Dec. 27, 2023
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Using a dark field microscopy technique, this photomicrograph revealed the presence of Treponema pallidum spirochetes. A diagnosis of syphilis is confirmed with dark field microscopy demonstrating T. pallidum in material from suspected lesions or regional lymph nodes. A positive dark-field result is an almost certain diagnosis of primary, secondary, or early congenital syphilis. (Source: CDC and WF Schwartz, 1961. Public Health Image Library, image 10179. Public domain.)