Self-reported health effects after one year from a viper bite: A prospective study from France

In France, the summer period (from mid-April to mid-September) is particularly prone to viper envenomations by the two most common species, Vipera aspis and Vipera berus, which represents a significant public health issue. Although mortality is extremely low and systemic signs are rare, some patients experience long-term functional sequelae, highlighting the need for further exploration of the prolonged effects of snakebites. We conducted an observational study of viper bite cases in France collected during routine follow-ups by four Poison Control Centers. Patients were followed up by toxicologists using a standardized survey to assess recovery time and health indicators. Over two years, 170 patients were included, with a sex ratio of 1.54 (103 males vs. 67 females) and a median age of 46.2 years. The median recovery time was 21 days, with 84 % of patients healed by 6 months, and recovery probabilities of 0.47, 0.65, and 0.86 at 14, 30, and 180 days, respectively. Parameters associated with delayed recovery were severe bite, lower limb bite, female gender, inappropriate treatment, and time to hospital admission. Age and time to administration of antivenom had no effect. One month after the bite, 12.8 % of patients avoided the activity during which they were bitten, 5.6 % frequently thought about the bite, and 22.3 % were afraid of snakes; these figures increased to 14.6 %, 4.5 %, and 38.2 %, respectively, after one year. Other factors than severity of envenomation should be taken into account in the long-term prognostic assessment of patients. Psychological impacts, though not clinically classified as traumatic events, suggest a need to consider mental health in recovery. Prompt administration of antivenom and compliance with recommended management remain key elements of effective care. It is important to re-evaluate the need for patient follow-up in the light of the factors identified as affecting the early favourable evolution of symptoms.