Specific immunofluorescence staining of Treponema pallidum in smears and tissues

Syphilis in the United States: an update for clinicians with an emphasis on HIV coinfection

Diagnosis and treatment of syphilis are challenging because of its variable clinical presentation and course and the lack of definitive tests of cure after treatment. This review of the most recent literature on the epidemiology, clinical manifestations, current diagnosis, and treatment of syphilis is focused toward clinicians who treat patients with this disease. Syphilis coinfection with human immunodeficiency virus is emphasized because it is increasingly common in the United States and affects the initial presentation, disease course, diagnosis, and treatment of syphilis. Of particular consequence is the effect of human immunodeficiency virus on the clinical diagnosis, prevalence, and course of neurosyphilis, one of the most serious consequences of syphilis infection.

[Role of biological assays in the diagnosis of Lyme borreliosis presentations. What are the techniques and which are currently available?]

The biological diagnosis of Borrelia burgdorferi sensu lato infection is usually made by antibody detection in patient sera. Thus, serological testing (Elisa, immunoblotting) is essential for a biological diagnosis. Specific antibody detection is usually done in serum and CSF of patients suspected of Lyme borreliosis. Laboratories must follow European recommendations to validate these assays in routine practice. Antibody detection lacks sensitivity in the early cutaneous phase of the infection. Therefore, serological testing is not recommended for the diagnosis of erythema migrans. The interpretation of serology must take into account the variability of Elisa sensitivity and specificity and the lack of standardization for Western-blotting in Europe. Besides these indirect diagnosis techniques, there is also direct detection of spirochetes by culture or by in vitro DNA amplification but these require adequate samples. These molecular tests must not be performed routinely, but only for specific clinical situations and in specialized laboratories only.

Syphilis and HIV Infection: an Update

Although once on decline in the United States and Europe, the incidence of syphilis has been on the rise since 2000. This increase is noteworthy because there is a high coinfection rate with HIV, especially among men who have sex with men. In light of high coinfection rates, all HIV-infected patients should be tested for syphilis and vice versa. HIV can alter the clinical manifestations of syphilis and, in turn, syphilis has the potential to change the course and transmission of HIV. This article addresses variations in clinical presentation, diagnosis, and management of individuals coinfected with HIV and syphilis.

Syphilis: review with emphasis on clinical, epidemiologic, and some biologic features

Syphilis is a chronic disease with a waxing and waning course, the manifestations of which have been described for centuries. It occurs worldwide, and the incidence varies significantly with geographic location. Transmission is mainly by sexual contact. The causative organism, Treponema pallidum, was first described in 1905, but because of the inability to culture the organism and the limitations of direct microscopy, serologic testing is the mainstay of laboratory diagnosis. The disease has been arbitrarily divided into several stages. The primary stage is defined by a chancre at the site of inoculation. The secondary stage is characterized by a polymorphic rash, lymphadenopathy, and other systemic manifestations. A variable asymptomatic latent period follows, which for epidemiologic purposes is divided into early (<1 year) and late (>1 year) stages. The early stages (primary, secondary, and early latent) are potentially infectious. The tertiary stage is the most destructive and is marked by cardiovascular and neurologic sequelae and gummatous involvement of any organ system. Congenital infection may result in protean early or late manifestations. Unlike many other bacteria causing infectious diseases, the organism remains sensitive to penicillin, and this remains the mainstay of therapy.

HIV-1 and other sexually transmitted infections in a cohort of female sex workers in Chiang Rai, Thailand

OBJECTIVES

To determine demographic and behavioural factors and sexually transmitted infections (STIs) associated with prevalent HIV-1 infection among brothel based and other female sex workers (FSWs) in Chiang Rai, northern Thailand.

METHODS

Data were collected from questionnaires, physical examinations, and laboratory evaluations on Thai FSWs enrolled in a prospective cohort study in Chiang Rai, Thailand, from 1991 to the end of 1994.

RESULTS

HIV-1 seroprevalence was 32% among 500 women: 47% for 280 brothel workers and 13% for 220 other FSWs (p < 0.001); 96% of infections were due to HIV-1 subtype E. At enrolment, other STIs were common: chlamydia, 20%; gonorrhoea, 15%; active syphilis (serological diagnosis), 9%; genital ulcer, 12%; seroreactivity to Haemophilus ducreyi, 21%, and herpes simplex virus type 2 (HSV-2), 76%. On multiple logistic regression analysis, HIV-1 was associated with brothel work, birth in upper northern Thailand, initiation of commercial sex at < 15 years of age, syphilis, HSV-2 seropositivity, and genital ulcer.

CONCLUSIONS

Young Thai FSWs working in brothels in northern Thailand in the early phase of the HIV epidemic have been at very high risk for HIV-1 infection and several other STIs. Programmes are needed to prevent girls and young women from entering the sex industry and to reduce the risk of infection with HIV-1 and other STIs.

Laboratory diagnosis and interpretation of tests for syphilis

The lack of a method for demonstrating the presence of Treponema pallidum by growth necessitates the use of alternative methods. Traditionally, these methods are divided into direct detection methods (animal inoculation, dark-field microscopy, etc.) and serologic tests for the presence of patient antibody against T. pallidum. Serologic methods are further divided into two classes. One class, the nontreponemal tests, detects antibodies to lipoidal antigens present in either the host or T. pallidum; examples are the Venereal Disease Research Laboratory and rapid plasma reagin and tests. Reactivity in these tests generally indicates host tissue damage that may not be specific for syphilis. Because these tests are easy and inexpensive to perform, they are commonly used for screening, and with proper clinical signs they are suggestive of syphilis. The other class of test, the treponemal tests, uses specific treponemal antigens. Confirmation of infection requires a reactive treponemal test. Examples of the treponemal tests are the microhemagglutination assay for antibodies to T. pallidum and the fluorescent treponemal antibody absorption test. These tests are more expensive and complicated to perform than the nontreponemal tests. On the horizon are a number of direct antigen, enzyme-linked immunosorbent assay, and PCR techniques. Several of these techniques have shown promise in clinical trials for the diagnosis of congenital syphilis and neurosyphilis that are presently difficult to diagnose.

Placental histopathology in syphilis

Placental evaluation is important in congenital syphilis (CS) since clinical and serologic findings necessary to fulfill the diagnostic criteria of syphilis may be absent at birth, making early accurate diagnosis difficult. We examined 25 placentas from mothers with syphilis as confirmed by positive RPR rapid plasma reagin and fluorescent treponemal antibody absorption tests to determine which histopathologic features should raise the suspicion of CS. The 25 examined placentas were from 162 syphilitic mothers who delivered at our institution in 1990. Of the 27 infants delivered (including two pairs of twins), four were stillborn and three died at 1 day of age. Eleven of 23 liveborn infants fulfilled the Centers for Disease Control criteria of probable CS. Seven of the 25 placentas showed a well-defined constellation of histopathologic changes that included proliferative vascular changes, chronic villitis, relative villous immaturity, and, in six placentas, acute villitis. All seven of these placentas showed the presence of spirochetes by special stains. Six also had plasma cells in the basal decidua. Recognition of these placental changes, although nondiagnostic, should lead the pathologist to seek additional clinical history and ancillary tests. Placental histopathologic examination is an additional parameter to be considered in the diagnosis of CS.

Specific immunofluorescent staining of pathogenic treponemes with a monoclonal antibody

Two hybrid cell lines which produced mouse monoclonal antibody to the DAL-1 street strain of Treponema pallidum subsp. pallidum were established. These monoclonal antibodies strongly reacted with T. pallidum subsp. pallidum (Nichols strain, DAL-1, and two other street strains, strains MN-1 and MN-3) and T. pallidum subsp. pertenue by indirect microimmunofluorescent antibody and enzyme-linked immunosorbent assay techniques, but they did not react with normal rabbit testicular tissue. These monoclonal antibodies did not react with nonpathogenic treponemes, such as T. phagedenis Reiter, T. denticola MRB, T. refringens Noguchi, or other spirochetes, such as Borrelia burgdorferi and Leptospira interrogans serovar pomona in microimmunofluorescent antibody smear slides or in Western blots (immunoblots). While unlabeled antibodies are useful for investigating the antigenic structures of T. pallidum, we labeled these monoclonal antibodies with fluorescein isothiocyanate and used them for diagnosing syphilis by direct staining of lesion exudate or T. pallidum subsp. pallidum in formalin-fixed tissues from patients suspected of having syphilis. Both monoclonal antibodies were directed against antigens of T. pallidum subsp. pallidum with a molecular weight of 37,000 as determined by the Western blotting technique.