The sometimes-deadly disease syphilis is exploding in the United States, with most of the increase since 1995 among men who have sex with men (MSM), according to a new report from the Atlanta-based Center for Disease Control (CDC).

As recently as 2000, researchers believed the total elimination of syphilis was within reach. The recent dramatic increases in infections, coupled with the observation that syphilis closely tracks with other diseases like AIDS, have the medical and scientific community deeply concerned. The CDC report considers “the increase in syphilis among MSM is a major public health concern.”

According to the report, “During 2005-2013, the number of primary and secondary syphilis cases reported each year in the United States nearly doubled, from 8,724 to 16,663; the annual rate increased from 2.9 to 5.3 cases per 100,000 population.”

The report also says that “men contributed an increasing proportion of cases, accounting for 91.1% of all primary and secondary syphilis cases in 2013.” Most of the increases came from men who have sex with men, which were responsible for 77% of cases in 2009 but 83.9% in 2012, what the report calls “the vast majority of male… syphilis cases.”

The report warns that the numbers in the new report are likely far less than the true number because only 34 states and the District of Columbia fully report sex of sex partners.

The report raises a particular concern about what it calls “co-infection rates.” “There are reported rates of 50%-70% HIV co-infection among MSM infected with primary or secondary syphilis…”

The notion of co-infection follows closely a report just published by independent researcher Dale O’Leary in the prestigious Linacre Quarterly of the Catholic Medical Association, found at the bottom of this article.

O’Leary reports that researchers understand the problems of health among MSM are now so vast and interrelated they are considered a “syndemic,” a linked set of health issues involving two or more afflictions acting in concert within a specific population. According to the medical literature, among MSM these would include diseases like syphilis, gonorrhea, and HIV but also such pathologies as partner violence, drug abuse, and psychological disorders. Treating a single part of this puzzle would not solve the whole problem.

The HIV/AIDS infection rate alone is bleak. From 2008 to 2010 the new HIV infection rate grew 12%, from 26,700 to 29,800 cases reported. One in five sexually active MSM carry the AIDS virus, but nearly half of those don’t even know it. However, HIV/AIDS is not the only problem, as the new CDC report on syphilis makes clear. According to the Linacre paper, “MSM are far more likely to be diagnosed with other STDs, some of which have become resistant to commonly used antibiotics.”

The paper reports on a 2004 outbreak of something called lymphogranuloma venereum (LGV), considered rare in the developed world prior to 2003, which includes “tender, enlarged lymph nodes in both groins.” A 2004 outbreak in the Netherlands among MSM has led to its spread in the European Union and the United States almost exclusively among the HIV-positive.

Another linked pathology is Hepatitis C, “which can lead to liver cancer, can be [sexually] transmitted and is spreading not only among HIV-positive gay men, but also among HIV-negative MSM.” Human papillomavirus is epidemic and has led to a “dramatic increase in anal cancer among MSM, especially those who are HIV positive.”

Included in this particular syndemic, according to the Linacre paper, are issues related to mental health, including higher risks of “suicidal ideation, substance misuse, and deliberate self harm than heterosexual people.” According to the paper, even the Southern Poverty Law Center, an advocacy group for MSM, admits “that LGBT people suffer higher rates of anxiety, depression and depression-related illnesses and behaviors like alcohol and drug abuse than the general population,” though they chalk this up to “homophobia.”

Drug abuse is quite common among this population and feeds into significant risk factors. Ecstasy, crystal meth, ketamine (animal tranquilizer), poppers (amyl nitrate for sniffing), Viagra, and even more exotic items like GHB, a nervous system depressant, are used at higher levels among MSM than the general population.

One of the more interesting problems facing the MSM community is the addiction many men have to using anabolic steroids in order to build muscle mass and appear more masculine to potential partners. According to a study released earlier this year the journal Pediatrics, 21% of gay or bisexual boys said they had ever used steroids compared to only 4% of heterosexual boys. Among those who used steroids 40 times or more, 8% of gay or bi boys did so while their heterosexual counterparts reported only 2%.

Read Dale O’Leary’s report below:

Dale O’Leary Paper