General toxicologic hazards and risks for search-and-rescue dogs responding to urban disasters

In large-scale disasters, it is not always possible to identify every potential toxic agent to which SAR dogs may be exposed. However, an understanding of the basic means by which dogs may be exposed to toxic agents can aid veterinarians in determining basic risks for particular SAR sites and allow veterinarians to institute general preventive measures (eg, frequent eye washes) to minimize exposure. Discussions with public health and other authorities on-site may aid in identifying site-specific risks for SAR dogs. Finally, ensuring that SAR dog handlers are aware of basic risks, precautions, and decontamination measures is essential, as handlers are the first line of defense in preventing illness or injury to SAR dogs as they work a disaster area.     

A nervous syndrome in dogs responding to treatment with thiamine

Abstract

Extract

Sir,—Following letters of Mayhew and Stewart 1969) Mayhew, I. G. and Stewart, J. M. 1969. Nervous syndrome in dogs possibly associated with a thiamine deficiency. N.Z. vet. J., 17: 91–92. [Taylor &; Francis Online] , [Google Scholar]and Stirling (1969) Stirling, T. 1969. Possible thiamine deficiency in dogs. N.Z. vet. J., 11: 160–160.  [Google Scholar], I feel that the following case report may be of interest.     

Pathology and toxicology findings for search-and-rescue dogs deployed to the September 11, 2001, terrorist attack sites: initial five-year surveillance

A long-term surveillance study was conducted on 95 search-and-rescue (S&R) dogs deployed to the September 11, 2001, terrorist attack sites; an additional 55 nondeployed S&R dogs served as controls. After 5 years of surveillance, 32% of the deployed dogs have died and 24% of the nondeployed dogs. The mean age at the time of death in these 2 groups of dogs is not significantly different. Causes of death in both groups of dogs include inflammatory, degenerative, and proliferative conditions. No primary pulmonary tumors have been identified to date nor has any significant level of toxicant been found in the tissues from these dogs using assays for general organic compounds and metals or, specifically, for polychlorinated biphenyls. However, significant numbers of both deployed and nondeployed dogs have evidence of inhaled matter as demonstrated by the presence of anthracotic pigments or refractile particulate matter in pulmonary tissue. Although S&R activities in response to the 9/11 terrorist attacks exposed dogs to a wide variety of potentially toxic compounds, to date, these dogs do not appear to suffer from higher mortality or increased pulmonary disease compared with nondeployed dogs. To the authors' knowledge, the current survey represents the first long-term and large-scale survey of the pathology and toxicology of S&R dogs deployed to a major disaster site.     

Nasal sensory receptors responding to capsaicin, water and tactile stimuli in sevoflurane-anesthetized dogs.

Responses of nasal receptors to capsaicin and water were studied from afferent recordings of the posterior nasal nerve (PNN) in 12 anesthetized dogs. Out of 12 non-respiration-modulated nasal receptors, 7 responded only to capsaicin, 3 responded to both water and capsaicin, and 2 to neither of them. All the fibers showed a rapid adaptation to mechanical probing of the nasal mucosa. These results indicate that the presence of sensory receptors responding to capsaicin and water are involved in PNN afferents of the dog.     

Toxicologic studies of a conjugate of asparaginase and polyethylene glycol in mice, rats, and dogs

A conjugate of asparaginase and monomethoxypolyethylene glycol was evaluated in acute, subacute, and subchronic toxicologic studies in mice, rats, and dogs. The drug induced low-grade toxicosis. The appearance and behavior of rats and dogs were not affected by the treatment. Only large doses produced inactivity, loss of appetite, and loss of weight. The LD50 could not be established. The drug retarded slightly body weight gains in dogs and female rats and produced mild anemia in 30% of the female rats. Urinalysis and blood chemical determinations in rats and dogs were generally not affected by the treatment. Monomethoxypolyethylene glycol-asparaginase was detectable in the plasma of mice 13 days after IV, intraperitoneal, or IM administration, and in dogs for 3 to 4 weeks.     

The resistance to chemotherapeutic agents of Escherichia coli from domestic dogs and cats

The prevalence of antibiotic resistant Escherichia coli in the rectal flora of 168 healthy dogs and 93 cats in the Brisbane area was investigated. Rectal swabs were plated on MacConkey agar with and without antibiotics, and 690 isolates confirmed as faecal E. coli were tested for resistance to tetracycline, streptomycin, chloramphenicol, ampicillin, neomycin, furazolidone and sulphanilamide. Resistant isolates were obtained from 101 (60%) of the dogs and 24 (26%) of the cats sampled. A high percentage of the isolates was resistant to tetracycline, streptomycin, ampicillin and sulphanilamide. Multiple resistance to 3 or more of the drugs was exhibited by the majority of isolates and a total of 31 different multiple resistance patterns was demonstrated. Of the 50 strains tested for transfer of resistance, 30 (60%) transferred some or all of their resistance determinants to an E. coli K12F - recipient.     

Comparison of nonionic contrast agents iohexol and iotrolan for cisternal myelography in dogs

During this investigation, the use of iohexol was compared with iotrolan for canine cisternal myelography. Iohexol and iotrolan myelography was done in 6 dogs by cisternal puncture with a 6-week interval between both procedures; each dog served as its own control. Cerebrospinal fluid (CSF) was collected for baseline analysis from each dog immediately before the contrast agent was injected. Cerebrospinal fluid samples were obtained at 1, 3, 7, and 14 days after injection of each contrast medium for cytologic and chemical analysis. Total CSF leucocyte count and glucose concentration did not change significantly in comparison with baseline data in any of the samples. After the injection of iohexol, protein concentration increased significantly in the 24-hour sample, and lactate dehydrogenase activity increased significantly in the 3-day sample. Significant difference was not found between the different samples collected at 1, 3, 7, and 14 days, compared with both contrast media. None of the dogs had seizure activity during a 5-hour postmyelographic observation period. Pathologic changes were not found by gross or microscopic examination of the spinal cord. Although a degradation in time of radiographic quality of all myelograms took place, the average radiographic score decreased more rapidly with iohexol. The average score at 90 minutes with iotrolan was comparable with the score at 45 minutes with iohexol, and the average score at 150 minutes with iotrolan was better than the score at 90 minutes with iohexol. At 5 and 10 minutes after cisternal injection, no significant difference was observable between the myelograms, but from 45 minutes onward, myelograms with iotrolan were superior.     

Seroprevalence of antibodies to Neospora caninum in urban and rural dogs in north-west Italy

Sera were collected from 490 dogs from north-west Italy. One hundred and eighty-eight dogs were urban, while 302 dogs were rural. Among the latter, 190 were shepherd dogs and 112 were cattle farm dogs. Sera were tested for the presence of antibodies against Neospora caninum using the Neospora agglutination test. Seroprevalence at 1/40, 1/80, 1/160 dilution titres was significantly higher in rural (36.4%, 19.5%, 9.9% respectively) than in urban dogs (20.2%, 10.6%, 4.8% respectively). Seroprevalence did not differ significantly in males and females. In shepherd dogs, prevalence increased according to dogs' age, thus suggesting a post-natal exposure by horizontal transmission. The observed higher seroprevalence in rural dogs suggests the importance of lifestyle and alimentary habits (i.e. aborted foetuses, placentas and small mammals) in the acquisition of N. caninum infection. Our results confirm that dogs are exposed to N. caninum and play an important role in the epidemiology of N. caninum.     

Reciprocal attention of dogs and owners in urban contexts

Laboratory-based studies have shown that paying attention to humans is an important determinant of dogs' behavior. However, there are no data on how gaze is deployed between dogs and owners in non-laboratory conditions. This study aimed at characterizing dogs' and owners' attention to each other in 2 urban contexts, characterized by a different density of dynamic stimuli. Short videos of 176 dog–owner couples walking in streets and squares of the city center (CC) or green areas (GAs) of the center of Padova (Italy) were recorded. Continuous sampling was used for recording when dogs and owners were visually oriented toward their respective partners. These data allowed calculation of the average length of continuous gazes, number of gazes per minute, and the percentage of time in which dogs and owners were oriented toward their partners; also computed were the frequency and duration of mutual gazes. Eighty-three dogs and 32 owners never looked at their reciprocal partners for the entire duration of the video. On average, dogs were oriented to owners for 0.6% of the time and looked at them 0.5 times per minute, in bouts of 0.5 seconds. All parameters of dogs' attention were higher for off-leash dogs in GAs than for on-leash dogs in both GAs and CC. Although such limited attention to owners may reflect the requirements of ongoing action, it also suggests that most dogs do not need to look at their owners during walks, possibly because they are not confronted with situations of uncertainty. Owners were oriented to their dogs for 5.3% of the time and looked at them 1.7 times per minute, in bouts of 1.4 seconds. Owners' attention was lower in CC than in GAs, which may reflect differences between contexts in the number of distracting stimuli or in owners' motivations for looking at their dogs while walking in these different contexts.     

Use of hyaluronidase for the treatment of extravasation of chemotherapeutic agents in six dogs

Six dogs had perivascular extravasation of antineoplastic agents during IV administration. Treatment with 300 units of hyaluronidase injected locally in the affected site was initiated following the extravasation event. Injections were repeated weekly until signs of toxic effects within the tissues resolved satisfactorily. All dogs recovered within 6 weeks, and residual fibrosis at the extravasation sites most was considered minimal. Many chemotherapeutic agents cause severe cytotoxic reactions when extravasated during cycles of chemotherapy, resulting in tissue necrosis with ulceration and sloughing of skin during the following weeks. Surgical treatments and skin grafting are often necessary to achieve healing. The sequelae of extravasation may result in discontinuation of chemotherapy or euthanasia of the animal. Hyaluronidase appears to be a safe treatment for the adverse effects of extravasation of various chemotherapeutic agents and may be used effectively to reduce the severity of cutaneous toxicosis.