How is Yaws diagnosed?

Yaws is a tropical infectious disease caused by the bacterium Treponema pallidum pertenue. It primarily affects the skin, bones, and cartilage, leading to the development of painful ulcers and lesions. Diagnosing yaws involves a combination of clinical examination, laboratory tests, and consideration of the patient's medical history and symptoms.

Clinical examination: A healthcare professional will carefully examine the patient's skin for characteristic signs of yaws. These may include painless, raised, and crater-like ulcers, known as raspberry-like papillomas, which are typically found on the face, limbs, and genital areas. The examination may also reveal other skin lesions, such as scaly patches or nodules.

Laboratory tests: To confirm the diagnosis, several laboratory tests can be performed:

• Dark-field microscopy: A sample of fluid from an ulcer or lesion is collected and examined under a dark-field microscope. This technique allows the visualization of the spiral-shaped Treponema pallidum pertenue bacteria, which are responsible for yaws.


• Serological tests: Blood samples are taken to detect the presence of specific antibodies produced by the body in response to the infection. These tests include the rapid plasma reagin (RPR) test and the venereal disease research laboratory (VDRL) test. Positive results indicate an active or past infection with yaws.

Medical history and symptoms: The healthcare provider will inquire about the patient's medical history, including any recent travel to yaws-endemic regions. They will also ask about symptoms such as skin lesions, joint pain, and bone deformities. This information helps in assessing the likelihood of yaws and guiding further diagnostic investigations.

It is important to note that yaws can sometimes be misdiagnosed as other skin conditions, such as syphilis or certain fungal infections. Therefore, a comprehensive evaluation by a healthcare professional is crucial for an accurate diagnosis.