Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0014070 (encephalomyelitis)
 13,017 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report the outcome of a 30-month programme to rederive 310 specific pathogen-free mouse strains to populate a new individually ventilated cage barrier facility at the Mary Lyon Centre (MLC), Medical Research Council (MRC) Harwell. The mice were rederived in a self-contained quarantine suite and embryo-recipient females were health-screened to assess microbiological status, before moving their offspring into the new facility. The MLC currently houses approximately 49,000 mice in about 9750 cages and we have 30 months of follow-up health screen data. Embryo rederivation and hysterectomy have high safety margins; however, the precaution of performing the programme in isolators facilitated the containment and decontamination of two mouse hepatitis virus (MHV) infection outbreaks. Rederivation of the colony has eliminated endemic MHV, mouse adenovirus type 2 (MAV-2), Theiler's murine encephalomyelitis virus, pinworms, intestinal protozoa, Pasteurella pneumotropica, Helicobacter spp. and mites. The improvements in microbiological status have had notable benefits for mouse health and welfare and the science at MRC Harwell. Previously important clinical entities such as sudden death associated with lactation ileus in C3H/HeH mice, early weight loss associated with inflammatory bowel disease in B6-TgN(HDexon1)61Gpb and B6TgN-(HD82Gln)81Dbo (Huntington) mice and early weight loss in male mice mutagenized with N-ethyl-N-nitrosourea have been markedly reduced or eliminated.
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PMID:Upgrading mouse health and welfare: direct benefits of a large-scale rederivation programme. 1843 71

Although some previously common infections, such as Sendai virus and Mycoplasma pulmonis, have become rare in laboratory rodents in North American research facilities, others continue to plague researchers and those responsible for providing biomedical scientists with animals free of adventitious disease. Long-recognized agents that remain in research facilities in the 21st century include parvoviruses of rats and mice, mouse rotavirus, Theilers murine encephalomyelitis virus (TMEV), mouse hepatitis virus (MHV), and pinworms. The reasons for their persistence vary with the agent. The resilience of parvoviruses, for example, is due to their resistance to inactivation, their prolonged shedding, and difficulties with detection, especially in C57BL/6 mice. Rotavirus also has marked environmental resistance, but periodic reintroduction into facilities, possibly on bags of feed, bedding, or other supplies or equipment, also seems likely. TMEV is characterized by resistance to inactivation, periodic reintroduction, and relatively long shedding periods. Although MHV remains active in the environment at most a few days, currently prevalent strains are shed in massive quantities and likely transmitted by fomites. Pinworm infestations continue because of prolonged infections, inefficient diagnosis, and the survivability of eggs of some species in the environment. For all of these agents, increases in both interinstitutional shipping and the use of immunodeficient or genetically modified rodents of unknown immune status may contribute to the problem, as might incursions by wild or feral rodents. Elimination of these old enemies will require improved detection, strict adherence to protocols designed to limit the spread of infections, and comprehensive eradication programs.
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PMID:Old enemies, still with us after all these years. 1850 62

Periodic health screening of rodents used in research is necessary due to the consequences of unwanted infections. One determinant of the risk of infection for any given agent is its prevalence; other factors being equal, a prevalent agent is more likely than a rare one to be introduced to a research facility and result in infection. As an indicator of contemporary prevalence in laboratory populations of rats and mice, the rate of positive results in the samples received at a major commercial rodent diagnostic laboratory was compiled for this paper. Although samples from laboratory rodent vendors have been excluded, results are tabulated from samples from more than 500,000 mice and 80,000 rats submitted over several years from pharmaceutical, biotechnology, academic, and governmental institutions in North America and Europe, allowing meaningful determination of which agents are common in the research environment versus which agents are rare. In mice, commonly detected infectious agents include mouse norovirus, the parvoviruses, mouse hepatitis virus, rotavirus, Theiler's murine encephalomyelitis virus, Helicobacter spp., Pasteurella pneumotropica, and pinworms. In rats, commonly detected infectious agents include 'rat respiratory virus', the parvoviruses, rat theilovirus, Helicobacter spp., P. pneumotropica, and pinworms. A risk-based allocation of health-monitoring resources should concentrate frequency and/or sample size on these high-risk agents, and monitor less frequently for the remaining, lower-risk, infectious agents.
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PMID:Contemporary prevalence of infectious agents in laboratory mice and rats. 1901 79

Wild rodents are a potential source for pathogen introduction into laboratory animal research facilities. A study was designed to assess wild mice found at our institution by infectious disease surveillance. Wild white-footed mice (Peromyscus leucopus) were captured with live capture traps placed in areas in which wild mice had been reported in several animal facilities. Captured animals were euthanized by inhalation of CO(2), blood was collected by cardiocentesis (n = 10), and necropsy was performed (n = 8). Serum samples were negative for antibodies to mouse parvovirus (types 1 and 2), mouse minute virus, Sendai virus, pneumonia virus of mice, mouse hepatitis virus, Theiler murine encephalomyelitis virus, reovirus, rotavirus, lymphocytic choriomeningitis virus, mouse adenovirus, ectromelia virus, K virus, cilia-associated respiratory bacillus, and Mycoplasma pulmonis. Of the 8 animals that were necropsied, pelt and cecal examinations were negative for ectoparasites and pinworms, respectively. Histopathologic examination of brain, heart, lungs, liver, kidney, spleen, stomach, and small intestine revealed bacteria morphologically compatible with Helicobacter spp. in the cecal and colonic glands and occasionally in the gastric lumen and pits. Mesenteric lymph nodes and feces from 8 of the animals were submitted for PCR analysis for the detection of mouse parvovirus, mouse minute virus, mouse hepatitis virus, and Helicobacter spp.; 7 of the samples were PCR-positive for Helicobacter spp. At this time, wild mice found in our animal facilities do not appear to be a significant source of common laboratory mouse viral pathogens. However, they are a potential source of Helicobacter infections.
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PMID:Helicobacter spp. in wild mice (Peromyscus leucopus) found in laboratory animal facilities. 1993 Aug 23

Parasitic infections are a concern in animal facilities, in view of their influence on physiological processes and the immune status of animals. Pinworms are effectively controlled with the anthelminthic fenbendazole (FBZ, [5-(phenylthio)-1H-benzamidazol-2-yl]carbamic acid methyl ester; C(15)H(13)N(3)O(2)S); however, questions remain as to whether prolonged FBZ exposure alters the disease course in specific experimental models, such as those pertaining to the immune system. We report that a three-month regimen of FBZ-medicated feed severely affected the onset and disease severity of murine experimental autoimmune encephalomyelitis (EAE), a disease that mimics multiple sclerosis. Differences were recorded between mouse strains used. Our data suggest that where the use of FBZ is mandatory, its full effect should be verified on the particular EAE variant adopted by the laboratory.
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PMID:Strain-related effects of fenbendazole treatment on murine experimental autoimmune encephalomyelitis. 2045 28

Detection of mouse parvovirus (MPV) and other murine pathogens in research colonies is dependent on the transmissibility of the agents and the sensitivity of sentinels to those agents. Transmissibility is based on several agent-dependent properties including mode of transmission, infectivity, and environmental stability, whereas host susceptibility can vary according to mouse age, strain, and sex. In this study, 4-wk-old, 12-wk-old, and aged Swiss Webster female sentinel mice were compared for their ability to detect infectious agents by using a standardized health surveillance program, to determine whether sentinels should be replaced more frequently to improve the efficiency of detection of infectious agents within a murine colony. Both experimentally and naturally infected mice were used to transmit MPV and other infectious agents from index mice to sentinels. First, Swiss Webster mice were inoculated with MPV, and transmission to 4-, 12-, and 24-wk-old contact and soiled-bedding sentinels was determined. Second, mice naturally infected with 9 infectious agents were obtained from 2 local pet stores, and transmission to 4-wk-old contact sentinels and 4-, 12-, and 44-wk-old soiled-bedding sentinels was determined. For agents that were transmitted via soiled bedding (MPV, mouse hepatitis virus, murine norovirus, Theiler murine encephalomyelitis virus, and pinworms), transmission did not differ in regard to the age of the sentinels. In conclusion, susceptibility to several infectious agents did not differ according to sentinel age in a health-surveillance protocol that used mice older than 12 wk.
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PMID:Age-associated variability in susceptibility of Swiss Webster mice to MPV and other excluded murine pathogens. 2329 85