Danielle Malta Lima

Background/Objectives: Guillain–Barré syndrome (GBS) is a neurological disease that affects the peripheral nerves. The exact cause of this condition is still uncertain, but cross-reactivity between pathogen antigens and nervous tissue may play a crucial role in disease pathogenesis. Roseolovirus humanbeta6 (HHV-6), a neurotropic virus with latency capacity, may be considered a significant candidate for triggering or worsening neurological conditions. In this study, we aimed to investigate the detection of HHV-6 in the CNS from GBS patients. Of the 23 individuals suspected of having GBS, 13 were confirmed as having the disease. We then analyzed the frequency of herpesviruses in the cerebrospinal fluid (CSF) samples from these 13 individuals with GBS who were also tested for enteroviruses and arboviruses and had negative results. Results: After extraction of viral DNA from CSF samples, real-time PCR (qPCR) methodology was used to analyze the frequency and viral load of herpesviruses. Sociodemographic and clinical data were collected for analysis and verification through statistical tests such as Fisher’s exact test and the Mann–Whitney test. Thirteen individuals diagnosed with GBS were tested. Among the 13 patients analyzed, 61.5% were men, 38.4% (5/13) tested positive for HHV-6, 61.5% of the patients tested positive for a herpesvirus, 30.8% had two viral DNAs identified, and one patient presented three different strains. Patients who tested positive for HHV-6 had a significantly longer average length of stay (25.6 days versus 11 days for negative patients). HHV-6 was the most frequent subtype detected in patients positive for herpesviruses (62.5%, 5/8). Discussion/Conclusions: Our results show a possible relationship between HHV-6 and GBS cases despite the small number of patients, raising the question of whether the presence of HHV-6 influences GBS, since its investigation using qPCR is not routinely used. This may have some impact on prognosis, since antiviral therapy is not included in the standard treatment of GBS patients, and viral DNA load may interfere with the inflammatory process of GBS.

A group of children with clinical suspicion of dengue were assessed to determine if there was an overestimation of dengue compared with that of leptospirosis and leishmaniasis. This descriptive and analytical cross-sectional study, based on the active search of participants with acute febrile illness, was conducted at two pediatric hospitals. The collection of clinical and epidemiological data was performed using questionnaires, and laboratory tests specific for dengue were performed using immunochromatographic, serological, and molecular methods. Dengue-negative samples were assessed for Leptospira and Leishmania spp. using molecular tests. Data were assessed using analysis of variance (ANOVA), the chi-square test, and Fisher’s exact test. In total, 86 participants were evaluated, of whom 39 (45%) were positive for dengue fever, 4 (5%) for leptospirosis, and 1 (1%) for leishmaniasis. Forty-two participants (49%) presented dengue-like symptoms. The predominant age range for the virus was 3–10 years. Most clinical manifestations were nonspecific, with frequent concomitant gastrointestinal and respiratory symptoms. Furthermore, we found that the acute febrile syndrome in childhood persists as a challenge for health professionals, especially in the early days of the disease, due to a plurality of diagnostic hypotheses, associated with the difficulty of establishing well-defined symptoms in children, especially in infants. Dengue fever continues to be a frequent pathology with acute febrile infections in childhood; however, there is an overestimation of the disease, especially in endemic regions, when one considers only the clinical epidemiological diagnosis.

Brazil is renowned for its extensive plant biodiversity, with emphasis on Cymbopogon, C. citratus and C. nardus, with broad antimicrobial potential. Candidemias caused by Candida albicans are highly prevalent in immunosuppressed individuals and are associated with infections by biofilms on medical devices. The aim of this study was to evaluate the antimicrobial potential of essential oils C. citratus and C. nardus against C. albicans in planktonic and biofilm forms. Essential oils were obtained by hydrodistillation and chemical composition evaluated by GC-FID and GC-MS. The minimum inhibitory concentration was determined by the broth microdilution method and the synergy effect of essential oils and amphotericin B were evaluated by the checkerboard test. Biofilm activity was determined by the XTT assay. Cytotoxicity assays performed with VERO cells and molecular docking were performed to predict the effect of oil interaction on the SAP-5 enzyme site. The results showed activity of essential oils against planktonic cells and biofilm of C. albicans. Furthermore, the oils had a synergistic effect, and low cytotoxicity. Molecular docking showed interaction between Cadinene, Caryophyllen oxide, Germacrene D with SAP-5. The results indicate that Cymbopogon spp. studied are anti-Candida, with potential for further application in therapy against infections caused by C. albicans.

The emergence and continued geographic expansion of arboviruses and the growing number of infected people have highlighted the need to develop and improve multiplex methods for rapid and specific detection of pathogens. Sequencing technologies are promising tools that can help in the laboratory diagnosis of conditions that share common symptoms, such as pathologies caused by emerging arboviruses. In this study, we integrated nanopore sequencing and the advantages of reverse transcription polymerase chain reaction (RT-PCR) to develop a multiplex RT-PCR protocol for the detection of Chikungunya virus (CHIKV) and several orthoflaviviruses (such as dengue (Orthoflavivirus dengue), Zika (Orthoflavivirus zikaense), yellow fever (Orthoflavivirus flavi), and West Nile (Orthoflavivirus nilense) viruses) in a single reaction, which provides data for sequence-based differentiation of arbovirus lineages.

Dengue and Zika, arboviruses are common in Brazil and present with similar clinical symptoms making specific diagnoses difficult. Therefore, a Duplex One-step RT-PCR method for dengue and zika virus was developed and validated in vitro and in silico, based on the dengue's NS1 region and zika's Envelope region.

Reverse transcription loop-mediated isothermal amplification (RT-LAMP) is a rapid method that can replace RT-qPCR. A simple molecular assay for SARS-CoV-2 RNA detection in gold-standard diagnosis through swabs and alternative specimens such as saliva could be helpful in promoting genomic surveillance. A multicenter study was conducted to evaluate the RT-LAMP assay method as an alternative for the molecular detection of SARS-CoV-2 lineages in swab and saliva samples. A total of 350 swabs from individuals with (n = 276) or without (n = 74) COVID-19 tested by RT-qPCR were collected. Paired saliva was also collected from 90 individuals who had SARS-CoV-2 RNA that was detectable (n = 30) or undetectable (n = 60) via RT-qPCR. For the RT-LAMP methodology, six primers were used for ORF1 gene amplification. As for SARS-CoV-2 genotyping, 39 swabs had the whole genome sequenced by MinION. The sensitivity of RT-LAMP to the swab was 90.2%. For the swab samples with Ct ≤ 30, the sensitivity improved by 96%. Considering saliva with Ct ≤ 30 in RT-qPCR testing, the RT-LAMP sensitivity was 100%. The RT-LAMP specificity was 100% for both the swab and saliva samples. This RT-LAMP assay was capable of detecting all the SARS-CoV-2 lineages circulating in the Brazilian swab samples. The RT-LAMP method has significant potential for use in clinical routines since it was capable of detecting SARS-CoV-2 RNA in swab and saliva samples.

Key words: Dengue; Aedes Aegypti; Aedes Albopictus; Virus