Virus detection methods: Electron Microscopy
المؤلف:
Patricia M. Tille, PhD, MLS(ASCP)
المصدر:
Bailey & Scotts Diagnostic Microbiology
الجزء والصفحة:
13th Edition , p807
2025-12-17
45
Very few laboratories use electron microscopes (EM) to detect viruses, because it is labor intensive and relatively insensitive. EM is most helpful for detecting viruses that do not grow readily in cell culture and works best if the titer of virus is at least 106 to 107 particles per milliliter. Immune EM allows visualization of virus particles present in numbers too small for easy direct detection. The addition of specific antiserum to the test suspension causes the virus particles to form antibody-bound aggregates, which are more easily detected than are single virus particles. In the clinical virology laboratory, EM is most useful for detecting gastroenteritis viruses that cannot be detected by other methods (e.g., astroviruses) and encephalitis-causing viruses that are undetectable with cell culture (HSV, measles virus, and JC polyomavirus) (Figure 1). In addition, the etiology of newly recognized viral syndromes can be recognized rapidly by identifying characteristic viral morphology by EM in infected tissue. This was exemplified by the early recognition of Ebola virus as the cause of an outbreak of viral hemorrhagic fever (Ebola hemorrhagic fever) in Africa in the 1970s and sin nombre virus (hanta pulmonary syndrome) as the cause of fatal pneumonia in the Four Corners area of the southwest United States in the 1990s.
Fig1. Electron micrographs of viruses. A, Rotavirus. B, Adenovirus. C, Norwalk agent virus. D, Coronavirus.
Fig1. cont’d E, Herpes simplex virus. F, Measles virus. G, Negatively stained preparation of JC virus in brain tissue. (C from Howard BJ, Klaas J, Rubin SJ, et al: Clinical and pathogenic microbiology, St Louis, 1987, Mosby; D and F from US Department of Health, Education, and Welfare, Public Health Service, Centers for Disease Control, Atlanta, Ga; G courtesy Dr. Gabriele M. ZuRhein, UNW-Madison, Madison, Wisconsin.)
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