Serological survey of selected pathogens of free-ranging foxes in Southern Argentina, 1998-2001

A serological survey was conducted in the Patagonia region of Argentina to estimate the prevalence of nine disease agents within the populations of free-ranging culpeo (Dusicyon culpaeus) and grey (Dusicyon griseus) foxes. The disease agents were Aujeszky's disease virus (ADV), Brucella, canine adenovirus (CAV), canine distemper virus (CDV), canine parvovirus (CPV), Encephalitozoon cuniculi, Leptospira, Neospora caninum, and Toxoplasma gondii. A total of 84 foxes were sampled (28 culpeo and 56 grey), and 73% of the sera had antibodies against one or more pathogens. Among these seropositive sera, 47% of them reacted to only one antigen, while the other 53% reacted to multiple antigens. The presence of antibodies to Toxoplasma (20%), Neospora (44%), Leptospira (30%) and Brucella (18%) suggests that these organisms actively circulate in the area. Antibodies against CDV, CAV and CPV were detected in 2%, 5% and 5% of foxes, respectively. Regarding Encephalitozoon cuniculi and ADV, no evidence of either was found.

One-month safety study of intraperitoneal VRCTC-310-Onco (crotoxin + cardiotoxin) in rats

To evaluate the toxicity of VRCTC-310-Onco (Crotalus durissus terrificus crotoxin + cardiotoxin from Naja naja atra), 10 Sprague-Dawley rats were implanted with intraperitoneal slow-release devices and subjected to treatment with 0.5 microgram/g body weight/d for 14 days. Biochemical evidence at days 7 and 14 showed blood, muscular, renal and metabolic disturbance, mostly reversed by day 28. No significant changes were found in necropsy. The limited toxicity of i.p. VRCTC-310-Onco in rats deserves further study.

A note on diseases of mink

The paper describes in brief the findings in 5,616 autopsies of adult mink, performed at the Institute of Pathology-CIC, La Plata, during the last five years. Nearly all these carcasses, coming from the most important ranches, were examined bacteriologically and histopathologically. Observations about the incidence of different causes of death, its distribution annually and prophylactic measures were reported. It concludes that Aleutian disease is the most important cause of death and produces severe economic losses.

A survey on perinatal mortality in young mink

The incidence of perinatal mortality in mink was investigated in commercial farms in Argentina. Of a total of 2122 kits, 548 of those that were born alive died within the first four weeks of life (25.8% mortality) and there were also 62 stillborn kits. Death resulted from a variety of causes of which septicaemia, starvation and hypothermia were the most common conditions. The highest mortality occurred within the first week of life (61.9%). The lesions found in young kits at post-mortem examination are described and related to contributory factors such as weight, litter size and age at death.

Studies on the mechanism of the acute and carcinogenic effects of N-nitrosodimethylamine on mink liver

Outbreaks of liver necrosis and liver hemangiosarcoma were detected in a mink breeding colony in Argentina. Analysis of the Minks' food revealed the presence of 2.6 ppm dimethylnitrosamine (NDMA) in it, apparently as a result of the addition of nitrite as preservative. Previous studies gave evidence of the particular susceptibility of minks to NDMA and other hepatic insults. We have determined several biochemical parameters known to correlate with NDMA hepatotoxic effects and compared them with those in rat liver. NDMA administration to both species resulted in the formation of reactive metabolites able to interact with liver DNA to give N7-methylguanine and O6-methylguanine adducts. Biotransformation of NDMA by liver slices to CO2 was significantly lower in the mink than in the rat, whereas the covalent binding (CB) to nucleic acids was slightly lower than in in the rat. Aminopyrine N-demethylase activity was also significantly less in mink than in rat liver. The CB of NDMA reactive metabolites to microsomal proteins was not significantly lower in mink as compared to the rat, and the same holds true for the biotransformation of NDMA to formaldehyde by microsomal preparations. Results suggest that the high susceptibility of minks to NDMA might be partially due to a decreased ability to detoxicate NDMA but also to a higher intrinsic susceptibility of their liver cells to a given chemical insult.