Hui B, Fairley C K, Chen M, Grulich A, Hocking J, Prestage G, Walker S, Law M, Regan D
The Kirby Institute, UNSW Australia, Sydney, Australia.
School of Population and Global Health, University of Melbourne, Melbourne, Australia Melbourne Sexual Health Centre, Alfred Health, Melbourne, Australia Australian Research Centre in Sex, Health and Society, La Trobe University, Melbourne, Australia.
Sex Transm Infect. 2015 Aug;91(5):365-9. doi: 10.1136/sextrans-2014-051760. Epub 2015 Jan 16.
Despite early treatment of urethral infection, gonorrhoea is endemic in urban populations of men who have sex with men (MSM) in Australia. By contrast, gonorrhoea is not common in urban heterosexual populations. Sexual activities among MSM usually involve anal or oral sex, and as these behaviours are becoming increasingly common among heterosexuals, there is a need to investigate their roles in transmission of gonorrhoea.
We developed individual-based models of transmission of gonorrhoea in MSM and heterosexuals that incorporate anatomical site-specific transmission of gonorrhoea. We estimated the probabilities of transmission for anal sex and oral sex by calibrating an MSM model against prevalence of gonorrhoea and sexual activity data. These probabilities were then applied to a heterosexual model in order to examine whether gonorrhoea can persist in a heterosexual population through the addition of anal sex and oral sex.
In the MSM model, gonorrhoea can persist despite prompt treatment of urethral infections. The probability of gonorrhoea persisting is reduced if use of condom for oral sex is increased to more than 15% of acts. Assuming that treatment of symptomatic infections is prompt, gonorrhoea is unlikely to persist in a heterosexual population even with the addition of anal and oral sex.
Our models suggest that oral sex has an important role in sustaining gonorrhoea in a population of MSM by providing a pool of untreated asymptomatic infection. The importance of anal sex or oral sex in sustaining gonorrhoea in a heterosexual population remains uncertain due to the lack of information linking different types of sex acts and transmissibility.
尽管对尿道感染进行了早期治疗，但淋病在澳大利亚与男性发生性行为的男性（男男性行为者）的城市人群中仍呈地方性流行。相比之下，淋病在城市异性恋人群中并不常见。男男性行为者之间的性活动通常包括肛交或口交，随着这些行为在异性恋者中越来越普遍，有必要研究它们在淋病传播中的作用。
我们开发了男男性行为者和异性恋者中淋病传播的个体模型，该模型纳入了淋病在特定解剖部位的传播情况。我们通过根据淋病患病率和性活动数据校准男男性行为者模型来估计肛交和口交的传播概率。然后将这些概率应用于异性恋模型，以研究淋病是否可以通过增加肛交和口交在异性恋人群中持续存在。
在男男性行为者模型中，尽管对尿道感染进行了及时治疗，淋病仍可持续存在。如果口交时使用避孕套的比例增加到超过性行为的15%，淋病持续存在的概率会降低。假设对有症状感染的治疗及时，即使增加肛交和口交，淋病在异性恋人群中也不太可能持续存在。
我们的模型表明，口交通过提供一批未经治疗的无症状感染源，在男男性行为者人群中维持淋病方面发挥着重要作用。由于缺乏将不同类型性行为与传播性联系起来的信息，肛交或口交在异性恋人群中维持淋病方面的重要性仍不确定。
