Comparison of regular insulin infusion doses in critically ill diabetic cats: 29 cases (1999–2007)

Objective – To compare biochemical parameters, neurologic changes, length of hospital stay, and clinical improvement in 3 groups of cats with diabetic ketosis/diabetic ketoacidosis (DK/DKA) prescribed varied doses of regular insulin as a continuous rate of infusion (CRI). Design – Retrospective study. Setting – University teaching hospital. Animals – Twenty‐nine client‐owned cats with DK/DKA prescribed a regular insulin CRI. Interventions – Cats were grouped as follows: 7 cats each in Group 1 and 2, (prescribed 1.1 and 2.2 U/kg/d, respectively), and 15 cats in Group 3 (prescribed increasing doses as needed). Measurements and Main Results – None of the groups received the total prescribed dose of insulin. The mean actual dose administered/kg/d ranged from 0.30 (0.21) to 0.87 (0.32) U/kg/d in Groups 1, 2, and 3. There was no difference in mean minimum blood glucose (BG) per 4 hours or change in BG from baseline per 4 hours between Groups 1 and 2 (P=0.63, 0.50). There was no difference between groups regarding the time required to reach a BG ≤13.9 mmol/L (250 mg/dL), serum phosphorus or potassium concentrations relative to baseline values (P=0.53, 0.90), length of time until urine or serum ketones were no longer detected (P=0.73), the animal commenced eating (P=0.24), or length of hospital stay (P=0.63). Four of the cats had declining mentation during hospitalization; there were no relationships between osmolality at presentation, either prescribed or administered insulin dose, and mentation changes. Three of the 4 cats with declining mentation survived. Twenty‐seven of the 29 cats (93%) survived to discharge. Conclusions – In this study, prescribing the published canine dose (2.2 U/kg/d) of regular insulin to cats with DK/DKA does not appear to increase the frequency of adverse neurologic or biochemical sequelae compared with cats that are prescribed the published cat dose (1.1 U/kg/d). The use of a sliding scale for determination of infusion rates significantly reduces the amount of insulin cats receive in this setting. Determination of whether adverse sequelae would occur more frequently if cats with DK/DKA received the full insulin prescribed doses of 1.1, 2.2, or >2.2 U/kg/d is warranted. Further controlled studies are necessary to determine if higher doses of insulin are associated with beneficial effects on morbidity or mortality.     

Modelling the impacts of agriculture in mixed-use landscapes: a review and case study involving two species of dabbling ducks

Context

This study synthesizes evidence from three separate surveys of American Black Duck and Mallard breeding habitat usage to quantify the effects of agriculture at the landscape scale.

Objectives

To assess duck breeding activity in agricultural landscapes within the Canadian maritimes in order to measure the overall impact of agricultural land use, the response to particular agricultural activities, and the influence of landscape configuration.

Methods

Models, constructed using a long-term census (SURVEY1), were used to predict habitat selection for two other independent surveys (SURVEY2, SURVEY3). Predictions incorporated information about wetland area and diversity, as well as anthropogenic factors, allowing subsequent analyses to focus on the remaining residual error attributable to agricultural effects.

Results

SURVEY2 results demonstrated that the proportion of active agriculture is an important indicator of the severity of human disturbance, yielding threshold estimates of 39% for Mallards and 60% for Black Ducks, with an overall average of 50%. Agricultural conversion beyond these thresholds deterred breeding ducks independently of other factors. SURVEY3 land cover information demonstrated that the presence of cropland intensified this deterrence effect, even at levels as low as 10%. Woodland cover (in excess of 30%) was important for both species, but its configuration was not.

Conclusions

In addition to quantifying threshold effects, this study reaffirms that woodland is an important part of the maritime landscape matrix, and contributes positively to habitat diversity in mixed use, moderate intensity agricultural regions. Wetland restoration in agricultural landscapes should monitor and promote less crop-intensive, mixed-use practices.

     

Evolution of rotavirus C in humans and several domestic animal species

Rotavirus C (RVC) causes enteric disease in multiple species, including humans, swine, bovines, and canines. To date, the evolutionary relationships of RVC populations circulating in different host species are poorly understood, owing to the low availability of genetic sequence data. To address this gap, we sequenced 45 RVC complete genomes from swine samples collected in the United States and Mexico. A phylogenetic analysis of each genome segment indicates that RVC populations have been evolving independently in human, swine, canine, and bovine hosts for at least the last century, with inter‐species transmission events occurring deep in the phylogenetic tree, and none in the last 100 years. Bovine and canine RVC populations clustered together nine of the 11 gene segments, indicating a shared common ancestor centuries ago. The evolutionary relationships of RVC in humans and swine were more complex, due to the extensive genetic diversity and multiple RVC clades identified in pigs, which were not structured geographically. Topological differences between trees inferred for different genome segments occurred frequently, including at nodes deep in the tree, indicating that RVC's evolutionary history includes multiple reassortment events that occurred a long time ago. Overall, we find that RVC is evolving within host‐defined lineages, but the evolutionary history of RVC is more complex than previously recognized due to the high genetic diversity of RVC in swine, with a common ancestor dating back centuries. Pigs may act as a reservoir host for RVC, and a source of the lineages identified in other species, including humans, but additional sequencing is needed to understand the full diversity of this understudied pathogen across multiple host species.     

The effect of rehabilitation of northern elephant seals (Mirounga angustirostris) on antimicrobial resistance of commensal Escherichia coli

The aim of this study was to determine if antimicrobial drug use increases resistance of commensal gastrointensinal Escherichia coli of wild northern elephant seals (Mirounga angustirostris) treated in rehabilitation, and, if so, identify the risk factors involved. Minimum inhibitory concentration (MIC) levels of twelve antimicrobial drugs were determined for 289 E. coli isolates from 99 seals sampled at admission and 277 isolates obtained at release from rehabilitation using broth microdilution. Prevalence of E. coli antimicrobial resistance, MIC(50), MIC(90), and clustering of MIC values were determined for seals and the data were analyzed using Fisher's exact test, ordinal logistic regression and negative binomial regression. At release from rehabilitation 77.8% of the seals had antimicrobial resistant E. coli compared to 38.4% of the seals at admission. The MIC(90) for amoxicillin-clavulanic acid, chloramphenicol, enrofloxacin, ticarcillin-clavulanic acid, and trimethoprim-saulfamethoxazole were at levels considered to be sensitive at admission but they increased to levels of resistance at release. E. coli were grouped into four clusters by their MIC values, with increasing levels of resistance going from Cluster 1 to 4. A primary risk factor associated with the probability of a seal having E. coli in Clusters 3 and 4 was time in rehabilitation, regardless of whether the animal received treatment with antimicrobial drugs, suggesting nosocomial infection. The results of this study provide evidence that increased levels of hygiene and appropriate use of antimicrobial therapy might be important in the rehabilitation of wild animals to prevent rise in the prevalence of antimicrobial resistant bacteria.     

Control of terrestrial animal rabies in Anne Arundel County, Maryland, after oral vaccination of raccoons (1998-2007)

Objective-To evaluate the effectiveness of an oral rabies vaccination (ORV) project conducted from 1998 through 2007 in Anne Arundel County, Md, for the control of rabies in terrestrial animals. Design-Retrospective analysis of surveillance data (1997 through 2007). Animals-Free-ranging raccoons (Procyon lotor) and other terrestrial mammals. Procedures-Vaccinia-rabies glycoprotein recombinant virus oral rabies vaccine-bait units were distributed annually by aircraft and ground teams targeting free-ranging raccoons. Approximately 2 to 4 weeks following the vaccine-bait placement, raccoons were live trapped, sedated, processed, and then released. Serologic samples were tested for the presence of rabies virus-neutralizing antibodies (RVNAs). Bait acceptance was estimated by analysis of tetracycline biomarking of sampled teeth. Rabies incidence was determined by the passive identification of rabid terrestrial animals. Results-The incidence of rabies in terrestrial animals decreased 92% between 1997 (the year prior to the start of the ORV project) and 2007. The mean RVNA prevalence across all years was 33% among trapped raccoons in areas baited with a fish meal polymer bait type, whereas the mean bait acceptance was 30%. Adult raccoons had a seropositivity rate twice that of juvenile raccoons, whereas the bait acceptance rate between adults and juveniles did not differ significantly. For areas baited with a coated sachet bait, adults and juveniles had the same seroprevalence. Juveniles had better seroprevalence when the annual campaign started in September and October, compared with August. Conclusions and Clinical Relevance-The ORV project contributed to a significant decrease in annual incidence of terrestrial animal rabies in Anne Arundel County, Md, during the 10-year project period. For fish meal polymer baits, juvenile raccoons accessed bait at the same rate as adult raccoons but had a significantly lower prevalence of RVNAs. For coated sachet baits, seroprevalence was the same in both age groups. The time of year the bait distribution occurred and the bait type used may be partial explanations for the difference in RVNA seroprevalence between adults and juvenile raccoons.