This prospective, randomized, complete crossover study evaluated the effects of supplemental oxygen on arterial oxygenation and recovery quality in adult capuchin monkeys ( Sapajus spp.; n = 8; 6 males and 2 females) chemically restrained with intramuscular butorphanol (0.5 mg/kg), ketamine (15 mg/kg), and midazolam (1 mg/kg). Each monkey underwent 2 anesthetic events, separated by a 2-week interval: one breathing room air (G AIR ) and one receiving oxygen via face mask at 3 L/min (G OXY ), both conducted during dorsal recumbency. Heart rate (HR), respiratory rate (RR), peripheral oxygen saturation (SpO 2 ), and rectal temperature were registered every 10 minutes for 45 minutes. Arterial blood gases were analyzed at 10 and 30 minutes postrestraint, with oxygen supplementation in G OXY initiated after the 10-minute time point and maintained for 35 minutes. Recovery was continuously video-recorded for later assessment of time to standing and recovery quality by one blinded and one nonblinded observer. At 10 minutes, 14 of 16 monkeys exhibited hypoxemia (partial pressure of arterial oxygen [PaO 2 ] range: 48-81 mm Hg). By 30 minutes, PaO 2 and arterial oxygen saturation (SaO 2 ) increased significantly in G OXY , reaching 298-458 mm Hg and 100%, respectively, whereas G AIR animals remained hypoxemic (47-70 mm Hg and ≤92%, respectively). Pulse oximetry-derived SpO 2 consistently overestimated saturation at low SaO 2 values. The partial pressure of carbon dioxide (PaCO 2 ) rose significantly in G OXY , with hypercapnia (PaCO 2 range: 33-57 mm Hg) documented in 6/8 individuals at 30 minutes. In contrast, no cases of hypercapnia were observed in G AIR (PaCO 2 range: 22-45 mm Hg) at the same time point. No significant between-group differences were detected in SpO 2 , HR, RR, or temperature over time. Time to standing and recovery quality were similar between groups. Supplemental oxygen via face mask effectively corrected hypoxemia in Sapajus spp. chemically restrained with butorphanol, ketamine, and midazolam.
African spiny mice (Acomys spp.) are an emerging animal model for regeneration due to their remarkable healing capabilities. Defining characteristics of these species include fragile skin that sloughs easily and shedding of the tail skin when grabbed, making handling and administration of parenteral drugs difficult in conscious animals. In addition, many studies in spiny mice involve painful procedures. To our knowledge, there are no reports regarding analgesia in Acomys spp. This prospective study aimed to assess 3 sustained-release buprenorphine formulations-lipid-bound extended-release buprenorphine (XRB), polymeric sustained-release buprenorphine (SRB), and long-acting transdermal buprenorphine (TB)-in spiny mice. Adult male and female Cairo spiny mice (Acomys cahirinus) were included and administered 1 of the 3 treatments (XRB 3.25 mg/kg, SRB 1 mg/kg, or TB 20 mg/kg). Tail flick assays to assess nociception and terminal blood collection for pharmacokinetic analysis were performed at baseline and a set timepoint following treatment administration (1, 2, 4, 8, 24, 48, and 72 hours) (n = 3 of each sex per timepoint per treatment group). Additional animals underwent repeated serial tail flick assays at 1, 2, 4, 8, 24, 48, and 72 hours following the administration of treatment or sterile saline (n = 5-8 of each sex per treatment group). XRB displayed the longest duration at which mean plasma buprenorphine concentrations were >1 ng/mL, with the drug remaining above this level for 48-72 hours, compared with 24-48 hours in spiny mice receiving TB and 8 hours in those receiving SRB. On serial tail flick assays, the mean percentage of maximum possible efficacy was highest at all timepoints up to 72 hours in the TB group, followed by the XRB group, suggestive of greater analgesic efficacy. Several spiny mice receiving SRB developed ulcerative skin lesions within 24 hours of administration, so this treatment is not recommended in Acomys without additional evaluation. XRB and TB are promising analgesic therapies in spiny mice, and treatment selection should be based on whether duration of action or ease of application is the priority.
Despite the substantial growth of cephalopod research over the past 15 years, effective pain management for these animals remains largely unstudied, and no US federal regulations currently address cephalopod analgesia. This 2-phase study evaluated the feasibility and efficacy of lidocaine, bupivacaine, and extended-release bupivacaine injections for producing analgesia in juvenile Octopus bimaculoides in an established model of arm regeneration. Phase I served as a pilot to assess adverse effects, practicality, and histopathologic consequences of drug administration. Forty-nine animals were randomized to the saline control or treatment groups. Phase II assessed lidocaine, bupivacaine, and saline in an additional 34 animals, using behavioral metrics at multiple time points, including a posture and gait analysis during a walking assessment and mechanical allodynia evaluation via the von Frey filament test. Health indicators, such as weight change and respiratory rate, were also monitored. Finally, wound healing and arm regeneration were followed with photo documentation. Although all animals displayed statistically significant changes in arm posture and gait immediately postsurgery, these changes invariably resolved within 72 hours irrespective of treatment group. Moreover, health and regenerative outcomes did not differ significantly among the treatment groups. The failure of local anesthetic efficacy highlights the need for alternative analgesic regimes for octopus research.
Measuring the effect of laboratory animal facilities employees' motivational training on laboratory animal welfare is essential to study the impact of the human factor on experimental results. To test this, 15 volunteers were initially recruited, with 14 completing the motivational training, and its impact on animal welfare was evaluated in 174 Swiss mice, specifically primiparous pregnant females. The mice were grouped into a control group (n = 90), observed before the motivational training, and a treated group (n = 84), observed immediately after training. Animal welfare was assessed through various measures, including nesting ability, scored from 0 to 5, time to integrate into nest test, and maternal behavior (considering rates of maternal care such as licking/grooming and staying with the pups). Each volunteer's motivational level was evaluated using the Utrecht Work Engagement Scale, PERMA (positive emotion, engagement, relationships, meaning, and accomplishment) Profiler, and The Authentic Happiness Inventory. The motivational training was based on Yale University's course "The Science of Well-Being," the book The How of Happiness, and "Motivation and Action." Results indicated that the methods used to assess mouse welfare might have been influenced by environmental differences at each research center, resulting in a lack of reproducibility. The motivational training effect varied across research centers, suggesting context-dependent outcomes potentially influenced by environmental or institutional factors for nesting scores and maternal behavior tests. However, no effect of motivational training was observed on the time to integrate into nest test, although facility-related differences were significant. The questionnaires revealed improvements in personnel well-being, although the effect on happiness was attenuated in one facility, indicating possible institutional barriers to intervention efficacy.
Maintaining the core body temperature of anesthetized rodents is essential because of the depression of physiologic homeostasis caused by anesthetics. The maintenance of core body temperature is influenced by the ability of the heating device to provide sufficient heat, the presence of material that might alter heat transfer, and the administration of heat in the period surrounding anesthesia. In this study, optimal heat transfer from 4 unique heating devices, with or without insulating drapes, was determined initially with an inert model. Optimal animal recovery, as evaluated by recovery to baseline activity and normothermic temperature of postoperative animals implanted with an intrabdominal thermometer and monitored with a digitally ventilated caging, was achieved by a device that provided consistent electrically supplied heat at 40 °C throughout the perianesthesia period including 35 minutes before isoflurane anesthetic induction. Animals without preoperative heating required at least 24 hours to return to normal core temperature and normal circadian activity levels.
This study compares 2 rhesus macaque populations, one captive (the California National Primate Research Center [CNPRC]) and one seminatural (the Cayo Santiago [CS] population), to evaluate the impact of colony management on genetic structure. While the CNPRC houses its 4,000-plus animals in different housing enclosures, CS has a seminatural, free-ranging population of ∼1,900 individuals. Pedigrees of 3,679 animals at the CNPRC and 2,147 animals at CS were analyzed to assess cross-generational genome uniqueness (GU), inbreeding coefficients, mean kinship (MK), founder equivalents, and founder genome equivalents. An estimated 30% of the 409 CS founders contributed to the present population, compared with <10% of the 2,980 founders and subsequently introduced animals at the CNPRC. Differences in pedigree structure and potential inbreeding risk, particularly at the CNPRC, indicate a more genetically subdivided population there than at CS. The CNPRC also exhibited a lower GU than CS, whereas the MK of both colonies showed a similar upward trend over the study period (2000-2024). Also revealed are significant differences in reproductive activity, lifespan, and the number of families per individual between the 2 colonies. There are challenges in maintaining captive-bred colonies, such as the CNPRC, where restricted gene flow and inbreeding lead to dramatic declines in genetic variability. Strategies such as equalizing reproductive success, implementing cross-fostering programs for infants, and introducing new animals are insufficient to combat inbreeding, genetic subdivisions, and the loss of founder representation. Findings highlight the need for ongoing monitoring of inbreeding coefficients, GU, and MK to safeguard genetic integrity and ensure the long-term viability of captive-bred colonies. The analysis also offers insights for managing these colonies, highlighting MK as a key metric for preserving genetic diversity because it integrates founder representation, drift, and inbreeding into a colony-wide measure that directly informs colony management decisions.
Social housing of animals is well recognized as a fundamental element in providing for the well-being of social animals during laboratory research activities but is contraindicated in some experimental designs. To ascertain if social housing represented a potential confounder in studies determining influenza A virus (IAV) pathogenicity conducted in the ferret model, we analyzed data from ferrets inoculated with 56 distinct IAV strains, where animals were housed either singly or in pairs postinoculation. Parameters examined included frequency of lethal outcomes, timing and magnitude of clinical signs (weight loss and fever), and magnitude and kinetics of viral shedding in the upper respiratory tract. Statistical differences between IAV-inoculated ferrets housed in either setting were not consistently detected among any parameters examined, supporting that data from ferrets inoculated with a diverse range of avian- and mammalian-origin IAV housed singly or in social pairs may be combined and analyzed without confounding based on this variable. This study supports the utility of performing retrospective analyses to ensure results obtained from in vivo experimentation are interpreted to the highest standard possible. Further, it aligns with ethical obligations of researchers who perform in vivo experimentation to ensure these studies are designed to meet both animal welfare considerations and research goals.
Modeling disease in rodents is essential for preclinical research, particularly in the development of drugs and therapies. Traditional disease modeling approaches often rely on invasive and stressful procedures such as repeated injections and/or surgical approaches. These methods raise welfare concerns and can introduce stress-related variables that compromise model reliability. Cuprizone (CPZ) is a copper-chelating compound widely used to induce CNS demyelination in mice over a 6-week period via incorporation into ground rodent chow. However, the presumed adverse taste of CPZ reduces food intake, resulting in weight loss, inconsistent consumption, and variable levels of demyelination, complicating disease comparison. To address this, we proposed that mixing CPZ into peanut butter (CPZ-PB) would promote voluntary intake, standardize daily dosing, and minimize weight loss, while maintaining effective demyelination. Thirty mice were divided into control, CPZ-PB, or CPZ-chow groups and received treatment daily for 6 weeks. Body weight and CPZ intake were recorded daily. The effect of demyelination through mechanical allodynia was assessed via the dynamic plantar aesthesiometer. Immunohistochemical analysis of myelin proteins and astrocyte activation was conducted on the brain and spinal cord after 6 weeks of treatment. Voluntary consumption of CPZ-PB successfully ameliorated weight loss concerns and achieved consistent daily CPZ dosing. Behavioral and immunohistochemical analyses confirmed effective demyelination comparable to traditional CPZ-chow methods. This study introduces an improved CPZ administration strategy that enhances animal welfare and provides a more reliable model for demyelination research.
Repeated survival surgical oocyte collection in African clawed frogs (Xenopus laevis) is commonly performed to access high-quality, viable oocytes for research procedures and to reduce the number of animals used in research. Despite this common practice, there is no evidence-based limit for the total number of survival celiotomies that can be performed. To provide an improved reference, a retired colony of experimental frogs (n = 31) was euthanized for gross and histopathologic evaluation and then compared with 4 experimentally naive age-matched controls (n = 4). Experimental animals underwent 4-11 celiotomies (average 6 ± 2) and were between 180 and 1,646 days (average 448 ± 245.2 days) from their last surgery. Body weight, residual skin, and coelomic wall sutures were counted. Surgically incised skin and coelomic wall musculature were collected for histopathology. A cumulative skin score and a coelomic wall score were developed to reflect all histopathologic evidence of acute and chronic inflammation. The cumulative skin score was significantly predicted by the number of surgeries (P = 0.003), but not predicted by the number of skin sutures remaining (P = 0.14). The coelomic wall score was significantly predicted by the number of coelomic sutures placed (P < 0.001) and the number of surgeries (P < 0.001). Neither one of the histopathology scores correlated to the number of days since the last surgery (P > 0.2). As one would expect, increasing the number of surgeries and coelomic sutures correlated with the histopathologic finding of a chronic inflammatory process in the skin. Although a specific recommendation for a maximum number of surgeries could not be discerned, this study provides an improved reference for Xenopus survival surgical oocyte collection underscoring the recommendation to use absorbable sutures within the body cavity and to remove all external nonabsorbable sutures 10-14 days postoperatively.
Jugular vein (JV) blood sampling is widely employed in pharmacological, toxicological, and pharmacokinetic studies due to its ability to provide large and repeatable blood volumes. However, current approaches are constrained by low convenience, safety concerns, and variable sample quality. Here, we report the development of a new single-operator JV blood sampling technique for conscious rats. By optimizing animal restraint, puncture site localization, and procedural standardization, the method significantly reduced sampling time, puncture attempts, pain-related behaviors, and hemorrhagic injury, while ensuring consistent blood yield. Compared with the conventional approach, it achieved a 100% success rate, halved the average sampling time, and maintained stable serum biochemical, coagulation, and hematologic parameters. The utility of this method was further confirmed in an intraperitoneal glucose tolerance test and a cisplatin-induced acute kidney injury model, where data consistency was preserved. This technique provides a convenient, safe, and reliable alternative for repeated blood collection in conscious rats, ensuring animal welfare and supporting the generation of high-quality data in preclinical research.
Compounded sustained-release buprenorphine (SRB) has historically been used at our institution for postoperative analgesia in African green monkeys (AGMs), but it is not FDA approved and lacks species-specific data. With the recent FDA indexing of pharmaceutical-grade extended-release buprenorphine (EXR; Ethiqa XR; Fidelis), we aimed to compare the pharmacokinetic (PK) profile using serial plasma sampling up to 96 hours and postoperative analgesic efficacy of EXR compared with SRB. A total of 10 AGMs (n = 5 per test article) received 0.2 mg/kg SC of either EXR or SRB to complete the PK study. For the efficacy study, 20 animals (n = 10 per test article) were monitored for 3 days postoperatively after EEG telemetry surgery with femoral artery catheterization for behavioral indicators of pain and adverse effects. Plasma buprenorphine levels were analyzed using liquid chromatography-tandem mass spectrometry. PK study observations included appetite, fecal output, and injection site reactions. Both formulations achieved plasma concentrations above the presumed therapeutic threshold (0.1 ng/mL) for up to 96 hours. SRB produced higher mean plasma levels at early time points (30 minutes, 4 hours), but the overall PK profiles were similar. Injection site reactions were minimal and resolved spontaneously. For the efficacy assessment, clinical observations were evaluated using a postoperative score sheet. No significant differences were observed in postoperative pain scores between groups. Both EXR and SRB at 0.2 mg/kg SC provided sustained therapeutic plasma levels up to 96 hours and were well tolerated in AGMs, with comparable efficacy in postoperative pain control. EXR offers a compliant and effective alternative to compounded SRB for analgesia in AGMs, supporting its use in laboratory settings and regulatory compliance with current guidelines.
The human-animal relationship is undergoing a profound cultural shift, reshaping how societies-and professionals-understand animal welfare. In biomedical research, these changing attitudes have begun to influence the role of laboratory animal veterinarians, whose work now sits at the intersection of care, ethics, and compliance. While compassion-driven caution is laudable, the growing tendency toward moral gatekeeping risks impeding ethically justified science. This piece argues for renewed partnership between veterinarians and scientists grounded in evidence, trust, and shared responsibility. Sustaining both animal welfare and scientific progress requires not greater division, but deliberate collaboration-anchored in the belief that ethical research involving animals is a moral good.
Upon importation, laboratory mice may undergo prophylactic antiparasitic treatment during quarantine to prevent the introduction of parasites into established colonies. While quarantine protocols vary across institutions, ivermectin is commonly used, administered either orally or topically. However, the impact of these practices on the fecal microbiome remains poorly understood, raising concerns about unintended consequences for experimental outcomes. This study investigated the effects of ivermectin on fecal microbiome composition in naïve, healthy male and female C57BL/6J mice. Animals received either ivermectin-impregnated feed (12 ppm, ad libitum for 4 weeks), weekly topical ivermectin solution (2.0 mg/kg for 4 weeks), or no treatment (controls). Fecal samples were collected for 16S rRNA-based microbiome analysis before ivermectin treatment, immediately posttreatment, and 4 weeks after treatment cessation. Weekly body weights were recorded, and histopathologic evaluation of the small intestine and colon was performed at study completion. Both oral and topical ivermectin treatments resulted in significant alterations in microbiome α and β diversity at the end of treatment, with more pronounced effects observed in female mice. Some of these changes persisted for up to 4 weeks after treatment cessation. Furthermore, the findings indicate a sex-specific effect of ivermectin on specific bacterial orders, with Bacillales predominantly affected in male mice, whereas Coriobacteriales and Bacteriodales were primarily impacted in female mice. During treatment, males receiving topical ivermectin weighed significantly less than controls, while females receiving dietary ivermectin weighed significantly more. Histopathological analysis revealed no abnormalities in intestinal tissues across all groups at 4 weeks posttreatment. These findings demonstrate that ivermectin administration induces measurable and persistent changes in the fecal microbiome of healthy mice. Researchers should consider these effects when designing experiments, and institutions must weigh the benefits of colony protection against potential microbiome-related confounding variables.
Rodents are highly susceptible to peri-anesthetic hypothermia because of their small body size, large surface area to volume/mass ratio, and anesthetic-induced thermoregulatory depression. Early heat loss during induction is rapid and can be difficult to reverse, emphasizing the need for simple, reliable warming solutions during anesthetic induction. We designed and validated a low-cost, Arduino-controlled heated induction chamber for mice and evaluated its safety and efficacy in preventing early hypothermia. The device uses proportional integral derivative control to regulate a heated chamber floor. Bench testing quantified warm-up time, steady-state stability, and the temperature offset between the embedded thermistor and surface temperature. In a randomized, paired, repeated-measures design, 10 adult C57BL/6 mice underwent 2 experimental conditions, unheated induction compared with heated induction, followed by a standardized 10-minute anesthetic maintenance phase on a prewarmed, heated surgical monitoring platform. Core body temperature was measured with intraperitoneal radio frequency identification transponders, while rectal temperature and physiologic parameters (peripheral oxygen saturation, heart rate, respiratory rate) were recorded during maintenance. Recovery time was measured from isoflurane discontinuation until the first voluntary movement. The heated chamber reached thermal stability within 10 minutes; at steady state, a constant average surface temperature near 37.5 °C was reliably obtained. During induction, unheated controls showed a rapid decline in core temperature, while during the heated-chamber induction, they maintained normothermia. The control group did not regain baseline temperature until several minutes into the maintenance phase and stabilized at values ∼1 °C lower than those of the heated group. Both groups remained physiologically stable during anesthetic maintenance and recovered within comparable times. This cost-effective, Arduino-based chamber prevented early hypothermia without compromising physiologic stability and represents a practical refinement to improve rodent anesthetic procedures, animal welfare, and experimental reproducibility.
Cage changes can be a stressful period in a mouse's life due to the rapid change of environment. It is essential to study the behavioral effects of a cage change on mice, including drinking, eating, aggression, and sleep, as these can affect research variability. This study evaluated the effects of a cage change on behavior and whether transferring nesting material could mitigate the negative effects of a cage change. Using home cage monitoring with computer vision artificial intelligence, 40 C57BL/6 mice were continuously monitored for 2 consecutive cage changes. Mice received either new nesting material (control) or transferred soiled nesting material at cage change. Data were analyzed before and after a cage change and reported for at least 3 days or until baseline behavior resumed. Parameters collected included time spent drinking, eating, sleeping, and aggression. Two hours after a cage change, drinking and eating significantly increased, and sleep significantly decreased compared with pre-cage change values. Long-term effects ranged from decreased sleep in the first 24 hours to decreased eating for 3 days post-cage change. Total distance traveled was increased up to day 4 post-cage change, and rearing time was increased for 3 days after a cage change. All significant behaviors gradually stabilized by day 5. Transfer of old nesting material had no significant impact at any time point. These results show that there are both long-term and short-term effects of a cage change, and nest transfer may not influence these parameters in C57BL/6 mice.
Humans work with animals in many different ways. In some contexts, animals are allowed to 'retire' and be rehomed in sanctuaries or private homes when they are no longer able or needed to work. Similarly, laboratory animals can be rehomed at the end of a study. However, there is relatively little research on stakeholders' perceptions of rehoming. We explored the views of three key groups: the people who adopt these animals, the animal technicians who care for these animals prior to rehoming, and the researchers who are normally responsible for most of the interactions between people and these animals. To do this, we carried out a thematic analysis of semistructured interviews. Our aim was to obtain insights that could inform reflection and guide future research priorities around rehoming programs. Our study demonstrated support for laboratory rat rehoming in all stakeholder groups. Rehomers' and technicians' comments focused chiefly on the potential benefits of rehoming to the animal and benefits to institutional openness. Researchers made similar comments, but these were tempered by concerns around the welfare of the animals after rehoming, the fate of animals that cannot be rehomed, rehomers' health and wellbeing, and the potential risks associated with the transparency of individual's and the institution's use of animals in research. We discuss these themes in the context of the ethics of laboratory animal use, manifesting a culture of care, and challenges around enhancing institutional openness on animal research.
Tunnel handling is a widely recommended, less-aversive method for improving laboratory mouse welfare by reducing handling-induced anxiety. While its effects on behavioral tests and physiologic outcomes have been reported, little is known about its impact on stress responses to brief restraint procedures commonly used in daily health checks and experimental work. This study aimed to investigate whether tunnel or tail handling influences the physiologic stress response of mice following a brief scruff restraint. Female BALB/c mice were assigned to one of 4 groups combining 2 handling methods (tail or tunnel) with or without a 10-second scruff restraint. Both single and repeated restraint procedures were evaluated separately. Voluntary interaction with the handling device was used to assess the suitability of the handling method. Plasma corticosterone (pCORT) concentrations were measured 20 minutes after restraint to evaluate the physiologic stress response. Tunnel-handled mice showed longer voluntary interaction times than tail-handled mice, indicating reduced handling aversion. Scruff restraint increased pCORT concentrations in both tail- and tunnel-handled mice. However, the handling method did not significantly affect pCORT concentrations following either single or repeated restraint. These findings suggest that the handling method has minimal impact on physiologic stress following brief restraint, supporting the use of less-aversive handling techniques without concern for confounding stress effects.
Single housing of animals, or social isolation, is a known stressor for many species. Generally, laboratory animals are housed in social groups as a default to support their behavioral welfare. In some research protocols, investigators may request exemptions from social housing policies after surgical procedures due to concerns that cohoused animals may damage implanted devices, remove each other's wound closures, or cause other stress or injury that may interfere with the study. However, the practice of singly housing postoperative animals may result in greater stress for animals and unintended consequences for research being conducted. Therefore, the IACUC or relevant ethical body should judiciously consider any request for single housing and require adequate justification for making this exception. This review discusses the social nature of some common research animals, the research effects of single housing, the regulatory requirements for social housing, and successful cases of socially housing postoperative and/or instrumented animals in the research setting with the goal of promoting social housing of postoperative animals.
Corynebacterium bovis is an opportunistic bacterium that infects the skin of immunodeficient mice used in biomedical research. C. bovis was first deemed clinically significant in the mid-1990s. To date, only limited data are available on the prevalence of this infection among research institutions in the United States. Here we define prevalence as the proportion of institutions that have C. bovis-infected mice in their care. To determine the national prevalence of C. bovis infections, we performed a survey of animal resource program directors and veterinarians at the NIH top 50 funded academic institutions and all Designated Cancer Centers of the National Cancer Institute. This survey was initially performed in 2015 and then expanded and repeated in 2023. Survey questions assessed institutional C. bovis status (positive, negative, or unsure), surveillance practices, and attempts to establish C. bovis-free colonies through bioexclusion. Responses were obtained from 81 institutions in 2015 and 85 in 2023, achieving 100% participation in both years. Between 2015 and 2023, C. bovis-positive status declined slightly (49% to 45%), negative responses dropped more sharply (38% to 22%), and uncertainty increased (12% to 33%), resulting in an overall shift in response distribution (P = 0.002). Despite the increased uncertainty, 69% (59/85) of all institutions in 2023 performed active surveillance for C. bovis in some form. Similarly, of institutions that self-report as having C. bovis-infected mice, 84.2% (32/38) performed C. bovis surveillance, and 78.9% (30/38) have used bioexclusion techniques. Overall, 71.7% (61/85) of institutions recognize C. bovis as an actionable pathogen. Conversely, between 20% and 28% (17 and 24/85) of institutions in 2023 did not see C. bovis as an actionable pathogen and, if present, chose to tolerate it.
A female, research-naive, strain 13 guinea pig with no previous significant health history was noted to have a persistent vaginal discharge. On physical examination a soft mass was noted in the lower abdomen accompanied by a serosanguineous vaginal discharge. Due to a poor prognosis, the animal was euthanized. At necropsy, the left uterine horn was markedly enlarged and contained a large amorphous mass. Light microscopy examination showed that the mass had dense areas containing stromal cells surrounded by connective tissue, congested blood vessels, areas of necrosis, hemorrhage, and occasional cyst formation. In some areas numerous bacteria, both rods and cocci, were noted and the uterine wall showed increased thickness caused by a polymorphonuclear cell inflammatory infiltrate. Bacteriological culture and isolation from the vaginal discharge revealed a mixed infection with Escherichia coli, Bacteroides fragilis, Proteus mirabilis, Enterococcus spp., and α-hemolytic Streptococcus spp. while culture and isolation from the uterus revealed a mixed infection with E. coli, Pseudomonas aeruginosa, B. fragilis, and Globicatella sanguinis. The pathology findings were consistent with decidual cell reaction and endometritis. Vaginal bleeding is not a common clinical sign in decidual cell reaction and usually does not require treatment since the lesion in many cases resolves on its own by apoptosis and resorption. However, in this case, systemic antibiotics may have been beneficial to treat the endometrial infection. These findings suggest that decidual cell reactions may occur accompanied by, or as a result of, intrauterine infections in guinea pigs. The potential role of bacteria in decidual cell reaction should be further explored in guinea pigs.
