Detection of Antibodies Directed Towards Powassan Virus by PRNT<<Return to Laboratory
Serological detection of neutralizing antibodies directed towards Powassan (POW) virus by Plaque Reduction Neutralization Test (PRNT).
- Powassan encephalitis
Serum. Minimum volume of 250 µl required.
2 mL screw cap tubes.
Store samples refrigerated or frozen until shipped for testing. Ship frozen samples on dry ice, and refrigerated samples on wet ice
Shipping of specimens shall be done by a TDG certified individual in accordance with TDG regulations. For additional information regarding classification of specimens for the purposes of shipping, consult either Part 2 Appendix 3 of the TDG Regulations or section 3.6.2 of the IATA Dangerous Goods Regulations as applicable.
Suspected Powassan infection. Submitted samples will first be analysed by the Viral Zoonosis Diagnostic Laboratory by Powassan HAI to determine if the patient has developed anti-flavivirus antibodies. Samples that are reactive can be further analysed for the presence of neutralizing antibodies. Samples that are HAI non reactive (negative) will not be tested by PRNT. This is not a routine test. Please contact the Viral Zoonosis Diagnostic Laboratory before sending specimens.
Completed Viral Zoonoses requisition including sender laboratory name, address and telephone number. Patient name and / or identifier (specimen reference number), date of birth, test(s) requested, collection date of specimen, date of on-set of symptoms, and clinical and travel history of patient.
This is not a routine test. Please contact the Viral Zoonoses Diagnostic Laboratory before sending specimens. Specimens positive by Powassan HI will be forwarded for Dengue and Powassan PRNT confirmation to determine potential flavivirus cross reactivity.
The detection of IgG antibodies in a single serum sample is indicative of past or present exposure to this virus. A 4 fold rise or greater in neutralizing antibody titre, or seroconversion in paired sera, is required to document a "confirmed case" of infection.
IgM can persist in serum for up to a year or more after arbovirus exposure. Thus, detection of IgM by itself is not sufficient for confirmation of acute infection, but is consistent with an exposure at an undetermined time.
Isolation of an arbovirus or detection of nucleic acid by real-time RT-PCR in a clinical specimen provides clear evidence of infection associated with the current clinical illness.
14 Calendar days after the completion of HAI testing.
- WHO. 2007. Guidelines for plaque reduction neutralization testing of human antibodies to dengue viruses.