|  |  |  | INTRODUCTIONIn Serbia, only three species of venomous snakes exist, each with 
			one or two subspecies: the nose-horned viper (Vipera ammodytes), the 
			adder (V. berus), and the meadow viper (V. ursinii) [1-4]. All are 
			strictly protected or protected by law [5]. In our country, 
			including the surroundings of the city of Vršac (Banat region, 
			Vojvodina province, northeastern Serbia), the Balkan adder, Vipera 
			berus subsp. bosniensis occurs (Figure 1A,B) [1,2,6]. Another viper, 
			V. ammodytes, widely distributed south of the Danube and Sava 
			rivers, also was recorded approximately 40 kilometers to the south 
			from Vršac [7]. The experts did not exclude the possibility that in 
			rare remnants of steppe habitats in Vojvodina the third viper 
			occurs, V. ursinii, subsp. rakosiensis [1]. Figure 1. Vipera berus bosniensis from the Vršačke 
			planine Mts.: A) an adult in the open, and B) a specimen well hidden 
			in dry grass (Photos: Milivoj Krstić).Slika 1. Vipera berus bosniensis sa Vršačkih planina: A) odrasla 
			jedinka na otvorenom i B) jedinka dobro sakrivena u suvoj travi 
			(Fotografije: Milivoj Krstić).
 
			 According to the World Health Organization, two of the vipers 
			present in Serbia are medicinally important – the nose-horned viper 
			and the adder; the meadow viper is only moderately harmful to humans 
			[8].The venoms of adder and nose-horned viper differ in composition and 
			effects [9]. Neurotoxic effects of adder venom are known for a long 
			time, as are the differences in venom composition and in 
			consequences of envenomation between two of the adder subspecies 
			present in the Balkans, V. b. berus and V. b. bosniensis [10,11]. 
			Resulting from the distribution patterns of the species, bites by V. 
			ammodytes are more frequent than those by V. berus in all 
			ex-Yugoslav countries for which the overview publications could be 
			found [Nikolić, unpublished].
 In Serbia, bites by venomous snakes do occur every year [Nikolić, 
			unpublished], but their analyses are not being performed and made 
			publicly available. A central register of the incidences of venomous 
			snakebites still does not exist in Serbia: its making was initiated 
			only in 2018, and the collected data were not available at the time 
			of this manuscript preparation [12].
 In general, published information concerning the bites of Vipera b. 
			bosniensis are almost inexistent. Detailed case reports from the 
			neighboring countries date back only to the 2010s [11,13,14]. On the 
			other hand, the first adder bites in Vojvodina were described by a 
			medical professional already in 1901 [15], although from the Fruška 
			gora Mt., Srem region. Only one publication was found regarding 
			adder bites in the Vršac area, presenting six cases [16]. Between 
			these two reports, a 100-years gap exists. After the year 2000, 
			nothing of a kind was published for Vojvodina: several other cases 
			previously treated in the Vršac hospital were not presented in the 
			scientific literature. In general, in Serbia, only two additional 
			publications were found concerning venomous snakebites, regarding V. 
			ammodytes [17,18]. Importantly, no fatal outcomes were recorded.
 People often cannot recognize snake species, but in our case, no 
			doubts existed regarding the identification of the “culprit”: the 
			professional was bitten, who clearly recognized the species.
 With this case report, we intended to contribute to the collecting 
			and publishing of the data regarding the seriously neglected 
			venomous snakebites.
 CASE REPORTOn April 25, 2019 at around 10:40 a.m., one of the authors, an 
			experienced 43-year old field investigator, ranger in the Landscape 
			of Outstanding Features “Vršačke planine”, encountered an adder and 
			wanted to photograph it, for the documentation. It was a sub-adult 
			almost melanistic male (Figure 2A). Although well aware of the 
			potential threat and despite handling the snake with due caution, 
			for a moment his attention dropped and the snake bit him at the tip 
			of his left-hand middle finger. The single fang only scratched the 
			skin under the nail (Figure 2B). Figure 2. A) The snake that inflicted the bite; B) 
			tip of the patient’s left-hand middle finger a week after the bite 
			(Photos: Milivoj Vučanović).Slika 2. A) Zmija koja je nanela ujed; B) vrh srednjeg prsta leve 
			ruke pacijenta nedelju dana nakon ujeda (Fotografije: Milivoj 
			Vučanović).
 
			 The patient squeezed and intuitively sucked the bite wound and 
			probably ingested a bit of venom. During the first ten minutes, 
			there was no reaction to the bite. After those ten minutes, “an 
			initially unidentifiable change in the body” was felt. The injured 
			man started driving his car towards the hospital by himself but 
			accompanied by a colleague. Along the way he felt sudden exhaustion 
			and noted that the colors of the surroundings had changed, i.e. 
			brightened (the sky was brightly shining, leaves turned fluorescent 
			green, the road shimmered like ice). The hospital was reached after 
			about 35 minutes.On admission, approximately 40 minutes after the bite, the patient 
			was sweating and he complained of nausea and exhaustion but was able 
			to explain what happened. He sat on the chair and vomited for the 
			first time. Since he was unable to stand alone, he was put in a 
			wheelchair. While being driven to the Infectious diseases 
			department, he was unable to keep his feet lifted.
 Of average osteomuscular build, he was conscious, oriented in space, 
			time and towards faces, afebrile, acyanotic, anicteric, eupneic at 
			rest, with no signs of hemorrhagic syndrome. His systolic blood 
			pressure was 80 mmHg, but the diastolic was immeasurable. He denied 
			chronic diseases and allergies to medications; he is a non-smoker 
			and does not consume alcohol. During the admission, the patient 
			vomited watery contents twice but he did not have diarrhea. Physical 
			findings on head and neck were normal; there was no strabismus or 
			diplopia. Auscultation showed normal breath sounds, cardiac action 
			was rhythmic with clear tones; TA 80/NA (still immeasurable) mmHg. 
			The abdomen was soft, insensitive on palpation; liver at right 
			costal margin, renal succussion negative. There was no swelling or 
			deformities on extremities, only the bitten finger was slightly 
			hyperemic: although the bite mark was not visible, minor swelling 
			and redness developed at the place of bite. The patient had no 
			neurologic deficits; meningeal signs were negative. Slight ptosis of 
			the left eyelid developed. After being put to bed, the patient 
			vomited three more times and had mild but uncontrollable diarrhea. 
			He was conscious but was too weak to talk or keep his eyes open.
 Immediately after the admission, the patient received the 
			antihistamine Synopen (hloropiramin) i.v., and Lemod-Solu 
			(metilprednizolon) 80 mg. Intravenous infusions were introduced – 
			sol NaCl (natrii chloridi infundibile) 0.9% 500.0, sol Dextrosae 
			(glucose) 5% 500.0, and the Jugocilin (benzilpenicilin-prokain) 
			antibiotic 1,600,000IU was given i.m.
 A single dose (5 ml) of the equine viper venom antiserum Viekvin® 
			was administered i.m. at 11:45 a.m., approximately 65 min after the 
			bite, at the place of bite on the hand and in the forearm. After an 
			hour, the patient started feeling better.
 At 12:20 p.m. tension still 80/NA mmHg; infusion application 
			continued (sol NaCl 0.9% and sol Dextrosae 5%). Slight ptosis of the 
			left eyelid became evident. The patient appeared drowsy, his talk 
			was slow and slurry. Nevertheless, after two hours, all sensations 
			were back to normal, and the patient felt good, except he could not 
			control his eyelids.
 At 13:20 p.m., the patient felt better, with TA 120/70 mmHg and 
			diuresis of 350 ml (the single instance from the admission, at 13 
			p.m.). During the afternoon the ptosis of both eyelids developed: he 
			could not open the eyes.
 At 18:30 p.m. the patient’s TA was 140/100 mmHg. At 22:00 p.m. TA 
			was unchanged, and body temperature was 37.5°C. The patient was 
			stable.
 During the first day in the hospital, the patient was given 3 l of 
			liquid i.v. He was not given anti-tetanus protection because he had 
			already received the third dose of Tetalpan in February 2018, i.e. 
			he was regularly vaccinated previously.
 On April 26, the patient felt well, his TA was 120/80 mmHg and 
			diuresis 2.250 ml (from admission until 6 a.m.). Ptosis was less 
			prominent than on the previous day. Physical findings were normal.
 On the third day, April 27, ptosis was still present but weaker: the 
			patient could keep his eyes open, but still did not completely 
			regain eyesight. Findings on the place of the bite were normal.
 On April 28, ptosis receded almost completely; the patient had no 
			objective sight problems. On April 29, the ptosis receded 
			completely.
 The patient was released from the hospital on April 30, the sixth 
			day after the bite. Although clinically well, his sight did not 
			fully recover: he still had trouble “sharpening” images for a couple 
			of seconds after turning his head. In addition, after two or three 
			hours of activity, his head would start aching. Subjectively, he 
			fully recovered after 10–12 days. The bitten fingertip remained numb 
			for about a month.
 Laboratory tests: Laboratory analyses were performed at the 
			admission, on the second day of hospitalization and before the 
			patient was released. Values of the tests that departed from normal 
			are provided in Table 1. Other hematological, biochemical and 
			hemostatic parameters were within their reference ranges. Urine was 
			tested only on the second day, and all parameters were 
			normal/negative (pH, density, appearance, color, blood, bilirubin 
			and urobilinogen, leucocytes, ketones, proteins, nitrites, and 
			glucose).
 Table 1. Results of laboratory analyses during the 
			course of hospitalization. Elevated values are given in boldface, 
			lowered are italicized.Tabela 1. Rezultati laboratorijskih analiza vršenih tokom 
			hospitalizacije. Povišene vrednosti su podebljane, a snižene 
			iskošene.
 
			 DISCUSSIONAlthough previously healthy and practically merely scratched on 
			the finger with only one snake’s fang, the patient experienced 
			moderately severe envenomation and spent six days in the hospital. 
			He encountered a snake in a place that is not isolated: weekend 
			house owners regularly use the road he took that day – mostly in 
			cars, but also on foot; other types of visitors are also quite 
			usual. Vipera b. bosniensis is long known for its potent neurotoxic 
			venom, and reactions to its bites similar to the one we described 
			were reported from Croatia, Bulgaria, and Hungary, in addition to 
			the previous six cases from the Vršac hospital [11,13,14,16]. 
			Although sometimes causing severe clinical pictures, adder bites are 
			rarely fatal [e.g. 19]. Importantly, the antivenin manufactured in 
			Serbia is effective in the cases of adder bites, although it is made 
			from the venom of Vipera ammodytes [17,20].Our laboratory analyses of blood and urine did not show dramatic 
			aberrations from reference values. Varga et al. [14] provided a list 
			of papers presenting and discussing laboratory findings in the cases 
			of V. berus bites: among the previously reported, we found elevated 
			levels of glucose and CRP. We also had increases in erythrocytes, 
			but lowered monocytes %, while the numbers/percentages of lympho- 
			and granulocytes oscillated from below to above the reference 
			ranges. Systemic symptoms did develop but did not last for long. The 
			only persistent effects were problems with eyes – blepharoptosis and 
			vision impairment.
 The cases of adder bites previously described from the surroundings 
			of Vršac [16] were similar to the one we reported of here. Of the 
			six patients treated during 18 years, three got bitten to the 
			fingers while attempting to catch the snakes; two sucked the wound 
			and one squeezed it (the remaining three did not apply the first 
			aid). Both local and systemic symptoms were mild to moderate, with 
			complications in a person suffering from asthma. All patients (22–57 
			years of age) received antivenin within 30 min to 4 hours after the 
			bite, and they spent 2–8 (4.8 on average) days in the hospital.
 In general, adder bites in the surroundings of Vršac are not 
			frequent and they are surely not lethal, as the media like to 
			present them, using the phrases like “he barely survived the attack 
			of a snake”.
 Vršačke planine Mts. are one of only several remaining lowland/hilly 
			habitats of Vipera berus in Serbia [1,6,21]. Like in its other 
			non-mountainous habitats, due to the constant spreading of human 
			influences, the adder is often found near the settlements and arable 
			land [21]. This makes it vulnerable to various anthropogenic 
			influences [6] and poses the potential threat to people. In Serbia, 
			the species is strictly protected by national legislation and was 
			recently designated as vulnerable; the prescribed fine for its 
			killing is 100.000 dinars (app. 850 €) [2,5,22].
 In our case, the snake bit an experienced and cautious person, a 
			professional biologist, who was aware that his own mistake during 
			the handling of the animal led to the bite. Laypeople either fear 
			snakes enough to wish to kill them all, or they want to show off 
			trying to catch or/and torture them. Those are the situations in 
			which many of the bites occur [16,23,24].
 CONCLUSIONAlthough the distribution of vipers in Serbia is comparatively 
			well explored, some new populations of all three species might be 
			“discovered” in suitable habitats, like in e.g. Hungary [25]. The 
			exchange of information is necessary among scientists (professionals 
			in biology and medicine), and between the experts and the general 
			public, including the media. With humble effort, proper education 
			could be provided to the target population and the risk of 
			snakebites could be minimized.
 Acknowledgements
 Sonja Nikolić is financed through the Project No. 173043 of the 
			Ministry of Education, Sciences and Technological Development of the 
			Republic of Serbia. Milivoj Krstić kindly allowed us to use his 
			photographs of the adders from the Vršačke planine Mts. This study 
			did not receive any specific funding. We are grateful to the 
			anonymous reviewer whose constructive critique and comments helped 
			us improve the manuscript.
 
 Conflicts of interest
 None.
 REFERENCES
				Jelić D, Ajtić R, Sterijovski B, Crnobrnja-Isailović J, Lelo 
				S,Tomović L. Distribution of the genus Vipera in the western and 
				central Balkans (Squamata: Serpentes: Viperidae). Herpetozoa 
				2013; 25 (3/4): 109–32.Ajtić R, Tomović L. Vipera berus (Linnaeus, 1758). In: 
				Tomović L, Kalezić M, Džukić G, editors. Red book of fauna of 
				Serbia II – Reptiles. University of Belgrade, Faculty of 
				Biology, and Institute for Nature Conservation of Serbia, 
				Belgrade; 2015. p. 241–7.Tomović L. Vipera ammodytes (Linnaeus, 1758). In: Tomović L, 
				Kalezić M, Džukić G, editors. Red book of fauna of Serbia II – 
				Reptiles. University of Belgrade, Faculty of Biology, and 
				Institute for Nature Conservation of Serbia, Belgrade; 2015. p. 
				233–9.Tomović L, Ajtić R. Vipera ursinii (Bonaparte, 1835). In: 
				Tomović L, Kalezić M, Džukić G, editors. Red book of fauna of 
				Serbia II – Reptiles. University of Belgrade, Faculty of 
				Biology, and Institute for Nature Conservation of Serbia, 
				Belgrade; 2015. p. 249–54.Anonymous. Pravilnik o proglašenju i zaštiti strogo 
				zaštićenih i zaštićenih divljih vrsta biljaka, životinja i 
				gljiva [Regulation on the designation and conservation of the 
				strictly protected and protected wild species of plants, animals 
				and fungi]. Službeni glasnik Republike Srbije [Official Gazette 
				of the Republic of Serbia] 2011; Nos. 5/2010 and 47/2011.Tomović L, Ajtić R, Ljubisavljević K, Urošević A, Jović D, 
				Krizmanić I, et al. Reptiles in Serbia – Distribution and 
				diversity patterns. Bull Nat Hist Mus Belgr 2014; 7: 129–58.
				
				https://doi.org/10.5937/bnhmb1407129T7. Džukić G, Kalezić M, Marković M. Poskok (Vipera 
				ammodytes) – autohtona zmija Vojvodine! [Nose-horned viper 
				(Vipera ammodytes) – autochthonous snake in Vojvodina!] Godišnji 
				bilten Prirodnjačkog društva Gea 2005; 5: 13.WHO – World Health Organization. Health Systems and 
				Services: Quality and Safety of Medicines – Blood Products and 
				related Biologicals. Available at
				
				http://apps.who.int/bloodproducts/snakeantivenoms/database/default.htm 
				(Last accessed on 11 September 2019).Latinović Z, Leonardi A, Šribar J, Sajevic T, Žužek MC, 
				Frangež R. et al. Venomics of Vipera berus berus to explain 
				differences in pathology elicited by Vipera ammodytes ammodytes 
				envenomation: Therapeutic implications. J Proteomics 2016; 146: 
				34–47.
				
				https://doi.org/10.1016/j.jprot.2016.06.020Radovanović M, Martino K. Zmije Balkanskog poluostrva. 
				Srpska akademija nauka, Naučno-popularni spisi, Knjiga 1; 
				Institut za ekologiju i biogeografiju, Knjiga 1. [Snakes of the 
				Balkan Peninsula. Serbian Academy of Sciences, 
				Scientific-popular writings, Book 1. Institute for Ecology and 
				Biogeography, Book 1] Naučna knjiga, Belgrade. 1950: p. 43.Malina T, Krecsák L, Jelić D, Maretić T, Tóth T, Šiško M. et 
				al. First clinical experiences about the neurotoxic envenomings 
				inflicted by lowland populations of the Balkan adder, Vipera 
				berus bosniensis. NeuroToxicology 2011; 32: 68–74.
				
				https://doi.org/10.1016/j.neuro.2010.11.007Dobaja Borak M, Babić Ž, Bekjarovski N, Cagánova B, Grenc D, 
				Gruzdyte L. et al. Epidemiology of Viperidae snake envenoming in 
				central and south-eastern Europe: CEE Viper Study. In: Abstracts 
				from the 39th International Congress of the European Association 
				of Poisons Centres and Clinical Toxicologists (EAPCCT) 21–24 May 
				2019, Naples, Italy. Clin Toxicol 2019; 57(6): 470.Westerström A, Petrov B, Tzankov N. Envenoming following 
				bites by the Balkan adder Vipera berus bosniensis – First 
				documented case series from Bulgaria. Toxicon 2010; 56: 1510–5.
				
				https://doi.org/10.1016/j.toxicon.2010.08.01214. Varga C, Malina T, Alföldi V, Bilics G, Nagy F, Oláh T. 
				Extending knowledge of the clinical picture of Balkan adder 
				(Vipera berus bosniensis) envenoming: The first 
				photographically-documented neurotoxic case from South-Western 
				Hungary. Toxicon 2018; 143: 29–35. https://doi:10.1016/j.toxicon.2017.12.053
Mirković S. Kako prost narod u Fruškoj gori i Sriemu lieči 
				rane nastale ujedom otrovnih zmija [How laypeople in Fruška gora 
				and Sriem heal the wounds resulting from venomous snake bites] 
				Liečnički Viestnik 1901; 23: 246–8. [In Serbian].Častven J, Šinžar T, Kovačević D, Moroanka E, Mitrović D, 
				Stanivuković M. Zmijski ujedi u području Vršačkih planina – 
				prikaz slučajeva [Snakebites in the region of Vršac mountains – 
				case reports]. Acta Infectologica Yugoslavica 2000; 5: 75–82. 
				[In Serbian with summary in English]Milićević M. Prikaz bolesnika ujedenih od otrovnih zmija 
				lečenih od 1960. do 1968. godine / Vorstellung der Kranken die 
				von Giftschlangenbissen im Jahre 1960 bis 1968 behandelt wurden 
				[Presentation of the patients bitten by venomous snakes treated 
				between 1960 and 1968]. Srpski arhiv za celokupno lekarstvo1968; 
				96(10): 999–1006. [In Serbian with summary in German].Stojanović M, Stojanović D, Živković Lj, Živković D. 
				Hemoragijski sindrom kod zmijskog ujeda [Hemorrhagic syndrome in 
				snakebite]. Apollineum Medicum et Aesculapium 2007; 5(3-4): 
				8–10. [In Serbian with summary in English]Tranca S, Cocis M, Antal O. Lethal case of Vipera berus 
				bite. Clujul Med 2016; 89(3): 435–7.“Torlak” Institute of Virology, Vaccines and Sera, Belgrade, 
				Serbia. User’s manual for Viekvin®:
				
				www.torlakinstitut.com/pdf/Viekvin-en.pdf Nikolić S, Simović A. First report on a trichromatic lowland 
				Vipera berus bosniensis population in Serbia. Herpetol Conserv 
				Bio 2017; 12(2): 394–401.Anonymous. Pravilnik o odštetnom cenovniku za utvrđivanje 
				visine naknade štete nedozvoljenom radnjom u odnosu na strogo 
				zaštićene i zaštićene divlje vrste [Regulation on the 
				compensation charges for the damages caused by illegal actions 
				towards strictly protected and protected wild species]. Službeni 
				glasnik Republike Srbije 2010; No. 37/2010.Stahel E, Wellauer R, Freyvogel TA. Vergiftungen durch 
				einheimische Vipern (Vipera berus und Vipera aspis). Eine 
				retrospektive Studie an 113 Patienten [Poisoning by domestic 
				vipers (Vipera berus and Vipera aspis). A retrospective study of 
				113 patients]. Schweiz Med Wochenschr 1985: 115(26): 890–6. [In 
				German with abstract in English]Warrell DA. Treatment of bites by adders and exotic venomous 
				snakes. BMJ 2005; 331: 1244.
				
				https://doi.org/10.1136/bmj.331.7527.1244 Malina Т, Schuller P, Krecsák L. Misdiagnosed Vipera 
				envenoming from an unknown adder locality in northern Hungary. 
				North-West J Zool. 2011; 7(1): 87–91. |  |  |  |