STD increase in MSM

the old STD syphillis has increased in MSM...

CDC report:

In 2015, the rate of reported primary and secondary syphilis in the United States was 7.5 cases per 100,000 population, nearly four times the previous lowest documented rate of 2.1 in 2000 (1). In 2015, 81.7% of male primary and secondary syphilis cases with information on the sex of the sex partner were among gay, bisexual, and other men who have sex with men (collectively referred to as MSM) (1)...

...The overall rate of primary and secondary syphilis among MSM was 106.0 times the rate among men who have sex with women only and 167.5 times the rate among women.*

ironically, most of the increase was in the south:

Rates of primary and secondary syphilis among MSM varied by U.S. Census region and by state, with the highest rates in the South and West. Four of the five states with the highest primary and secondary syphilis rates among MSM were southern states (Louisiana, Mississippi, North Carolina, and South Carolina) (Table 2). Among states with the 10 highest rates of primary and secondary syphilis in the United States in 2015 (1), five states (Arizona, Louisiana, Mississippi, Nevada, and North Carolina) also ranked among the top 10 states with the highest rates of primary and secondary syphilis among MSM (Table 2).

 meaning they were less likely to be screened and treated? the talk of "secondary" syphillis makes one worry about not being diagnosed early.

On the other hand, the rates might be a reporting error:

Second, the denominators used in calculating the rates of primary and secondary syphilis were estimates of the number of MSM in each state, based on the reporting of same-sex households in the American Community Survey; underreporting of same-sex households could result in an underestimation of the MSM population and an overestimation of primary and secondary syphilis rates.

one also wonders if the rate is local, i.e. in cities. Often due to the stigma, MSM travel to bars away from home and manage to catch STD's but don't tell their local docs (yes, patient privacy... in the good old days we knew this was nonsense so didn't put it into the record, or used code words. Now the Feds want to have everything there, all nice and written out on the computerized files for the Russian/chinese hackers or your ex wife to find it).