As syphilis resurges  in the United States, cases are largely seen among men who have sex with men (MSM), who have dramatically higher rates of the sexually transmitted infection (STI) compared with men who have sex with women (MSW) and women, MedPage Today reports.

Publishing their findings in the Morbidity and Mortality Weekly Report, Centers for Disease Control and Prevention (CDC) researchers relied on U.S. Census Bureau estimates of households including male-male couples to estimate of the size of the MSM population per county throughout 44 states. These states provided information on the sex of partners of those diagnosed with syphilis in at least 70 percent of cases. Of the 23,872 syphilis diagnoses seen in 2015, these states accounted for 83.4 percent.

The estimated syphilis diagnosis rate per 100,000 people was 309 cases among MSM, 2.9 cases among MSW and 1.8 cases among women.

Among MSM, the lowest state-specific diagnosis rate per 100,000 MSM was 73.1 cases in Alaska, while the highest was 748.3 cases in North Carolina. Regionally, the diagnosis rate among MSM was highest in the South and West.

Compared with MSW and women, the diagnosis rate per 100,000 people was a respective 106 and 167.5 times higher among MSM.

To read the MedPage Today article, click here.

Centers for Disease Control and Prevention; 2016 STD Prevention Conference.