Camila Malta Romano

Transfusion-transmitted dengue remains a relevant risk during outbreaks. We report a transfusion-transmitted severe dengue case in a stem cell transplant recipient during the 2024 epidemic in Brazil, supported by phylogenetic linkage, evolving to a fatal outcome. This sentinel case highlights the potential severity of transfusion-transmitted dengue, particularly in immunocompromised hosts.

Human endogenous retroviruses (HERVs), remnants of ancient germline infections, constitute ~8% of the human genome. Although mostly silenced, these elements can be expressed and play physiological or pathological roles. We investigated HERV expression dynamics, proviral load, and systemic inflammatory status in young and older adults, as well as the impact of regular physical exercise. PBMC and serum samples were collected from 30 young controls (YC), 30 inactive older adults (INAC) and 30 regularly exercising older adults (REG). Expression of HERV-W, -K, -H, Syncytin-1 and -2 was assessed by qPCR using the −2ΔΔCt method, and proviral load (HERV-W, -K, -H) was estimated by relative copy number. Serum cytokines (IL-1β, IL-6, IL-17, TNF-α, IFN-γ, IL-10) were quantified by ELISA. Statistical significance was set at p < 0.05. INAC participants showed higher proviral load of HERV-K, -W and -H compared to YC (p = 0.025), but overall lower HERV expression, except for HERV-K. REG presented increased expression of HERV-W (~1.5-fold, p < 0.0001), HERV-H (~1.8-fold, p < 0.0001; higher than YC p = 0.01), HERV-K (vs. YC p = 0.02) and Syncytin-1 (~1.4-fold vs. INAC and YC, p < 0.01). HERV-K was the most upregulated element in INAC. HERV-W and HERV-H expression were strongly correlated in all groups. INAC showed a pro-inflammatory profile, with elevated IL-6/IL-10, IL-1β/IL-10, and IFN-γ/IL-10 ratios. Older adults exhibit higher HERV proviral load, suggesting possible age-related insertions. Regular physical exercise modulates HERV expression, whereas inactivity is associated with reduced expression and increased inflammation. HERV-W and HERV-H maintain coordinated expression across ages, indicating interplay between inflammatory balance, aging, and retroviral activity.

Neurological manifestations associated with COVID-19 remain partially described, mainly in low- and middle-income countries where diagnostic tools are limited. To address this, we assembled medical centers in Brazil with the goal of describing neurological syndromes associated with COVID-19 during the first wave of the pandemic. From June 1st, 2020 to June 1st, 2021, non-consecutive adult patients with new onset of six neurological syndromes up to 60 days after confirmed COVID-19 were included. Data were compiled from four tertiary centers and compared with general local COVID-19 data, as well as with a previous cohort focused on vascular syndrome. 197 patients were included, presenting with vascular syndromes (81), encephalopathy (68), encephalitis (19), Guillain-Barré syndrome (13), other neuropathies (12), and myelitis (4). The incidence curve of neurocovid mirrored that of COVID-19. Neurological syndromes were present regardless of COVID-19 severity. The median time from COVID-19 to onset of neurological symptoms was 14 days, suggesting a post-infectious immune-mediated mechanism. Patients were 10 times more likely to die (χ2 (1) = 356.55, p < 0.01, OR = 10.89) and 38 times more likely to be hospitalized than other COVID-19 patients (χ2 (1) = 1167.9, p < 0.01, OR = 38.22). Those developing vascular syndromes patients were 3 times more likely to require ICU (χ2 (1) = 37.12, p < 0.01, OR = 3.78) and 4 times more likely to die (χ2 (1) = 58.808, p < 0.01, OR = 4.73) than patients with vascular syndromes due to different etiologies. Our study corroborates the association of neurological syndromes with COVID-19. The incidence correlated with local waves of COVID-19, and patients with neurocovid exhibited a higher susceptibility to adverse outcomes compared to other COVID-19 patients. Among all neurological syndromes, vascular syndromes were the most common, and their severity surpassed that of vascular syndromes not attributed to COVID-19.

Background: Rabies poses a serious public health challenge in Brazil, and its epidemiology has undergone significant changes over the past two decades. Although canine transmission of rabies has been controlled through national vaccination programs, new risks have emerged, particularly from wildlife reservoirs. Methods: We performed a retrospective analysis of human rabies cases reported in Brazil between 2001 and 2025 using epidemiological surveillance data, scientific literature, and public health reports. We focused on trends in transmission sources, changes in affected populations, and challenges in prevention and treatment, particularly regarding the availability of post-exposure prophylaxis (PEP). Results: A total of 188 human rabies cases were reported in Brazil between 2001 and 2025 (average: 7.52 cases per year). Most of the cases occurred in the northern and northeastern regions of the country. Bats were the most common source of transmission, followed by dogs and non-human primates. Although rabies is preventable, most of the cases reported within the study period resulted in death. PEP was administered in most cases; however, the treatment may have been delayed, incomplete, or initiated after the onset of symptoms, which limited its effectiveness. Only two patients survived, and both of them received intensive care and were treated using modified therapeutic protocols. Conclusion: The transition from canine- to bat-mediated rabies highlights the need for enhanced surveillance and targeted prevention strategies. Despite advances in canine rabies control, ensuring PEP accessibility and strengthening public health interventions in high-risk areas remain critical for reducing the incidence of human rabies in Brazil.

Mosquitoes (Diptera: Culicidae) are arthropods of medical importance because they can carry arboviruses. High-throughput sequencing (HTS) technology and metagenomic approaches conducted in mosquitoes have contributed to the discovery of many insect-specific viruses (ISVs), which have the potential to affect their vector competence. Mosquitoes were collected in urban parks in Sao Paulo city, Brazil and 20 pools with female mosquitoes were subjected to HTS by HiSeq 2500 sequencing system (Illumina). Long viral sequences (1,585-6,701 base pairs) were recovered from two pools of Aedes scapularis. BLASTx analyses revealed they had greater identity with segment L and S of Salarivirus and segment M of Furrundu phlebovirus, which encode, respectively, the RNA-dependent RNA polymerase (RdRd), the nucleocapsid protein, and a polyprotein. Phylogenetic tree of the segment L and S of the Phenuiviridae Family showed our sequences grouped with unverified sequences of Furrundu phlebovirus, an unclassified ISV that belongs to the Hareavirales Order and was first reported in mosquitoes in the Brazilian Pantanal, the largest natural tropical wetland worldwide. We report the second detection of Furrundu phlebovirus in mosquitoes collected in urban parks, showing it could be in mosquitoes from natural places and in green areas in urban cities. We conclude that Furrundu phlebovirus possibly occurs in Aedes scapularis in green areas, in Sao Paulo. Further studies should elucidate the role of this virus in the vector competence of Aedes scapularis and its interaction with different arboviruses.

Human T-lymphotropic virus type 1 (HTLV-1) remains frequently underrecognized despite its association with severe diseases in 3–5% of infected individuals. This lack of awareness, coupled with the limited availability of complete HTLV-1 genome sequences in public databases, impairs progress in understanding the virus. Current sequencing techniques, such as Sanger and Illumina, are often costly, and/or time-consuming. Expanding our knowledge of HTLV-1’s genomic structure is crucial for advancing our understanding of its basic biology, improving epidemiological studies, and investigating how genetic variation contributes to the diverse clinical manifestations of HTLV-1-associated diseases. To address these gaps, we developed an efficient and cost-effective method for amplifying and sequencing the complete HTLV-1 genome using Nanopore technology on the MinION platform. This approach offers significant advantages, including real-time sequencing, portability, and relatively low cost compared to traditional methods. Our protocol can facilitate studies on HTLV-1's genetic diversity and pathogeny.

Background: Oropouche virus (OROV; species Orthobunyavirus oropoucheense ) is an arthropod-borne virus that has caused outbreaks of Oropouche fever in Central and South America since the 1950s. This study investigates virological factors contributing to the reemergence of Oropouche fever in Brazil between 2023 and 2024. Methods: In this study, we combined OROV genomic, molecular, and serological data from Brazil from 1 January 2015 to 29 June 2024, along with in vitro and in vivo characterization. Molecular screening data included 93 patients with febrile illness between January 2023 and February 2024 from the Amazonas State. Genomic data comprised two genomic OROV sequences from patients. Serological data were obtained from neutralizing antibody tests comparing the prototype OROV strain BeAn 19991 and the 2024 epidemic strain. Epidemiological data included aggregated cases reported to the Brazilian Ministry of Health from 1 January 2014 to 29 June 2024. Findings: In 2024, autochthonous OROV infections were detected in previously non-endemic areas across all five Brazilian regions. Cases were reported in 19 of 27 federal units, with 83.2% (6,895 of 8,284) of infections in Northern Brazil and a nearly 200-fold increase in incidence compared to reported cases over the last decade. We detected OROV RNA in 10.8% (10 of 93) of patients with febrile illness between December 2023 and May 2024 in Amazonas. We demonstrate that the 2023-2024 epidemic was caused by a novel OROV reassortant that replicated approximately 100-fold higher titers in mammalian cells compared to the prototype strain. The 2023-2024 OROV reassortant displayed plaques earlier than the prototype, produced 1.7 times more plaques, and plaque sizes were 2.5 larger compared to the prototype. Furthermore, serum collected in 2016 from previously OROV-infected individuals showed at least a 32-fold reduction in neutralizing capacity against the reassortment strain compared to the prototype. Interpretation: These findings provide a comprehensive assessment of Oropouche fever in Brazil and contribute to a better understanding of the 2023-2024 OROV reemergence. The recent increased incidence may be related to a higher replication efficiency of a new reassortant virus that also evades previous immunity.