Figure 1
From: Detection and identification of Variola virus in fixed human tissue after prolonged archival storage
Gross and microscopic images of a human forearm and hand, presumably from a child. (a) All sides of the specimen are similarly affected with discrete and confluent lesions, representing 95% involvement. Note that the exanthem consist of raised or umbilicated lesions compatible with vesicles or pustules (arrows) primarily around the wrist and on all surfaces of the hand and digits. Crusted or excoriated lesions (arrowheads) predominate the lightly keratinized forearm. Upon receipt of the specimen, it was noted that some lesions had already been collected. Bar=5 cm. (b) Macroscopic image of smallpox virus infected skin from the palmar surface of the specimen in the previous figure. Note that the section has lost its thick stratum corneum covering, giving the lesion a pseudoexophytic appearance. The floor of the vesicle (arrowheads) is formed by the remaining stratum germinativum. The vesicle is subdivided, often in a reticular pattern, by remaining strands and septa of intact epidermis that demarcate microvesicles of varied size (arrows); and is filled with proteinaceous material admixed with inflammatory cells, and cellular debris (asterisk) (hematoxylin–eosin, original magnification × 1). Higher magnification inset illustrates reticular pattern of microvesicles (hematoxylin–eosin, original magnification × 10). (c) Transmission electron micrograph of smallpox virus infected keratinocyte from the palmar surface of the specimen in (a). Although preservation is not optimal, many immature (arrowheads) and mature (long arrows) intracellular virions are readily evident in these rounded epidermal cells. Also note intercellular edema and loss of desmosome attachment; D, desmosomes; T, tonofilaments; inset, higher magnification of immature intracellular virions; (original magnification × 3,500).
