Specimen type, collection methods, and diagnostic assays available for the detection of poxviruses from human specimens by the Poxvirus and Rabies Branch, Centers for Disease Control and Prevention1.

Specimen Orthopoxvirus Parapoxvirus Yatapoxvirus Molluscipoxvirus Specimen type collection method PCR6 Culture EM8 IHC9,10 Serology11 PCR12 EM8 IHC9,10 PCR13 EM8 PCR EM8 Lesion material

Fresh or frozen            Swab 5          Lesion material [dry or in media ] [vesicle / pustule Formalin fixed       skin, scab / crust, etc.] Paraffin block          

Fixed slide(s)      

Container          Lesion fluid Swab [vesicle / pustule          [dry or in media5] fluid, etc.] Touch prep slide           

Blood

EDTA2 EDTA tube 7  Spun or aliquoted Serum  before shipment Spun or aliquoted Plasma  before shipment CSF3,4 Sterile    1. The detection of poxviruses by electron microscopy (EM) and immunohistochemical staining (IHC) is performed by the Infectious Disease Pathology Branch of the CDC. 2. EDTA — Ethylenediaminetetraacetic acid. 3. CSF — Cerebrospinal fluid. 4. In order to accurately interpret test results generated from CSF specimens, paired serum must also be submitted. 5. If media is used to store and transport specimens a minimal amount should be used to ensure as little dilution of DNA as possible. 6. Orthopoxvirus generic real-time polymerase chain reaction (PCR) assays will amplify DNA from numerous species of virus within the Orthopoxvirus genus. Species-specific real-time PCR assays are available for selective detection of DNA from variola virus, vaccinia virus, monkeypox virus, and cowpox virus. 7. Blood is not ideal for the detection of orthopoxviruses by PCR as the period of viremia has often passed before sampling occurs. 8. EM can reveal the presence of a poxvirus in clinical specimens or from virus culture, but this technique cannot differentiate between virus species within the same genus. EM will also not differentiate between genera of Poxviruses with the exception of the Parapoxviruses which have a distinctive morphology. EM cannot be performed on material that has been frozen. 9. Fresh, non-frozen tissue is preferred for testing by IHC. 10. IHC will only identify viruses to the genus level. 11. Serology testing is performed by enzyme-linked immunosorbent assay (ELISA) for the detection of immunoglobulin G and M. Antibodies are typically broadly cross-reactive across orthopoxvirus antigens. 12. Parapoxvirus generic real-time PCR assays will amplify DNA from multiple species of virus within the Parapoxvirus genus. Specific-specific real-time PCR assays are available for selective detection of DNA from orf virus, pseudocowpox virus, bovine popular stomatitis virus, and sealpox virus. 13. Yatapoxvirus generic real-time PCR assay will amplify DNA from viruses within the Yatapoxvirus genus. A specific standard PCR assay is available to detect tanapox virus.