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# Non-venereal treponemes (yaws, bejel and pinta)

- Bacterium
- Does not Gram-stain
- For completeness

Relatives of the syphilis agent spread by skin contact among children in poor tropical areas: yaws, bejel and pinta.

Updated 2026-11-01

Also called: frambesia, carate

## Key points

- Same genus and species as syphilis, but spread by skin contact among children, not sexually or congenitally.
- VDRL and FTA-ABS are positive: they do not separate these from syphilis.
- Yaws: raspberry lesion; pinta: blue, then white, patches.
- Single-dose azithromycin is the backbone of the yaws eradication programme.

## At a glance

**Gram**
Does not Gram-stain

**Shape**
Spirochaete

**Family**
Treponemataceae

**Stain**
Not seen on Gram stain; dark-field microscopy of lesions

## Morphology

- Thin spirochaetes identical to Treponema pallidum under the microscope
- Yaws: T. pallidum subspecies pertenue; bejel: subspecies endemicum; pinta: Treponema carateum
- Cannot be grown on artificial media

## Transmission

- Direct skin contact with lesions, helped by small wounds
- Bejel: also mouth to mouth and through shared utensils
- Not sexually transmitted and not passed from mother to fetus

**Reservoir:** Humans

### Isolation precautions

What the care team adds to standard precautions.

- Standard

## Virulence factors

- Few surface proteins, which hampers the immune response
- Chronic lesions that destroy skin, bone and cartilage if untreated (yaws, bejel)
- Pinta stays confined to the skin

## Diseases it causes

- Yaws (frambesia) [Yaws and endemic treponematoses →](https://durgical.com/en/conditions/yaws-and-endemic-treponematoses/)
- Bejel (endemic syphilis)
- Pinta (carate)

## Clinical picture

- Yaws: a papule that grows like a raspberry and ulcerates; later multiple lesions, pain and deformity of long bones and fingers
- Bejel: mouth and skin lesions, periostitis and destruction of nose and palate
- Pinta: skin patches that turn from bluish to depigmented, resembling vitiligo

## Diagnosis

- Clinical and epidemiological diagnosis
- Syphilis serology (treponemal and non-treponemal) is positive and does not tell them apart
- PCR to confirm yaws and to monitor azithromycin resistance

## Treatment

Macrolides (single-dose azithromycin, the first choice in yaws) or benzathine penicillin. WHO uses community-wide mass treatment with azithromycin to eradicate yaws.

Drug class only; doses and regimens are set by the clinician from the current guideline.

In Pharmacology:

- [Azithromycin](https://durgical.com/en/pharmacology/azithromycin/)
- [Benzathine benzylpenicillin](https://durgical.com/en/pharmacology/benzathine-benzylpenicillin/)

## Prevention

- Treating the whole community and all contacts
- Hygiene, water and soap
- Active case finding among children

## In Colombia

According to WHO, Colombia has reported suspected but not confirmed yaws cases. Pinta has been described among Indigenous populations of Mexico, Central America and South America.

## Memory aid

"Three cousins, no sex": raspberry yaws, mouth-borne bejel and pinta that paints the skin; they share syphilis serology, not its route.

## Test yourself

Think of the answer, then tap the question to see it.

## What causes pinta?

Treponema carateum.

## Why does a positive VDRL in a child from a yaws-endemic area not confirm syphilis?

Non-venereal treponemes give the same positive serology; they are told apart by the clinical picture and epidemiology.

## Which antibiotic does WHO use for mass treatment of yaws?

Single-dose azithromycin.

## How does the spread of yaws differ from that of syphilis?

Yaws spreads by skin contact with lesions, mostly among children; it is not sexual and does not pass to the fetus.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/microbiology/non-venereal-treponemes/)

## Related

- [Treponema pallidum](https://durgical.com/en/microbiology/treponema-pallidum/)
- [Leptospira interrogans](https://durgical.com/en/microbiology/leptospira-interrogans/)

## Related conditions

- [Yaws and endemic treponematoses](https://durgical.com/en/conditions/yaws-and-endemic-treponematoses/)

## What the colours mean

**Gram-positive**
Thick peptidoglycan wall: stains purple.

**Gram-negative**
Thin wall with an outer membrane: stains pink.

**Acid-fast**
Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain.

[← Back to the group: Other clinically important bacteria](https://durgical.com/en/microbiology/groups/other-clinically-important-bacteria/)

Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Yaws](https://www.who.int/news-room/fact-sheets/detail/yaws) (WHO, 2024); [Bejel, Pinta, and Yaws - Infectious Disease - MSD Manual Professional Edition](https://www.msdmanuals.com/professional/infectious-diseases/spirochetes/bejel-pinta-and-yaws) (MSD Manual Professional Edition, 2025).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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Source: https://durgical.com/en/microbiology/non-venereal-treponemes/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/non-venereal-treponemes/