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• The performance of SARS-CoV-2 serological tests remains markedly low until the 14th day of symptoms, and their use is not recommended at this stage. • The performance of SARS-CoV-2 serological tests increases with the duration of symptoms and the clinical severity of the disease. • In general, IgM and IgA antibodies are not earlier or more sensitive markers for SARS-CoV-2 diagnosis, reaching their highest positivity rate after 14 days of the onset of symptoms. • LFIA tests are more specific than ELISA tests for SARS-CoV-2 diagnosis. • Infectious diseases prevalent in tropical regions, such as HIV, leishmaniasis, arbovirus, and malaria, may be linked to false-positive results in SARS-CoV-2 tests. Timely and accurate laboratory testing is essential for managing the global COVID-19 pandemic. Reverse transcription polymerase chain reaction remains the gold-standard for SARS-CoV-2 diagnosis, but several practical issues limit the test's use. Immunoassays have been indicated as an alternative for individual and mass testing. Objectives: To access the performance of 12 serological tests for COVID-19 diagnosis. We conducted a blind evaluation of six lateral-flow immunoassays (LFIAs) and six enzyme-linked immunosorbent assays (ELISAs) commercially available in Brazil for detecting anti-SARS-CoV-2 antibodies. Considering patients with seven or more days of symptoms, the sensitivity ranged from 59.5% to 83.1% for LFIAs and from 50.7% to 92.6% for ELISAs. For both methods, the sensitivity increased with clinical severity and days of symptoms. The agreement among LFIAs performed with digital blood and serum was moderate. Specificity was, in general, higher for LFIAs than for ELISAs. Infectious diseases prevalent in the tropics, such as HIV, leishmaniasis, arboviruses, and malaria, represent conditions with the potential to cause false-positive results with these tests, which significantly compromises their specificity. The performance of immunoassays was only moderate, affected by the duration and clinical severity of the disease. Absence of discriminatory power between IgM/IgA and IgG has also been demonstrated, which prevents the use of acute-phase antibodies for decisions on social isolation. [ABSTRACT FROM AUTHOR]

Background Visceral leishmaniasis (VL) affecting HIV-infected patients is considered a challenging condition because of its high mortality and relapse rates. The approach of this condition is still surrounded by many uncertainties, especially regarding the criteria to institute and discontinue secondary prophylaxis for VL. The aim of this study was to evaluate the Leishmania parasitism kinetic assessed by polymerase chain reaction (PCR) as a possible tool in the prognostic assessment in a context in which patients are receiving highly active antiretroviral therapy and secondary prophylaxis. Methods A prospective observation of Leishmania -HIV-co infected patients was performed and two groups with distinct clinical prognosis unpredicted by their CD4 count at the moment of VL diagnosis and not related to their HIV load control were confirmed. Results Relapsing (R) and non-relapsing (NR) patients had similar antiviral therapy use rates, CD4 lymphocyte count medians and HIV load levels at VL-diagnosis. At the 12-month follow-up, R-patients presented a significantly lower CD4 lymphocyte count than NR-patients, without difference in HIV load control. The time between HIV and VL diagnoses was longer in the R than NR-group. Comparison between Kaplan-Meier relapse-free survival curves (time to relapse) using a log rank test showed that patients presenting circulating Leishmania DNA had a significantly higher risk of clinical VL relapse within 4 months after a positive test (p = 0.001). Conclusions These results reinforce that a negative PCR could be a useful tool to support prophylaxis interruption among patients with CD4 counts above 200 cells/mm 3 and that a positive PCR suggests imminent VL relapse. [ABSTRACT FROM AUTHOR]

Background Preoperative bathing with 4% chlorhexidine is recommended as a measure to prevent surgical site infection (SSI) despite uncertainty regarding the effectiveness of the intervention. This review aimed to assess the effect of bathing with 4% chlorhexidine on the prevention of SSIs in clean surgeries compared with bathing with placebo solution or soap. Methods Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for systematic reviews and the Cochrane manual were followed. Sources were MEDLINE and Latin American and Caribbean Health Sciences Literature databases and manual search of references from evaluated studies. We included randomized studies evaluating clean surgical wounds and reporting SSIs after preoperative bathing with 4% chlorhexidine. Results A total of 243 primary studies were identified and 8 were considered methodologically appropriate based on the Jadad Scale. Data were gathered from 10,655 patients. The global SSI rate was 7.2%. The SSI rate for chlorhexidine bathing, placebo, and soap without antiseptic groups was 7.1%, 9.1%, and 5.1%, respectively. A significant reduction in the infection rates was not found in the comparison between patients subjected to preoperative bathing with 4% chlorhexidine versus placebo solution (relative risk, 0.91; 95% confidence interval, 0.76-1.09). The same absence of benefit was observed comparing chlorhexidine bathing with soap (relative risk, 1.06; 95% confidence interval, 0.68-1.66). Conclusions Controlled clinical trials are needed to assess the effect of preoperative chlorhexidine bathing on infection rates following clean surgery before the incorporation of this intervention in health care services. [ABSTRACT FROM AUTHOR]

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• A new Leishmania protein classified as hypothetical was cloned, expressed and purified. • It was evaluated in ELISA experiments against 395 canine and human serum samples. • Sensitivity and specificity values of 100% were found for both serum classes. • Better performance than two distinct commercial kits was verified. • The protein was also well-evaluated as a prognostic marker for human leishmaniasis. Laboratory diagnosis of leishmaniasis shows variable efficacy in detecting infected mammalian hosts and there is a need to identify suitable antigens to improve the accuracy of diagnostic tests. In the present study, a L. infantum hypothetical protein called LiHyQ was evaluated for the diagnosis of tegumentary (TL) and visceral (VL) leishmaniasis using canine and human samples. A collection of dog sera (n=155) were tested and contained samples from asymptomatic (n=20) and symptomatic (n=25) VL animals, from healthy dogs living in endemic (n=25) or non-endemic (n=25) areas of disease, from Leish-Tec® vaccinated dogs (n=20) or from dogs infected with Ehrlichia canis (n=15), Babesia canis (n=10) and Trypanosoma cruzi (n=15). Sensitivity (Se), Specificity (Sp), Positive Predictive Value (PPV) and Negative Predictive Value (NPV) of 100% were observed for rLiHyQ with these samples, whereas the Se, Sp, PPV and NPV values with L. infantum Soluble Leishmania Antigen (SLA) preparation were 60.0%, 99.0%, 96.0% and 86.0%, respectively. A collection of human sera (n=305) were tested and contained samples from TL (n=50) and VL (n=40) patients, from VL/HIV co-infected patients (n=35), from patients infected with HIV alone (n=30), Chagas Disease (n=30), malaria (n=10), tuberculosis (n=10), paracoccidioidomycosis (n=15), leprosy (n=30) or aspergillosis (n=15); and from healthy subjects (n=40). Se, Sp, PPV and NPV values of 100% were observed for rLiHyQ with these samples, whereas the Se, Sp, PPV and NPV values with SLA were 58.0%, 76.0%, 50.0% and 82.0%, respectively. The antibody reactivity against the protein was compared with commercial kits, and the kappa index varied from 0.95 to 1.00 for rLiHyQ, and of 0.55 to 0.82 for the kits. In addition, the serological follow-up of treated patients showed a significant reduction in rLiHyQ-specific IgG antibody levels. All canine and human samples were tested at the same time using the same reagents, in order to reduce experimental variation and interference in data interpretation. In conclusion, our preliminary data suggest a diagnostic and prognostic role for rLiHyQ against leishmaniasis. [Display omitted] [ABSTRACT FROM AUTHOR]