Imaging diagnosis--magnetic resonance imaging findings in a dog with sequential brain infarction

An adult greyhound was evaluated on three occasions for acute, intracranial neurologic signs. Based on magnetic resonance (MR) imaging, there were T2‐hyperintense and T1‐hypointense, noncontrast enhancing lesions in the cerebellum, and brain stem. Using diffusion‐weighted imaging (DWI), the lesions were characterized initially by restricted water diffusion. The presumptive diagnosis on each occasion was acute ischemic cerebrovascular accident leading to infarction. This allowed us to characterize the changes in appearance of infarcted neural tissue on the standard MR sequences over time, and to confirm that the DWI could be successfully used in low‐field imaging. © 2012 Veterinary Radiology & Ultrasound.     

Efficacy and toxicity of carboplatin in the treatment of macroscopic mesenchymal neoplasia in dogs

Palliative chemotherapy options for dogs with macroscopic non-osseous mesenchymal tumours are limited. The purpose of this study was to assess the response rate of these tumours to carboplatin chemotherapy. Medical records of 28 dogs treated with carboplatin for macroscopic mesenchymal neoplasia between 1990 and 2022 were retrospectively reviewed. Sixteen dogs with soft tissue sarcoma and 12 dogs with haemangiosarcoma were included. Responses observed included one complete response and three partial responses, for an overall response rate of 14.2% (4/28) and median time to progression of 42 days (range 21–259 days). Responses were only seen in patients with haemangiosarcoma, for a response rate of 33.3% (4/12) and median time to progression for responders of 103 days (range 39–252 days). Median time to progression for dogs with metastatic disease was similar to those with only local disease (distant median: 44 days; local median: 23 days, p = 0.56). Dogs with chemotherapy-naïve disease were compared to dogs having received previous chemotherapy treatment and had a median time to progression of 75 days and 40.5 days respectively (p = 0.13). Twenty-two dogs experienced 48 adverse events, with most being grade 1 or 2 (79%). Carboplatin was well tolerated, with variable macroscopic anti-tumour activity and short response duration. Carboplatin may be an acceptable rescue option for dogs with macroscopic haemangiosarcoma, especially those patients that cannot receive doxorubicin.     

Quantitative Risk Assessment for Zoonotic Transmission of Cryptosporidium parvum Infection Attributable to Recreational Use of Farmland

Cryptosporidiosis caused by Cryptosporidium parvum infection is a major cause of enteric illness in man and there is a significant reservoir in animals, particularly young ruminant species. To preliminary assess the magnitude of the risk posed by contact with faeces produced by infected livestock, two microbiological risk assessments have been developed: one for the risk of human infection with C. parvum while camping on contaminated land recently grazed by infected suckler cattle and a comparable risk assessment for camping on land recently spread with contaminated cattle slurry. Using a worst‐case scenario approach, the upper level of risk was estimated to be one infection in every 6211 person‐visits for a camping event on land recently grazed by infected cattle. Translated into camping events of 100 persons, this risk estimate would most likely lead to zero (98% likelihood) or one infection (1% likelihood). The results for cattle slurry model are similar despite different pathways. Sensitivity analysis was conducted for the grazing cattle model only. This suggested that the time between grazing and camping was the most important control strategy, but increasing hand‐washing frequency and the removal of cattle faeces before camping would also be beneficial. If the upper level of risk were to be judged unacceptable then further data would be required to more accurately estimate the risk of infection through these scenarios. Further research would also be required to assess the fraction of cases attributable to camping and/or environmental contact with Cryptosporidium oocysts.     

Prevalence of ectoparasites in a population of feral cats from north central Florida during the summer

Ectoparasites are a common and important cause of skin disorders in cats. Ectoparasites are capable of disease transmission and can cause life-threatening anemia in young or debilitated animals. The objective of this study was to determine the potential feline ectoparasites in domestic cats by using a cohort of feral cats from north central Florida that have not received veterinary care and have no known exposure to insecticide application. A total of 200 feral cats were randomly selected for this study. Four monthly sessions were scheduled for feral cat ectoparasite examination and sample collection. Five minutes flea combing revealed that 185/200 (92.5%) of the cats were infested with fleas. The cat flea, Ctenocephalides felis was the most common flea infesting 92.5% feral cats (mean = 13.6; standard deviation +/- 16.4 fleas per cat). Pulex simulans was identified on 9/200 (4.5%) (mean = 1 +/- 0.50 fleas per cat). Echidnophaga gallinacea was found on 11/200 (5.5%) of cats (mean = 14.8 +/- 9.63 fleas per cat). There was a significant difference (P = 0.0005) in the average number of C. felis counted per cat between months. Mean counts in June (18.3 +/- 2.4) and July (16.6 +/- 2.1) were significantly (P < 0.01) higher than in August (8.4 +/- 2.5) and September (7.7 +/- 2.0). Only 15/200 cats had skin disease. Flea infestation may potentially be the underlying cause in 10/15. Otoscopic examination of both ears revealed mite movement and black ceruminous exudate typically indicative of the presence of Otodectes cynotis in 45/200 (22.5%) cats. Examination of a swab specimen from both ear canals of all cats revealed O. cynotis in 74/200 (37%) cats. Of 74 cats positive on ear swab, 8 (10.8%) showed a normal ear canal appearance (no or mild ceruminous exudate) in both ears upon otoscopic examination. A total of nine ticks were recovered from five cats. The number and species of ticks recovered were: one adult female Rhipicephalus sanguineus; one adult female Amblyomma americanum; one adult male A. americanum; five adult female Dermacentor variabilis; and one adult female Ixodes scapularis. All superficial skin scrapes were negative. Hair clippings from the abdomen of all cats revealed 2/200 (1%) of the cats were infested with Felicola subrostratus.     

Effect of hybrid, maturity, and mechanical processing of corn silage on intake and digestibility by beef cattle

A study involving a 2 x 2 x 2 factorial arrangement of treatments was conducted to evaluate effects of hybrid (Pioneer 3335 and 3489), maturity (half milkline and blacklayer), and mechanical processing (field chopper with and without on-board rollers engaged) on intake and digestibility of corn silage. Forty Angus steers (322 +/- 5.2 kg BW) were assigned to the eight silage treatments (five steers per treatment) and individually fed using electronic gates. Diets consisted of 60% corn silage and 40% chopped alfalfa hay (DM basis). Following a 5-d adaptation period, intake was measured for 7 d and subsequently fecal samples were collected for 5 d. Chromic oxide (5 g/d) was fed beginning 7 d before fecal sample collection and digestibility was determined by the ratio of Cr in the feed and feces. Steers were reallocated to treatments and these procedures were repeated, providing 10 observations per treatment. In addition, all silages were ruminally incubated in six mature cows for 0, 8, 16, 24, 48, and 96 h to determine extent and rate of DM, starch, NDF, and ADF disappearance. Processing increased DMI of hybrid 3489 but did not affect DMI of hybrid 3335 (hybrid x processing; P < 0.06). Total tract digestibility of DM, starch, NDF, and ADF decreased (P < 0.01) as plant maturity increased. Maturity tended to decrease starch digestibility more for hybrid 3489 than for hybrid 3335 (hybrid x maturity; P < 0.10). Processing increased (P < 0.01) starch digestibility but decreased (P < 0.01) NDF and ADF digestibility, resulting in no processing effect on DM digestibility. There was a numerical trend for processing to increase starch digestibility more for latethan for early-maturity corn silage (maturity x processing; P = 0.11). Processing increased in situ rates of DM and starch disappearance and maturity decreased in situ disappearance rates of starch and fiber. These data indicate that hybrid, maturity, and processing all affect corn silage digestibility. Mechanical processing of corn silage increased starch digestibility, which may have been associated with the observed decreased fiber digestibility.     

Verocytotoxin-producing Escherichia coli O157 on a farm open to the public: outbreak investigation and longitudinal bacteriological study

Verocytotoxin-producing Escherichia coli (VTEC) O157 phage type 2 (PT2) was isolated from three calves and two goats on a farm open to the public. Phenotypic and DNA-based typing showed that the strains were identical or very closely related to those obtained from an outbreak of VTEC O157 infection in two separate family groups who visited the farm. No VTEC O157 PT2 was isolated again from the farm during a 12-month longitudinal bacteriological study undertaken after the infected animals had been removed. However, phenotypically and genotypically indistinguishable VTEC O157 PT2/28 strains were detected in two of 474 faecal samples collected at monthly visits from 15 species of animals of various ages. The two isolates were obtained from calves from different sources sampled 146 days apart, suggesting that the infection had persisted on the farm although it was not detected in the other species. The same strain was subsequently isolated from another calf housed in the same pen as one of the infected calves. The longest period during which the organism was excreted was seven days. No VTEC O157 was isolated either from 204 replacement animals (including 138 orphan lambs and 10 calves) brought in from various sources, and sampled while they were kept in isolation for two weeks before being introduced to the farm, or from environmental samples. During the study a visitor became ill with VTEC O157 PT2. However, the isolate was distinct from those recovered from the farm and there was no evidence to suggest that the visit was the source of the infection.