Vipera Berus Research Articles

Genetic study of an isolated population of adders Vipera berus founded by historic translocation: implications for conservation

Adder Vipera berus populations in Great Britain have undergone substantial declines in recent decades. Isolation due to habitat fragmentation particularly threatens the demographic and genetic health of small populations. Despite the potential benefit of population supplementation in the conservation management of affected populations, there are currently no consensus guidelines for conservation-motivated translocations of this species. Translocations of adders for ecological mitigation of land development are more frequently undertaken, although these are typically poorly documented and insufficiently monitored, representing a wasted opportunity for strategic learning and improvements. We studied an isolated adder population on a protected site in eastern England, founded in 1999 by the translocation of adders from a development site. With known numbers, age and sex of released individuals, this represented an opportunity to improve our understanding of the genetic outcome of a newly created population. Although apparently thriving despite a low founder number, the finding in 2015 of a stillborn clutch of adders raised the possibility of inbreeding in the population. We sampled adders from the translocated population in 2017, and two individuals from the donor site in 2018. Although we found no increase in homozygosity, relatedness and maximum likelihood sibship analysis revealed high levels of consanguinity, especially within the subgroup of adults. Demographic modelling with Approximate Bayesian Computation supported the known origin of the population, but also a subsequent, undocumented adder release to the site, accounting for the observed healthy proportion of young adders with lower levels of consanguinity. Despite the protected habitat site, the population remains isolated, and thus demographically and genetically vulnerable. We highlight the importance of careful post-translocation monitoring including targeted genetic analyses. Strategic data gathering coupled with careful management of translocations, whether for ecological mitigation or conservation rescue, could support significant improvements to the conservation management of this species, including reintroduction initiatives. Keywords: relatedness, inbreeding, stillbirth, foundation bottleneck, population supplementation

Comparative venom analysis between melanistic and normally coloured phenotypes of the common adder (Vipera berus).

Snake venom is an ecologically relevant functional trait directly linked with a snake's fitness and survival, facilitating predation and defence. Snake venom variation occurs at all taxonomic levels, but the study at the intraspecific level is still in its early stages. The common adder (Vipera berus) exhibits considerable variation in colour phenotypes across its distribution range. Melanistic (fully black) individuals are the subject of myths and fairytales, and in German folklore such 'hell adders' are considered more toxic than their normally coloured conspecifics despite any formal investigation. Here, we provide the first comparative analysis of venoms from melanistic and normally coloured common adders. Specifically, we compared the venom profiles by sodium dodecylsulfate polyacrylamide gel electrophoresis and reversed-phase high-performance liquid chromatography and tested the venoms' protease, phospholipase A2 and cytotoxic activities. Phospholipase A2 activity was similar in both phenotypes, whereas general protease activity was higher in the melanistic venom, which was also more cytotoxic at two concentrations (6.25 and 12.5 µg ml-1). These minor differences between the venoms of melanistic and normally coloured adders are unlikely to be of clinical relevance in the context of human envenomation. In light of our results, the claim that melanistic adders produce more toxic venom than their normally coloured conspecifics appears rooted entirely in folklore.

Patterns of spatial and temporal association between Zootoca vivipara, Anguis fragilis, Vipera berus and Natrix helvetica at artificial refuges

A 15-year data set of reptile observations at corrugated iron refuges was analysed to describe the spatial and temporal associations between species pairs of viviparous lizards Zootoca vivipara, slow worms Anguis fragilis, northern vipers Vipera berus and grass snakes Natrix helvetica. Of the two snake species, only the viper is known as a routine lizard predator. We analysed two variables expressing pairwise reptile associations at refuges. The first analysis was of monthly spatial overlap assessed as the proportion of unique refuge positions used in common, but not necessarily used simultaneously. The second analysis was of a more precise spatial and temporal assessment based on counts of reptile pairs cohabitating at the refuges (i.e. using the same refuges simultaneously). Apart from viviparous lizards paired with either of the two snake species, the frequencies for both variables were either as expected or significantly greater than expected by chance; in particular grass snakes cohabited much more frequently than expected with both vipers (+327%) and slow worms (+218%). In contrast, for the viviparous lizard/viper pair both variables were statistically significantly less frequent than expected by chance - monthly overlap (-35%) and cohabitation (-87%). As viviparous lizards are predated by vipers, cohabiting would be much reduced but the significantly lowered monthly spatial overlap may indicate active avoidance. For the viviparous lizard/grass snake pair the spatial overlap was as expected by chance but, as with vipers, the frequency of cohabiting was significantly less than expected by chance (-75%). These observations are discussed in relation to the known kairomonal responses of this lizard to viper and grass snake deposits. Viper deposits are also believed to act as a kairomone for slow worms, but we found no evidence that they avoided vipers, supporting existing literature showing that V. berus is unlikely to be an important slow worm predator. Keywords: species associations, cohabitation, corrugated iron refuges, viper kairomone, chalk grassland

Peculiarities of microscopic and histochemical changes in the structure of the liver of experimental rats under the influence of viper venom Vipera berus nikolskii

Peculiarities of microscopic and histochemical changes in the structure of the liver of experimental rats under the influence of viper venom Vipera berus nikolskii

Morphological state of lungs of rats under the influence of Vipera berus berus venom

About 5.4 million snake bite cases are registered worldwide every year. About half of them cause 81,000-138,000 deaths or disabled 400,000 people. Despite this, this problem is neglected in many countries in Asia, Africa and Latin America. It is believed that death from snakebites is associated with poverty since the lack of proper access to medical facilities in such sections of the population causes the development of fatal complications. The purpose of the study is to study the morphological state of rats' lungs under exposure to Vipera berus berus venom. Experimental studies were carried out on white, non-linear male rats. Animals were conditionally divided into control and experimental groups, ten individuals each. Experimental rats were injected intraperitoneally with a semi-lethal dose (LD50) (1.576 mg/g-1) of Vipera berus berus venom in a physiological solution. Animals of the control group were injected intraperitoneally with only a physiological solution. Rats were removed from the experiment 24 hours after exposure to the poison and anaesthetized by cervical dislocation. Lung tissue samples were taken for microscopic examination. Fixation of the material and preparation of paraffin blocks were carried out according to generally accepted methods. Staining of histological preparations of the lungs was carried out with hematoxylin and eosin, according to Masson, and the PAS+"Hale" reaction was carried out according to the Mowry method. Histological preparations were studied using an SEO SСAN light microscope. The toxic effect of Vipera berus berus venom caused significant changes in the vascular, stromal and parenchymal components, which was confirmed by histological, histochemical and morphometric data. In the lungs of experimental animals, the vascular bed is primarily restructured, forming coagulopathies and thrombosis. The development of DIC syndrome and haemorrhages accompanies an increase in the permeability of the vessel wall. Inflammatory phenomena are found in the bronchi and respiratory departments' walls. There is a remodelling of the respiratory department components, with the formation of significant areas of dis- and atelectasis and zones of emphysema, which is confirmed morphometrically.

A Guide to the Clinical Management of Vipera Snakebite in Italy.

The genus Vipera encompasses most species of medically significant venomous snakes of Europe, with Italy harbouring four of them. Envenomation by European vipers can result in severe consequences, but underreporting and the absence of standardised clinical protocols hinder effective snakebite management. This study provides an updated, detailed set of guidelines for the management and treatment of Vipera snakebite tailored for Italian clinicians. It includes taxonomic keys for snake identification, insights into viper venom composition, and recommendations for clinical management. Emphasis is placed on quick and reliable identification of medically relevant snake species, along with appropriate first aid measures. Criteria for antivenom administration are outlined, as well as indications on managing potential side effects. While the protocol is specific to Italy, its methodology can potentially be adapted for other European countries, depending on local resources. The promotion of comprehensive data collection and collaboration among Poison Control Centres is advocated to optimise envenomation management protocols and improve the reporting of epidemiological data concerning snakebite at the country level.

A longitudinal study of the blood and urine metabolome of Vipera berus envenomated dogs

Envenomation of dogs by the common European adder (Vipera berus) is associated with high morbidity. The cytotoxic venom of Vipera berus contains enzymes with the potential to cause acute kidney injury, among other insults, however robust biomarkers for such effects are lacking. A prospective observational follow-up study of naturally envenomated dogs and controls was conducted to fill knowledge gaps regarding canine Vipera berus envenomation, attempt to identify novel biomarkers of envenomation and related kidney injury, and elucidate potential long-term effects. Blood and urine samples were analyzed with a global metabolomics approach using liquid chromatography-mass spectrometry, uncovering numerous features significantly different between cases and controls. After data processing and feature annotation, eight features in blood and 24 features in urine were investigated in order to elucidate their biological relevance. Several of these are associated with AKI, while some may also originate from disturbed fatty acid β-oxidation and soft tissue damage. A metabolite found in both blood and a venom reference sample may represent identification of a venom component in case dogs. Our findings suggest that envenomated dogs treated according to current best practice are unlikely to suffer permanent injury.

Influences of ski-runs, meadow management and climate on the occupancy of reptiles and amphibians in a high-altitude environment of Italy.

Alpine ecosystems harbour a rich and highly specialised biodiversity, which is particularly susceptible to anthropogenic disturbances such as habitat loss and fragmentation as well as to climate change. Combined with other forms of land-use conversion, construction and maintenance of ski resorts can have severe consequences on alpine biodiversity. In this study, we show how one amphibian and two reptile species, namely Rana temporaria, Zootoca vivipara and Vipera berus, respond to such impacts by means of a multi-season occupancy analysis. We found all three species both in and outside ski-runs, showing that these habitats do not necessarily preclude their occurrence. Contrarily, this is influenced more by microhabitat availability, such as ground vegetation, humid areas and rock cover, rather than by macro-characteristics like elevation or habitat type. Moreover, we found a climatic influence on the year-to-year occupancy change of the species, with activity-month conditions being more relevant than overwintering ones. Our results demonstrate how, in the specific case of reptiles and amphibians, ski resorts do not necessarily limit species' occurrence and that a mild series of management actions might secure the species' persistence in the area.

Analytical and quantitative assessment of the structural components of the adrenal glands of rats under the conditions of exposure to the venom of vipers Vipera berus berus and Vipera berus nikolskii

Snakebite envenoming is a common but neglected public health problem worldwide, especially in tropical countries. Annual mortality as a result of snakebites exceeds 138,000. It is believed that this problem is underestimated, and in many countries, individual cases of bites are not subject to proper fixation. The purpose of the study is the analytical and quantitative assessment of the structural components of the rats' adrenal glands under exposure to the venom of Vipers Vipera berus berus and Vipera berus nikolskii. Experimental studies were carried out on white, non-linear male rats. Vipera berus berus and Vipera berus nikolskii viper venom were obtained from V. N. Karazin Kharkiv National University. The freeze-dried native venom was stored at -20 °C and dissolved in saline immediately before the experiment. The animals were divided into three groups (control and 2 experimental groups) of 10 individuals each. Experimental rats were injected intraperitoneally in a physiological solution with a semi-lethal dose (LD50) (1.576 mg/g-1) of Vipera berus berus and Vipera berus nikolskii venoms. Animals of the control group were injected intraperitoneally with only a physiological solution. Rats were removed from the experiment 24 hours after exposure to the poison and anesthetised by cervical dislocation. Statistical analysis of the area of the microcirculatory channel and the nuclear-cytoplasmic index was performed using Fiji: ImageJ program and processed in Excel. Administration of the venom of the vipers Vipera berus berus and Vipera berus nikolskii to rats was accompanied by a significant increase in the area of the microcirculatory bed relative to the control group (2.9 times for Vipera berus berus and 6.5 times for Vipera berus nikolskii). Exposure to Vipera berus berus viper venom was associated with a significant decrease in the nuclear-cytoplasmic index in rats of the experimental group compared to the control group (13 % and 42 %, respectively), which is evidence of a decrease in the area of the nuclei of endocrinocytes of the adrenal cortex. This indicator in rats under the administration of Vipera berus nikolskii venom was even lower and amounted to 12 %. According to the statistical analysis of the quantitative assessment of the state of the cortical substance of the adrenal glands, it is worth noting the similar effect of the poisons of both types of snakes at the cellular level. At the same time, at the tissue level, the effect of Vipera berus nikolskii venom is more pronounced than that of Vipera berus berus - this is evidenced by the higher degree of disruption of the structure of the hemomicrocirculatory channel in the adrenal cortex of animals from the group that was affected by this venom. It led to an increase in the area of vessels due to their expansion and ruptures of their walls and haemorrhages into the surrounding parenchyma and stroma.

Sexual dimorphism and allometry in the head and body size of two viperid snakes (genus Vipera)

Sexual dimorphism in the size and shape of the body and head is the result of manifold selective pressures acting on organisms. In snakes, sexual size dimorphism is common and has been well-studied. However, intersexual differences in relative head size and shape have attracted far less attention. Similarly, the allometric properties of head shape and size in snakes are poorly known. Here, we analyse sexual dimorphism in two viperid species: European adder Vipera berus (Linnaeus, 1758) and Steppe viper Vipera renardi (Christoph, 1861). We measured body length, tail length and several head characteristics: head length, head width, head height, pileus length, interorbital distance and internarial distance. Our findings were that males and females of both species did not differ in body length (SVL), but that males tended to have significantly longer tails; there were also significant differences in head characteristics – males tended to have higher heads, and larger internarial and interorbital distances. The head dimensions displayed negative allometry when compared against SVL but when scaled against head length, dimensions like head height and head width exhibited positive allometry. We argue that these differences may be related to sexual selection and that the wider heads may also serve as antipredatory signal.

Anaphylaxis as probable cause of death in a rare case of fatal Vipera berus bite.

This case report describes the death of a 52-year-old male who was bitten by a venomous snake, Vipera berus (common European adder), on his left wrist. Despite experiencing symptoms, the patient refused medical care and self-medicated with alcohol instead. He was later found dead in his residence. Autopsy and histological examination revealed evidence of an anaphylactic reaction in response to the snake bite, with additional findings of alcohol intoxication and other underlying medical conditions.

An overview of the Scottish National Adder Survey 2022-24

A study was commissioned by NatureScot to analyse changes in the status of the adder (Vipera berus) and other native reptiles at 16 sites across mainland Scotland, the Isle of Skye and the Isle of Arran over a 30-year period from 1992-93 to 2022-24. In 2022-24, volunteer surveyors revisited sites that were previously surveyed in 1992-93 to identify changes in occupancy. Visual surveys recorded adder, common lizard (Zootoca vivipara), slow-worm (Anguis fragilis), common frog (Rana temporaria), common toad (Bufo bufo), smooth newt (Lissotriton vulgaris), and palmate newt (Lissotriton helveticus). Adders were observed in comparable or even greater numbers at eight sites (seven of the original sites surveyed in 1992-93), but an apparent loss of adders at three of the original sites, and major declines at a previously favourable site on the Scottish Borders are cause for concern. Of the other reptiles, common lizards were the most widespread, recorded at 12 sites; and slow-worms were least often recorded, in low numbers at only four sites, though this could be expected in visual surveys for this cryptic species. This publication reviews the factors most likely to be affecting adders in Scotland, particularly the loss of suitable habitat, the likely historic impact of persecution and the potential effects of disturbance by recreational site users. It highlights the importance of sympathetic habitat management, with a particular focus on maintaining favourable micro-habitats for reptiles.

Acidente ofídico em equinos no Bioma Amazônico, Pará, Brasil

ABSTRACT: Bothrops atrox is the most common viper in the Amazon, and its venom causes local and systemic changes. This report describes the clinicopathological and laboratory findings of ophidism due to Bothrops in six horses in Pará, Brazil. The animals, which belonged to five different rural properties, showed clinical signs of apathy, anorexia, and increased touch sensitivity in areas of increased volume. Three animals were bitten in the distal part of the pelvic limbs and three in the head area. The affected animals in the distal limb area exhibited marked edema extending from the fetlock to the thigh and had difficulty moving. Those affected in the head region exhibited an increase in volume that gave the appearance of a “rhinoceros head,” as well as blackening of the mucosa of the lips and gums. All animals exhibited tachycardia and tachypnea, and laboratory findings of two animals showed anemia, leukocytosis, increased clotting time, and elevated liver (AST and GGT) and kidney enzymes (urea and creatinine). Treatment was ineffective, and three of four treated animals died. Necropsy was performed on three animals, revealing extensive hemorrhage in the tissues at the snake bite sites and incoagulable bloody fluid in the cavities. Congestion was observed in the diaphragm, in the serosa of the small intestine, and in lighter areas on the renal surface. Histopathology showed muscle degeneration, necrosis, acute tubular necrosis, hemorrhage, and hyaline casts in the kidneys. This case report highlights the clinicopathological findings of snakebite in horses. In addition, this seems to be the first report of bothropic envenom in a mule in Brazil.

The highest-altitude recorded find of the adder <i>Vipera berus</i> (Linnaeus, 1758) in Slovenia on Mt Mali Kanin (Western Julian Alps)

The article describes the find of a single individual of the adder (Vipera berus) on Mt Mali Kanin (Western Julian Alps, Slovenian-Italian border) at 2,570 m a.s.l. on 8.7.2023. The animal with a total length of about 40 cm was photographed on a patch of soil and low alpine vegetation in a predominantly rocky habitat. According to the available published and unpublished data, this find is 325 m higher than the previous highest-altitude recorded find of the species in Slovenia.

Peculiarities of the microscopic structure of rat testis under the influence of Vipera berus berus venom

Morpho-functional changes in the organs of the male reproductive system are usually associated with injuries, infectious diseases, age, lifestyle, the presence of bad habits (abuse of alcohol, drugs), the influence of environmental factors, etc. However, the action of natural toxins, in particular those that are components of animal venoms, including the venoms of snakes and vipers, is no less important. The aim of the research is to study the features of the microscopic structure of the testis of rats under the influence of Vipera berus berus venom. Experimental studies were carried out on white non-linear male rats. Animals were conditionally divided into two groups – control and experimental, 10 individuals in each. Experimental rats were injected intraperitoneally with a semi-lethal dose (LD50) (1.576 mg/g-1) of Vipera berus berus venom in physiological solution. Animals of the control group were injected intraperitoneally with only saline solution. Rats were removed from the experiment 24 hours after exposure of the venom, anesthetized by cervical dislocation. Testis samples were taken for microscopic examination. Fixation of the material and preparation of paraffin blocks were carried out according to generally accepted methods. Staining of histological preparations of the testis was carried out with hematoxylin and eosin. Histological preparations were studied using a SEO SСAN light microscope. Administration of Vipera berus berus venom to rats leads to the development of pathogistological changes in the parenchymal elements of the testis of animals, among which desquamation and disorganization of all stages of spermatogenic cells development, disruption of spermatogenesis processes were the most pronounced. Spermatogenic cells of the seminiferous tubules of the testis were distinguished by changes in morphology and location, lost the regularity of their placement, and their number decreased. The cells detached from the basement membrane and did not form a continuous layer. A characteristic feature was the presence of clusters of erythrocytes in the lumen of the seminiferous tubules, which may indicate the development of hemorrhagic complications. In addition, an increase in the number of Leydig cells was detected, which is probably the cause of changes in the hormonal regulation of the organ's function.

Histological changes in the liver of rats under the influence of Vipera berus berus venom

Animal venoms contain a whole complex of compounds, among which there are peptides, proteins, as well as other organic molecules and salts. Their toxins are able to cause pronounced disturbances in the functioning of physiological systems, leading to the appearance of pathological conditions, complications, or even death. The aim of the research is to study the histological changes in the liver of rats under the influence of Vipera berus berus venom. Experimental studies were carried out on white non-linear male rats. The animals were conditionally divided into two groups – a control and an experimental group of 10 individuals in each. Experimental rats were injected intraperitoneally with a semi-lethal dose (LD50) (1.576 mg/g-1) of Vipera berus berus venom in saline solution. Animals of the control group were injected intraperitoneally with only saline solution. Rats were removed from the experiment 24 hours after exposure to the venom, anesthetized by cervical dislocation. Liver samples of animals of all groups were taken for microscopic examination. Histological preparations of the liver were stained with hematoxylin and eosin. Histological preparations were studied using a SEO SСAN light microscope. To identify the key enzyme of the citric acid cycle – succinate dehydrogenase, histochemical studies were performed according to the Nakhlas method. To study the features of glycogen accumulation in hepatocytes, sections were stained using Schiff's reagent, after pretreatment with iodic acid (PAS reaction) in Shabadash's modification. An immunohistochemical research method was used to detect a subpopulation of CD86+ cells in the liver of experimental animals. Under the influence of Vipera berus berus venom, the development of alterative changes in the liver parenchyma and vascular disorders were microscopically revealed. The appearance of foci of leukocyte infiltration was established, which indicates the development of inflammatory processes. A histochemical study of the content of succinate dehydrogenase in the liver of animals injected with Vipera berus berus venom showed uneven activity of the mitochondrial enzyme in the lobules. A histochemical study of glycogen in hepatocytes of the liver of rats exposed to Vipera berus berus venom showed a decrease in the content of trophic inclusions. An increase in the population of CD86+ cells indicates reactive inflammatory processes observed in the body as a result of the action of components of Vipera berus berus venom.

Biting as an intraspecific behaviour of a male Common European Adder (Vipera berus, Linnaeus 1758) during courtship and mating competition

The article describes the first record of biting as an intraspecific behaviour of a male Common European Adder (Vipera berus) during courtship and mating. In venomous snakes this behaviour is rather rare and in Vipera berus this is the first time it has been observed in the wild. This behaviour is compared to similar observations in snakes and potential reasons are discussed.

Improving attitudes towards adders (Vipera berus) and nature connectedness in primary‐age group children

Abstract Adder ( Vipera berus ) populations are experiencing declines in many countries, including the United Kingdom. Perceptions of adders and other venomous snakes are generally negative, making conservation of these species a challenge, and persecution remains within the top five perceived causes for adder declines in the United Kingdom. Improved understanding and attitudes are needed to support current conservation efforts. However, ensuring these positive attitudes continue into the future relies on addressing children's loss of connection to nature, and intervention at this early attitude‐formation stage can be crucial for traditionally ‘unpopular’ species, such as snakes. An adder‐focussed public engagement project, Adders are Amazing !, was carried out in Pembrokeshire, United Kingdom, in 2018–19 to improve understanding and attitudes towards adders using a blended science‐creative arts approach. The project included half‐day primary school‐based workshops to inform 111 pupils aged 8–11 about adder ecology, alongside creative art experiences. Questionnaires were used to measure the children's attitudes towards adders and their nature connectedness both before and after the workshops and these were compared with equivalent questionnaires carried out at a control school (57 pupils) where no workshops were conducted. The project demonstrated that engagement that blends both art and science can significantly change attitudes towards adders without any direct contact with the animals themselves; specifically, participants' scores for ‘Wonder’, ‘Learning Interest’ and ‘Conservation Concern’ increased. The workshops also significantly increased measures of the children's general connectedness to nature (specifically, ‘Enjoyment of Nature’ and ‘Responsibility for Nature’). We recommend conservation bodies focus on, and not shy away from, so‐called ‘unpopular’ species, to promote understanding and acceptance of these species and support their conservation. Blended arts–science initiatives, which can be easily adapted to suit a wide range of species and the artistic practices of local communities, are an effective way to achieve this. Read the free Plain Language Summary for this article on the Journal blog.

Comparative success of two sampling techniques for high-altitude Alpine grassland reptiles under different temporal designs

Abstract Monitoring of wildlife populations is essential for their conservation and requires a carefully chosen methodology. We compared survey effectiveness of reptiles using coverboards and visual encounter surveys in two study sites in the Italian Alps with similar habitats and reptile communities. The two sites shared similar methodologies, cover boards and visual encounter surveys (VES), except for the temporal approach, with one employing a long-lasting monitoring scheme and the other operating on a much shorter time-frame. Coverboards were placed two years before the beginning of the monitoring in the first site, while they were installed only for ten days and then removed each year in the second site. Similarly, VES were spread across the whole reptile activity season (May-September) in the first site, while conducted over nine consecutive days in the second site. Although the observation rate of any species was mainly associated with its relative abundance, reptiles preferred long-established coverboards and all three species present (Zootoca vivipara, Anguis veronensis and Vipera berus) were found underneath them. Only Zootoca vivipara used recently installed ones. On the other hand, short-term daily visual encounter surveys led to a much higher observation rate of Z. vivipara than those spread over the entire season. Our results suggest that coverboards may provide a valuable monitoring tool for reptiles when projects are conducted over long periods. Conversely, when only short-term assessments are possible, no real difference exists between the two methods and observation rate is more influenced by the species abundance than by the chosen method.

Changes in the microscopic organisation of rat adrenal glands under the influence of Vipera berus berus venom

Snakebite envenoming is a common but neglected public health problem worldwide. Annual mortality as a result of snakebites exceeds 138,000. The organs of the endocrine system are among the first to react to the effects of snake and viper toxins. Under these conditions, the adrenal glands are involved in the pathological process and contribute to the formation of the adaptation syndrome, undergoing complex structural changes. The research aims to study the changes in the microscopic organization of the adrenal glands of rats under the influence of Vipera berus berus venom. Experimental studies were carried out on white non-linear male rats. The animals were conditionally divided into a control and an experimental group of 10 individuals. Experimental rats were injected intraperitoneally in a saline solution with a semi-lethal dose (LD50) (1.576 mg/g-1) of Vipera berus berus venom. Animals of the control group were injected intraperitoneally with only saline solution. Rats were removed from the experiment 24 hours after exposure to the venom and anaesthetized by decapitation. Adrenal gland samples were taken for microscopic examination. Fixation of the material and preparation of paraffin blocks were carried out according to generally accepted methods. Histological preparations of the adrenal glands were stained with hematoxylin and eosin. Histological preparations were studied using an SEO SСAN light microscope. Under the influence of Vipera berus berus venom in zona glomerulosa of the adrenal cortex, moderately pronounced pathological changes were found, including vacuolization and granularity of the cytoplasm of endocrinocytes, loss of precise contours of nuclei, their hyperchromasia, expansion of lumens of sinusoidal capillaries, accumulation of erythrocytes in them. Under these conditions, zona fasciculata is characterized by significant cell granularity and perinuclear edema. Less pronounced structural organization changes were noted in the zona reticularis of the adrenal cortex. Endocrinocytes of this zone had small sizes, eosinophilic cytoplasm and dark nuclei. In the medulla of the adrenal glands, the cells were large in size and had indistinct contours, the cytoplasm was characterized by basophilic granularity, and the nuclei were light due to the predominance of euchromatin. The most pronounced effect of Vipera berus berus venom was on the zona glomerulosa and zona fasciculata of the adrenal cortex; most of the morphological signs of pathology in which were caused by a violation of protein metabolism in the cells of the parenchymal and stromal elements of this organ.