Vipera berus Bites in Germany From 2012 to 2023

A retrospective analysis of poison center databases

The common European adder (Vipera berus) is Germany’s primary species of venomous snake. While rarely life-threatening to humans, its venom contains major enzymatic components—phospholipases A2 (PLA2), snake venom metalloproteinases (svMP), and snake venom serine proteases (svSP)—and can cause significant local swelling, pain, and systemic symptoms such as nausea, hypotension, and shock (1, 2). Prompt treatment can greatly alleviate the symptoms. As it is not mandatory to report snakebites in Germany, no comprehensive national database of cases exists. To provide the first description of V. berus bites in Germany, we analyzed anonymized data on V. berus bites to humans reported to German Poison Control Centers (PCC) between 2012 and 2023.

Methods

We contacted all seven German PCC (in Berlin, Bonn, Erfurt, Freiburg, Göttingen, Mainz, and Munich) to collect data for retrospective analysis of V. berus bites in Germany. These centers are frequently contacted by lay persons and medical professionals in their respective catchment areas and provide advice. Duplicate entries were identified on the basis of age, sex, federal state, and telephone contact date and were removed. Demographic data, seasonal trends, and the geographic distribution of cases were summarized, and the yearly incidence rate was estimated. Ethical approval was waived by the Hamburg Medical Association as the patient data were anonymized before analysis (2024–300447-WF).

Results

All PCC provided data with the exception of Mainz, responsible for calls from Saarland, Rhineland–Palatinate, and Hesse. Altogether, the PCC registered 735 V. berus bites during the study period. The median (interquartile range, IQR) annual number of cases was 58 (55; 67), ranging from 54 cases in 2012 to 77 in 2013. This corresponds to a median (IQR) incidence rate of 0.70 (0.67; 0.81) cases per one million persons annually. Most bites occurred between May and August (74% of reported cases), and 56% of bites were to an upper extremity. Geographically, the highest number of bites was reported in Bavaria (14.3 cases per year, range: 3–19) (Figure 1).

Figure

Distribution of Vipera berus bites to humans reported to the poison control centers between 2012 and 2023

The median (IQR) age of bite victims was 33 years (12; 53), with 32% of cases involving persons under the age of 18 years (and 26% under 15 years). Males were bitten more often, accounting for 61% of cases. Data on symptoms were recorded in 63% of the cases. Of these, 70% reported local signs, while 17% reported systemic symptoms. Only 2.5% of cases were classified by the PCC as severe.

Discussion

These findings provide the first insights into the distribution of V. berus bites in Germany. Case numbers were highest in Bavaria. Overall, more cases occurred during the summer months, probably due to increased snake and human activity. The incidence in Germany was lower than in the nearby countries of Sweden (3), Belgium, France, and Poland (4), where the rates range from 4.3 to 26 cases per one million inhabitants annually. Since cases in Germany are not registered uniformly and reporting is not mandatory, the calculated incidence probably represents an underestimate.

Although it is probable that some cases are not included in the PCC data, a search for hospital admissions with the ICD-10 code T63.0 (Toxic effect of contact with venomous animals: Snake venom) in the German Federal Statistical Office (DESTATIS) database revealed significantly lower numbers (2021–2023: 614 cases, including bites by other snakes). This indicates that PCC data remain the most comprehensive information source in Germany. While data from the Mainz PCC were unavailable, the limited distribution of V. berus (5) and the very small number of cases from Saarland, Rhineland–Palatinate, and Hesse registered in the DESTATIS data suggest a low number of bites in this region.

The limitations of the data analyzed included incomplete information on treatment, severity grading based on symptoms reported by the caller, the lack of systematic patient follow-up, and possible misidentification of the snake species. Standardized data collection with patient follow-up could provide a clearer clinical picture of common European adder bites in Germany.

As yet, there are no standardized clinical management guidelines for V. berus bites in Germany. Nevertheless, key aspects of treatment should be considered to ensure effective case management: close monitoring during the first 24 hours, ideally in the hospital setting; supportive care, such as pain relief, tetanus vaccination boosters, and fluid resuscitation if and as needed; and administration of antivenom in the event of severe swelling (> 50% of the affected extremity) or systemic symptoms (e.g., hypotension and shock) only. Prophylactic antibiotic treatment is not recommended, as infections are rare. There is also no evidence for the benefit of corticosteroids. Antivenom for V. berus is available from the emergency depots of the individual federal states. Information on availability can be accessed through public or hospital pharmacies.

Jade Rae, Paul Rahden, Deborah Hosemann, Tim Lüddecke, Jörg Blessmann, Sebastian Matzke, Sophie Kappel, Dagmar Prasa, Rafael Wagner, Raphael Stich, David Steindl, Uwe Stedtler, Benno Kreuels

Research Group Neglected Diseases and Envenoming, Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg (Rae, Rahden, Hosemann, Blessmann, Matzke, Kreuels); [e-mail]

Research Group Animal Venomics, Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Gießen (Lüddecke)

Poison Control Center, Center for Pediatric Medicine, University Hospital Bonn (Kappel)

Joint Poison Control Center of the Federal States Mecklenburg–West Pomerania, Saxony, Saxony–Anhalt and Thuringia, HELIOS Hospital Erfurt (Prasa)

Poison Control Center North of the Federal States Bremen, Hamburg, Lower Saxony, and Schleswig–Holstein (GIZNord), University Medical Center Göttingen (Wagner)

Department of Clinical Toxicology and Poison Hotline Munich, Department of Medicine II, TUM School of Medicine and Health, TUM University Hospital, Technical University of Munich (Stich)

Charité Poison Hotline, Charité – University Medical Center Berlin (Steindl)

Poison Control Center Freiburg, Center for Pediatric Medicine, University Hospital Freiburg (Stedtler)

Conflict of interest statement
The authors declare that no conflict of interest exists.

Manuscript received on 23 February 2025, revised version accepted on 15 May 2025

Cite this as:
Rae J, Rahden P, Hosemann D, Lüddecke T, Blessmann J, Matzke S, Kappel S, Prasa D, Wagner R, Stich R, Steindl D, Stedtler U, Kreuels B: Vipera berus bites in Germany from 2012 to 2023: A retrospective analysis of poison center databases. Dtsch Arztebl Int 2025; 122: 447–8. DOI: 10.3238/arztebl.m2025.0091

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