BejelA65.x

Bejel, also known as endemic syphilis, is a (non-venereal) endemic treponematosis. Affected is mainly the population living in the middle hygiene status. The thesis of a non-venereal infection seems to be no longer tenable after investigations on syphilitic patients showed the presence of Treponema pallidum subsp. endemicum. See below for references (Noda AA et al. 2018).

Africa, Near East; South America. The World Health Organization (WHO) estimates that there are 12 million new cases of syphilis annually, and the total number of cases of Bejel, Yaws, and Pinta is about 2.5 million worldwide, although good epidemiological data are not available on this. Infections caused by T. pallidum are characterized by periods of active clinical disease interspersed with episodes of asymptomatic latent infection, and can cause lifelong infections in untreated individuals (Centurion-Lara A et al. 2006; Nyatsanza F et al. 2016)

Phylo-genomic, pan-genomic, core-genomic and singleton analyses reveal the close association between all strains of T. pallidum. Based on genome plasticity analysis, differences in the presence/absence of pathogenicity islands (PAIs) and genomic islands (GIs) can be detected on a subsp. basis. Some genes related to lipid and amino acid biosynthesis are found to be present only in the subsp. of T. pallidum, compared to T. pallidum subsp. endemicum and T. pallidum subsp. pertenue. The subspecies T. pallidum subsp. endemicum and T. pallidum subsp. pertenu are so similar that they cannot be distinguished serologically. They are antigenically cross-reactive (Jaiswal AK et al. 2020). Their morphology is also indistinguishable. In the 1980s, very limited genetic diversity was found between these pathogen species. Later, it was demonstrated that the genomes of syphilis, yaws and bejel treponemes have an overall similarity of 97-100% and the molecular organization is also identical. This evidence suggests that only small genetic changes in key genes between these organisms are responsible for the reported differences in disease pathogenesis. When looking at the genes in PAIs and GIs, it is noticeable that there are no pathogenicity islands in any of the subspecies. Genes present in pathogenicity islands (PAIs) or genomic islands (GIs) of subspecies pallidum are absent in subspecies endemicum and pertenue (Jaiswal AK et al. 2020).

Transmission of spirochetes by smear infection or everyday objects.

The primary lesion usually remains undetected. Secondary and tertiary lesions run the same course as in syphilis acquisita, in some cases also similar to that of frambosia. Rarely, birth of a child with syphilis connata in a mother suffering from endemic syphilis.

The Bosnia A strain was isolated in Bosnia, southern Europe, in 1950. The complete genome of the Bosnia A strain has been amplified and sequenced and is considered the reference for T. pallidum subsp. endemicum. The size of the Bosnia A genome is 1,137,653 bp, i.e. 1.6-2.8 kbp, which is shorter than all previously published genomes of non-culturable pathogenic treponemes. Compared to other sequenced syphilis and Yaws treponemes, conserved gene synteny was found in the Bosnia A genome. The TEN Bosnia A genome is distinct from, but very similar to, the genome of T. pallidum subsp. pertenue (TPE) strains. The Bosnia A genome contains several sequences that have previously only been uniquely identified in syphilis treponemes (Staudová B et al. 2014).

Positive syphilis serology (explanation see below Diagnostics).

Bejel, caused by Treponema pallidum subsp. endemicum (TEN), was previously considered a non-venereal disease endemic to areas with hot and dry climates. In a recent study of syphilitic patients in Cuba with molecular identification of the pathogens, revealed in a high percentage the detection of Treponema pallidum subsp. endemicum. These studies highlight the limitations of a diagnosis based solely on serology, geographic occurrence, clinical symptoms, and anamnestic data. This finding has important implications for global public health systems, including a paradigm shift in the location of endemic outbreaks, clinical aspects, and transmission of this neglected disease(Noda AA et al. 2018).

1. Centurion-Lara A et al. (2006) Molecular differentiation of Treponema pallidum subspecies. J Clin Microbiol 44:3377-3780.
2. Giacani L et al (2014) . The endemic treponematoses. Clin Microbiol Rev 27:89-115.
3. Jaiswal Arun Kumar et al. (2020) The pan-genome of Treponema pallidum reveals differences in genome plasticity between subspecies related to venereal and non-venereal syphilis BMC Genomics 21: 33.
4. Mitja O et al (2013) Advances in the diagnosis of endemic treponematoses: yaws, bejel, and pinta. PLoS Negl Trop Dis 7:e2283.
5. Noda AA et al. (2018) Bejel in Cuba: molecular identification of Treponema pallidum subsp. endemicum in patients diagnosed with venereal syphilis. Clin Microbiol Infect 24:1210.e1-1210.
6. Nyatsanza F et al (2016) Syphilis: presentations in general medicine. Clin Med (Lond) 16:184-188.
7. Radolf JD et al. (2016) Treponema pallidum, the syphilis spirochete: making a living as a stealth pathogen. Nat Rev Microbiol 14:744-759.
8. Staudová B et al. (2014) 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. PLoS Negl Trop Dis;8(11):e3261.