Snakebite and snake envenoming in Europe is uncommon and the most important group of venomous snakes are Vipera spp.

Table 1: Severity grading for European viper (Vipera spp.) envenomation based on the modification by Boels et al.1
Clinical Features
Venom concentrations
Not envenomed
No local reaction or edema. Fang marks may be present.
< 5ng/ml
Minor envenoming
Local edema at the bite site. No systemic effects.
< 5ng/ml
Moderate envenoming
Regional swelling and edema (most of the bitten limb) and/or hematoma; enlarged lymph nodes
7ng/ml (0 to 15)
Moderate envenoming
Systemic symptoms (vomiting, diarrhoea, abdominal pain)
Mild hypotension (systolic BP<90mmHg) not requiring treatment
Hemotological abnormalities: white cell count > 15 x 10-9; platelets < 150 x 10-9; fibrinogen < 2g/l; INR > 1.5
Evidence of neurotoxicity
7ng/ml (0 to 15)
Severe envenoming
Extensive edema spreading to the trunk; severe hypotension/shock (systolic BP<80mmHg), bleeding
23ng/ml (10 to 35)
INR – international normalised ratio;