La reemergencia de la sífilis en Barcelona 2003-2015.

Abstract

Since 2000, substantially higher syphilis rates have been reported in association with high-risk factors in metropolitan areas of Western countries. This thesis analyzes the situation in Barcelona based on two studies: a retrospective study and a prospective study, both undertaken at the Vall d’Hebron-Drassanes STI Unit in Barcelona and described herein. In the retrospective study, the same upward trend was also observed from 2003 to 2013. In fact, a 300% increase in cases of early syphilis was found especially among men who have sex with men, 30% of whom were HIV-positive. This surge was related to high numbers of contacts and condomless anal sex, which were more common risk factors in HIV-positive patients. Clinically, secondary syphilis was seen most often, followed by primary syphilis and early latent syphilis. During the study period, a rise was observed in the number of syphilis cases diagnosed during routine screening and, consequently, also in the number of latent syphilis cases, especially in HIV-negative patients. Patients with a history of syphilis presented less often with primary syphilis, probably in relation to immunological factors. HIV-positive patients and/or patients with previous syphilis had higher RPR titers than patients who were HIV-negative and/or had no history of syphilis, with similar clinical progress seen in both groups. A detailed analysis of the epidemiological, clinical, and microbiological findings was undertaken in patients with early syphilis diagnosed in 2015. In terms of epidemiology, two-thirds of participants had engaged in occasional condomless anal sex with a median of 10 contacts in the previous 12 months, and over half had participated in group sex and/or used drugs for sex. In the comparative study, HIV-positive patients were more likely to have had condomless anal sex with a higher number of contacts, to have participated in group sex, to have practiced serosorting, and to have chemsex. Clinically, secondary syphilis was the most common stage in both the overall study population and in HIV-positive patients, with primary syphilis seen less often in the latter group. In primary syphilis, anal chancre was more common in HIV positive patients. T. pallidum typification was performed to determine if a specific type might explain some clinical manifestations, but the results were not conclusive due to the wide variety of types observed and the small sample size. RPR titers were higher in HIV-positive patients, a finding also true after stratifying by stage and previous syphilis, with no difference in cure rates between HIV-positive and HIV-negative patients. One-third of patients experienced a Jarisch-Herxheimer reaction, a response seen more often in patients with primary and secondary syphilis and less often in early latent syphilis. The most common sign was fever. An analysis of the risk factors associated with J-H reaction suggested no relationship with HIV serostatus, history of syphilis, or RPR titers, with patients treated with doxycycline found to be less likely to experience this reaction. When analyzing whether the reaction might be related to a particular serovar, no specific trends were observed, as T. pallidum type varied considerably. In the study of patients who consulted in the context of contact tracing, condomless anal sex was the only variable still significant when comparing risk factors between patients with versus without post-contact syphilis, demonstrating the importance of early epidemiological treatment in these patients. In view of this large study, we concluded that the approaches used to control syphilis should be similar as those proposed almost one hundred years ago: widespread screening, timely treatment, contact tracing, patient education, professional training and participation, public health measures and ongoing research.

Date of Award	29 Nov 2019
Original language	Spanish
Supervisor	Martí Vall Mayans (Director) & Carlos Pigrau Serrallach (Tutor)