Syphilis in Darker Skin: Epidemiology and Pathophysiology

00:00 Welcome to our lecture on syphilis.

00:04 Syphilis is a sexually transmitted infection caused by Treponema pallidum. Females are affected, and there's about 17.2 cases per 100,000 people. Males. We get about 17.7 cases per 100,000.

00:27 The prevalence of syphilis varies by region.

00:31 You have the highest prevalence in South and Southeast Asia, and the second highest is in sub-Saharan Africa.

00:40 Acquiring syphilis escalates the risk of HIV acquisition by 2 to 5 times and enhances the efficiency of HIV transmission.

00:51 So what causes syphilis? Syphilis is caused by Treponema pallidum, which is a spirochete.

00:57 It's a strictly human pathogen.

01:00 It doesn't natural occur in other species.

01:03 Transmission routes, direct contact with an infectious lesion during sexual intercourse, and it can also be transplacental transmission in congenital syphilis.

01:17 Blood transfusion is possible transmission route.

01:20 However, it is rare because all donors are screened and Treponema pallidum cannot survive longer than 24 to 48 hours under blood bank storage conditions.

01:33 Now let's talk about pathophysiology of syphilis.

01:37 Only individuals with active primary or secondary syphilitic lesions are infectious, meaning they can transmit the bacteria.

01:45 The routes of transmission include sexual intercourse, kissing only if person has visible sores in the mouth, as well as by touching a syphilitic sore.

01:59 Treponema pallidum usually penetrates the skin through microscopic abrasions that are formed during sexual intercourse.

02:08 Let's take a look at the various stages of syphilis.

02:11 There's primary, secondary, latent, and tertiary syphilis. So how about primary syphilis? The incubation period is about 3 to 6 weeks.

02:22 One gets an ulcerative lesion that we call a chancre at the primary site of inoculation. It resolves within 3 to 12 weeks with or without treatment.

02:34 Secondary syphilis takes about 4 to 10 weeks after the appearance of the primary lesion. There's multiplication and spread of spirochetes throughout the body with various clinical manifestations.

02:48 Latent syphilis features have been resolved by patients are still seroactive in this form of syphilis.

02:58 In tertiary syphilis, this develops years later if syphilis is left untreated.