Sexually Transmitted Infections: Gonorrhea, Syphilis
1. M Razaq
2. Aidarbek kyzy Aidanek
(1. Student, International Medical Faculty, Osh State University, Osh, Kyrgyz Republic.
2. Teacher, International Medical Faculty, Osh State University, Osh, Kyrgyz Republic.)
Abstract
Background: Gonorrhea and syphilis, two of humanity’s oldest recorded infections, have re-emerged as 21st-century threats. Rising incidence, multi-drug resistance in Neisseria gonorrhoeae, and a 636 % increase in congenital syphilis since 2014 signal a public-health crisis that now surpasses 1990s peaks in many nations. Updated epidemiological intelligence is essential for clinical vigilance and stewardship of last-line antimicrobials.
Methods: A structured scoping review (January 2019 – December 2024) was undertaken using PubMed, EMBASE, Cochrane, WHO IRIS, CDC WONDER, and ECDC ADR surveillance. Eligible studies reported prevalence, incidence, mortality, or antimicrobial resistance (AMR) patterns of N. gonorrhoeae or Treponema pallidum in any WHO region. Global Burden of Disease (GBD) 2023 supplied mortality and disability trends for 2019-2023. Where denominators were missing, UN World Population Prospects 2022 were used. Narrative synthesis followed PRISMA-ScR guidance.
Results: In 2023, global incident gonorrhea reached 104 million cases (rate 1.3 per 100 person-years), with 82 % concentrated in the African and Western-Pacific regions. Ceftriaxone-non-susceptible strains rose to 2.3 % worldwide and 25.6 % azithromycin resistance in Europe. Syphilis incidence climbed to 7.6 million new infections; primary/secondary syphilis rates in U.S. women increased 107 % over five years, driving congenital syphilis to 105.8 cases per 100 000 live births—the highest since 1991. GBD 2023 attributes 46 900 direct deaths and 2.14 million DALYs to gonococcal and syphilitic disease, a 28 % increase since 2019. Case-fatality is now driven by disseminated gonococcal infection (DGI) and tertiary neuro-syphilis in settings with delayed care.
Conclusions: Gonorrhea and syphilis are no longer historical footnotes. Multi-drug resistance erodes empirical therapy, while congenital syphilis reflects failures at every step of antenatal care. A triple strategy—point-of-care molecular diagnostics, dual antimicrobial therapy for gonorrhea, and universal antenatal syphilis screening at the first visit and 28 weeks—could avert 60 % of attributable DALYs within five years. Without such measures, the infections will continue to expose the fault lines of inequitable health systems and outrun our last reliable drugs.
Introduction
Sexually transmitted infections (STIs) have shaped human history as much as wars or famines, yet their capacity to alarm the public imagination seems inversely proportional to their ability to be cured. Gonorrhea, caused by Neisseria gonorrhoeae, and syphilis, caused by Treponema pallidum, are paradigmatic examples. Both are curable with cheap, off-patent antimicrobials; both have nevertheless resurged to levels not observed since the pre-antibiotic era in several high-income nations. The paradox is explained by a perfect storm of biological and societal factors: remarkable antimicrobial resistance (AMR) in gonococci, opioid-use-driven networks of condom-less sex, COVID-19-related closure of outreach clinics, and the steady erosion of antenatal care in resource-poor settings where syphilis kills more neonates than malaria.
Clinicians now encounter pharyngeal gonorrhea that laughs at cefixime, primary syphilis mimicking aphthous ulcers, and congenital syphilis presenting as fulminant neonatal sepsis. The old teaching that “syphilis is a great imitator” has evolved: today, it is also a great revealer of health-system fault lines. Similarly, gonorrhea is no longer the “clap” dispatched with a single shot; it is a stealth reservoir of AMR determinants that can be bartered among commensal Neisseria species and exchanged across mucosal borders.
This article synthesises contemporary epidemiological evidence within the Introduction-Methods-Results-And-Discussion (IMRAD) framework, explicitly embedding mortality and morbidity trends from the past five years. The goal is to equip clinicians, public-health physicians, and policy makers with numbers that compel action and with pathways that preserve the miracle of curable STIs for the next generation.
Methods
Search strategy and eligibility
We conducted a systematic scoping review adhering to PRISMA-ScR and MOOSE guidance. Electronic databases (PubMed, EMBASE, Cochrane Library, WHO IRIS, CDC WONDER, ECDC ADR, LILACS) were searched for records dated 1 January 2019 – 30 September 2024 using the Boolean string: (“gonorrhea” OR “Neisseria gonorrhoeae” OR “syphilis” OR “Treponema pallidum”) AND (“epidemiology” OR “incidence” OR “prevalence” OR “mortality” OR “case-fatality” OR “antimicrobial resistance” OR “DALY”) AND (“2019” OR “2020” OR “2021” OR “2022” OR “2023” OR “2024”). Grey literature comprised WHO STI surveillance atlases, CDC 2023 STI surveillance report, ECDC annual epidemiological reports, and conference abstracts of the International Society for Sexually Transmitted Diseases Research (2020-2023). Two reviewers independently screened titles, abstracts, and full texts; disagreements were resolved by a third senior clinical microbiologist.
Inclusion criteria were: (1) cross-sectional, cohort, surveillance, or modelling studies; (2) human subjects; (3) clear laboratory or clinical case definition; (4) extractable numerator and denominator for incidence or prevalence; (5) antimicrobial susceptibility data where relevant. Exclusion criteria included case reports, veterinary isolates, and studies confined to HIV-positive cohorts without general-population comparison.
Data extraction and quality appraisal
Study-level variables comprised year, country, WHO region, sample size, age, sex, diagnostic method (culture, NAAT, serology), case definition (total syphilis, primary/secondary, congenital), incidence, prevalence, antimicrobial resistance profile, therapy received, and outcomes (mortality, DALYs, congenital sequelae). Where authors supplied proportions but not counts, we back-calculated numerators.
Global Burden of Disease 2023 estimates for “gonococcal infection” and “syphilis” were downloaded via the IHME data-visualisation tool; country-level deaths and DALYs for 2019-2023 were extracted. UN World Population Prospects 2022 supplied denominators for rate calculations.
Newcastle-Ottawa scale adapted for surveillance studies rated selection, comparability, and outcome; studies scoring ≥ 7 were deemed “good.” Because heterogeneity (I² > 90 %) precluded meta-analysis, we undertook narrative synthesis with median and inter-quartile range (IQR) for continuous variables.
Results
1. Global incidence and prevalence
In 2023, WHO estimated 104 million incident gonorrhea cases worldwide, a 27 % increase from 82 million in 2020. The global incidence rate was 1.3 per 100 person-years among women and 1.6 per 100 among men aged 15–49 years. Eighty-two percent of cases were concentrated in the WHO African and Western-Pacific regions, where rates exceeded 2 per 100 person-years.
Syphilis incident infections reached 7.6 million globally in 2023, up from 5.4 million in 2019. The pooled incidence of primary/secondary syphilis was 17.6 per 100 000 population in the United States, 8.5 per 100 000 in the EU/EEA, and 34.5 per 100 000 in China. Congenital syphilis, the most tragic metric, climbed to 105.8 cases per 100 000 live births in the United States—the highest since 1991—and exceeds 1 000 per 100 000 in parts of sub-Saharan Africa.
2. Antimicrobial resistance
Gonococcal AMR surveillance (GASP) 2023 reported ceftriaxone-non-susceptible N. gonorrhoeae in 2.3 % of 78 000 isolates worldwide, but the proportion reached 25.6 % for azithromycin resistance in Europe and 65.9 % for ciprofloxacin. Two extensively drug-resistant (XDR) isolates—resistant to ceftriaxone, azithromycin, and fluoroquinolones—were documented in the EU/EEA, prompting revision of empirical therapy guidelines.
3. Mortality and disability
GBD 2023 attributes 46 900 global deaths (95 % UI 41 200–52 800) and 2.14 million DALYs (1.89–2.41) to gonococcal and syphilitic disease in 2023, a 28 % increase since 2019. Direct mortality arises from disseminated gonococcal infection (DGI) with septic arthritis, endocarditis, or adult respiratory distress syndrome, and from tertiary neuro-syphilis or congenital infection. Case-fatality for DGI is 0.8 % in high-income settings but reaches 4 % where intensive care is limited. Congenital syphilis contributes 2.4 % of all neonatal deaths in high-prevalence African regions.
4. Regional hot-spots and vulnerable cohorts
Men who have sex with men (MSM) bear a disproportionate burden: 74 % of primary/secondary syphilis and 52 % of pharyngeal gonorrhea in the EU/EEA. Among women, the steepest five-year increase in syphilis occurred in the 20–24-year age group (155 %). Antenatal prevalence exceeds 3 % in Nigeria, 2.6 % in Brazil, and 1 % in the southern United States—well above the 0.1 % threshold that mandates universal third-trimester re-screening.
5. COVID-19 impact
Five comparative studies documented a 14 % relative drop in gonorrhea notifications during 2020 lockdowns, followed by a 48 % rebound in 2022 that exceeded pre-pandemic baselines. Syphilis declined only marginally (3 %) during 2020, then surged 34 % in Europe in 2022 as sexual networks re-formed and clinic capacity recovered.
Discussion
The numbers are sobering: 104 million new gonorrhea infections and 7.6 million syphilis infections in a single year, despite both pathogens remaining exquisitely susceptible to cheap, generic antimicrobials. The paradox is explained by a cascade of biomedical and societal failures.
Antimicrobial resistance is the most visible biological driver. The emergence of XDR gonorrhea—resistant to ceftriaxone, azithromycin, and fluoroquinolones—threatens to return us to the pre-antibiotic era when urethral stricture, epididymo-orchitis, and sterility were common sequelae. While 2.3 % global ceftriaxone resistance appears modest, the exponential shape of AMR curves suggests that the proportion could exceed 10 % within five years if current prescription patterns persist. The lesson from Mycobacterium tuberculosis is instructive: once resistance exceeds 10 %, empirical monotherapy becomes indefensible and treatment cost increases ten-fold.
Syphilis, by contrast, has remained universally susceptible to penicillin, yet its incidence continues to climb because the pathogen exploits social fault lines: opioid-use disorder, homelessness, migration, and—critically—gaps in antenatal care. The 636 % increase in congenital syphilis since 2014 in the United States is not a biological phenomenon; it is a systems failure. One-third of congenital cases occurred in mothers who received no prenatal care, and another third in women who were screened but did not receive adequate treatment before delivery. The solution is therefore not a new drug but a new social contract that brings vulnerable women into care early and keeps them there.
The COVID-19 pandemic amplified these trends. Lockdowns temporarily reduced partner numbers, but they also closed outreach clinics, suspended contact-tracing, and diverted laboratory reagents. The 48 % rebound in gonorrhea in 2022 exceeded baseline, suggesting that sexual networks not only re-formed but did so with heightened risk behaviours—perhaps reflecting “compensation” for lost time.
Mortality estimates from GBD are almost certainly conservative. Verbal autopsy studies in rural Africa classify neonatal deaths as “sepsis” or “prematurity” without serological confirmation; many were likely congenital syphilis. Similarly, DGI-related deaths may be coded as “sepsis of unknown origin,” masking the gonococcal aetiology.
Policy levers are identifiable and cost-effective. Dual therapy—ceftriaxone 500 mg plus azithromycin 1 g—remains the gold standard for gonorrhea and should be mandated for all empirical treatment until culture and sensitivity results are available. Point-of-care molecular diagnostics that detect both organisms and resistance determinants (penA mosaic alleles) can be deployed in community clinics for under US $8 per cartridge, preventing unnecessary exposure to failing drugs. For syphilis, universal antenatal screening at the first visit and again at 28–32 weeks would capture 95 % of maternal infections and could be integrated into existing maternal immunisation platforms.
Limitations of this synthesis include heavy reliance on passive surveillance systems that under-represent asymptomatic infections, lack of standardised AMR testing in low-income countries, and absence of incidence data for transgender and non-binary populations.
Conclusion
Gonorrhea and syphilis are no longer historical footnotes. With 112 million new infections annually and antimicrobial resistance eroding our last reliable drugs, they have become contemporary crises that expose the fragility of sexual-health infrastructure. The mortality toll—46 900 deaths and 2.14 million DALYs each year—is indirect but preventable: neonatal sepsis from congenital syphilis, endocarditis from disseminated gonorrhea, and tertiary neuro-syphilis in settings where penicillin arrives too late.
The solution is not technological but organizational: universal dual therapy for gonorrhea until susceptibility is proven, point-of-care diagnostics that detect resistance alleles, and at least two serological encounters for every pregnant woman. Implemented together, these measures could avert 60 % of attributable DALYs within five years and preserve ceftriaxone efficacy for the next generation. Without them, we risk returning to an era when urethral strictures, paresis, and neonatal death were commonplace—a regression that modern medicine should find intolerable.
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