Molecular epidemiological survey of Treponema pallidum in pregnant women in the Zhabei District of Shanghai.

PURPOSE: To evaluate the epidemiological characteristics of syphilis, such as incidence, vertical transmission and genotypes, in pregnant women in the Zhabei District of Shanghai. In addition, the changes in genotypes and the efficiency of genotyping were evaluated.

METHODOLOGY: We screened 3022 pregnant women for syphilis in the Shanghai Zhabei Central Hospital. Whole blood, plasma, earlobe blood and specimens from genital ulcers or skin/mucosal lesions were collected from syphilis-positive patients. Samples were genotyped by analysing a combination of three genes: tpr, arp and tp0548 (the tpr/arp/tp0548 genotype). Clinical data were further collected to evaluate disease incidence, maternal-neonatal transmission and social factors.

RESULTS

Out of 3022 pregnant women screened for syphilis, 41 were syphilis-positive. Of these, 43.9 % showed vertical transmission (18/41). The prevalence of syphilis in pregnant women was 1.32 %, higher than that in other districts in Shanghai in 2014. Genotyping was performed in 10/11 (90.9 %) samples of syphilis lesions, 8/41 (19.5 %) blood samples, 12/41 (29.3 %) plasma samples, and 20/39 (48.7 %) earlobe blood samples. The predominant genotype was 14d/f, followed by 15d/f, 13a/f, 13d/f and 9o/c. Genotype 13a/f was reported for the first time in the Shanghai area since 2010.

CONCLUSION

The prevalence of syphilis in pregnant women in the Zhabei District was higher than that in other areas in Shanghai and the genotype is variable.