The Venereal Disease Research Laboratory (VDRL) test has long been considered the best serological test for the diagnosis of neurosyphilis. The goal of this study was to find out if the Rapid Plasma Reagin (RPR) could be an alternative to the VDRL. Cerebrospinal fluid (CSF) and sera samples from patients in the following stages of syphilis were tested: 8 had symptomatic and 16 asymptomatic neurosyphilis, 4 were in the primary stage, 6 had secondary syphilis, and 92 were in the latent stage. We have also studied 61 samples from individuals with treated syphilis and 126 with other neurological diseases than neurosyphilis. All the CSF samples were studied with both RPR and VDRL tests. RPR and VDRL test results were mostly concordant. The specificity of these tests for current neurosyphilis was 99% for the VDRL and 99.3% for the RPR, whereas the sensitivity was 70.8 and 75%, respectively, for the VDRL and RPR. In view of these results it seems to us that the RPR could be an alternative to the VDRL in the diagnosis of neurosyphilis.

A combined treponemal and nontreponemal rapid diagnostic test was found to have good sensitivity and specificity for both syphilis and yaws. The performance of both the treponemal and nontreponemal test components was strongly associated with the rapid plasma reagin titer.

In this study, polymerase chain reaction (PCR) techniques were used to detect Treponema pallidum DNA in samples from patients with latent syphilis. Sixty-nine patients with latent syphilis and 18 with treated syphilis were included. Whole blood, plasma, sera and ear scrapings, totalling 235 samples from patients with latent syphilis, were obtained. Three PCR assays (47-PCR, polA-PCR and M-PCR assays) were performed. The 47-PCR yielded the highest number of positive samples -92/235 (39.1%), followed by M-PCR -90/235 (38.3%) and polA-PCR -73/235 (31.1%). Ear scrapings presented the highest number of positives (47/84 -56%), followed by plasma samples (36/84 -42.9%), whole blood (32/84 -38.1%) and sera (21/84 -25%). In conclusion, we have confirmed that T. pallidum can be found in blood of patients with latent syphilis. The 47-PCR technique was found to be the most sensitive, whereas ear lobe scrapings seem to be the best specimen for detection of T. pallidum DNA in latent syphilis.

Sexually transmitted infections are frequently asymptomatic and cause maternal-foetal morbidity. The opportunity that pregnancy offers for screening and counselling should not therefore be missed, especially in adolescents.

The objectives of this study were to evaluate the reproducibility of a molecular method for the subtyping of Treponema pallidum subsp. pallidum and to discriminate strains of this microorganism from strains from patients with syphilis. We studied 212 specimens from a total of 82 patients with different stages of syphilis (14 primary, 7 secondary and 61 latent syphilis). The specimens were distributed as follows: genital ulcers (n ‫؍‬ 9), skin and mucosal lesions (n ‫؍‬ 7), blood (n ‫؍‬ 82), plasma (n ‫؍‬ 82), and ear lobe scrapings (n ‫؍‬ 32). The samples were assayed by a PCR technique to amplify a segment of the polymerase gene I (polA). Positive samples were typed on the basis of the analysis of two variable genes, tpr and arp. Sixty-two of the 90 samples positive for polA yielded typeable Treponema pallidum DNA. All skin lesions in which T. pallidum was identified (six of six [100%]) were found to contain enough DNA for typing of the organism. It was also possible to type DNA from 7/9 (77.7%) genital ulcer samples, 13/22 (59.1%) blood samples, 20/32 (62.5%) plasma samples, and 16/21 (76.2%) ear lobe scrapings. The same subtype was identified in all samples from the same patient. Five molecular subtypes (subtypes 10a, 14a, 14c, 14f, and 14g) were identified, with the most frequently found subtype being subtype 14a and the least frequently found subtype being subtype 10a. In conclusion, the subtyping technique used in this study seems to have good reproducibility. To our knowledge, subtype 10a was identified for the first time. Further studies are needed to explain the presence of this subtype in Portugal, namely, its relationship to the Treponema pallidum strains circulating in the African countries where Portuguese is spoken.