Methicillin‐resistant Staphylococcus aureus in urban Norway rat (Rattus norvegicus) populations: Epidemiology and the impacts of kill‐trapping

Urban Norway rat (Rattus norvegicus) populations can carry the bacteria methicillin‐resistant Staphylococcus aureus (MRSA). There are numerous knowledge gaps in the epidemiology of MRSA in these populations that limit understanding of its ecology in urban environments. For example, fecal shedding of MRSA, which may increase environmental contamination, has been reported in other species; however, it is unknown whether Norway rats carry the bacteria rectally. Furthermore, while intermittent MRSA shedding has been shown in other species and may dictate when the risk of transmission is highest, duration of carriage has not been examined for Norway rats. Previous work has shown that lethal animal‐control methods may increase the level of pathogens within reservoir populations, possibly by disrupting ecological patterns. However, the impact of rodent‐control on potentially environmentally acquired pathogens like MRSA has not been tested. Using capture‐mark‐recapture methods in an inner‐city neighborhood in Vancouver, Canada, we show that rats intermittently carry MRSA both in the rectum and oropharynx. By assessing the prevalence of MRSA before and after enacting a pest‐control intervention, we report that kill‐trapping had no impact on the prevalence of carriage of this environmentally‐acquired agent.     

Farmers’ perceptions of the causes of low reproductive performance in cows kept under low-input communal production systems in South Africa

The objective of the study was to determine farmers’ perceptions of the causes of low reproductive performance in Nguni cows raised on communal rangelands in the Eastern Cape Province of South Africa. Data were collected using participatory rural appraisals and structured questionnaires that were administered to 551 randomly selected farmers from ten communities in the Eastern Cape. Cattle herd sizes ranged from 3 to 11 and were mainly composed of cows. Cattle sales were ranked as the most important use of cattle in all the villages. Tick-borne diseases and poor animal condition were reported as chief constraints of cattle production in most communities. More than 60% of the interviewees reported that the age at puberty and age at first calving for their cows varied between 18 and 36, and 24 and 48 months, respectively. About 95% of the respondents reported long calving intervals and low bull numbers as major causes of low reproductive performance in cows in the communal areas. It was concluded that farmers perceived delayed age at puberty and at first calving, long calving intervals and low bull numbers as the major causes of low reproductive performance in Nguni cows raised on communal rangelands in South Africa.     

Nonlinear increasing axial gap stiffness in type II external skeletal fixation: a mechanical study

OBJECTIVE: To quantify the effect on gap stiffness and cranial to caudal bending stiffness of conversion of the 6 distal clamps of planar bilateral fixator models to sliding clamps and the effect of attachment of composite beams to the sliding clamp models. STUDY DESIGN: Mdash;Mechanical testing performed on models. SAMPLE POPULATION: Five models using birch dowels and a commercially available external skeletal fixator system. METHODS: A segmentally comminuted, middiaphyseal fracture was simulated with the use of wooden dowels, and a bilateral 6-pin fixator was applied to create each of 5 models. The models were mechanically tested with all fixed clamps, with the 6 distal clamps converted to sliding clamps and with composite beams attached to the sliding clamp models. Testing was carried out in axial loading with physiologically relevant loads for a canine model, and in bending in the cranial to caudal plane. RESULTS: Sliding clamp fixators with composite beams attached exhibited a nonlinear increase in axial loading gap stiffness as load increased. The composite beam group also exhibited an increase in cranial to caudal bending stiffness as compared with fixed clamp and sliding clamp models. CONCLUSIONS: Using composite beam elements, planar bilateral external fixators can be constructed such that the fracture site would undergo controlled amounts of displacement at low loads and lessening displacement at higher loads. CLINICAL RELEVANCE: The nonlinear stiffness profile attained by the addition of composite beam elements to a planar external fixator allows controlled axial micromotion at the fracture site. Because controlled axial micromotion appears to stimulate fracture healing, a nonlinear stiffness profile of this type should enhance fracture healing.     

Multiple cutaneous leiomyomas in the perineum of a horse.

Multiple cutaneous masses developed in the perineum of a 14-year-old Saddlebred stallion over a period of approximately 5 years. Clinically, the masses ranged in size from 3- to 9-mm diameter and were not ulcerated, painful, or pruritic. Three of the masses were surgically excised and submitted for microscopic evaluation. The masses were dome shaped to nodular, located in the superficial dermis, and composed of haphazardly arranged bundles of plump spindle-shaped cells. The tumor cells immunoreacted with monoclonal antibodies directed against desmin, muscle-specific actin, and smooth muscle actin, confirming a smooth muscle origin. Multiple cutaneous leiomyomas have not been reported previously in horses.     

Suture Materials and Suture Selection for Use in Exotic Pet Surgical Procedures

Exotic animals are becoming increasingly popular and more exotic pet owners are seeking veterinary care. This has led to a demand for properly trained veterinarians who are capable of providing quality, up-to-date medical and surgical treatments. Many surgeries are now performed on exotic pets, and selection of the appropriate suture material is an important part of the treatment protocol. An understanding of different available suture materials, healing times of different tissues, and knowledge of different anatomic and physiologic characteristics in different species is important in the selection of the most appropriate suture material. This review will summarize important aspects of suture selection in exotic animals.     

Utility of two‐view vs. three‐view abdominal radiography in canines presenting with acute abdominal signs

There are clear differences in the normal radiographic appearance of the abdominal organs between a left lateral vs. a right lateral view. While a few veterinary academic institutions have transitioned to a three‐view abdominal radiographic study protocol, obtaining only two views of the canine abdomen remains the current standard in veterinary medicine. In this combined retrospective and prospective, case‐controlled study, 48 canine patients presenting with signs of acute abdomen were recruited. Four board‐certified veterinary radiologists and four general practice veterinarians with greater than 3 years of experience in small animal practice were asked to determine if 10 predetermined findings were present within the set of images and if surgery was recommended based on those findings. Image readers were unaware of the clinical history. Three‐view studies did not yield statistically significantly greater accuracy than two‐view studies when evaluating all readers together. No statistically significant associations between the availability of the third view and increased accuracy or confidence were found in evaluations of general practitioners specifically. Evaluation of three‐view radiographic examination, as compared to two‐view examination, did not have perceived or statistically significantly increased diagnostic utility. Based on our findings, there is no statistically increased utility to justify a standard three‐view abdominal radiographic examination over a two‐view study for canines presenting with signs of acute abdomen.     

Cerebrospinal fluid glutamine,tryptophan, and tryptophan metabolite concentrations in dogs with portosystemic shunts

OBJECTIVE: To determine whether glutamine (GLN), tryptophan (TRP), and tryptophan metabolite concentrations are higher in cerebralspinal fluid (CSF) dogs with naturally occurring portosystemic shunts (PSS), compared with control dogs. ANIMALS: 11 dogs with confirmed PSS and 12 control dogs fed low- and high-protein diets. PROCEDURE: Cerebrospinal fluid and blood samples were collected from all dogs. Serum and CSF concentrations of GLN, alanine, serine, TRP, 5-hydroxyindoleacetic acid (5-HIAA), and quinolinic acid (QUIN) were measured. RESULTS: Cerebrospinal fluid concentrations of GLN, TRP, and 5-HIAA were significantly higher in PSS dogs, compared with control dogs fed high- or low-protein diets. Cerebrospinal fluid QUIN concentration was significantly higher in PSS dogs, compared with control dogs fed the low-protein diet. Serum QUIN concentration was significantly lower in PSS dogs, compared with control dogs fed either high- or low-protein diets. CONCLUSIONS AND CLINICAL RELEVANCE: An increase in CNS GLN concentration is associated with high CSF concentrations of TRP and TRP metabolites in dogs with PSS. High CSF 5-HIAA concentrations indicate an increased flux of TRP through the CNS serotonin metabolic pathway, whereas high CSF QUIN concentrations indicate an increased metabolism of TRP through the indolamine-2,3-dioxygenase pathway. The high CSF QUIN concentrations in the face of low serum QUIN concentrations in dogs with PSS indicates that QUIN production from TRP is occurring in the CNS. High concentrations of QUIN and other TRP metabolites in the CNS may contribute to neurologic abnormalities found in dogs with PSS and hepatic encephalopathy.     

Cloning,expression, purification,and biological activity of five feline type I interferons

Type I interferons (IFN) are important mediators of the host defense against viral infections in mammals. In humans multiple subtypes of IFN-alpha exist, most of which possess antiviral activity. Little is known about the type I IFN genes in cats and the role they may play in feline immunological responses to viruses. We have isolated cDNAs encoding five feline IFN-alpha (feIFN) subtypes that share from 95 to 99% amino acid sequence identity. FeIFN-alpha5 has five additional amino acids inserted at position 139, which are not present in the other four subtypes. Sequence identity of the feIFN proteins encoded by the five clones compared to human IFN-alpha2 is approximately 60%. Unlike most of the human subtypes, each of the five feline IFN sequences has an N-glycosylation recognition site. Expression of all five feIFN-alpha subtypes in Chinese hamster ovary (CHO) cells was confirmed by Western blot analysis, and all resulting proteins were glycosylated. The antiviral activity of each feIFN-alpha subtype produced in transiently transfected CHO cell cultures was tested in vitro. In addition, subtype feIFN-alpha6 was expressed in the yeast, Pichia pastoris. The resulting secreted mature recombinant protein was purified and demonstrated significant antiviral activity and induction of 2',5'-oligoadenylate synthetase activity in vitro.     

Complications after implantation of a modular total hip prostheses compared with fixed head prostheses

164 total hip prostheses of different manufacturers were implanted over an 8-year period. Clinical records were evaluated with a complication rate of 29.0% (42 of 145 joints) or 31.7% (39 of 123 dogs). The complications encountered in dogs that received the modular hip prosthesis (Biomécanique, Bretigny-sur-orge, France) amounted to 16.3% (15 of 92), dogs that received a fixed head prosthesis (5 different manufactures) had 39% complications (28 of 72). Although the complication rate was influenced by different surgeons (n = 5) with different system predelictions and a different learning curve it was obvious that luxations (n = 6 of 10) and stem fractures (n = 5) more often occurred with the fixed head prosthesis systems. These stem fractures might be due to implant material failure or due to improper cementation followed by fatigue material failure. Femur fracture or infection were encountered with both prosthesis systems.     

Serum concentrations of 1,25-dihydroxycholecalciferol and 25-hydroxycholecalciferol in clinically normal dogs and dogs with acute and chronic renal failure

OBJECTIVE: To compare serum concentrations of 1,25-dihydroxycholecalciferol (1,25-[OH]2D3) and 25-hydroxycholecalciferol (25-[OH]D3) in healthy control dogs and dogs with naturally occurring acute renal failure (ARF) and chronic renal failure (CRF). ANIMALS: 24 control dogs, 10 dogs with ARF, and 40 dogs with CRF. PROCEDURE: Serum concentrations of 1,25-(OH)2D3 were measured by use of a quantitative radioimmunoassay, and serum concentrations of 25-(OH)D3 were measured by use of a protein-binding assay. RESULTS: Mean +/- SD serum concentration of 1,25-(OH)2D3 was 153 +/- 50 pmol/L in control dogs, 75 +/- 25 pmol/L in dogs with ARF, and 93 +/- 67 pmol/L in dogs with CRF. The concentration of 1,25-(OH)2D3 did not differ significantly between dogs with ARF and those with CRF and was in the reference range in most dogs; however, the concentration was significantly lower in dogs with ARF or CRF, compared with the concentration in control dogs. Mean +/- SD concentration of 25-(OH)D3 was 267 +/- 97 nmol/L in control dogs, 130 +/- 82 nmol/L in dogs with ARF, and 84 +/- 60 nmol/L in dogs with CRF. The concentration of 25-(OH)D3 was significantly lower in dogs with ARF or CRF, compared with the concentration in control dogs. CONCLUSIONS AND CLINICAL RELEVANCE: The concentration of 1,25-(OH)2D3 was within the reference range in most dogs with renal failure. Increased serum concentrations of parathyroid hormone indicated a relative deficiency of 1,25-(OH)2D3. A decrease in the serum concentration of 25-(OH)D3 in dogs with CRF appeared to be attributable to reduced intake and increased urinary loss.