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Volume 14, Number 4—April 2008


Retrospective Analysis of Monkeypox Infection

Melissa E. Dubois* and Mark K. Slifka*Comments to Author 
Author affiliations: *Oregon Health and Science University, Beaverton, Oregon, USA;

Main Article


Comparison of monkeypox-specific diagnostic tests*

Patient no. Serologic techniques Cellular techniques Direct viral detection Postadsorption ELISA Postadsorption Western blot†
Paired IgG Peptide ELISA 39 kDa 124 kDa 148 kDa
447 C C C C C + + +
452 C C C C C + + +
453 C C C P/S C + + +
461 C C C NA C + +
462 C C C C C +
481 C C C NA C + +
482 C C C NA C + +
484 C C C NA C +
489 C C C NA C + +
473 C C C NA C + +
519 C C C C C + +
520 C C C C C + +
446‡ C C C ND U
449‡ C C U ND U +
450 C C C P/S C +
451 C C C C C +
454 C C C P/S C + + +
455‡ C C C ND U +
463 C C C C C +
500 C C C ND C +

*These studies are based on persons who were infected with monkeypox during the 2003 outbreak in Wisconsin and who were tested by independent laboratories by using serologic (6), cellular (6), and virologic (4) techniques. Serologic techniques included identification of monkeypox peptide-specific immunoglobulin (Ig) G by peptide ELISA and kinetic analysis of IgG to orthopoxvirus in paired plasma samples (2–4 mo and 1 y postinfection) by endpoint ELISA. Orthopoxvirus-specific CD8+ T cells were measured by using intracellular cytokine staining analysis. Plasma samples were obtained 2–4 mo postinfection, except for patients 473 and 500 (6 mo), 519 and 520 (12 mo), and 557 (30 mo). Virologic confirmation was obtained by viral culture, PCR, electron microscopy, and immunohistochemical analysis of tissue samples (4). C, confirmed; P/S, probable/suspected; NA, not available; ND, not done; U, unconfirmed.
†A + indicates that at least 5/6 analysts scored the band of interest as positive.
‡Clinically inapparent monkeypox infection in previously vaccinated persons as determined by cellular and serologic retrospective diagnostic techniques (6).

Main Article