Polio laboratory findings
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]
Overview
Poliovirus may be isolated from pharyngeal secretions during the first week of the disease, and from feces during several weeks. Isolation of virus from the cerebrospinal fluid (CSF) is diagnostic, however this is rarely accomplished. Following isolation, the serotype and origin of the virus may be characterized by genomic sequencing. The CSF may show unspecific findings of aseptic meningitis, which are common to those found in infections by other viruses. When the virus cannot be isolated, serologic tests, using antibodies targeted to the 3 different serotypes may be used.[1][2]
Laboratory Findings
Viral Isolation
If poliovirus is isolated from a person with acute flaccid paralysis, or if it occurs in an area where there is low incidence of the disease, it must be further tested in order to assess the source of the virus. The virus may be "wild-type" (occurs naturally) or vaccine related (OPV).[1][2] The characterization of the source of the virus may be achieved by genomic sequencing.[3][2]
Cerebrospinal Fluid
In poliovirus infection, the CSF usually contains an increased number of white blood cells (10–200 cells/mm3, primarily lymphocytes) and mildly elevated protein (40–50 mg/100 mL).[1] However, these findings are similar to those of aseptic meningitis caused by other viruses.
The isolation of poliovirus from the CSF is particularly important in cases of paralytic poliomyelitis following administration of the vaccine. Since viral shedding in feces occurs during several weeks after the person has been vaccinated, isolation of the virus in the CNS, and its characterization as "wild-type" or "vaccine related", is the only way of proving an association between the disease and the vaccine.[2]
Serology
If the virus cannot be isolated, the diagnosis of poliomyelitis may be established serologically. Serology tests may be performed by pairing patient's acute and convalescent sera, with neutralizing antibodies, targeted to all three serotypes of the virus. However, serologic tests cannot distinguish between the "wild-type" and "vaccine-type" polioviruses.[2]
References
- ↑ 1.0 1.1 1.2 "Poliomyelitis".
- ↑ 2.0 2.1 2.2 2.3 2.4 Mandell, Gerald (2010). Mandell, Douglas, and Bennett's principles and practice of infectious diseases. Philadelphia, PA: Churchill Livingstone/Elsevier. ISBN 0443068399.
- ↑ Kew, Olen M.; Mulders, Mick N.; Lipskaya, Galina Yu.; da Silva, Edson E.; Patlansch, Mark A. (1995). "Molecular epidemiology of polioviruses". Seminars in Virology. 6 (6): 401–414. doi:10.1016/S1044-5773(05)80017-4. ISSN 1044-5773.