Poisoning of dogs with tremorgenic Penicillium toxins.

Fungi in the genus Penicillium, particularly P. crustosum, produce tremorgenic mycotoxins, as well as suspected tremorgenic compounds. The accidental intoxication of six dogs with such toxins are reported. The clinical signs included vomiting, convulsions, tremors, ataxia, and tachycardia, all of which are indicators of intoxications affecting the nervous system. This symptomatology caused us to think that the dog poisoning was the result of tremorgenic mycotoxins. One dog was euthanized in the acute phase, while three others recovered completely within a few days. However, neurological symptoms were still observed four months after the poisoning of two of the dogs. One of these recovered completely within the next 2-3 months, while the other still suffers from ataxia three years later. Available samples of feed, stomach content and/or tissues from the intoxications were subjected to mycological and chemical analysis. Penitrem A was found in all reported poisonings and roquefortine C in all cases when this toxin was included in the analysis. The producer of these toxins, Penicillium crustosum, was detected in all cases where material suitable for mycological examinations (feed or vomit) was available. To our knowledge, this is the first report documenting the presence of penitrems and roquefortine C in organs from poisoned dogs. Furthermore, the report indicates that the recovery period after severe poisonings with P. crustosum may be protracted.

Toxicokinetics of cotyledoside following intravenous administration to sheep.

Cotyledoside, a bufadienolide cardiac glycoside, was administered intravenously to sheep in 2 studies. In experiment 1, sheep (n = 4) received 0.0135 mg/kg daily on 5 consecutive days and in the 2nd experiment, sheep (n = 4) received 0.027 mg/kg as a single dose. Jugular blood was collected at different time intervals and kinetic parameters were determined. The data fitted a 1-compartmental model. In both experiments a short half-life (t1/2) and mean residence time (MRT), a relative small volume of distribution (Vd(ss)) and rapid clearance were calculated. In the 1st experiment, t1/2 and MRT increased significantly (P < 0.007) from Day (D) 0 to D4. It is suggested that the rapid decline in plasma cotyledoside concentrations in sheep denotes rapid distribution of cotyledoside to the tissues or extracellular spaces and possible accumulation at the biophase.

Tremorgenic neuromycotoxicosis in 2 dogs ascribed to the ingestion of penitrem A and possibly roquefortine in rice contaminated with Penicillium crustosum.

Two dogs developed alarming tremorgenic nervous stimulation shortly after ingesting discarded rice that had been forgotten in a refrigerator for an undetermined period and that was covered with a grey-green mould. Both dogs exhibited vomition followed by slight salivation, tremors and ataxia and 1 showed such severe agitation and seizures that it necessitated anaesthesia with thiopentone followed, on recovery, by xylazine. The other dog was only sedated with xylazine. They made an uneventful recovery. The rice vomitus yielded a pure culture of Penicillium crustosum. On chemical analysis it was negative for organochlorine, organophosphor and carbamate insecticides, as well as for strychnine, but contained 2.6 microg/g of the mycotoxins penitrem A as well as 34 microg/g of roquefortine as determined by LC-MS and confirmed by MS-MS. This is the 1st South African case of naturally occurring penitrem A toxicosis and also the 1st case where quantification of the levels of mycotoxins in dog vomitus is reported. The tremorgenicity of roquefortine and its contribution towards this syndrome, is questioned.

Seasonal variation in cotyledoside concentration of Tylecodon wallichii (Harv.) Tölken subsp. wallichii sampled in a krimpsiekte-prevalent region.

Krimpsiekte, an economically important neuromuscular affliction of small stock, follows upon ingestion of certain members of the Crassulaceae (plakkies) containing cumulative neurotoxic bufadienolides. Tylecodon wallichii (Harv.) Tölken subsp. wallichii is probably the most important species of the group of plants causing krimpsiekte. The growing tip of the stem and various other plant parts of T. wallichii, when available, were collected monthly. The seasonal variation in cotyledoside content of the plant was measured. Cotyledoside concentration was determined by high performance liquid chromatographic-electrospray mass spectrometry analysis (HPLC-ESMS). The cotyledoside concentration in the plant stems fluctuated substantially during the year, but tended to be higher in the cold winter months and increased again in the spring and early summer. Elevated plant stem concentrations corresponded with natural field outbreaks of krimpsiekte, which usually occur during the winter to early summer. The highest cotyledoside concentrations were detected in the flowering stalk. Cotyledoside was not the only component of this type in the plant, as mass spectrometry revealed the presence of other, possibly related, compounds.

Determination of toxaphenes in fish and marine mammals.

An analytical method for the determination of toxaphene in biological materials using gas chromatography with an electron capture detector (GC-ECD) has been established and validated for three single congeners (chlorinated bornanes (CHB) 26, 50 and 62). The analytical method was based on a method for determination of PCB, DDT and other chlorinated pesticides. To include toxaphene congeners an extra step, adsorption chromatography on silica columns, was introduced to separate the pesticides from PCB. The recovery of CHB-26, 50 and 62 were 97+/-11%, 94+/-10% and 99+/-12%, respectively. Samples from cod, ringed seal and polar bear from the Norwegian arctic environment have been analysed. The levels of CHB-26 and 50 found were 13-55 ng/g fat in cod, 1.3-7.7 ng/g fat in ringed seal and 0.4-119 ng/g fat in polar bear. The levels of CHB-62 were 2.0-13, 0.8-3.4, 0.2-11 ng/g fat in cod, ringed seal and polar bear, respectively.

The occurrence of HT-2 toxin and other trichothecenes in Norwegian cereals.

A total of 449 grain samples, 102 barley, 169 wheat and 178 oat samples were collected from different regions of Norway from 1996-1998 crops, mainly from grain loads and silos. The samples were analysed for type A and B trichothecenes, the largest groups of mycotoxins produced by the Fusarium species, by gas chromatography with mass spectrometric detection (GC-MS). Factors affecting the presence of the different trichothecenes are discussed. Deoxynivalenol (DON) and HT-2 toxin were the trichothecenes most frequently detected, followed by T-2 toxin, nivalenol, and scirpentriol, scirpentriol being detected only in seven samples (> 20 micrograms/kg). Oats were the grain species most heavily contaminated with an incidence (% > 20 micrograms/kg) and mean concentration of positive samples of 70% (115 micrograms/kg) for HT-2 toxin, 30% (60 micrograms/kg) for T-2 toxin, 57% (104 micrograms/kg) for DON, and 10% (56 micrograms/kg) for nivalenol. The corresponding values for barley were 22% (73 micrograms/kg), 5% (85 micrograms/kg), 17% (155 micrograms/kg) and 6% (30 micrograms/kg), and for wheat 1.2% (20 micrograms/kg), 0.6% (20 micrograms/kg), 14% (53 micrograms/kg) and 0% for HT-2, T-2, DON and nivalenol, respectively. Norwegian oats were found to contain HT-2 and T-2 toxin in concentrations that might be at threat to human health for high consumers of oats. The amount of DON was significantly lower than in the crop from previous years.

Mycotoxin production and cytotoxicity of Fusarium strains isolated from Norwegian cereals.

Thirty-four isolates of the eight most common Fusarium species isolated from Norwegian cereals; F. avenaceum, F. culmorum, F. equiseti, F. graminearum, F. poae, F. sporotrichioides, F. torulosum and F. tricinctum were studied for their cytotoxicity and ability to produce mycotoxins. The strains were cultivated on rice, and analysed for trichothecenes (all species), zearalenone (all species), fusarochromanone (F. equiseti), wortmannin (F. torulosum), moniliformin and enniatins (F. avenaceum, F. tricinctum and F. torulosum). The cytotoxicity of the extracts were examined with an (in vitro) MTT-cell culture assay. All F. graminearum and five of seven F. culmorum isolates belonged to chemotype IA, producing deoxynivalenol and 3-acetyl-deoxynivalenol, while the two other F. culmorum strains were nivalenol producers (chemotype II). The F. equiseti isolates and one of the F. poae isolates produced both type A and B trichothecenes, and relatively large quantities of fusarochromanone were detected in the F. equiseti cultures. All Fusarium species studied showed significant cytotoxicity, but with a large variation between species, and also within each species. F. sporotrichioides and F. equiseti showed the highest average cytotoxicity.