The purpose of this study was to evaluate the effects of 2 methods of blood collection in unanesthetized mice. The saphenous venipuncture method was compared with a modified tail-clip technique that requires minimal restraint. Mice were evaluated through behavioral observation and plasma corticosterone levels. The results showed that the 2 methods produced similar corticosterone responses and that the tail-clip method produced fewer behavioral reactions. In addition, the effects of saphenous venipuncture method appeared to be dependent on the handler's technical expertise. When a series of 4 blood collections were performed over 1 wk, the 2 methods yielded similar corticosterone levels that did not increase over time. Some of the behavioral signs appeared to increase over the series of blood collections obtained by the saphenous venipuncture method. Serial complete blood counts showed that the tail vessels yielded higher total white blood cell, neutrophil, and lymphocyte counts than did the saphenous vein. Neither method appeared to cause stress-associated changes in the leukogram after serial blood collection. Overall, the effects of modified tail-clip method were similar to those of the saphenous venipuncture method in unanesthetized mice.

Studies on humans and rodents indicate possible long-term cognitive impairment after surgery or general anesthesia. The goal of this study was to evaluate the effect of various anesthetic concentrations on spatial learning in adult mice. The behavior of adult mice in a T-maze was assessed 28 h after anesthesia (control [0%], low [1%], or high [2%] isoflurane concentration). The mice anesthetized with 1% isoflurane had a significantly poorer performance than did the other 2 groups. The performance of the mice anesthetized with 2% isoflurane was not statistically different from that of the control group. Therefore, low, not high, isoflurane concentration impaired spatial learning in mice.

A breeding colony consisting of 250 different strains of mice was treated with the topical acaricide selamectin for the mouse fur mite Myocoptes musculinus, with no apparent ill effect, suggesting that this drug is safe for use in mice. To further evaluate their efficacy in treating Myocoptes spp., we compared selamectin with another acaricide, moxidectin, in a controlled manner. Infested mice were treated with selamectin or moxidectin at the time of cage change, and a subset of mice was retreated 10 d later. Mice underwent routine cellophane tape examination of the pelage for 1 y. Although no adult mites were found in any group at 1 mo after treatment, egg casings were found in the selamectin treatment group as late as 6 mo after treatment, prompting concern about its effectiveness. Moxidectin used in combination with cage changing was effective in eradicating mites, with mice negative for traces of mites on cellophane tape examination of the pelage from months 2 through 12 after treatment.

Murine norovirus (MNV) causes subclinical chronic infections in adult immunocompetent mice and is endemic in many mouse colonies. The susceptibility of neonatal mice to MNV infection was investigated. Intestinal homogenates from Swiss Webster (SW) mice inoculated orally with MNV-L on postpartum days (ppd) 1 to 3 were negative for MNV by RT-PCR at postinoculation days (pid) 3 and 7. In contrast, 69% of intestinal homogenates prepared on pid 3 and 7 from mice inoculated orally at ppd 5 to 8 were MNV-positive by RT-PCR. Because only mice 10 d of age or older were infected by contact with infected dams, a study was performed to determine whether fostering of neonatal mice from MNV-infected to MNV-naïve dams could be effective at preventing infection of neonatal mice. Four litters each of 1-, 2-, 4-, or 6 d-old mice from MNV-L– infected dams were transferred to naïve dams with similar-aged litters and vice versa. On ppd 21, feces from all MNV-infected dams and litters transferred to them were MNV-positive. In contrast on ppd 21, feces from all MNV-naïve dams and litters transferred to them were MNV-negative. Fostering of 2-d-old mice from 5 of 5 MNV-C–, 5 of 6 MNV-D–, and 7 of 8 MNV-G– infected dams onto MNV-naïve dams prevented MNV infection of the foster mice. In the 2 litters where MNV was detected, dams were infected within 7 d of transfer, suggesting that the neonatal mice had served as fomites. In summary, fostering was effective at preventing MNV infection in 33 of 35 litters of neonatal mice. Precautions to prevent transmission of virus on the surface of neonatal mice to foster dams could increase the efficiency of the fostering process.

According to serologic surveys, murine norovirus (MNV) is the most prevalent viral pathogen infecting mice used in biomedical research. However, the use of sentinel mice to detect MNV-infected mouse populations has not been evaluated thoroughly. To this end, an experimental method of soiled bedding transfer was created to mimic a quarterly sentinel monitoring program. Soiled bedding (15 or 30 cm³) from ICR mice experimentally infected with MNV4 was transferred weekly to cages of pair-housed 4-wk-old ICR mice. After 12 wk, both mice in 80% (4 of 5) of cages receiving either 15 or 30 cm³ of soiled bedding were seropositive for MNV and were shedding virus in feces. To evaluate the stability of MNV RNA in mouse feces, fecal pellets from MNV-infected sentinel mice were stored at room temperature for as long as 14 d. After storage, all fecal samples tested positive for MNV by RT-PCR. To determine whether fecal samples could be pooled for MNV detection, 1 MNV-positive fecal pellet was combined with either 9 or 19 MNV-negative fecal pellets. All pooled fecal samples were positive for MNV by RT-PCR at both dilutions. These data indicate that although MNV-infected mouse populations can be detected by exposing sentinel mice to MNV-contaminated bedding, detection failures can occur. In addition, there was high agreement in the MNV infection status of cohoused sentinel mice. These data also demonstrate that MNV is readily detectable in pooled fecal samples and in mouse feces stored at room temperature for 2 wk.

Because microsatellite markers have a high degree of genetic variability, they are an effective tool for genetic monitoring. We have developed a genotyping panel containing 87 microsatellite markers that are polymorphic among commonly used inbred rat strains, including ACI, Fischer 344, Lewis, Brown Norway, Wistar–Furth, and Wistar–Kyoto. The markers are located at approximately 15- to 20-cM intervals along each of the 20 autosomes. By using fluorescently labeled primers and multiplex PCR analysis, the entire genome can be assayed with only 8 reactions. The resulting amplicons from these reactions can be distinguished from one another by both their size and the fluorescent dye associated with them. Amplicons are analyzed and allele sizes are determined by using automated capillary-based instrumentation. These multiplex panels provide a cost-effective and rapid method for genetic monitoring for applications ranging from assessing genetic contamination in a rat colony to moving mutations from one genetic background to another by using a speed congenic approach.

The American bullfrog (Rana catesbeiana) is an aquatic, carnivorous member of the family Ranidae that is used extensively in physiology education programs and in various physiology, toxicology, sensorineural, and genetics research. Eleven bullfrogs purchased from a vendor distributing wild-caught frogs for use in a physiology research protocol were emaciated but otherwise showed no apparent clinical signs of illness. Necropsies performed on selected emaciated frogs indicated heavy infestation with multiple species of endoparasites. Identified helminths included Gorgodera amplicava, Haematolechus breviplexus, Clinostomum spp, Contracaecum spp, Cosmocercoides dukae, and Eustrongyloides spp. Grossly, parasitized bullfrogs showed encysted trematode larvae within skeletal muscle, nematode impaction of the intestinal tract, and lack of coelemic fat stores. Histopathologic lesions were restricted primarily to the gastrointestinal tract and consisted of parasitic granulomas associated with Contracaecum spp. The parasitic lesions may have been associated with the poor body condition of the bullfrogs. Food crickets maintained in-house were negative for parasite larvae or ova. Heavy parasitism of wild-caught bullfrogs may confound research protocols and markedly impair animal health. We encourage researchers to purchase laboratory-bred and -reared bullfrogs and to routinely monitor the parasite status of colony frogs.

Regulatory guidelines and best practices in the care of research animals allow diets milled for laboratory animals to be used within 180 d of formulation but otherwise permit latitude and professional judgment in how and when feed is offered. As such, practices at some research institutions allow for the replenishment ('topping up') of fresh chow over that existing in the cage food hopper, rather than complete replacement of the diet on a regular basis. To determine the depletion rate of a pelleted diet as fed from a conventional overhead food hopper, the consumption of full hoppers of food was measured for breeding pairs of mice in production and gender-specific groups of weanlings and juvenile mice kept in ventilated cages at 71.9 ± 0.2 °F (approximately 22.6 °C) and 40% ± 5% relative humidity. Breeding pairs of mice depleted 97% of a 250-g ration within 44 d of offering and consumed diet at a rate of 4.7 ± 0.5 g per mouse daily. Gender-grouped weanling and juvenile mice housed 5 to 6 per cage exhausted more than 99% of a 500-g ration of diet in 24 d and consumed chow at a rate of 3.4 ± 0.3 g per animal daily. These findings suggest that breeding pairs and groups of mice kept 5 to 6 per cage deplete feed at such a rate that diets can be fed by using replenishment provided diet is offered within 5 mo of the milling date.

We describe a method for managing environmental enhancement plans for individual research projects at a national primate research center where most monkeys are assigned to active research projects. The Psychological Well-being Program (PWB) at the University of Washington National Primate Research Center developed an Environmental Enhancement Plan form (EEPL) that allows PWB to quantify and track changes in enrichment allowances over time while ensuring that each animal is provided with as much enrichment as possible without compromising research. Very few projects involve restrictions on toys or perches. Some projects have restrictions on food treats and foraging, primarily involving the provision of these enrichments by research staff instead of husbandry staff. Restrictions are not considered exemptions unless they entirely prohibit an element of the University of Washington Environmental Enhancement Plan (UW EE Plan). All exemptions must be formally reviewed and approved by the institutional animal care and use committee. Most exemptions from elements of the UW EE Plan involve social housing. Between 2004 and 2006, the percentage of projects with no social contact restrictions increased by 1%, but those prohibiting any tactile social contact declined by 7%, and projects permitting tactile social contact during part of the study increased by 9%. The EEPL form has facilitated informing investigators about the enrichment their monkeys will receive if no restrictions or exemptions are requested and approved. The EEPL form also greatly enhances PWB's ability to coordinate the specific enrichment requirements of a project.

Here we describe the epizootiology and pathology of spontaneous, fatal acute intestinal pseudoobstruction that occurred in a mouse colony of 1000 breeding pairs, mainly of the C57Bl/6 strain and free from known pathogenic agents. Most of the mice affected were dams in the second week of lactation. At necropsy, segments of the small intestines were distended with fluid contents. Widespread apoptosis of the villus epithelium of the small intestine and superficial epithelial cells of the large intestine, associated with strong expression of active caspase 3, was a distinctive feature. Necrotic enterocytes, mucosal erosions, and acute mucosal inflammation were prominent in some mice, and morphologic signs of toxemia were generally present. No light microscopic neuronal changes were apparent in the gut, and no etiologic agents were identified. These results indicate that sudden activation of apoptosis in the trophically stimulated gut epithelium during peak lactation was instrumental for the fatal outcome of the condition, but the primary cause of the motility dysfunction of the bowel was not established.

We describe a case of methicillin-resistant Staphylococcus non-aureus infection in a rhesus macaque (Macaca mulatta). The nonhuman primate described was part of a research project that involved whole-body gamma irradiation and subsequently developed acute generalized dermatitis with skin dryness, peeling, and erythema around the eyes. After initial evaluation, which included microbiologic culture and 6 d of medical treatment, the animal was euthanized due to concern regarding a possible outbreak of infectious or zoonotic disease. On the basis of skin culture, diagnosis of methicillin-resistant Staphylococcus non-aureus was confirmed. This report underscores the importance of the occupational risk of methicillin-resistant Staphylococcus non-aureus to research and animal care staff in a research animal facility setting.

A 6.5-y-old cynomolgus monkey was referred to the Veterinary Medical Teaching Hospital at Chungnam National University for suspected bone fracture. The monkey had been reared singly in a cage at a laboratory facility. An animal caretaker incidentally found a bone fragment protruding through the skin of the right leg. Radiographic examination revealed 2 new bone fragments clearly distinguishable from the original femurs; the fragments seemed to be inserted into both femurs. One of the new bone fragments was easily separated surgically from the right femur. Although the bone fragment consisted of a medullary cavity and bone cortex, the periosteal structure was incomplete. New bone formation in nonhuman primates, as manifested in this case, has been reported previously. However, growth of an additional long bone from the original, penetrating the skin without motional disturbance, has not been reported previously.