THE MOST COMMON INTENTIONAL POISONING OF DOGS AND CATS ON THE TERRITORY OF THE REPUBLIC OF SERBIA

Th e paper presents the most common toxic substances used in malicious poisoning of dogs and cats in the territory of the Republic of Serbia, mechanisms of their action, symptoms that occur in poisoned animals, antidote therapy and in the case of death, pathomorphological changes. Th e understanding of the mechanisms of toxic action of the most common substances used and the clinical symptoms in poisoned dogs and cats contribute to a faster diagnosis and the prompt suitable therapy application. Th e participation of forensic veterinarians in offi cial procedures prior to criminal proceedings is necessary, considering its importance in the recognition and prosecution of acts defi ned in Article 269 of the Criminal Code (Of-fi cial Gazette of RS, No. 85/2005, 88/2005 - amended, 107/2005 - amended, 72/2009, 111/2009, 121/2012, 104/2013, 108/2014, 94/2016 and 35/2019). reliable fi ndings of forensic veterinarians and confi r-mation of poisoning. Judicial diffi cult better chemical-toxicological


INTRODUCTION
Chemical injuries (Laesio valetudinis violenta chemica) or animal poisoning are a global worldwide problem (Wang et al., 2007;Ladislav et al., 2011). Th ey have become an increasingly frequent occurrence on the territory of the Republic of Serbia. Toxins are substances that, depending on the concentration, amount and manner of reaching the body, lead to various toxic eff ects (Aleksić and Aleksić, 2019). Regarding the intentions of poisoning, they can be unintentional (accidental) and intentional (murderous). Accidental animal poisonings have been documented worldwide (Berny et al., 2010; 2010a, Guitart et al., 2010b), they cannot be prevented and their percentage is low compared to intentional poisoning (Giorgi et al., 2007;Berny et al., 2010). Intentional poisoning means the abuse of toxic substances and malicious intent of the perpetrator, but also an act of revenge against a certain animal or its owner or keeper (Merck, 2007).
Th e Animal Welfare Law, among other things, prohibits the use of poisons and other chemical agents that cause pain, suff ering and death of animals, except for the purpose of controlling rodent populations, i.e. rodent control and animal testing for scientifi c research purposes (Animal Welfare Law, Article According to the provisions of the Criminal Code, any person that causes danger to a human life by means of fi re, fl ood, explosion, poison or poisonous gas, radioactive or other ionizing radiation, electricity, motor force or any other dangerous action that has a potential to endanger human life or habitat, will be prosecuted. In addition to a fi ne, a prison sentence of six months to fi ve years is imposed for this crime. If the crime was committed in a place where a large number of people gather (e.g., in a park, on the street, in a square), and there are signs of a more severe form of poisoning, then a stricter prison sentence is prescribed, from one to eight years, along with a fi ne.
In most cases, according to the clinical course, intentional poisonings are peracute or acute, so in order to respond in a timely manner and implement appropriate therapy, it is important that veterinarians have information on the most commonly used types of poisons used by perpetrators. According on our case law, perpetrators have most commonly been using anticoagulant rodenticides, organophosphate and carbamate insecticides, creosote and molluscicides (metaldehyde) in the recent years.
Th e prevalence of poisoning is higher in dogs compared to cat poisoning, which has been established in the countries of the European Union: Belgium, France, Greece, Italy, Spain, Austria (Berny et al., 2010;Wang et al., 2007). Dogs account for about 75% of cases, and cats for about 15% of reported cases of intentional poisoning (Gwaltney-Brant, 2012). Th e higher incidence of dog poisoning is understandable given their nonselective eating habits compared to cats (Medeiros et al., 2009).
During a six-year period (2006)(2007)(2008)(2009)(2010)(2011)(2012), the Department of Veterinary Forensic Medicine and Legislations of the Faculty of Veterinary Medicine in Belgrade autopsied 48 corpses of dogs with suspected poisoning. Anticoagulant rodenticide poisoning was suspected in 20 cases, creosote poisoning in 17 cases, and organophosphate and carbamate pesticides in 11 cases. According to the data provided by the Public Utility Company "Veterina Belgrade", in 2018, 58 death cases of animals with suspicion of poisoning were reported in Belgrade, while 41 cases were recorded in 2019. Th ere are no offi cial data on the number of intentionally or accidentally poisoned dogs and cats on the territory of the Republic of Serbia (RS), on an annual basis (Aleksić J. et al., 2014).
Th e diagnosis of poisoning is based on anamnestic data, clinical, autopsy, histopathological and toxicological fi ndings (Jubb et al., 2007), and in medical-legal cases the chemical-toxicological fi ndings play a crucial role. Th e aim of this paper is to point out the most commonly used agents for the purpose of intentional poisoning of dogs and cats in the territory of the Republic of Serbia, the characteristics and mechanism of toxic eff ects of the most commonly used poisons, the clinical picture of poisoned animals, antidote therapy and autopsy fi ndings.

ANTICOAGULANT RODENTICIDE POISONING
Rodenticides are used to control the population of harmful gophers and are the most commonly used type of poison for the purpose of intentional poisoning. Th e reasons for frequent poisonings by these compounds are their pleasant taste (due to sucrose which is added to make them more attractive to gophers) and lack of odors (Eason et al., 2002;Endepols et al., 2003;Binev et al., 2005;Svendsen et al., 2002). Th ere are diff erent fi rst and second-generation anticoagulants. Th e fi rst generation includes indandione derivatives (difacion, chlorofacion) and coumarin (warfarin, coumachlor, coumatetralyl). Th is generation of anticoagulants is characterized by the need for repeated oral administration in order for non-target species to be poisoned. Over time, due to the emergence of rodent resistance to fi rst-generation anticoagulants, second-generation coumarin derivatives have also been developed, which are very toxic to dogs and cats, and therefore poisoning can occur even aft er single consumption. Difenacoum is the fi rst in a series of second-generation coumarin anticoagulants, and bromadiolone and brodifacoum are also used. Brodifacoum is more recent and has several times higher toxicity than bromadiolone. Th e oral LD 50 of brodifacoum for cats is 25 mg/kg and from 0.25 to 3.6 mg/kg of body weight for dogs (Eason and Wickstrom, 2001). In our country, the most used coumarin derivatives are warfarin, bromadiolone and brodifacoum.
Anticoagulant rodenticides act as antagonists of vitamin K and the enzyme vitamin K-epoxide reductase, which participates in the recycling of vitamin K. factors) (Sheafor and Couto, 1999;Merola, 2002). As a result, the synthesis of blood coagulation factors is blocked: II (prothrombin), VII (proconvertin), IX (antihemolytic factor B) and X (Stuart's factor) (Sheafor and Couto, 1999;Merola, 2002). In terms of chemical structure, coumarin is similar to vitamin K 1 , and for that reason it competes with vitamin E for its place on the enzyme epoxy reductase (competitive inhibition). Th ere is a reduced regeneration of vitamin K 1 , which is essential for the synthesis of coagulation factors. Coumarin is also thought to have a direct toxic eff ect on capillaries, but the mechanism of action has not yet been suffi ciently clarifi ed (Ćupić, 2015).
Th e latent period depends on the type and amount (dose) of anticoagulant taken, but poisoned individuals usually do not show clinical symptoms in the fi rst 24 to 48 hours aft er ingestion. Newer anticoagulants have a longer biological half-life and therefore prolonged toxic eff ects, which requires prolonged treatment. Th e plasma half-life of warfarin is 15 hours, it is 5 days for diphacinone, and 6 days for bromadiolone. Brodifacoum can be detected in blood serum for up to 24 days. Aft er a drop in a serum concentration, all anticoagulants can be identifi ed in the liver (Khan and Schell, 2014). When a clinical manifestation occurs, the most common signs of poisoning are lethargy, dyspnea, cough and blood in the sputum (Merola, 2002). Clinical signs depend on the site of bleeding, which may be from the oral cavity, nose, vulva, foreskin or rectum. Internal bleeding in the lungs, mediastinum, thymus or trachea can manifest itself in the form of acute dyspnoea, and bleeding in the muscles or subcutaneous tissue in the form of larger hematomas. Bleeding into the joint cavities causes lameness, and in cases of bleeding in the brain or spinal cord, neurological symptoms can develop. Extensive bleeding in the abdomen leads to pallor of the visible mucous membranes, weakness and lethargy of the animal. Bleeding has also been reported in various structures of the eye -subconjunctivally, in the eye cavity, retina, and the presence of blood in the anterior chamber of the eye, between the iris and the cornea has been recorded (Petterino et al., 2004;Cullen et al., 2013, Griggs et al., 2015. Haematological examination revealed a decrease in hematocrit and blood plasma proteins, as well as a violation of coagulation parameters, namely prothrombin time (PT), activated partial thromboplastin time (aPTT), activated coagulation time (ACT) and protein induced by vitamin K defi ciency (PIV-KA) (Murphy, 2007).
In the cases of suspected anticoagulant rodenticide poisoning, treatment is based on general, supportive and specifi c therapy. General therapy includes the use of emetics or gastric lavage, the use of adsorbents and laxatives. In cases of heavy bleeding or a signifi cant drop in hematocrit, supportive therapy is applied, which is based on the use of fresh plasma or whole blood transfusion every 4 to 8 hours (Chalermchaikit et al., 1993). Specifi c therapy is the use of vitamin K 1 . Th e recommended doses are 1.5 -2.5 mg/kg/twice daily, orally, for 3 -4 weeks. Prolonging the therapy for an additional week will not result in side and harmful eff ects, and premature cessation of treatment can be a vital threat to poisoned dogs and cats. Th e most reliable way to determine when therapy should be performed is to check the prothrombin time, 72 hours aft er the last dosing. If the prothrombin time in that period has a physiological value, vitamin K 1 should be excluded from the therapy, and if the prothrombin time is still extended, the treatment with vitamin K 1 should be given for another week. Vitamin K 1 should be applied with small amounts of foods rich in fats (milk, meat, cheese), because fats improve its absorption. Applying half of the total daily dose every 12 hours ensures a constant level of vitamin K 1 . When coagulation factors are not within physiological value levels and the animal shows clinical signs of poisoning, parenteral administration should be avoided due to the risk of bleeding and/or hematoma formation at the injection site, unless vitamin K 1 cannot be administered orally to the animal. Anaphylactic reactions are possible with parental administration of vitamin K 1 (Khan and Schell, 2014).
Anticoagulant rodenticides, especially coumarin, lead to generalized bleeding in various organs (liver, kidneys, intestines, heart and lungs). Th e autopsy shows bleeding in the meninges, thymus, larynx, kidneys, liver, pericardium, gastrointestinal tract, nasal cavities, joints, muscles and mediastinum, in the chest and abdomen. Petechiae and ecchymoses are oft en present on the skin, mesentery and mucous membranes of the gastrointestinal tract. Th e most common postmortem fi ndings are hemoperitoneum, hemothorax, and bleeding in the lung parenchyma (DuVall et al., 1989). Histopathologically, degeneration of the heart muscle, infl ammation of the bladder and hepatic dystrophy can be found in dogs (Srebočan and Glomerčić, 1996).

ORGANOPHOSPHATE INSECTICIDE POISONING
Organophosphates are phosphoric acid esters by chemical composition. Th ey include some of the most important compounds for the development of life processes such as nucleic acids (DNA and RNA) and essential cofactors, and some compounds from this group are used in human medicine in the treatment of glaucoma (echothiophate, isofl urophate), Alzheimer's disease, myasthenia gravis and dysfunction urinary tract. In veterinary medicine, they are used as anti ectoparasitics (diazinon) and anthelmintics (trichlorfon). Th ey are oft en used as pesticides for plant protection in agriculture and forestry (malathion, parathion, diazinon, fenthion, dichlorphos, chlorpyrifos). Th roughout history, they have also been used as nerve agents (sarin, soman, tabun, VX) (Gupta and Milatović, 2012).
Th ey can be taken orally, through the skin and by inhalation. Aft er absorption, they are distributed in the body, and the highest concentration due to lipophilicity is in adipose tissue and the brain . Th e order of the most frequently used organosphosphate pesticides from extremely toxic to less toxic is the following: disulfoton, terbufos, forate, parathion, chlorpyrifos, fenthion, diazinon, malathion, tetrachlorvinphos. Chlorpyrifos is particularly toxic to cats, with an oral LD 50 of 10 to 40 mg/kg (Fikes, 1992). Organophosphates act by inhibiting acetylcholine esterase (AChE), an enzyme that breaks down the neurotransmitter acetylcholine (ACh) within the synapses of the autonomic nervous system, neuromuscular synapses, and cholinergic synapses of the CNS. Inhibition of AChE results in accumulation of ACh and overstimulation of postsynaptic neurons or muscle cells (Ivanović et al, 2016). Organophosphate compounds have the property of "aging complex" with AChE molecules, which results in irreversible inhibition of this enzyme, which is why the eff ects of organophosphate are much longer-lasting and more pronounced compared to the toxic eff ects of carbamates (Merck, 2007).
Clinical signs of organophosphate poisoning are the result of excessive stimulation of nicotine and muscarinic receptors. Signs of excessive stimulation of nicotinic receptors are tremor of the muscles, tetanic spasms, stiffness accompanied by general weakness of the animal, paresis and paralysis. Peripheral muscarinic signs are salivation, lacrimation, frequent urination and defecation, miosis, increased bronchial secretion, dyspnoea, bradycardia, and abdominal pain. Central cholinergic signs are anxiety, restlessness, generalized convulsions, and in the later course of CNS depression and in the terminal phase coma. In some cases, not all symptoms are present, and their intensity varies depending on the dose administered, the mode of exposure, the type of animal, and the type of organophosphate compound (Merck, 2007). In dogs and cats, CNS stimulation usually progresses to convulsions. In dogs, disorders of the gastrointestinal tract oft en occur with diarrhea, vomiting and abdominal pain, and in cats, muscarinic eff ects dominate. Th e onset of clinical symptoms aft er exposure to organophosphates usually occurs within a few minutes to several hours. In some cases, delayed onset of symptoms may follow aft er a few days. Death is a result of respiratory disorders (bronchoconstriction, bronchosecretion, laryngospasm) or paralysis of respiratory muscles (diaphragm, intercostal muscles).
An unavoidable procedure in the diagnosis of organophosphate poisoning is the determination of AChE activity in erythrocytes, which is structurally similar to AChE in nerve tissue and as a surrogate marker refl ects its activity in synapses. However, inhibition of AChE in erythrocytes is not always closely correlated with the intensity of the clinical picture. Signs of poisoning are manifested when erythrocyte AChE activity is inhibited >70%. In order to reliably diagnose poisoning, the activity of AChE erythrocytes is determined immediately before and a few minutes aft er the application of oximes used in the therapy of poisoning with these compounds. If aft er the application of oxime there is a noticeable increase in AChE activity, poisoning with these compounds is confi rmed. Th is method also confi rms those poisonings in which the initial values of AChE were within physiological limits (Izraeli et al., 1986).
Proving the presence of organophosphates in biological materials is uncertain, because these compounds are degradable and do not remain in their original form in tissues for long. In order to identify and quantify the organophosphate compound, a sample of gastric contents is delivered to the laboratory and analyzed by gas-mass chromatography (GC-MS) or with more advanced instrumental techniques (e.g. LC/MS/MS). Blood/serum and urine residues can also be analyzed for organophosphate residues or their metabolites. More than 70% of organophosphates produce one or more dialkyl phosphates (dimethyl phosphate, diethyl phosphate, dimethyl thiophosphate, diethyl thiophosphate, dimethyl dithiophosphate and diethyl dithiophosphate).
Th ree groups of drugs are used in the treatment of organophosphate poisoning: (1) emetics and adsorbents in order to reduce further absorption; (2) muscarinic receptor antagonists; (3) AChE reactivators. Atropine sulfate blocks the central and peripheral muscarinic eff ects of organophosphate. In dogs and cats, it is administered in a dose of 0.2 to 2 mg/kg (lower limit of the dose range for cats), every 3 to 6 hours or as oft en as the severity of the clinical picture requires. Atropinization is adequate when mydriasis occurs, salivation stops, and the animal appears more conscious (awake). Animals initially respond well to atropine sulfate, but aft er repeated treatments, the intensity of the response decreases, so excessive use of atropine should be avoided. However, since atropine does not reduce the nicotinic cholinergic eff ects (fasciculations and paralysis of the intercostal muscles and diaphragm), lethal outcome is still possible due to respiratory insuffi ciency. Experimental studies in primates have shown that the inclusion of diazepam in therapy reduces the frequency of muscle convulsions and increases survival rates. Th e effi cacy of the treatment is increased by combining atropine with oximes (2-PAM, pralidoxime chloride) that reactivate inhibited AChE. Th e dose of 2-PAM is 20 -50 mg/kg and is applied as a 5% solution i.m. or slow i.v. (for 5 to 10 minutes), with a repeated half dose as needed. Th e i.v. administration of 2-PAM must be carried out slowly to avoid skeletal muscle paralysis and respiratory arrest. As the possibility of AChE reactivation weakens with time aft er exposure, oxime application must be started as soon as possible, no later than 24 to 48 hours. Th e rate at which the enzyme-organophosphate complex reacts to reactivators varies depending on the type of organophosphate compound (Gupta and Milatović, 2012;Gupta, 2014a).
Th ere are no specifi c pathoanatomical changes at autopsy. Th e hair coat or stomach contents may smell of kerosene, sulfur or garlic. Th ere may be pale mucous membranes, bleeding in the digestive tract, congestion of the stomach, especially the fundus. Th e liver is pale with multifocal fi elds of necrosis, and congestion and hemorrhage are present in the lungs. Splenomegaly, mild meningeal congestion, and multifocal necrosis fi elds in the kidney have been observed (Ola-Davies et al., 2018). Pathohistologically, pulmonary edema and pancreatitis can be established (Merck, 2007;Srebočan and Glomerčić, 1996).

CARBAMATE INSECTICIDE POISONING
Carbamates are esters of carbamic acid and have a less complex chemical structure compared to organophosphates. Regarding the total consumption in the world, they are ahead of organophosphates, because they are considered safer to use. In veterinary medicine, they are available as anti ecto parasitics in various pharmaceutical formulations (powders, concentrated emulsions, sprays, shampoos, fl ea and tick collars). Th ey are used in agriculture for plant protection, and due to improper or malicious use, they are oft en the cause of acute poisoning of domestic animals, birds, fi sh and wild animals . In terms of toxicity, this group of insecticides includes substances with a wide range of LD 50 values. In rats, carbaryl has an oral LD 50 >300 mg/kg, and aldicarb, which is a highly toxic LD 50 , is 0.9 mg/kg. Highly toxic carbamates include methomyl (oral LD 50 for rats 17 mg/kg) and carbofuran (oral LD 50 for rats 8 mg/kg, for dogs 19 mg/kg), and propoxur has several times lower toxicity than the previous two compounds (oral LD 50 for rats 95 mg/kg). Animals usually ingest carbamates by ingestion, but percutaneous and inhalation routes of poisoning are also possible. Aft er absorption, this group of compounds is distributed in most tissues, it passes through the placental barrier and leads to inhibition of fetal AChE. In young animals, they are metabolized more slowly, which is why they are more toxic to them compared to older categories of animals. About 80% of the resorbed compound is excreted in the urine in the fi rst 24 hours aft er ingestion (Gupta, 2014b).
In our country, in order to intentionally poison animals from the carbamate group, the preparation "Furadan 35 ST" (FMC Corporation) whose active substance is carbofuran is most commonly used. Its trade and use has been legally prohibited in our country since December 31 st 2013, but the perpetrators are still used for the purpose of deliberate poisoning of dogs and cats.
In some parts of the world, intentional poisoning of dogs with the carbamate pesticide aldicarb is becoming more common (Frazier et  In the cases when clinical symptoms develop in dogs, muscle tremor, hypersalivation accompanied by vomiting, miosis, bradycardia, convulsions, and diffi culty breathing are observed (Verster et al., 2004). Frequent urination, paresis and paralysis may also occur. Death is a result of respiratory failure due to bronchospasm, paralysis of the diaphragm and intercostal muscles, and depression of the respiratory center (Fikes, 1990;Goswamy et al., 1994;Jokanović, 2009). In the acute course of poisoning, the appearance of acute necrotic-hemorrhagic pancreatitis is possible. Excessive cholinergic stimulation results in spasm of the Odi's sphincter and the consequent enzyme pathway in the pancreatic ducts, which increases intraductal pressure and creates the potential for enzyme transfer to the interstitium (Aslan et al., 2010;Makridges et al., 2005). In peracute cases of poisoning, this pathohistological fi nding is most oft en absent.
Carbamates act by the same mechanism as organophosphates -by inhibiting AChE at neuro-neuronal and neuro-muscular synapses. In the case of poisoning with carbamate compounds, the inhibition of AChE is reversible, because the formed bonds of carbamate with the enzyme are much weaker, and thus shorter, which is why the inhibition of AChE in the blood (erythro-cytes) during laboratory analysis is oft en not evident. Clinical signs of poisoning last shorter compared to organophosphate poisoning. Th ey include hypersalivation, gastrointestinal hypermotility, abdominal cramps, vomiting, diarrhea, sweating, dyspnoea, cyanosis, miosis, muscle fasciculations (in extreme cases, tetany accompanied by weakness and paralysis) and convulsions. Th e most pronounced clinical manifestations of carbamate and organophosphate poisoning are salivation, lacrimation, urination, diarrhea (SLUD). Death is a result of hypoxia due to respiratory insuffi ciency caused by paralysis of the respiratory muscles, bronchoconstriction and tracheobronchial hypersecretion (Gupta, 2014b).
Th e diagnosis of poisoning is based on the anamnesis and a positive response to atropine therapy. However, when the history is unknown, and cholinergic signs and a clear positive response to atropine suggest carbamate or organophosphate poisoning, it is necessary to determine AChE activity in erythrocytes, whole blood (for live animals) or in the cerebral cortex (for dead animals). Enzyme activity that is signifi cantly inhibited (>50%) confi rms the suspicion of poisoning by these compounds. Clinical signs of hypercholinergic activity are observed when AChE inhibition is >70%. Identifi cation and quantifi cation of a particular carbamate and diff erential diagnosis of organophosphate insecticide poisoning is possible by examining the contents of the gastrointestinal tract using GC-MS (Gupta, 2014a).
Th e recommended dose range of atropine for dogs and cats is from 0.2 to 2 mg/kg, parenterally, with one-quarter of the dose administered i.v. and the remainder s.c. (lower dose range is recommended for cats). Dosing is repeated as needed. Th e use of oxime (2-PAM) alone is contraindicated in carbamate poisoning, because it is not eff ective, and it can also increase the toxic eff ect of carbamates. In combination with atropine, 2-PAM may also worsen the clinical picture, depending on the dose administered, and in the best outcome the combination with atropine gives only a slightly better therapeutic eff ect compared to atropine alone. Because of all this, the use of 2-PAM is useful only if the poisoning is caused by a mixture of organophosphates and carbamates or when there are symptoms of excessive cholinergic activity, which is the case with organophosphate poisoning. 2-PAM can be fatal if applied too quickly, so its careful and slow application is necessary, i.e. in 5% saline for 10 minutes, as described in the section on organophosphate poisoning therapy. It is important that the 2-PAM solution is fresh during application, because solutions that have been unused for a long time can lead to the formation of cyanide (Gupta and Milatović, 2012; Gupta, 2014a). As part of symptomatic therapy, fl uid, electrolyte replacement and vitamins B, C and E are used, because the mechanism of toxic action of organophosphates and carbamates partly takes place through oxidative stress. Th e use of morphine or barbiturates in carbamate poisoning is contraindicated.
Th e autopsy report is not specifi c. Congestion of parenchymal organs and pulmonary edema may be observed. Th e contents of the stomach or suspect substance may have the smell of oil, sulfur or garlic. For the purpose of pathohistological analysis, the tissue of the lungs, heart, liver, kidneys, pancreas and lumbar part of the spinal cord is sampled. Th e contents of the stomach, intestines, bladder and feces are sampled for chemical and toxicological analysis. Pathohistological changes are diverse and include lung congestion, hyperemia and degenerative changes of myocardial cells, renal hyperemia and renal tubular degeneration, hyperemia and necrotic fi elds in the liver parenchyma.
Examination of pancreatic tissue samples shows acute pancreatitis with wider fi elds of necrosis involving the parenchyma and interlobular connective tissue.

CREOSAN POISONING
Creosan (4-6 dinitro-ortho-cresol -DNOC) is a derivative of cresol and belongs to the chemical group of dinitrophenol, which includes dinoseb and dinotherb. It is used in agriculture as an insecticide, herbicide and fungicide, and due to its characteristic yellow color, it is known as "yellow powder", which can be seen in the dog shown in Figure 1  It enters the body orally, percutaneously and by inhalation. In terms of physical and chemical properties, it is less hydrosoluble, i.e., it has a more pronounced liposolubility, which is why it is characterized by rapid resorption (Agency for Toxic Substances and Disease Registry, 2018). Th e eff ect is achieved by separating the process of oxidation and phosphorylation in the respiratory chain in mitochondria. Oxidation cannot take place in the respiratory chain and the accompanying phosphorylation of ADP and the creation of the energy-rich adenosine triphosphate compound ATP are absent. As a result, there is a sharp increase in oxygen consumption and the release of a large amount of energy that is converted into heat (hyperthermia). In the organism of poisoned individuals, catabolic processes (glycolysis, glycogenolysis and metabolism of fatty acids) increase sharply. Due to the lack of ATP in vital organs (heart, respiratory muscles), their function may cease. Th e dominant symptom is high fever (malignant hyperthermia), which reaches a value of up to 42 °C. Dyspnoea, convulsions, coma, and lethal outcome with rapid development of corpse stiff ness are also present. Death is most oft en a result of cardiac arrest or paralysis of the respiratory center (Decision Guidance Document, 2005;Ćupić, 2015).
Th ere is no specifi c antidote and nonspecifi c therapy is used. If the poisoning occurred by ingestion, and the animal is conscious and actively manifests signs of anxiety, vomiting should be induced. If the animal has CNS depression, gastric lavage should be performed and activated charcoal should be used. In order to control hyperthermia, the procedure of physical cooling (cold baths, cold compresses) is recommended, without the use of antipyretics. Diazepam (not barbiturates) should be used to sedate the animal. Phenothiazines are contraindicated. Infusions of saline and/or dextrose solution in combination with diuretics contribute to the alleviation of dehydration and faster elimination of creosone from the body, since it is excreted in the urine. Th e success of therapy is signifi cantly contributed by i.v. sodium bicarbonate administration, parenteral vitamin A administration, and oxygen administration (Gupta, 2020).
Pathoanatomical changes are not specifi c. Th e contact of the animal with this compound is indicated by the discoloration of the dog's coat, skin and mucous membranes with an intense yellow color that is present for several weeks. Urine has a characteristic fl uorescent yellow color. Aft er death, corpse stiff ness develops rapidly. Th e dominant macroscopic fi ndings are round-shaped particles in gastric contents, intensely yellow in color. Th e gastric mucosa is hyperemic and wrinkled (Đurđević et al., 2018). Th e presence of this compound in the stomach contents is confi rmed by GC-MS.

MOLLUSCICIDES POISONING (METALDEHYDE)
Metaldehyde is a tetramer of acetaldehyde and belongs to the group of pesticides intended for the control of snail populations in the areas with wet soil. Although most poisonings with this neurotoxic substance have been reported in dogs, poisoning is also possible in other species of domestic and wild animals, and is associated with careless or malicious placement of baits. In commercial molluscicides, metaldehyde may be present in combination with other pesticides such as carbamates to make them more eff ective. Also, molluscicides can contain bran or molasses in order to be more attractive to snails, but in that way, they become more attractive for dogs and other types of animals. Metaldehyde is not considered a stable substance, but it may remain eff ective for 10 days. Th e preparations are usually in the form of blue-green granules or pellets with a mild odor of aldehyde and contain 1.5 to 5% of metaldehyde. During an autopsy of a dead dog, blue-green granules were found at the Department of Forensic Veterinary Medicine and Legal Regulations, Faculty of Veterinary Medicine, University of Belgrade, which indicates poisoning with molluscicidal preparations of metaldehyde ( Figure 2). In terms of toxicity, the oral LD 50 of metaldehyde is 100 mg/kg for dogs and about 200 mg/kg for cats (Dolder, 2003).
Metaldehyde aft er ingestion, under the action of gastric acid, undergoes partial hydrolysis to form acetaldehyde, and then both compounds are rapidly resorbed from the gastrointestinal tract. Th e properties of the stomach contents and the speed of its emptying signifi cantly aff ect the speed of absorption, and thus the beginning of the clinical manifestation of poisoning. Aft er absorption, metaldehyde is rapidly metabolized. Enterohepatic circulation can prolong the retention of metaldehyde in the body, but eventually both metaldehyde and acetaldehyde are excreted in the urine (Blakley, 2013). Clinical manifestations are primarily attributed to metaldehyde, because studies in mice have shown that metaldehyde crosses the blood-brain barrier and that its presence is detected in the brain (Puschner, 2001). Signs of toxicity may be due to a decrease in the concentration of γ-amino-butyric acid (GABA) in the brain as a major inhibitory amino acid, resulting in CNS excitation. As the concentration of GABA in the brain decreases, the mortality rate increases (Osweiler, 1996). Another factor that contributes to morbidity and mortality is hyperthermia. It most oft en appears secondary to neurological manifestations. Muscle tremor also occurs. When the body temperature exceeds 41.6 °C in all organ systems, cell necrosis begins in a few minutes. Metaldehyde also aff ects electrolyte balance and acid-base status by causing metabolic acidosis, which is oft en associated with central nervous system depression and hyperpnea (Puschner, 2001). In dogs, the signs of this toxicosis can occur from a few minutes to three hours aft er ingestion. Neurological symptoms are predominant, and muscle tremors, anxiety, hyperesthesia, ataxia, tachycardia, and hyperthermia may occur. Metabolic acidosis is present and as it is more pronounced, depression and hyperpnea can be further intensifi ed. Typical signs of advanced toxicosis are opisthotonus and continuous tonic convulsions that do not respond to external stimuli (unlike in cases of strychnine poisoning). Symptoms oft en include vomiting, diarrhea, hypersalivation, colic, cyanosis, mydriasis, and feline nystagmus. Deaths due to respiratory failure can occur within hours of ingestion (Blakley, 2013;Beasley, 1999;Booze and Oehme, 1985). Th e diagnosis is based on anamnestic data and clinical symptoms. Gastric contents, gastric lavage fl uid, and expired air may have an acetaldehyde odor that is similar to formaldehyde or acetylene but less intense. To confi rm the diagnosis of poisoning, it is important to analyze the contents of the stomach for metaldehyde and acetaldehyde.
Although there is no specifi c antidote, timely and intensive symptomatic therapy during the fi rst 24 hours allows most poisoned animals to recover within the next 2 to 3 days. Th e goals of symptomatic therapy are prevention of metaldehyde absorption, control of clinical symptoms, monitoring and correction of metabolic acidosis and dehydration. If no more than 30 minutes have elapsed since ingestion and if there are no contraindications in dogs and cats, vomiting with hydrogen peroxide (1 to 5 mL/kg, maximum 45 mL) or apomorphine hydrochloride should be induced. Otherwise, gastric lavage with animal anesthesia and endotracheal intubation should be undertaken to prevent aspiration (Plumb, 1999;Dorman, 1995). In dogs and cats, the use of activated charcoal in a dose of 1 to 4 g/kg TM is recommended, and repeated application of half of the original dose every 6 to 8 hours contributes to a better therapeutic eff ect. Enema with warm water is also used to eliminate metaldehyde from the gastrointestinal tract. To control convulsions, i.v. diazepam at a dose of 1 to 5 mg/kg TM. If necessary, other anticonvulsants can be used, such as inhalation anesthesia (for severe and persistent convulsions) or barbiturates, which must be used with caution because during biotransformation in the liver as a substrate may compete with enzymes involved in acetaldehyde metabolism (Plumb, 1999 Carson andOsweiler, 1997). Hyperthermia resulting from muscle tremors and seizures is usually corrected when tremor and seizures are kept under control. Th erefore, aggressive physical cooling measures such as ice baths should not be used, as they can cause hypothermia. Of essential importance for the correction of metabolic acidosis and electrolyte imbalance is i.v. application of sodium lactate or sodium bicarbonate, and i.v. administration of dextrose or calcium borogluconate may reduce liver damage. Prolonged excessive muscle activity (tremor, convulsive seizures) can cause myoglobinuria and secondary renal dysfunction. In such cases, the use of diuretics is recommended to prevent kidney damage (Dolder, 2003;Blakley, 2013).
In poisoned dogs, the autopsy fi nding is nonspecifi c. Hyperemia of the liver, lungs, and kidneys, infl ammation of the gastric mucosa, and subendocardial and subepicardial hemorrhages may be found (Beasley, 1999).

CONCLUSION
In order to reduce the frequency of malicious poisoning of dogs and cats on the territory of our country, it would be important to conduct strict control of the sale of agricultural preparations whose active substances have high toxicity for both humans and animals. In order to monitor the frequency of this phenomenon in our society, which is sanctioned by Article 269 of the "Crimi- Th e processing of cases of intentional poisoning of animals should be based on reliable fi ndings of forensic veterinarians and toxicological confi rmation of poisoning. Judicial practice indicates that such cases are diffi cult to process due to the lack of evidence linking the perpetrator to the abuse of toxic substances and in this sense better cooperation and coordination of state administration bodies (police, public prosecutor's offi ce, and veterinary inspectors), veterinarians and accredited laboratories performing chemicaltoxicological analyses is required.