Seroprevalence Of SARS-COV-2 infection in asymptomatic indigenous from the largest Brazilian periurban area.

This study assessed the seroprevalence of SARS-CoV-2 in 496 asymptomatic individuals from Mato Grosso do Sul, located in Dourados, the largest periurban indigenous area in Brazil, from January 25 to February 4, 2021. The volunteers participated before receiving their first dose of the CoronaVac inactivated vaccine. For screening, blood samples were collected and analyzed using SARS-CoV-2 rapid tests and the enzyme-linked immunosorbent assay (ELISA). We observed varying trends in total anti-SARS-CoV-2 antibodies across different variables. Seropositivity among the participants tested was 63.70% (316/496) using the rapid test and 52.82% (262/496) were positive using the ELISA method. The majority of participants identified with the Guarani-Kaiowá ethnic group, with 66.15% (217/328), and other ethnic groups with 58.84% (193/328). The median age of the subjects was 30.5 years, with 79.57% (261/328) being femaleThis research showed the elevated seroprevalence of SARS-CoV-2 antibodies in asymptomatic Brazilians. The findings indicate a high seropositivity rate among the asymptomatic indigenous population of Midwest Brazil. This underscores the overlooked status of these communities and underscores the need for targeted national initiatives that emphasize the protection of vulnerable ethnic groups in the fight against COVID-19.

Detection of Treponema pallidum in whole blood samples of patients with syphilis by the polymerase chain reaction.

Syphilis is caused by the bacterium Treponema pallidum. The diagnosis is based on clinical data and serological analysis; however, the sensitivity and specificity of such tests may vary depending on the type of test and stage of the infection. In order to overcome this premise, this study utilized the polymerase chain reaction (PCR) for the detection of T. pallidum DNA in whole blood samples of patients with syphilis. The blood samples from patients with or without symptoms of syphilis, but with positive results in enzyme-linked immunosorbent assay (ELISA), were included in this study. A venereal disease research laboratory (VDRL) test was performed for all collected sera samples. For PCR, the T. pallidum DNA was extracted from the collected blood samples and a specific primer set was designed to amplify 131 nucleotides of polA (Tp0105). The specificity of the primers was evaluated with the DNA of 17 different pathogens. From a total of 314 blood samples reactive in ELISA, 58.2% (183/314) of the samples were reactive in the VDRL test. In the PCR, 54% (168/314) of the ELISA-reactive samples were positive. In both tests (VDRL and PCR) 104 samples were positive. Of 104 positive samples for both tests, 71 were at the latent stage. Based on these results, it can be concluded that PCR with the designed set of primers can be utilized as a diagnostic method for T. pallidum detection in blood samples of patients with syphilis, especially those with latent infection. In addition, it can be utilized as a supplement for serological methods to improve the diagnosis of syphilis.

Detection of Treponema pallidum in whole blood samples of patients with syphilis by the polymerase chain reaction

ABSTRACT Syphilis is caused by the bacterium Treponema pallidum. The diagnosis is based on clinical data and serological analysis; however, the sensitivity and specificity of such tests may vary depending on the type of test and stage of the infection. In order to overcome this premise, this study utilized the polymerase chain reaction (PCR) for the detection of T. pallidum DNA in whole blood samples of patients with syphilis. The blood samples from patients with or without symptoms of syphilis, but with positive results in enzyme-linked immunosorbent assay (ELISA), were included in this study. A venereal disease research laboratory (VDRL) test was performed for all collected sera samples. For PCR, the T. pallidum DNA was extracted from the collected blood samples and a specific primer set was designed to amplify 131 nucleotides of polA (Tp0105). The specificity of the primers was evaluated with the DNA of 17 different pathogens. From a total of 314 blood samples reactive in ELISA, 58.2% (183/314) of the samples were reactive in the VDRL test. In the PCR, 54% (168/314) of the ELISA-reactive samples were positive. In both tests (VDRL and PCR) 104 samples were positive. Of 104 positive samples for both tests, 71 were at the latent stage. Based on these results, it can be concluded that PCR with the designed set of primers can be utilized as a diagnostic method for T. pallidum detection in blood samples of patients with syphilis, especially those with latent infection. In addition, it can be utilized as a supplement for serological methods to improve the diagnosis of syphilis.