Medically important snakes and snakebite envenoming in Iran.

Snakebite is a relatively common health condition in Iran with a diverse snake fauna, especially in tropical southern and mountainous western areas of the country with a plethora of snake species. The list of medically important snakes, circumstances and effects of their bite, and necessary medical care require critical appraisal and should be updated regularly. This study aims to review and map the distributions of medically important snake species of Iran, re-evaluate their taxonomy, review their venomics, describe the clinical effects of envenoming, and discuss medical management and treatment, including the use of antivenom. Nearly 350 published articles and 26 textbooks with information on venomous and mildly venomous snake species and snakebites of Iran, were reviewed, many in Persian (Farsi) language, making them relatively inaccessible to an international readership. This has resulted in a revised updated list of Iran's medically important snake species, with taxonomic revisions of some, compilation of their morphological features, remapping of their geographical distributions, and description of species-specific clinical effects of envenoming. Moreover, the antivenom manufactured in Iran is discussed, together with treatment protocols that have been developed for the hospital management of envenomed patients.

Individual variability of venom from the European adder (Vipera berus berus) from one locality in Eastern Hungary.

We have revealed intra-population variability among venom samples from several individual European adders (Vipera berus berus) within a defined population in Eastern Hungary. Individual differences in venom pattern were noticed, both gender-specific and age-related, by one-dimensional electrophoresis. Gelatin zymography demonstrated that these individual venoms have different degradation profiles indicating varying protease activity in the specimens from adders of different ages and genders. Some specimens shared a conserved region of substrate degradation, while others had lower or extremely low protease activity. Phospholipase A2 activity of venoms was similar but not identical. Interspecimen diversity of the venom phospholipase A2-spectra (based on the components' molecular masses) was detected by MALDI-TOF MS. The lethal toxicity of venoms (LD50) also showed differences among individual snakes. Extracted venom samples had varying neuromuscular paralysing effect on chick biventer cervicis nerve-muscle preparations. The paralysing effect of venom was lost when calcium in the physiological salt solution was replaced by strontium; indicating that the block of twitch responses to nerve stimulation is associated with the activity of a phospholipase-dependent neurotoxin. In contrast to the studied V. b. berus venoms from different geographical regions so far, this is the first V. b. berus population discovered to have predominantly neurotoxic neuromuscular activity. The relevance of varying venom yields is also discussed. This study demonstrates that individual venom variation among V. b. berus living in particular area of Eastern Hungary might contribute to a wider range of clinical manifestations of V. b. berus envenoming than elsewhere in Europe.

Envenoming following bites by the Balkan adder Vipera berus bosniensis - first documented case series from Bulgaria.

We report the first detailed accounts of bites by the Balkan adder, Vipera berus bosniensis from Bulgaria. Documentation of bites by this subspecies is very rare in the literature and most available accounts are from the northern limit of its distribution. V. berus bosniensis is considered to possess neurotoxic venom but little evidence has hitherto been available to support this supposition. In this case series symptoms typical of adder bites developed including oedema, nausea, dizziness, lymphangitis, vomiting, and diarrhoea together with aberrant symptoms such as diplopia and ptosis that confirm the presence of neurotoxic venom in Balkan adders. In addition, unusual and atypical symptoms of adder bites such as painless bites and muscle cramps appeared. The inadequate treatment in hospital and the remote habitats in which this species is encountered are potential sources of complication.