Journal of the American Association for Laboratory Animal Science : JAALAS最新文献

Diarrhea remains the largest disease burden of rhesus macaques in research. Often, the urgency to initiate targeted treatment needs to be balanced with the time needed to accurately diagnose the causative agent. Multiplex PCR gastrointestinal panel testing was compared with conventional fecal culture in a case control study of diarrhea in rhesus macaques. Animals enrolled in the study were from 2 different institutions and 2 different housing environments. Detection of Shigella and Yersinia by fecal culture had higher odds ratios of diarrhea and higher attributable diarrhea risk than did their detection by PCR testing. Multiplex PCR testing had a wider scope of detectable pathogens. The findings of this study provide odds ratios that indicate significant associations between pathogens and diarrhea and attributable diarrhea risk of pathogens that can be ranked relative to each pathogen to provide a guide to clinicians when choosing pathogens to treat with antimicrobials. We have shown that the attributable diarrhea risk of detected pathogens differs depending on which diagnostic method is used, and that our understanding of their detection should be reevaluated when new diagnostics are introduced.

The increased sensitivity of PCR testing for environmental health monitoring compared with soiled bedding sentinel (SBS) serology can identify rodent pathogens thought to be excluded from a research animal facility. Exhaust dust testing for rodent pathogen surveillance revealed the presence of Pneumocystis murina in 3 colonies that was undetected in previous years of SBS serologic testing. This case series describes the process of follow-up testing used to identify and eliminate or isolate animals infected with P. murina. PCR testing of exhaust dust at the rack, row, and cage level on individually ventilated cage (IVC) racks was leveraged to identify all infected cages. Based on our experience, IVCs and standard cage handling practices are sufficient to contain this organism in mice with altered immune systems, which can harbor chronic P. murina infections. Institutions with an active mouse import program are at ongoing risk of accepting P. murina-positive animals from institutions still relying on SBS serology to identify this pathogen. PCR testing of rodent cage-generated dust can be used to pinpoint P. murina-infected mice housed on IVC racks.

Environmental enrichment is a critical component of a high-quality animal care and use program to provide opportunities for species-specific behaviors and redirect abnormal repetitive behaviors. We used a scoring system to review our enrichment for singly housed mice to assess usage of supplied items. Following the confirmation of utilization of the selected enrichment, we applied the scoring system to address 2 cases of abnormal behavior. Repetitive food shredding in CD-1 mice was reduced by both manzanita sticks and running wheels; however, manzanita sticks were selected for operational ease. Focal auricular trauma associated with ear tags in BALB/c mice was decreased when gnawing items were provided, thus slowing the deterioration of ear tag condition. Scoring for all 3 studies focused on use of the enrichment, incorporation into the nest, or reduction of abnormal repetitive behavior. The development of a scoring system permits the objective assessment and selection of enrichment for unique scenarios, thus enhancing animal welfare and permitting a standardized way to evaluate enrichment for specialized projects.

Swine are commonly used in biomedical research as surgical models and in other experiments requiring the use of anesthesia. Isoflurane is a common inhalant anesthetic used in swine that has been shown to alter hematologic parameters in other species. However, the effects of isoflurane on hematologic parameters of swine over time have not been defined. In this study, we examined the effect of isoflurane anesthesia on hematologic parameters in 29 female Yorkshire/Landrace hybrid domestic swine at 3 timepoints. A secondary objective was to compare hematologic values in isoflurane-anesthetized animals that received intramuscular tiletamine-zolazepam (TZ) or a combination of ketamine-acepromazine-hydromorphone (KAH) for induction. Swine were induced with TZ or KAH, followed by nose cone delivery of 3.5% to 5% isoflurane to facilitate endotracheal intubation, and maintained with 1.75% to 3.5% isoflurane. Venous whole blood was collected for hematologic analysis at baseline upon recumbency after intramuscular administration of TZ or KAH, and at 30 min (T30) and 60 min (T60) of isoflurane administration. There were significant decreases in red blood cell (RBC) count, hematocrit (Hct), and hemoglobin after 30 min of isoflurane anesthesia, and between 30 and 60 min of isoflurane anesthesia. Hct decreased from 35.4% at baseline to 31.8% after 30 min of isoflurane anesthesia, and 31.1% after 60 min of isoflurane anesthesia. The decrease in RBC parameters was accompanied by a significant increase in reticulocyte count at T30 and T60 compared with baseline. When comparing the TZ and KAH groups, Hct and hemoglobin were significantly lower at T30 and T60 in the TZ group, and WBC and neutrophils were significantly higher at T60 in the KAH group. These results indicate that anesthesia alters certain hematologic parameters in swine, thus veterinarians and researchers should take care to avoid misinterpretation of CBCs when blood is collected from anesthetized swine.

This study aimed to evaluate the effect of opioids on thermal threshold in rabbits. Eight healthy female New Zealand White rabbits randomly received each of 10 treatments at least 7 d apart. Treatments were morphine (1, 3, and 5 mg/kg), buprenorphine (0.05, 0.1, and 0.2 mg/kg), butorphanol (0.4, 0.8, and 1.6 mg/kg), and 0.9% saline all in equivalent volume of saline administered subcutaneously. Sedation scores and thermal threshold were evaluated prior to and at 30, 60, 120, 180, 240, and 300 min after treatment by a blinded observer. Sedation was assessed using a scoring system from 0 (unconscious) to 4 (normal) plus an additional category of 5 for excited behavior or increased activity. Morphine, at all 3 doses tested, increased thermal excursion (thermal threshold minus skin temperature) with effects from 3 to 5 mg/kg lasting to the 240-min evaluation. All morphine doses produced some degree of sedation. Buprenorphine (0.1 mg/kg) increased thermal excursion at 60 and 120 min and produced mild sedation. Two, 6, and 7 of the 8 rabbits took 12 to 18 h to urinate after administration of buprenorphine at 0.05, 0.1, and 0.2 mg/kg, respectively. Both saline and butorphanol had no effect on thermal threshold. Behavioral effects of butorphanol varied with some animals being sedated and some displaying heightened activity. Following butorphanol at 1.6 mg/kg, 5 of the 8 rabbits scored 5 at some time point. All rabbits had eaten and defecated within 12 h of all treatments.

Murine pathogens affect laboratory animal health and research outcomes, and the prevention of pathogen incursion or the elimination of pathogen outbreaks is paramount. To this end, sensitive methods for pathogen detection are continually being developed and improved. Environmental health monitoring has become a popular and sensitive method for pathogen detection. Published methods for environmental sampling include the collection and testing of exhaust air filters, exhaust air duct swabs, and swabs or filter media placement in empty cages with soiled bedding. Our study tested soiled, cotton nesting material (Nestlet™) in occupied cages for the detection of nucleic acid from certain, high-prevalence, murine pathogens. Nesting material from cages housing mice positive for mouse norovirus, Helicobacter spp., and Rodentibacter heylii consistently tested positive for these agents. In addition, nesting material from cages housing naïve mice to which soiled bedding from the infected cages was transferred tested positive for these agents more often than testing the mice directly. This study concluded that testing of particulate material (for example, dust) from soiled nesting material is a sensitive detection method for certain, high-prevalence murine pathogens.

Reports of congenital heart disease in nonhuman primates are rare, and double-chambered right ventricle (DCRV), which is a rare congenital heart disease, in which an abnormal muscle bundle divides the right ventricle into 2 chambers (a proximal high-pressure chamber and a distal low-pressure chamber), has not been previously reported. We diagnosed DCRV antemortem in 2 monkeys bred at The Tsukuba Primate Research Center that presented with cardiac murmurs. Subsequent diagnostic evaluation confirmed DCRV in one case, with the other diagnosed with midventricular obstruction having a pathophysiology similar to DCRV. The monkey that had DCRV exhibited a pathophysiology similar to that in humans with DCRV, while the other monkey had a condition mimicking DCRV which was due to a thrombus. We believe this to be the first report of DCRV and a rare DCRV-like pathophysiology due to a thrombus in the ventricle in nonhuman primates.

Alfaxalone has been studied for anesthetic induction of rabbits with rapid onset and a short duration of action; however, it has been minimally evaluated as an option for anesthetic maintenance. This study compared alfaxalone-based total intravenous anesthesia maintenance protocols against inhaled isoflurane, the current standard for anesthetic maintenance in rabbits. Twenty-four male New Zealand White rabbits were assigned to 1 of 3 treatment groups: isoflurane alone, alfaxalone with buprenorphine, or alfaxalone with midazolam. All rabbits were premedicated with buprenorphine HCl (0.02 mg/kg SC) and induced with alfaxalone (6 mg/kg IM). Following intubation and with supplementation of 100% O2, rabbits were maintained for 1 h on either isoflurane (2.5%) or alfaxalone continuous rate infusion (CRI) (0.2 mg/kg/min). For rabbits on the alfaxalone CRI, boluses of buprenorphine HCl (0.01 mg/kg IV or SC) or midazolam (0.1 to 0.3 mg/kg SC) were given upon induction or adjunctively as needed dependent on positive tail-pinch responses that were conducted at timepoints t0, t15, t30, t45, and t60. Heart rate, invasive blood pressure, respiratory rate, end-tidal CO2, percent O2 saturation, and temperature were recorded every 5 min. Surgical plane of anesthesia was characterized by lack of positive response to a tail clamp and was reached in all anesthetic groups. Results showed significant reduction in heart rate of the alfaxalone groups while there was no significant difference in mean arterial pressure compared with the isoflurane groups. However, respiratory rate in the alfaxalone groups was decreased with associated increases in end-tidal CO2 levels. There were no significant differences noted between alfaxalone treatment groups. The results confirmed that CRI alfaxalone (total intravenous anesthesia) should be considered as a potential anesthetic alternative to isoflurane anesthesia in rabbits, although special attention to respiratory monitoring and management is warranted.