在經歷了數十年的穩步下降之后，性傳播疾病（STI）在發達國家中出現了抬頭跡象。這一現象帶來的后果異常嚴重。例如梅毒，每年在全球都會引發超過20萬例的死胎和嬰兒夭折，而且嬰兒在患病數年之后還會出現失明、癡呆或麻痹癥狀。性傳播疾病的再度猖獗有多方面的原因，包括未能堅持使用避孕套以及非法消遣性藥物的濫用。與此同時，由于抗生素耐藥性的原因，包括淋病和志賀氏菌病在內的一些普通性傳播疾病，正在變得越來越難治。在美國這個性傳播疾病發病率最高的發達國家中，疾病的蔓延每年所消耗的可預防醫療費用達到了約160億美元。

這個問題有多嚴重？

在美國，衣原體感染、淋病和梅毒這三種最常見、可治愈的性傳播疾病在2017年大幅增加了20多萬例，將患者總數推升至近230萬。以梅毒為例，美國依據報道的年發病率在近些年來將近翻了一番，從2012年的15.9例/10萬人增至2017年的31.4例/10萬人。在法國、比利時、愛爾蘭和英國，梅毒發病率也呈現出了類似趨勢。在澳大利亞，2016年淋病發病率較2012年增長了63%。2007至2016年法國的發病率增長了5倍，丹麥的發病率增長了4倍。

增長的原因何在？

原因很復雜。以梅毒為例：盡管每年約600萬例的新增病例都分布在中低收入國家，但高收入國家的增幅最高。在這些國家中，梅毒已經從一些高風險群體，例如同性戀和雙性戀男士向更廣泛的人群傳播。在美國，2013-2017年，女性早期梅毒患病比例飆升了156%。美國疾病防控中心稱，這一點與性化藥物使用的上升有關，例如使用麻黃堿或注射海洛因之類的毒品刺激自身與多名伴侶發生不安全性行為。同樣在歐洲，事實證明，稱為party and play （PnP）、chemsex或slamming的類似活動成為了性工作和高風險性行為的推手，尤其是同性之間的性行為。

存在其他因素嗎？

是的。例如在美國，20世紀90年代中期之后男同性戀群體艾滋病死亡率的下降一直伴隨著梅毒病例的上升。最近，艾滋病傳播預防藥物（又稱艾滋病暴露前用藥或PrEP）的面世，完全有望降低這些男性群體中的新增病例數量。它還與不常使用避孕套有關，而避孕套是抵御其他性傳播疾病最有效的方式之一。對PrEP使用群體進行更頻繁的性傳播疾病篩查測試會讓人們難以弄清楚此前未發覺或未治療的感染是否得到了確診或實際上是有所增加。更加頻繁的國際旅行和勞工遷移也意味著致病因子正在以更快的速度向更廣泛地區傳播。

有什么樣的后果？

每一種致病因子都具有其獨特的危險性。例如，在患有梅毒、且未得到治療的孕婦中，出現流產、死胎或嬰兒夭折的概率高達40%。存活下來的嬰兒可能會出現畸形，包括骨骼缺陷、聽力障礙以及會可能引發發育遲緩和癲癇的腦膜炎。自2013年以來，已報道的母嬰傳播梅毒病例在美國增長了一倍多，在2017年達到了20年來的新高——918例，其中70%的病例分布于佛羅里達、加利福尼亞州、亞利桑那州、得克薩斯州和路易斯安那州。以衣原體為例，80%的感染都沒有什么癥狀，但它仍然可以通過性行為傳播。這種感染在女性中尤為嚴重。如果不加以治療，它可能會轉移至上生殖系統，導致盆腔炎性疾病，繼而引發子宮外孕、慢性疼痛和不孕。在子宮內被感染的新生嬰兒可能會患上肺炎。支原體感染未得到治療的男性可能會患上關節炎。

抗藥性淋病有多嚴重？

非常嚴重。進化后的細菌已經能夠對抗多種抗生素，英國和澳大利亞分別出現了4例和2例已報道具有廣泛抗藥性的淋病。雖然細菌對于一些新出現的抗生素普遍較為敏感，但喉部感染的治療效果似乎要差一些。喉部的細菌可以在不經意間通過親吻傳播，也讓這類感染難以杜絕。關鍵問題在于，全球性病治療領域的主力軍頭孢曲松鈉正在失去其效力，因此加劇了抗藥性淋病出現的風險。當這種疾病無法得到治療時，它可能會導致男性和女性的不孕不育，而且有可能導致致命的血液感染。

我們能做些什么？

經驗告訴我們，鼓勵使用避孕套還不足以抑制疾病的傳播。我們還需要新工具以及包括抗病毒和抗生素在內的新治療劑。疫苗也可以作為一個重要的防御手段，它曾經大幅降低了人乳頭狀瘤病毒和乙肝病例數量。對于皮膚皰疹和艾滋病疫苗的研究正在向前邁進，而針對支原體、淋病、梅毒和滴蟲等其他常見性傳播疾病的疫苗依然處于早期開發階段。

世界其他地區是什么情況？

每一天都有100多萬人感染性傳播疾病，其中大多數都分布于中低收入國家。一般來說，性傳播疾病是衡量醫療服務可獲取性的一個指標：測試或治療水平最差的群體有著最高的發病率。世界衛生組織發現，女性性工作者、注射毒品使用者、同性戀人群以及變性女性最容易受到感染。在醫療站點提供更快、更可靠的測試將有助于疾病的早期檢測和治療，尤其是在發展中國家和偏遠地區。（財富中文網）

譯者：馮豐

審校：夏林

Sexually transmitted infections (STIs) are rebounding in developed countries after being firmly in retreat for decades. The consequences can be devastating. Syphilis, for example, causes more than 200,000 stillbirths and infant deaths worldwide annually, and years later can lead to blindness, dementia or paralysis. The resurgence is a result of multiple factors including inconsistent condom usage and the abuse of illicit recreational drugs. At the same time, some common STIs, such as gonorrhea and shigellosis, are becoming harder to treat due to antibiotic resistance. In the U.S., which has the highest rates of sexually transmitted disease in the developed world, the crisis is costing an estimated $16 billion annually in preventable health-care expenses.

How bad is the problem?

In the U.S., cases of chlamydia, gonorrhea, and syphilis — three of the most common, treatable sexually transmitted diseases — jumped by more than 200,000 in 2017 to almost 2.3 million, a record. With syphilis, the annual rate of reported cases in the U.S. has almost doubled in recent years, to 31.4 cases per 100,000 people in 2017 from 15.9 per 100,000 in 2012. The trend with syphilis has also been seen in such countries as France, Belgium, Ireland and the U.K. In Australia, reported cases of gonorrhea climbed 63 percent from 2012 to 2016, while they surged sixfold in France and almost fivefold in Denmark from 2007 to 2016.

What’s driving that rise?

It’s complicated. Take syphilis: While the bulk of the roughly 6 million cases occurring annually are in low- and middle-income countries, some of the largest annual increases are in high-income countries. In these countries, syphilis has spread from some high-risk groups, such as gay and bisexual men, to the wider community. In the U.S., rates of early-stage syphilis among women surged 156 percent from 2013 to 2017. The Centers for Disease Control and Prevention says that’s associated with a corresponding rise in sexualized drug use — using methamphetamines or injection drugs, including heroin, to facilitate unprotected sex with multiple partners. Similarly in Europe, such practices, known as “party and play (PnP),” “chemsex” or “slamming,” have been shown to spur sex work and risky behavior, especially among men who have sex with men.

Are there other factors?

Yes. In the U.S., for example, the decline in AIDS mortality since the mid-1990s has been associated with a rebound in syphilis cases among men who have sex with men. More recently, the introduction of drugs to prevent HIV transmission — called pre-exposure prophylaxis, or PrEP — has shown great promise in reducing new infections among these men. It’s also been associated with less consistent use of condoms — one of the best means of protection against other STIs. More routine STI screening tests among PrEP users has made it difficult to know whether previously unrecognized and untreated infections are now being diagnosed or if there has been an actual increase. More international travel and labor migration also mean that germs are spreading faster and wider.

What are the consequences?

Each infectious agent presents its own particular dangers. For example, up to 40 percent of pregnancies with untreated syphilis result in miscarriage, stillbirth or early infant death. The surviving babies may suffer from abnormalities including skeletal defects, hearing impairment and meningitis, which can cause developmental delays and seizures. Reported cases of syphilis passed from a mother to her baby have more than doubled in the U.S. since 2013, reaching a 20-year high of 918 in 2017. Florida, California, Arizona, Texas and Louisiana accounted for 70 percent of cases. With chlamydia, 80 percent of infections are asymptomatic, yet even then it can be spread via sex. The infection is particularly serious for women. If untreated it may move to the upper reproductive tract, resulting in pelvic inflammatory disease. That can lead to ectopic pregnancy, chronic pain and infertility. Newborns may get pneumonia if they are infected in the uterus. Men with untreated chlamydia may develop arthritis.

How serious is drug-resistant gonorrhea?

Very. The bacterium has evolved to thwart multiple antibiotics, leading to four reported cases of extensively drug-resistant disease in the U.K. and two in Australia. While the bacterium is broadly susceptible to some newer antibiotics, these appear to be less effective at clearing the infection from the throat. Germs in the throat can spread surreptitiously via kissing, making them harder to stop. A key concern is that ceftriaxone, a backbone of treatment globally, is losing its potency, hastening the threat of untreatable gonorrhea. When the disease isn’t treated, it can cause infertility in both women and men, and potentially lead to a lethal bloodstream infection.

What can be done?

Experience has shown that encouraging condom use isn’t sufficient to curb infections. New tools and therapeutic agents, such as antiviral and antibiotic drugs, are needed. Vaccines, which have significantly reduced cases of human papillomavirus (HPV) and hepatitis B cases, could be an important defense. Research into vaccines against herpes and HIV is advanced, while those for chlamydia, gonorrhea, syphilis and trichomoniasis, another common STI, are in earlier stages of development.

What about the rest of the world?

Most of the more than 1 million people who catch a sexually transmitted infection each day are in low- and middle-income countries. Broadly, STIs are a barometer of access to health care: The worst rates occur in groups least likely to be tested and treated. The World Health Organization recognizes female sex workers, people who inject drugs, men who have sex with men, and transgender women as being most vulnerable. Faster and more-reliable testing at the point of care would make it easier to detect and treat infections earlier, especially in developing countries and remote areas.