated the epidemiological characteristics of cases with snake, spider and scorpion bites. Methods: In this cross-sectional design, epidemiologic data of admitted cases to the Toxicology Department of Imam Reza Hospital of Mashhad, Iran were analyzed across a 7-yr period, from 2004 to 2011. SPSS was used for data analysis. Results: This study reports 686 admissions due to animal envenomation with an incidence rate of 2.9 per 1. Mean (SD, min-max) age of admitted patients was 30 (19, 1-90) yr, and 471 (69%) were male. Snakebite (n, percentage, annual incidence) (299, 44%, 1.3 per 1) and spider bite (188, 27%, 0.8 per 1) and scorpion sting (126, 18.4%, 0.5 per 1) were most frequent cases. Overall, case fatality rate was 0.09 per 1 which were due to scorpion and unknown bite. No cases of snakebites died in this period. The highest age-specific incidence rate was 4.6 per 1 and related to 10-20 yr of age. Conclusion: Animal envenomation is frequent in this area and a matter of health concern. While deaths related to snake bite are no longer reported-presumably due to using effective anti-venom managing unknown and scorpion bites need to be addressed. Envenomation was not overtly an agespecific event in this province.