Editing Treponema pallidum (section)

==Clinical significance==
The clinical features of syphilis, yaws, and bejel occur in multiple stages that affect the skin. The skin lesions observed in the early stage last for weeks or months. The skin lesions are highly infectious, and the spirochetes in the lesions are transmitted by direct contact. The lesions regress as the immune response develops against ''T. pallidum''. The latent stage that results can last a lifetime in many cases. In a few cases, the disease exits latency and enters a tertiary phase, in which destructive lesions of skin, bone, and cartilage ensue. Unlike yaws and bejels, syphilis in its tertiary stage often affects the heart, eyes, and nervous system, as well.<ref name=Giacani2014/>

===Syphilis===
{{Main|Syphilis}}
''Treponema pallidum pallidum'' is a motile spirochete that is generally acquired by close [[sexually transmitted disease|sexual contact]], entering the host via breaches in squamous or columnar [[epithelium]]. The organism can also be transmitted to a fetus by [[placenta|transplacental]] passage during the later stages of pregnancy, giving rise to congenital syphilis.<ref>{{cite journal |vauthors=Arora N, Sadovsky Y, Dermody TS, Coyne CB |title=Microbial Vertical Transmission during Human Pregnancy |journal=Cell Host Microbe |volume=21 |issue=5 |pages=561–7 |date=May 2017 |pmid=28494237 |pmc=6148370 |doi=10.1016/j.chom.2017.04.007 }}</ref> The helical structure of ''T. p. pallidum'' allows it to move in a corkscrew motion through mucous membranes or enter minuscule breaks in the skin. In women, the initial lesion is usually on the labia, the walls of the vagina, or the cervix; in men, it is on the shaft or glans of the penis.<ref name="NBK7716" /> It gains access to the host's blood and lymph systems through tissue and mucous membranes. In more severe cases, it may gain access to the host by infecting the skeletal bones and central nervous system of the body.<ref name="NBK7716"/>

The incubation period for a ''T. p. pallidum'' infection is usually around 21 days, but can range from 10 to 90 days.<ref>{{Cite web |date=2022-09-10 |title=Syphilis |url=https://www.pennmedicine.org/for-patients-and-visitors/patient-information/conditions-treated-a-to-z/syphilis |access-date=2024-09-11 |website=www.pennmedicine.org}}</ref>

=== Yaws ===
{{main|Yaws}}
The causative agent of yaws is ''Treponema pallidum pertenue'', which is transmissible by direct physical contact between infected people.<ref>{{Cite journal |last1=Dofitas |first1=Belen Lardizabal |last2=Kalim |first2=Sherjan P. |last3=Toledo |first3=Camille B. |last4=Richardus |first4=Jan Hendrik |date=2020-01-30 |title=Yaws in the Philippines: first reported cases since the 1970s |journal=Infectious Diseases of Poverty |volume=9 |issue=1 |pages=1 |doi=10.1186/s40249-019-0617-6 |doi-access=free |issn=2095-5162 |pmc=6990502 |pmid=31996251}}</ref> Yaws is not sexually transmitted, and occurs in tropical, humid environments of Africa, Pacific Islands, Asia and South America.<ref name=":1">{{Cite journal |last1=Mitjà |first1=Oriol |last2=Asiedu |first2=Kingsley |last3=Mabey |first3=David |date=2013-03-02 |title=Yaws |url=https://pubmed.ncbi.nlm.nih.gov/23415015/ |journal=Lancet |volume=381 |issue=9868 |pages=763–773 |doi=10.1016/S0140-6736(12)62130-8 |issn=1474-547X |pmid=23415015}}</ref><ref>{{Cite web |title=Yaws (Endemic treponematoses) |url=https://www.who.int/health-topics/yaws#tab=tab_1 |access-date=2024-11-20 |website=www.who.int |language=en}}</ref> Unlike syphilis, which displays [[vertical transmission]], one strain of ''T. p. pertenue'' researched was not vertically transmissible in a guinea pig model, and yaws cannot be spread from mother to offspring.<ref>{{Cite journal |last1=Wicher |first1=Konrad |last2=Wicher |first2=Victoria |last3=Abbruscato |first3=Frank |last4=Baughn |first4=Robert E. |date=June 2000 |editor-last=Barbieri |editor-first=J. T. |title=Treponema pallidum subsp. pertenue Displays Pathogenic Properties Different from Those of T. pallidum subsp. pallidum |journal=Infection and Immunity |language=en |volume=68 |issue=6 |pages=3219–3225 |doi=10.1128/IAI.68.6.3219-3225.2000 |issn=0019-9567 |pmc=97566 |pmid=10816466}}</ref><ref name=":1" /> Yaws appears as skin lesions, usually [[papule]]s, commonly on the lower extremities, but present in other areas such as the arms, trunk and hands.<ref name=":0">{{Cite journal |last1=Marks |first1=Michael |last2=Lebari |first2=Dornubari |last3=Solomon |first3=Anthony W. |last4=Higgins |first4=Stephen P. |date=2015-09-26 |title=Yaws |journal=International Journal of STD & AIDS |volume=26 |issue=10 |pages=696–703 |doi=10.1177/0956462414549036 |issn=1758-1052 |pmc=4655361 |pmid=25193248}}</ref> Three stages of yaws disease have been documented: primary yaws which presents as inflamed sores on the lower body, secondary yaws which presents as a variety of skin abnormalities along with bone inflammation, and tertiary yaws, also referred to as latent yaws, which occurs when ''T. p. pertenue'' is serologically detected in the host but no clinical signs are displayed until relapse, which often occurs years later.<ref>{{Cite journal |last=Marks |first=Michael |date=September 2018 |title=Advances in the Treatment of Yaws |journal=Tropical Medicine and Infectious Disease |language=en |volume=3 |issue=3 |pages=92 |doi=10.3390/tropicalmed3030092 |doi-access=free |pmid=30274488 |pmc=6161241 |issn=2414-6366}}</ref><ref name=":0" /> Yaws is treated with antibiotics such as [[azithromycin]] and [[Benzathine benzylpenicillin|benzathine penicillin-G]].<ref>{{Cite journal |last1=Mitjà |first1=Oriol |last2=Hays |first2=Russell |last3=Ipai |first3=Anthony |last4=Penias |first4=Moses |last5=Paru |first5=Raymond |last6=Fagaho |first6=David |last7=de Lazzari |first7=Elisa |last8=Bassat |first8=Quique |date=2012-01-28 |title=Single-dose azithromycin versus benzathine benzylpenicillin for treatment of yaws in children in Papua New Guinea: an open-label, non-inferiority, randomised trial |url=https://pubmed.ncbi.nlm.nih.gov/22240407/ |journal=Lancet |volume=379 |issue=9813 |pages=342–347 |doi=10.1016/S0140-6736(11)61624-3 |issn=1474-547X |pmid=22240407}}</ref>

=== Bejel ===
[[Nonvenereal endemic syphilis|Bejel]] is caused by ''Treponema pallidum endemicum'' and is a disease is that endemic in hot and dry climates. The transmission path has not been fully mapped, however infections are thought to be transmitted via direct contact with lesion secretions or fomites rather than by sexual transmission.<ref>{{Cite journal |last1=Štaudová |first1=Barbora |last2=Strouhal |first2=Michal |last3=Zobaníková |first3=Marie |last4=Čejková |first4=Darina |last5=Fulton |first5=Lucinda L. |last6=Chen |first6=Lei |last7=Giacani |first7=Lorenzo |last8=Centurion-Lara |first8=Arturo |last9=Bruisten |first9=Sylvia M. |last10=Sodergren |first10=Erica |last11=Weinstock |first11=George M. |last12=Šmajs |first12=David |date=2014-11-06 |title=Whole Genome Sequence of the Treponema pallidum subsp. endemicum Strain Bosnia A: The Genome Is Related to Yaws Treponemes but Contains Few Loci Similar to Syphilis Treponemes |journal=PLOS Neglected Tropical Diseases |language=en |volume=8 |issue=11 |pages=e3261 |doi=10.1371/journal.pntd.0003261 |issn=1935-2735 |pmc=4222731 |pmid=25375929 |doi-access=free}}</ref> Bejel typically causes skin lesions, which first appear as small ulcers in the mouth, and secondary lesions that form in the oropharynx, or around the nipples of nursing women.<ref name="linkinghub.elsevier.com"/> Bejel can be treated with [[Benzathine benzylpenicillin|benzathine penicillin-G]].<ref>{{Cite web |title=Penicillin g benzathine (intramuscular route) |url=https://www.mayoclinic.org/drugs-supplements/penicillin-g-benzathine-intramuscular-route/description/drg-20506360 |access-date=2024-11-06 |website=Mayo Clinic |language=en}}</ref>