Disease overview

Bacterial

Syphilis

梅毒

Evidence-backed informationEN 6/7 applicable sections · ZH 6/7 applicable sectionsUpdated Sep 3, 2026

Syphilis is a curable bacterial sexually transmitted infection caused by Treponema pallidum, characterized by staged clinical manifestations that may be asymptomatic for years if untreated ^[1]^[2]^[3]^[4]. The disease is preventable through safer sex practices and is a leading cause of preventable stillbirth and neonatal mortality when transmitted from mother to fetus ^[2]^[3]^[4]. Substantial global morbidity persists, with an estimated 8 million new adult infections in 2022 and rising case counts reported in multiple settings ^[4].

Read the full clinical and epidemiological profile7

Definition

Syphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum subspecies pallidum ^[1]^[2]^[3]^[4]. It is described as a preventable and curable bacterial STI that can cause serious health consequences when left untreated, and it is closely related to other treponemal diseases including yaws, pinta, and nonvenereal endemic syphilis ^[1]^[3].

Clinical features

Clinical manifestations are stage-dependent, classically described as primary, secondary, latent, and tertiary ^[1]^[2]^[4]. Primary syphilis typically presents as a single firm, painless, non-itchy chancre at the site of contact, although multiple lesions may occur ^[1]^[2]^[4]. Secondary syphilis is characterized by a diffuse rash that frequently involves the palms and soles, often accompanied by mucocutaneous lesions, lymphadenopathy, and oral or genital sores ^[1]^[2]^[4]. Latent syphilis is asymptomatic and may persist for years, while tertiary disease can involve gummas, cardiovascular complications, and neurological problems ^[1]^[4]. Because of its variable and sometimes subtle presentation, syphilis has been called "the great imitator" ^[1].

Epidemiology

Syphilis remains a significant global public health concern. In 2022, an estimated 8 million adults aged 18 to 49 years acquired syphilis worldwide ^[4]. Earlier estimates placed adult prevalence at roughly 0.5% with around 6 million new cases in 2012, and approximately 12 million additional infections in 1999, with over 90% occurring in the developing world ^[1]. In the United States, syphilis cases increased by 61% from 2019 to 2023, with diagnoses among females rising 112% and congenital syphilis cases rising 106% over the same period ^[4]. Syphilis affects an estimated 700,000 to 1.6 million pregnancies each year, contributing to miscarriages, stillbirths, and congenital infections, and accounts for roughly 20% of perinatal deaths in sub-Saharan Africa ^[1]^[3].

Transmission

Syphilis is transmitted through direct contact with infectious lesions during oral, vaginal, or anal sex, through blood transfusion, and transplacentally from a pregnant woman to her fetus ^[1]^[2]^[3]^[4]. Mother-to-child transmission, when untreated or inadequately treated during pregnancy, results in adverse birth outcomes in an estimated 50–80% of cases, including stillbirth, neonatal death, prematurity, low birth weight, and congenital infection ^[3]. Up to 40% of fetuses exposed in utero are stillborn or die during infancy from their infection ^[4].

Prevention

Syphilis is a preventable disease for which consistent and correct use of condoms during sex is the best protection, although transmission can still occur through contact with areas of the body not covered by a condom, including the genitals, anus, and mouth ^[2]. Identifying infection through laboratory or rapid testing and promptly treating positive cases prevents further transmission and complications, including congenital syphilis ^[2]. Pregnant women should be tested for syphilis at the first prenatal care visit and treated immediately if positive, since congenital syphilis can only be prevented by diagnosing and treating the mother with penicillin ^[2]. People at higher risk should be tested at least once a year, and individuals diagnosed with syphilis should notify their sexual partners to prevent new infections ^[2].

Surveillance note

GlobalID source-data note: Korea's historical surveillance contains separate primary, secondary, tertiary, and latent syphilis series as well as a broader syphilis series. The stage-specific rows are subdivisions, so a broad total must not be summed with its stage components; comparisons across the 2024 definition transition require the source period and label.

References

1Wikipedia contributors. Syphilis - Wikipedia [Internet]. Wikipedia. cited 3 Sept 2026.Available from: https://en.wikipedia.org/wiki/Syphilis
2World Health Organization. Syphilis [Internet]. cited 3 Sept 2026.Available from: https://www.who.int/news-room/fact-sheets/detail/syphilis
3World Health Organization. Syphilis -- Global [Internet]. cited 3 Sept 2026.Available from: https://www.who.int/health-topics/syphilis
4Chevalier FJ et al. Syphilis: A Review. JAMA. 2025 Dec 2. PMID: 41100079. doi: 10.1001/jama.2025.17362.PubMed: https://pubmed.ncbi.nlm.nih.gov/41100079/

Coding Register

ICD-10: A50-A53
ICD-11: 1A70

Key Statistics

Total cases: 9.4M
Total deaths: 1K
Peak month: 2024-03
Coverage: 37 reporting countries · 1924-01-01 → 2026-09-01

Coverage

Reporting countries and regions

37 locations

Trends by reporting country

Monthly patterns over time

Research Radar

Recent related research

View all research →

Peer reviewedOpen accessSyphilisTreatment

DOI 10.3389/fmed.2026.1899418 ↗

Case Report: A case of secondary syphilis with clinical manifestations resembling granuloma annulare

Ting Xu, Wanyuan Chen, Yuhuan Shen +1 more

Frontiers in MedicineAug 26, 2026

Open article ↗Syphilis surveillance →

Peer reviewedSyphilisTreatment

DOI 10.1097/qco.0000000000001234 ↗

Management of neonates born to mothers with reactive serologic tests for syphilis

Abigail Z. Nishikawa, W. Christopher Golden, Alexa J. Brumfiel +2 more

Current Opinion in Infectious DiseasesAug 24, 2026

Syphilis surveillance →

Peer reviewedOpen accessHepatitis BTransmission dynamics

DOI 10.3390/ijerph23081090 ↗

The Level of Knowledge, Attitude, Practice, and Adherence of Obstetricians and Gynecologists Towards the Triple Elimination Program (HIV, Syphilis, Hepatitis B) in Maternal Services at Government and Private Hospitals in Jakarta

Yudianto Budi Saroyo, Baihaki, Mohammad Adya F. Dilmy +2 more

International Journal of Environmental Research and Public HealthAug 21, 2026

Open article ↗Hepatitis B surveillance →

Peer reviewedOpen accessRubellaTransmission dynamics

DOI 10.7717/peerj.21632 ↗

Seroprevalence of toxoplasmosis, rubella, cytomegalovirus, herpes simplex, and syphilis infections among pregnant women and infants in Malaysia: a systematic review and meta-analysis

Abdirahman Hussein Elmi, Ahmad Adebayo Irekeola, Hafeez Abiola Afolabi +4 more

PeerJAug 18, 2026

Open article ↗Rubella surveillance →

Peer reviewedOpen accessSyphilisTransmission dynamics

DOI 10.1093/cid/ciaf504 ↗

State-of-the-Art Review: Congenital Syphilis in the Modern Era: Current Strategies and Future Directions

John M Flores, Ryan Rochat, Irene A Stafford +3 more

Clinical Infectious DiseasesFeb 4, 2026

Open article ↗Syphilis surveillance →

Showing 5 of 15 related publications.

Literature links are provided for discovery and do not alter or validate the surveillance series above.

Rows18,665

Updated2026-09-01

Coverage—

Partitions22

Source41 series · 8,932 observations

Official sourcesAuthority, cadence, notes113

monthlymicrosoft_bi

Australian national notifiable diseases surveillance dashboard.

monthlymicrosoft_bi

Australian NINDSS monthly state/territory notifications for Australian Capital Territory, kept separate from the Australia national aggregate.

monthlymicrosoft_bi

Australian NINDSS monthly state/territory notifications for New South Wales, kept separate from the Australia national aggregate.

monthlymicrosoft_bi

Australian NINDSS monthly state/territory notifications for Northern Territory, kept separate from the Australia national aggregate.

monthlymicrosoft_bi

Australian NINDSS monthly state/territory notifications for Queensland, kept separate from the Australia national aggregate.

monthlymicrosoft_bi

Australian NINDSS monthly state/territory notifications for South Australia, kept separate from the Australia national aggregate.

monthlymicrosoft_bi

Australian NINDSS monthly state/territory notifications for Tasmania, kept separate from the Australia national aggregate.

monthlymicrosoft_bi

Australian NINDSS monthly state/territory notifications for Victoria, kept separate from the Australia national aggregate.

monthlymicrosoft_bi

Australian NINDSS monthly state/territory notifications for Western Australia, kept separate from the Australia national aggregate.

annualofficial_ecdc_rest_aggregate

Belgium annual Member-State reported case counts from the ECDC Surveillance Atlas. Missing topic/year cells remain unknown and published zeroes are preserved. Data provided by ECDC based on data reported by EU/EEA Member States.

annualofficial_ecdc_rest_aggregate

Bulgaria annual Member-State reported case counts from the ECDC Surveillance Atlas. Missing topic/year cells remain unknown and published zeroes are preserved. Data provided by ECDC based on data reported by EU/EEA Member States.

ANNUALweb

Canada is the national jurisdiction; subdivision feeds are registered separately.

weeklyrest_api

Switzerland FOPH/BAG IDD mandatory reporting API normalized to national case rows. Monthly series may use the dashboard CHFL aggregate where CH-only monthly series are not exposed.

MONTHLYweb

Monthly notifiable infectious disease reports published by China CDC.

MONTHLYweb

Official China public health bulletin and query portal.

MONTHLYweb

Biomedical literature discovery feed used as supplementary context.