在 20 世纪前软下疳在全球范围内流行,但是现在最常见于加勒比海、非洲、亚洲(泰国除外)及拉丁美洲。1995 年,全球估计有 700 万的新发病例;[9]World Health Organization. Global prevalence and incidence of selected curable sexually transmitted diseases: overview and estimates. 1995 [internet publication].http://apps.who.int/iris/handle/10665/65969 然而,由于该病诊断及上报存在困难,真实病例数无从知晓。[10]Steen R. Eradicating chancroid. Bull World Health Organ. 2001;79(9):818-26.https://scielosp.org/scielo.php?script=sci_arttext&pid=S0042-96862001000900006&lng=en&nrm=iso&tlng=enhttp://www.ncbi.nlm.nih.gov/pubmed/11584729?tool=bestpractice.com 在某些国家/地区,软下疳的患病率明显下降,人们认为这得益于生殖器溃疡性疾病的综合性治疗管理和显著的社会变革。[8]González-Beiras C, Marks M, Chen CY, et al. Epidemiology of Haemophilus ducreyi infections. Emerg Infect Dis. 2016 Jan;22(1):1-8.https://wwwnc.cdc.gov/eid/article/22/1/15-0425_articlehttp://www.ncbi.nlm.nih.gov/pubmed/26694983?tool=bestpractice.com 在美国,软下疳发病高峰在1947年(病例超过9500例),自那以后发病率急剧下降。[11]Centers for Disease Control and Prevention. Sexually transmitted diseases surveillance 2016. Jan 2018 [internet publication].https://www.cdc.gov/std/stats16/default.htm 2016 年,美国仅有 7 例软下疳被报道。[11]Centers for Disease Control and Prevention. Sexually transmitted diseases surveillance 2016. Jan 2018 [internet publication].https://www.cdc.gov/std/stats16/default.htm
发病率周期性高峰是由于同期梅毒病例、使用可卡因者及通过性交获取药品者的数量增多。[1]Trees DL, Morse SA. Chancroid and Haemophilus ducreyi: an update. Clin Microbiol Rev. 1995 Jul;8(3):357-75.http://cmr.asm.org/content/8/3/357.longhttp://www.ncbi.nlm.nih.gov/pubmed/7553570?tool=bestpractice.com[12]Adams DA, Thomas KR, Jajosky RA, et al; Nationally Notifiable Infectious Conditions Group, CDC. Summary of notifiable infectious diseases and conditions - United States, 2015. MMWR Morb Mortal Wkly Rep. 2017 Aug 11;64(53):1-143.https://www.cdc.gov/mmwr/volumes/64/wr/mm6453a1.htm?s_cid=mm6453a1_whttp://www.ncbi.nlm.nih.gov/pubmed/28796757?tool=bestpractice.com 然而,软下疳一般报道的病例数低于实际病例数,因为只有通过培养找到病原体的病例才确诊。研究显示,维持传播时,每年人群的性伴侣人数最低为15-20人。[10]Steen R. Eradicating chancroid. Bull World Health Organ. 2001;79(9):818-26.https://scielosp.org/scielo.php?script=sci_arttext&pid=S0042-96862001000900006&lng=en&nrm=iso&tlng=enhttp://www.ncbi.nlm.nih.gov/pubmed/11584729?tool=bestpractice.com 通过性行为传播而发病的确切比率可能较高但具体不详。 单次暴露后传播的概率估计为0.35。[13]Spinola, SM. Chancroid and Haemophilus ducreyi. In: Holmes KK, Sparling PF, Stamm WE, et al, eds. Sexually transmitted diseases. 4th ed. New York, NY: McGraw-Hill, 2008:689-700.
在泰国,100% 避孕套使用政策以及对性交易场所的性工作者进行预防性治疗获得了非常显著的效果;自 1998 年以来未出现软下疳病例。在非洲,包皮环切率低且 HIV 感染率很高,因此软下疳仍然流行。某些国家(例如肯尼亚)的避孕套使用率高,且对性工作者进行常规体检和治疗,在这些国家软下疳的患病率较低。生殖器溃疡性疾病的综合治疗(对所有潜在的合并感染行同步治疗)已经在塞内加尔及印度等地方实施,已使该类疾病的发病率明显降低。[10]Steen R. Eradicating chancroid. Bull World Health Organ. 2001;79(9):818-26.https://scielosp.org/scielo.php?script=sci_arttext&pid=S0042-96862001000900006&lng=en&nrm=iso&tlng=enhttp://www.ncbi.nlm.nih.gov/pubmed/11584729?tool=bestpractice.com[14]Sharma VK, Khandpur S. Changing patterns of sexually transmitted infections in India. Natl Med J India. 2004 Nov-Dec;17(6):310-9.http://www.ncbi.nlm.nih.gov/pubmed/15736552?tool=bestpractice.com
地方性流行区域软下疳的男女发病率比为3:1,在发展中国家该病爆发时男女发病比达到25:1。 无症状携带者少见。[15]Morse SA. Chancroid and Haemophilus ducreyi. Clin Microbiol Rev. 1989 Apr;2(2):137-57.http://cmr.asm.org/content/2/2/137.longhttp://www.ncbi.nlm.nih.gov/pubmed/2650859?tool=bestpractice.com
在南太平洋地区与非洲,也出现了作为非性传播性皮肤溃疡病因的杜克雷嗜血杆菌。最近在雅司病流行地区进行的用于评估消除雅司病计划的流行病学调查显示,杜克雷嗜血杆菌是肢体溃疡的一种病原体。[2]Roberts SA, Taylor SL. Haemophilus ducreyi: a newly recognised cause of chronic skin ulceration. Lancet Glob Health. 2014 Apr;2(4):e187-8.http://www.ncbi.nlm.nih.gov/pubmed/25103048?tool=bestpractice.com[3]Mitjà O, Lukehart SA, Pokowas G, et al. Haemophilus ducreyi as a cause of skin ulcers in children from a yaws-endemic area of Papua New Guinea: a prospective cohort study. Lancet Glob Health. 2014 Apr;2(4):e235-41.http://www.ncbi.nlm.nih.gov/pubmed/25103064?tool=bestpractice.com[4]Spinola SM. Haemophilus ducreyi as a cause of skin ulcers. Lancet Glob Health. 2014 Jul;2(7):e387.http://www.ncbi.nlm.nih.gov/pubmed/25103386?tool=bestpractice.com[5]Marks M, Chi KH, Vahi V, et al. Haemophilus ducreyi associated with skin ulcers among children, Solomon Islands. Emerg Infect Dis. 2014 Oct;20(10):1705-7.https://wwwnc.cdc.gov/eid/article/20/10/14-0573_articlehttp://www.ncbi.nlm.nih.gov/pubmed/25271477?tool=bestpractice.com[6]Gangaiah D, Webb KM, Humphreys TL, et al. Haemophilus ducreyi cutaneous ulcer strains are nearly identical to class I genital ulcer strains. PLoS Negl Trop Dis. 2015 Jul 6;9(7):e0003918.http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0003918http://www.ncbi.nlm.nih.gov/pubmed/26147869?tool=bestpractice.com[7]Lewis DA, Mitjà O. Haemophilus ducreyi: from sexually transmitted infection to skin ulcer pathogen. Curr Opin Infect Dis. 2016 Feb;29(1):52-7.http://www.ncbi.nlm.nih.gov/pubmed/26658654?tool=bestpractice.com[8]González-Beiras C, Marks M, Chen CY, et al. Epidemiology of Haemophilus ducreyi infections. Emerg Infect Dis. 2016 Jan;22(1):1-8.https://wwwnc.cdc.gov/eid/article/22/1/15-0425_articlehttp://www.ncbi.nlm.nih.gov/pubmed/26694983?tool=bestpractice.com在巴布亚新几内亚的利希尔岛进行的一项研究发现,无症状儿童的皮肤、苍蝇和污染物上存在杜克雷嗜血杆菌 DNA。[16]Houinei W, Godornes C, Kapa A, et al. Haemophilus ducreyi DNA is detectable on the skin of asymptomatic children, flies and fomites in villages of Papua New Guinea. PLoS Negl Trop Dis. 2017 May 10;11(5):e0004958.http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0004958http://www.ncbi.nlm.nih.gov/pubmed/28489855?tool=bestpractice.com 杜克雷嗜血杆菌在疫病流行地区普遍存在的性质需要进一步评估。[16]Houinei W, Godornes C, Kapa A, et al. Haemophilus ducreyi DNA is detectable on the skin of asymptomatic children, flies and fomites in villages of Papua New Guinea. PLoS Negl Trop Dis. 2017 May 10;11(5):e0004958.http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0004958http://www.ncbi.nlm.nih.gov/pubmed/28489855?tool=bestpractice.com