Fenvalerate/N,N-diethyl-m-toluamide (Deet) toxicosis in two cats

Toxicosis attributable to fenvalerate and N,N-diethyl-m-toluamide (Deet) exposure was suspected in 2 cats. Clinical signs of toxicosis developed within 4 to 6 hours of dermal application of the pesticide. Clinical signs of toxicosis seen in both cats included hypersalivation, ataxia, and depression. In addition, seizures were seen in 1 cat. Both cats died. Analysis of skin, kidney/urine, liver, and brain tissues confirmed the presence of fenvalerate and Deet. The pyrethroid fenvalerate and the insect repellent Deet are used for the control of fleas and ticks on cats. Suspected fenvalerate/Deet toxicosis in cats is associated with tremors, hypersalivation, ataxia, vomiting, depression, and seizures.

Acute aflatoxicosis in feeder pigs, resulting from improper storage of corn

Aflatoxicosis was diagnosed in 600 feeder pigs, of which 400 died, 150 were destroyed, and 50 were marketed. The pigs were exposed to 2,500 to 3,500 micrograms of aflatoxins/kg of feed. Drought-stressed damaged corn infected with Aspergillus flavus was stored under ambient conditions in a glass-lined silo, and this storage environment provided conditions that favored rapid fungal growth and mycotoxin production.

Enterohepatic circulation of T-2 toxin metabolites in the rat

The enterohepatic circulation of T-2 toxin and its conjugated metabolites was examined in bile duct-cannulated male rats. Rats administered tritiated T-2 toxin intraduodenally (id) eliminated 44.65% and 57.25% of the administered dose in the bile within 4 and 8 hr post-dosing, respectively. TLC profiles of the T-2 metabolites were similar after intravascular and id administration. The major metabolites detected were 3'-OH-hydroxytryptamine-2 (HT-2), glucuronic acid conjugates, T-2 tetraol (TOL), 4-deacetylneosolaniol (4-DN), and HT-2. Tritium-labeled glucuronides obtained from the bile of rats administered [3H]T-2 toxin intravascularly were extracted and purified using C-18 and silica column chromatography. Enzymatic hydrolysis followed by TLC and GC/MS indicated that the aglycone portion of the glucuronides were composed of 3'-OH HT-2, HT-2, 4-DN, and TOL. After id administration of the glucuronides the rats eliminated 6.01% (4 hr) and 11.86% (8 hr) of the dose in the bile. No free metabolites of T-2 toxin were detected in the bile of any animals administered the purified glucuronides. Oral treatment of the rats with the beta-glucuronidase inhibitor, saccharolactone, did not produce a significant decline in the amount of radioactivity recovered in the bile following administration of the tritium-labeled glucuronides. These studies substantiate the enterohepatic circulation of T-2 toxin metabolites.

Evaluation of a superactivated charcoal paste and detergent and water in prevention of T-2 toxin-induced local cutaneous effects in topically exposed swine

T-2 toxin (6 mg) dissolved in 90% DMSO was topically applied to nine 9-cm2 sites on the dorsum of each of nine young, crossbred, specific pathogen-free, female pigs, 20.6 +/- 1.9 kg in weight. A superactive charcoal paste (SAC) and/or a soap-and-water wash (SOAP) was applied to eight of the T-2-exposed sites on each animal. These treatments were applied at various times postexposure ranging from 5 to 65 min. The site that received T-2 alone served as a positive control. DMSO was applied to a tenth site on each pig as a negative control. Animals were killed 1, 3, or 6 days after treatment. Skin lesions were examined and graded grossly and histologically. No adverse systemic clinical signs were observed in any of the animals. Marked reddening and slight swelling of the T-2 toxin-treated positive control sites were present throughout the study. Ulceration of this site was first noted on Day 3. All therapeutic regimens effectively reduced lesion severity resulting from T-2 toxin application. Significant differences in relative effectiveness were also seen between treatments. In each significant pair, the ordering of mean lesion severity was SAC/SOAP less than SAC or SOAP and SOAP less than SAC. As a single treatment, SOAP appears to be more effective than SAC in reducing lesion severity. These results failed to provide unequivocal evidence of an additive therapeutic effect when SAC and SOAP were used sequentially on the same site.

Cottonseed meal (gossypol) toxicosis in a swine herd

Cottonseed meal (CSM) that contained a high concentration of free gossypol was inadvertently used as a protein supplement, without appropriate iron supplementation, for a swine herd in Illinois. Fifty percent of 300 grower and finishing swine died, and an additional 20% became ill during a 4- to 6-week period. Clinical signs included respiratory distress and abdominal distention. At necropsy, the hearts were diffusely pale, flaccid, and rounded because of dilatation of all 4 chambers, the livers were large and congested, and hydropericardium, hydrothorax, and ascites were evident. Histologic changes consisted of diffuse myocardial fiber atropy with perinuclear vacuolation, and multifocal myocardial and skeletal muscle necrosis. Changes in the liver included marked centrilobular congestion, loss of hepatocytes, and fatty degeneration. Differential diagnoses included monensin, selenium, and gossypol toxicoses, and vitamin E/selenium deficiency. Analyzed feed samples did not contain monensin. Feed selenium concentrations ranged from 428 to 1,513 micrograms/kg, and iron concentrations from 160 to 180 mg/kg. Cottonseed meal (3 to 10%) was detected by feed microscopy. A sample of the 40% protein supplement contained 19% CSM and 1,300 mg of free gossypol/kg, whereas feed samples contained 200 to 400 mg of free gossypol/kg. The history, clinical signs, pathologic findings, and feed analyses were compatible with a diagnosis of gossypol toxicosis. Cottonseed meal, a high-protein supplement used widely in southern United States, may contain gossypol (a polyphenolic binaphthalene pigment), which in its free form is especially toxic to simple-stomached animals. If CSM is used, supplementation with ferrous sulfate is recommended at a 1:1 weight ratio with free gossypol, up to 400 mg of FeSO4/kg.

Hematologic changes induced by intravenous administration of diacetoxyscirpenol in pigs, dogs, and calves

Diacetoxyscirpenol (DAS) was given IV to pigs (0, 0.5, and 1.0 mg/kg of body weight), cattle (0 and 0.5 mg/kg), and dogs (0 and 0.5 mg/kg). Blood was collected and hemograms were done at 0.5-hour intervals for 8 hours. The animals were euthanatized at 8 hours after treatment, and bone marrow samples were taken and examined by light microscopy. Moderate to severe necrosis of bone marrow hematopoietic elements was found in animals given DAS. The sequential increase in the type and number of abnormal cells in the blood suggested a successive destruction of the hematopoietic elements. A marked left shift in the neutrophil population was found in animals given DAS. Metarubricytes and large platelets were found in the blood of animals given DAS. Lymphocytes were replaced with immature cells. Pathologic changes were most severe in the pigs given a dosage of 1.0 mg of DAS/kg. The order of species sensitivity to DAS was pigs greater than dogs much greater than cattle.

Dinoseb toxicosis in two dogs

Two male English Setters were noticed to be breathing rapidly, hyperexcitable, and atactic after roaming a rural area for 2 hours. Both dogs' cost were stained with yellow liquid. One dog died while en route to the veterinarian. Treatment was begun for the surviving dog for what was initially diagnosed to be organophosphorus or carbamate insecticide toxicosis. Before the diagnosis could be confirmed, the second dog died. The yellow liquid on the dogs' skin was identified as dinoseb in high concentrations. Dinoseb is an acutely toxic, substituted dinitrophenolic herbicide believed to act as an uncoupler of electron transport from oxidative phosphorylation.

Tissue residues of diacetoxyscirpenol in pigs and calves after intravenous dosing

Pigs (n = 19) were given 0, 0.1, 0.5, or 1 mg of diacetoxyscirpenol (DAS)/kg of body weight, and heifers (n = 7) were given 0 or 0.5 mg of DAS/kg. Animals were anesthetized and exsanguinated 8 hours after administration of DAS, and liver, kidney, skeletal muscle, mesenteric lymph node, and spleen were analyzed for DAS. Diacetoxyscirpenol was not detected in tissues from animals not given DAS. All tissues from pigs and calves given DAS contained at least traces (less than or equal to 10 ng/g of tissue) of DAS.

The role of intestinal microflora in the metabolism of trichothecene mycotoxins

The role of faecal and intestinal microflora on the metabolism of trichothecene mycotoxins was examined in this study. Suspensions of microflora obtained from the faeces of horses, cattle, dogs, rats, swine and chickens were incubated anaerobically with the trichothecene mycotoxin, diacetoxyscirpenol (DAS). Micro-organisms from rats, cattle and swine completely biotransformed DAS, primarily to the deacylated deepoxidation products, deepoxy monoacetoxyscirpenol (DE MAS) and deepoxy scirpentriol (DE SCP). By contrast, faecal microflora from chickens, horses and dogs failed to reduce the epoxide group in DAS and yielded only the deacylation products, monoacetoxyscirpenol (MAS) and scirpentriol (SCP), in addition to unmetabolized parent compound. Intestinal microflora obtained from rats completely biotransformed DAS to DE MAS, DE SCP and SCP; and T-2 toxin to the deepoxy products, deepoxy HT-2 (DE HT-2) and deepoxy T-2 triol (DE TRIOL). Rat intestinal microflora also biotransformed the polar trichothecenes, T-2 tetraol and scirpentriol, to their corresponding deepoxy analogues. Deepoxy T-2 toxin (DE T-2) was synthesized from T-2 toxin and demonstrated to be 400 times less toxic than T-2 toxin in the rat skin irritation bioassay and non-toxic to mice given 60 mg/kg ip, demonstrating that epoxide reduction is a significant single step detoxification reaction for trichothecene mycotoxins.

Experimental T-2 toxicosis in swine following inhalation exposure: clinical signs and effects on hematology, serum biochemistry, and immune response

Nine- to ten-week-old, male castrated, specific pathogen-free derived pigs, weighing 34 to 42 kg, were exposed to a T-2 toxin aerosol (390 micrograms/liter, 1.5 microM mass median aerodynamic diameter) for a time period which allowed an amount equivalent to 8 mg/kg to be nebulized (six pigs). Control animals (five pigs) were exposed to an equivalent amount of the nebulized vehicle. Pigs were immunized subcutaneously with sheep red blood cells on Days 0 and 21. Whole blood and serum samples were taken periodically for clinical pathologic and immunologic studies. Pigs were closely observed, and daily rectal temperatures and weekly weights were measured. The T-2-treated pigs vomited and exhibited cyanosis, anorexia, lethargy, lateral recumbency, slightly elevated rectal temperature, and depressed body weight gain. The lymphocyte count decreased while the neutrophil count increased. The concentrations of total serum protein and hemoglobin declined. There was a marked increase in serum alkaline phosphatase activity on Day 1, followed by a marked and persistent decrease. Mitogen-induced (Con A, PHA, and PWM) blastogenic responses of peripheral blood mononuclear cells and hemagglutination titers to SRBC were also transiently decreased. Thus, inhalation exposure of pigs to a sublethal dose of T-2 toxin caused clinical signs of toxicity and adverse effects on clinical pathologic parameters and immune responses; however, most of these effects were short-lived. The changes described in our study resemble those reported in pigs given T-2 toxin by intravascular injection.

Gas Chromatographic Screening Method for T-2 Toxin, Diacetoxyscirpenol, Deoxynivalenol, and Related Trichothecenes in Feeds

A gas chromatographic method for screening trichothecene mycotoxins in feeds is described. Feed is extracted with acetonitrile-water, and the toxins are purified with charcoal-alumina-Celite, Florisil, and silica mini-columns. Deoxynivalenol (DON), nivalenol (NIV), diacetoxyscirpenol (DAS), T-2 toxin, and their fungal metabolites are hydrolyzed to their corresponding parent alcohols (DON, NIV, scirpentriol, or T-2 tetraol) by alkaline hydrolysis. After derivatization to their pentafluoropropionyl analogs, they are quantitated by capillary gas chromatography with electron capture detection. Identity can be confirmed and sensitivity can be increased by using negative chemical ionization mass spectrometry with no additional sample workup. Recoveries of DAS, DON, and T-2 toxin averaged, respectively, 80, 65, and 85% in corn; 84, 65, and 88% in soybeans; and 70, 57, and 96% in mixed feeds at concentrations ranging from 0.1 to 2.0 ppm. Recoveries of 15-monoacetoxyscirpenol (MAS), HT- 2, NIV, and T-2 tetraol were 97, 97, 86, and 56%, respectively, in corn at a concentration of 0.25 ppm. A detection limit of 0.02 ppm in corn, soybeans, and mixed feeds, and 0.05 ppm in silages is estimated.

Gas chromatographic screening method for T-2 toxin, diacetoxyscirpenol, deoxynivalenol, and related trichothecenes in feeds

A gas chromatographic method for screening trichothecene mycotoxins in feeds is described. Feed is extracted with acetonitrile-water, and the toxins are purified with charcoal-alumina-Celite, Florisil, and silica mini-columns. Deoxynivalenol (DON), nivalenol (NIV), diacetoxyscirpenol (DAS), T-2 toxin, and their fungal metabolites are hydrolyzed to their corresponding parent alcohols (DON, NIV, scirpentriol, or T-2 tetraol) by alkaline hydrolysis. After derivatization to their pentafluoropropionyl analogs, they are quantitated by capillary gas chromatography with electron capture detection. Identity can be confirmed and sensitivity can be increased by using negative chemical ionization mass spectrometry with no additional sample workup. Recoveries of DAS, DON, and T-2 toxin averaged, respectively, 80, 65, and 85% in corn; 84, 65, and 88% in soybeans; and 70, 57, and 96% in mixed feeds at concentrations ranging from 0.1 to 2.0 ppm. Recoveries of 15-monoacetoxyscirpenol (MAS), HT-2, NIV, and T-2 tetraol were 97, 97, 86, and 56%, respectively, in corn at a concentration of 0.25 ppm: A detection limit of 0.02 ppm in corn, soybeans, and mixed feeds, and 0.05 ppm in silages is estimated.

Chemical Contaminants: Their Metabolism and their Residues

Chemical contaminants which food animals may be exposed to include agricultural chemicals (e.g. insecticides, herbicides, fungicides, fumigants), industrial chemicals, metals and natural toxins (e.g. mycotoxins, phytotoxins, bacterial toxins). In the past, most intoxications of food animals resulted from natural toxicants. However, rapid development and usage of synthetic chemicals, while greatly benefitting society, have also provided new sources of potential chemical contamination. Various sources of contamination exist, but generally at least 80% of all residues in food animals are estimated to occur through the feed. Residues from water contamination or other sources occur less frequently. This paper reviews the sources, metabolism and residue problems created by various contaminants and outlines factors and therapeutic approaches utilized in alleviating some of the common chemical residues in food animals.

Comparative in vitro metabolism of T-2 toxin by hepatic microsomes prepared from phenobarbital-induced or control rats, mice, rabbits and chickens

Hepatic microsomes were prepared from phenobarbital (PB)-treated and control rats, mice, rabbits and chickens and were incubated with T-2 toxin (100 micrograms/mg microsomal protein). Additional microsomes from PB-induced animals were incubated with T-2 toxin and the esterase inhibitor paraoxon (PA) at 2.5 nmol/mg microsomal protein. The major metabolite in microsomal preparations from both control and PB-induced rats, rabbits and mice was HT-2. In microsomes isolated from PB-treated chickens, 3'-hydroxy T-2 was the major metabolite, but 30 and 79% of the added T-2 toxin remained unmetabolized at 60 min in incubations from PB-induced and control birds, respectively. The percentage of hydroxylated metabolites formed in the microsomal preparations of the four species studied was significantly increased following PB treatment compared with the non-treated controls. The addition of PA to the incubation system effectively inhibited the hydrolysis of the ester groups in T-2 toxin, resulting in 1.4- and 1.25-fold increases in the percentage of 3'-hydroxy T-2 in the mouse and rat microsomal samples, respectively. In the rabbit microsomal preparations, 3'-hydroxy T-2, which was not detected in the absence of PA, represented 11% of the added substrate in the PB/PA incubation samples. Addition of PA did not cause a significant change in the amount of 3'-hydroxy T-2 formed in chicken microsomal samples, since competition between hydrolysis and hydroxylation pathways for the T-2 toxin substrate was not an important factor in this species. Two new metabolites, designated RLM-2 and RLM-3 were detected in chicken, rat and mouse microsomal preparations. On the basis of gas chromatography/mass spectrometry data, the compounds were tentatively identified as isomers of 3'-hydroxy T-2.

Distribution of blood flow to the gastrointestinal tract of swine during T-2 toxin-induced shock

Swine (6 per group) were used to study gastrointestinal blood flow during T-2 toxin-induced shock. Low- and high-dose groups were given T-2 toxin at 0.6 or 2.4 mg/kg via the pulmonary artery; controls were given the ethanol vehicle. Radiolabeled microspheres were administered into the left atrium to assess organ blood flow predosing and at 90-min intervals for 6 hr. Gastric blood flow decreased in both T-2 groups, and at 6 hr the high-dose group's value was 17% of the predose value. In the low-dose group, the lowest gastric blood flow (30% of predose) was observed 3 hr postdosing. Small-intestinal blood flow of the control group declined to 64% of the predose value. In the high-dose group, small-intestinal blood flow at 3 hr was 174% of predose, followed by a reduction to 62% at 6 hr, coinciding with a severe decline in cardiac output. Small-intestinal blood flow of the low-dose group was 159% of predose at 1.5 hr, then declined to the control value. The high-dose group's large-intestinal blood flow increased to 177% of predose at 3 hr, then declined to 66% at 6 hr. The low-dose group's large-intestinal blood flow increased to 200% of the predose value. The severe decline in gastric blood flow is probably related to the development in swine (given high doses of T-2 toxin) of a grossly bright red gastric fundus, with histologic evidence of vascular congestion and mucosal deterioration.(ABSTRACT TRUNCATED AT 250 WORDS)

The toxicity of T-2 toxin in swine following topical application. II. Effects on hematology, serum biochemistry, and immune response

T-2 toxin at 0 (6 pigs) or 15 mg/kg (8 pigs) in 0.75 ml of dimethyl sulfoxide was topically applied to 9- to 10-week-old, male castrated, specific-pathogen-free derived pigs which were immunized subcutaneously with sheep red blood cells (SRBC) on Days 0 and 21. Whole blood and serum samples were taken periodically for clinical pathologic and immunologic evaluations. The pigs were observed daily and weighed weekly; their rectal temperatures were measured periodically. The T-2-treated pigs displayed anorexia, lethargy, posterior weakness and paresis, persistent high fever, and reduced body weight gain. Prominent neutrophilia, decreased serum glucose, albumin, and alkaline phosphatase activity, and increased serum globulin were seen in the T-2-treated group. The responses of enriched peripheral blood mononuclear cells to mitogens concanavalin A, phytohemagglutinin, and pokeweed mitogen of the T-2-treated group were significantly lower than those of the control group both at early (3 to 5 days) and late (20 to 28 days) postdosing intervals. No significant effects were noted in the hemagglutination titer to SRBC. Thus, in addition to the severe local dermal injury reported previously, topical exposure of swine to a sublethal dose of T-2 toxin, 15 mg/kg, can cause significant systemic effects on parameters such as body weight gain, rectal temperature, hematology, serum biochemistry, and cellular immune response.

The toxicity of T-2 toxin in swine following topical application. I. Clinical signs, pathology, and residue concentrations

T-2 toxin at 0 or 15 mg/kg in 0.75 ml dimethyl sulfoxide was topically applied to 11- to 12-week-old specific-pathogen-free derived crossbred female pigs. Animals were killed on Days 1, 3, 7, or 14 after treatment. Clinical signs and morphologic changes in the skin and internal organs, as well as the residual concentrations of T-2 toxin and its metabolites in plasma, bile, urine, skin, and subcutaneous tissue, were examined. The T-2-treated pigs had signs of lethargy, anorexia, posterior weakness or paresis, and persistent fever. The skin at the site of application was red and swollen initially and progressively became dark red and then purple. By Day 7, at the margin of the exposed area, clefts had formed and were covered by serosanguinous exudate. By Day 14, the affected skin was focally separated from the underlying tissue and covered by a thick scab. The initial skin lesions were characterized as a spongiotic dermatitis and were located mainly in the dermal papillae and stratum germinativum of the epidermis. These lesions progressed to a locally extensive necrotizing dermatitis between Days 3 and 7 that was still evident at Day 14. Healing began on Day 7 and was more prominent on Day 14. Morphologic changes in the internal organs were minimal. They consisted of necrosis of single cells in the follicles of lymphoid tissues and in the exocrine pancreas.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of a general therapeutic protocol for the treatment of acute T-2 toxicosis in swine

T-2 toxin, a trichothecene mycotoxin suspected of being used as a chemical warfare agent, was administered iv to swine at a dose of 3.6 mg/kg body weight (iv LD50 approximately 1.2 mg/kg). Four different therapeutic protocols were assessed for their efficacy in the treatment of the resultant acute T-2 toxicosis syndrome. One therapeutic protocol included the combined use of metoclopramide, activated charcoal, magnesium sulfate, dexamethasone sodium phosphate, sodium bicarbonate and normal saline. The other 3 protocols utilized the same agents less 1 of the following: the combination of activated charcoal and magnesium sulfate, sodium bicarbonate, or normal saline. All 4 treatment groups showed improved survival times compared to a positive T-2 control group. Within the limits of the study, it would appear that the removal of activated charcoal and magnesium sulfate was most detrimental to the T-2 toxin-dosed swine.

Pharmacokinetics of diacetoxyscirpenol in cattle and swine: effects of halothane

In swine and cattle given 0, 0.1, or 0.5 and 0, 0.5 mg of diacetoxyscirpenol (DAS)/kg of body weight, IV, respectively; DAS had a large volume of distribution and total body clearance. The shortness of the interval between halothane and DAS exposures significantly (P greater than 0.05) decreased DAS biotransformation. Urinary excretion of DAS as a parent compound was not an important route of elimination. In swine and cattle, DAS was transformed by sequential deacetylation to monoacetoxyscirpenol and scirpentriol.

Experimental T-2 toxicosis in swine. III. Morphologic changes following intravascular administration of T-2 toxin

The gross and microscopic changes in swine following a single intravascular (iv) dose of T-2 toxin are described and evaluated quantitatively. T-2 toxin, in 70% ethanol, was given iv at 0 (5 pigs), 0.6 (5 pigs), 1.2 (1 pig), 4.8 (5 pigs), or 5.4 (2 pigs) mg/kg to 40 to 60 kg female crossbred pigs. The 4.8 and 5.4 mg/kg group pigs died between 5 and 10.5 hr after treatment, while the 0, 0.6, and 1.2 mg/kg pigs were killed at 24, 24, and 12 hrs after treatment, respectively. Morphologic examination was performed at the gross and light microscopic levels. In addition, a quantitative evaluation of microscopic changes present in lymphoid tissues and intestinal tract was performed using a semiquantitative scoring system. Gross lesions in the T-2-treated pigs consisted of edema, congestion, and hemorrhage of the lymph nodes and pancreas; congestion and hemorrhage of the gastrointestinal mucosa, subendocardium, adrenal gland, and meninges; and edema of the gall bladder. Histologic examination confirmed the gross observations. Additional microscopic lesions included widespread degeneration and necrosis of the lymphoid tissues as well as of the surface and crypt epithelium of the gastrointestinal mucosa; mild scattered necrosis of pancreatic acinar cells, myocardium, bone marrow cells, adrenal cortical cells, and tubular epithelium of renal medulla; and mild interstitial pneumonia. A dose-dependent increase in lesion severity was observed except for the pancreatic lesion which was slightly more apparent in the pigs from the 0.6 mg/kg group. These findings indicate that T-2 toxin-induced lesions in the lymphoid tissues and gastrointestinal tract of pigs are similar to those of other species the pancreas and heart should be considered as additional target organs in the pig, and both rapidly dividing cells and those with little or no turnover are damaged by T-2 toxin.

Experimental T-2 toxicosis in swine following inhalation exposure: effects on pulmonary and systemic immunity, and morphologic changes

Thirty-four, 9- to 11-week-old, male castrated, crossbred, specific pathogen-free derived pigs were exposed to a T-2 toxin aerosol at a nebulized dose of 0 or 9 mg/kg in pairs, each pair consisting of 1 control and 1 T-2 treated pig which were exposed on the same day. Twenty to 30% of the toxin (1.8 to 2.7 mg/kg) was retained by the pigs. Five pairs were killed on each of 1, 3 and 7 days after dosing. Two pairs of pigs were designated as a 0.33-day group when one T-2 treated pig died and the other was killed in a moribund state at 8 to 10 hours after dosing. The pulmonary and systemic immunity and morphologic changes of the lungs and other organs were examined. Bronchoalveolar lavage was performed to obtain alveolar macrophages (AM) and pulmonary lymphocytes (PL). The phagocytic ability of AM and mitogen-induced blastogenic responses of enriched PL and peripheral blood lymphocytes were evaluated. Clinically, all of the T-2 treated pigs vomited and were cyanotic, anorexic, lethargic and laterally recumbent. In the 0.33-, 1-, and 3-day T-2 treated pigs, there was a marked reduction in AM phagocytosis and mitogen-induced blastogenic responses of PL but not of peripheral blood lymphocytes. Mild to moderate, multifocal interstitial pneumonia was seen in the majority of the T-2 treated pigs. In pigs dying following inhalation of T-2 toxin, there was a more severe pneumonia, as well as marked necrosis of lymphoid tissues, severe necrohemorrhagic gastroenteritis and edema of the gall bladder wall, and multifocal necrosis of the heart and pancreas. Thus, inhalation exposure to T-2 toxin can result in clinical signs and morphologic changes resembling those reported previously in pigs given T-2 toxin intravascularly (iv) at a dose of 1.2 mg/kg (approximate LD50) or greater, as well as death. Mild pulmonary injury as well as transient impairment of pulmonary immunity was present in pigs surviving inhalation exposure.

Metabolism of three trichothecene mycotoxins, T-2 toxin, diacetoxyscirpenol and deoxynivalenol, by bovine rumen microorganisms

The three trichothecene mycotoxins T-2 toxin, diacetoxyscirpenol (DAS) and deoxynivalenol (DON) were incubated in vitro for 12, 24 and 48 h with rumen microorganisms obtained from a fistulated dairy cow. Gas chromatographic and gas chromatographic-mass spectrometric analyses of extracts indicated all three toxins were biotransformed to a variety of deepoxy and deacylated products. DON was partially converted to a product identified as deepoxy DON. DAS was rapidly converted to four products including 15-monoacetoxyscirpenol (MAS), scirpentriol and two new compounds identified as 15-acetoxy-3 alpha,4 beta-dihydroxytrichothec-9,12-diene (deepoxy MAS) and 3 alpha,4 beta,15-trihydroxytrichothec-9,12-diene (deepoxy scirpentriol). T-2 toxin was also completely biotransformed to the products HT-2, T-2 triol and two new metabolites identified as 15-acetoxy-3 alpha,4 beta-dihydroxy-8 alpha-(3-methylbutyryloxy) trichothec-9,12-diene (deepoxy HT-2) and 3 alpha,4 beta,15-trihydroxy-8 alpha-(3-methylbutyryloxy)trichothec-9,12-diene (deepoxy T-2 triol).

Therapeutic efficacy of superactive charcoal in rats exposed to oral lethal doses of T-2 toxin

Superactive charcoal, a compound known to complex with many toxins, was evaluated in this study for its effectiveness in preventing death in rats given an oral lethal dose of 8 mg/kg body weight of T-2 toxin. The median effective dose of oral superactive charcoal in preventing deaths in rats was 0.175 g/kg body weight. Concurrent use of cathartics, such as sorbitol, magnesium sulfate and sodium sulfate, to facilitate removal of the superactive charcoal:T-2 toxin complex formed in vivo did not enhance the survival rates of rats. One gram per kilogram body weight oral superactive charcoal enhanced survival times and survival rates in rats given 8 mg/kg of T-2 toxin as late as 3 hr after the T-2 toxin was administered. Some benefit in survival rate may be derived from giving the superactive charcoal as late as 5 hr after the T-2 toxin.

Assessment of potential therapies for acute T-2 toxicosis in the rat

The efficacy of a variety of approaches for the treatment of animals with acute T-2 toxicosis was assessed utilizing young female rats. A single large dose of the water soluble salt of methylprednisolone significantly prolonged survival times in T-2 toxin treated animals. The use of diltiazem hydrochloride, dazemgrel, N-acetylcysteine, dimethyl sulfoxide, adenosine triphosphate (ATP), ATP combined with magnesium chloride, ascorbic acid, and aprotinin did not prolong survival times at the dosages administered. Trichodermin, a trichothecene similar in structure and biochemical activity to T-2 toxin but much less acutely toxic, had a detrimental effect on survival times whether given 1 hr prior to or after T-2 toxin.