Tanapox, South Africa, 2022

Abstract

Tanapox is a rarely diagnosed zoonosis known to be endemic to equatorial Africa. All previously reported human cases were acquired within 10° north or south of the Equator, most recently 19 years ago. We describe a human case of tanapox in South Africa (24° south of the Equator). Expanded surveillance for this pathogen is warranted.

Keywords: DNA sequencing; PCR; South Africa; Tanapoxvirus; Yatapoxvirus; electron microscopy; light microscopy; vector-borne infections; viruses; zoonoses; zoonotic virus.

Figure 1

Geographic distribution of recorded human cases of tanapox. A) Locations of previous tanapox cases reported in the literature. Red dots indicate cases acquired locally; red outlines indicate regions of countries visited by travelers to Africa. B) Location of the case acquired in Kruger National Park, South Africa, 2022. Green shading shows the park’s location; black triangle indicates town of Skukuza.

Figure 2

Diagnostic light and electron microscopy of tanapox lesion biopsies from a case-patient, South Africa, 2022. A) High-power photomicrograph of initial skin biopsy, showing prominent vacuolation of epidermal keratinocytes, granular intracytoplasmic inclusions, and intranuclear pseudoinclusions. Hematoxylin and eosin stain; original magnification ×400. B) Low-power photomicrograph of initial skin biopsy, showing a superficially eroded hyperplastic epidermis, with cytoplasmic pallor and a dense underlying superficial dermal lymphoid infiltrate. Hematoxylin and eosin stain; original magnification ×40. C) Negatively stained tanapox virus virion with surface tubules evident beneath the remains of the surrounding membrane. Virion dimensions were 159–327 nm × 186–289 nm. Scale bar indicates 100 nm.