What methods are used to detect microorganisms and parasites in laboratory animals?

  For specific methods for detecting microorganisms and parasites in laboratory animals, please refer to "National Standard Laboratory Animal Microbiological Test Methods" (GB/T14926.1?14926.64) and "National Standard Laboratory Animal Parasite Test Methods" (GB/T14926.1 14926.64). The detection methods are outlined in pathogenicity testing and serological testing. Bacteria, fungi, and parasites are mainly detected by pathogens and supplemented by serological testing, but certain pathogens, such as Mycoplasma, Tizer pathogens and Toxoplasma, can be gradually detected by serological methods. The routine and routine detection of viruses is mainly serology, and the diagnosis of diseases is mainly pathogen detection.

  1. Selection of monitoring items

  After more than ten years of research on pathogenic microorganisms and parasitic infections of laboratory animals in different regions, China combined with the laws and regulations and experience of other countries to witness teeth, rabbits, and I prepared a dog. According to the microbiology and parasitology grade standards of monkeys and chickens, all regions and units can implement surveillance or select other projects based on the prevalence of local laboratory animal pathogens. 2. The number of samples can be determined according to national standards, while the number of samples for healthy animal groups depends on the size of the production and breeding unit (Table 2-10).

  3. Test frequency

  National standards (GB14922.1, GB14922.2) stipulate the testing frequency of experimental animals at different levels. At least every 3 months, tests should be performed on normal grade animals, clean grade animals, and animals with subspecific pathogens. Test sterile animals once a year, and test the animal’s living environment and stool samples every 2 to 4 weeks. Generally speaking, when a pathogen invades an animal population to cause an infection, it promotes the early isolation of the pathogen and subsequently increases the detection rate of antibodies. After a few months, this may be due to a decrease in antibody levels in some individuals and an increase in the number of uninfected newborns. For other reasons, the detection rate of antibodies has decreased.

  4. Sampling method

  Random sampling method or fixed-point animal method can be used. When random sampling is used for sampling, it is recommended to randomly select breeders from different locations in the animal group and select at least 4 different locations to collect samples. In the sentinel method, experimental animals of the same strain that meet the quality requirements after testing are put into the community, rearranged from time to time, raised for a period of time, and then dissected to check for antibodies and pathogens. When transporting the sampled samples from the sampling point to the laboratory, the safety of the animals must be ensured and contamination must be avoided. Generally speaking, regardless of pathogenicity or serology, a positive test result indicates that a group of animals is infected with the pathogen. However, as the pathogen of the disease, further analysis is needed. If the test result is negative, it can usually be used as a basis for the absence of pathogens. However, the test results are also affected by many factors. Examples: the number of samples collected, the level of infection rate, the frequency of collection, target selection (such as animal age, early or late disease) method selection (pathogenicity or serological testing), method sensitivity is closely related to the test result 5. Virus Testing methods (1) Serological testing: suitable for regular inspections and epidemiological monitoring of laboratory animals of various levels and types. Commonly used methods are enzyme-linked immunosorbent assay (ELISA) and immunofluorescence. test. FA), immunoenzyme staining test (IEA), hemagglutination test (HA), hemagglutination inhibition test (HI), virus neutralization test, complement fixation test, agar diffusion test, etc. (2) Pathogenicity test: It is suitable for a group of animals who are sick and need to detect or confirm the virus. Detection methods include virus isolation and identification, virus particles, antigen or nucleic acid detection, potential virus activation and antibody production tests. Example: Use immunohistochemical methods to detect specific antigens in diseased tissues under an optical microscope; HA or HI methods to detect hemagglutinin antigens in feces or tissue suspensions of diseased animals; use electron microscope or immunoelectron microscopy to detect tissues Or virus particles in excrement; Polypropylene gel electrophoresis (PAGE) is used to check viral proteins; detection of viral nucleic acid in tissues or excrement uses nucleic acid molecular hybridization technology or polymerase chain reaction (PCR).

  6. Bacteria detection method

  The most commonly used method is to isolate and cultivate pathogens or inoculate animals. Some pathogens, such as Brucella and Mycoplasma, can use serological methods. Taize pathogens cannot grow in artificial media, so it is recommended to use serological testing methods, animal induction experiments, tissue compression, microscopic examination and make the final diagnosis based on the pathological examination results. I will.

  7. Fungus detection method

  Currently, Sabouraud medium is mainly used for separation and cultivation. Dermatophytes are usually cultivated at 25°C, and deep fungi are usually cultivated at 37°C. Various fungi have specific colony characteristics and can be used in combination with microscope staining to identify species. Similarly, the results of biochemical reactions and immunological methods may need to be used for the final diagnosis.

  8. Parasite detection method

  (1) Extracorporeal parasites: visual observation, scotch tape sticking, repellent sampling, dandruff sampling, black background inspection, routine inspection under a dissecting microscope, etc. , It is mainly suitable for checking fleas, lice, crooks and other arthropods.

  (2) Internal parasites: mainly direct smear method (feces, blood, organs, intestinal contents), saturated saline suspension method or precipitation method, using cellophane to check the outline of animal tissues or organs around the blastoderm, insects and protozoa Embossing, sectioning or pressing of diseased tissue, centrifugation of urine (for example, bladder nematode detection).