Resurgence of human respiratory syncytial virus during COVID-19 pandemic in Southern Brazil

Respiratory Syncytial Virus (RSV) is an important cause of respiratory infection in humans. Severe cases are common in children ≤2 years old, immunocompromised individuals, and the elderly. In 2020, RSV infection reduced in Rio Grande do Sul (RS), southern Brazil; however, in 2021 resurgence of RSV was observed. This study analyzed epidemiological and genetic features of RSV infection cases reported in 2021 in RS. Nasopharyngeal samples collected from individuals with respiratory infection negative for SARS-CoV-2, Influenza A and B viruses were assessed for the presence of RSV by real time RT-qPCR. RSV-A and RSV-B genomic sequencing and phylogenetic reconstructions were performed for genotyping and clade characterization. Among 21,035 respiratory samples analyzed, 2,947 were positive for RSV, 947 of which were hospitalized patients. Positive cases were detected year-round, with the highest number in June-July (winter). Children <1 year comprised 56.28% (n = 533) of the hospitalized patients infected with RSV, whereas 14.46% (n = 137) were individuals >60 years. Of a total of 361 deaths, 14.68% (n = 53) were RSV positive, mostly patients >60 years old (73.58%, n = 39). Chronic kidney disease, cardiopathy, Down syndrome and neurological diseases were associated with RSV infection. RSV-A was identified in 58.5% (n = 117/200) of the patients, and RSV-B in 41.5% (n = 83/200). Of 95 RSV genomes recovered from SARI cases, 66 were RSV-A GA.2.3.5 genotype, while 29 were RSV-B GB.5.0.5a genotype. This study provides epidemiological and molecular data on RSV cases in RS during the COVID-19 pandemic and highlights that investigation of different respiratory viruses is essential for decision-making and disease prevention and control measures.

LED Colour Trap for Aedes aegypti Control

BACKGROUND

Aedes aegypti mosquitoes transmit dengue, zika, and chikungunya viruses, neglected diseases that are considered global health challenges. Due to the lack of antiviral drugs and vaccines for these illnesses, vector control with chemical insecticides is the principal strategy for preventing their spread. However, vector populations are becoming increasingly resistant to insecticides, and the development of other control measures is, therefore, imperative.

METHODS

A new insect trap (IT) was used to control Aedes aegypti. A specific light-emitting diode (LED) served as the attractant based on specific wavelength ranges (450-495, 500-550 and 570-600 nm). The IT utilized insect-attracting and killing mechanisms that included a black capture box, a suction-producing mechanism, an electric shock device and a nylon cloth device that held surviving mosquitoes, which died due to starvation. Capture assays of twenty non-feeding females inside a cage were performed in triplicate using different LED intensities. A commercial trap (ultraviolet lamp attractant and suction system) was used as a positive control.

RESULTS

Capture assays of A. aegypti with different intensities and LED combinations showed that the tricolored trap captured 100% of the females, followed by the Green LED 8 set, which captured 91%; in comparison, commercial traps captured approximately 25% of the insects. Although there were no significant differences between the experimental groups, the tricolored trap probably will capture more mosquito females considering the vision variation in individual females.

CONCLUSION

We herein present a green technology-based IT that is effective, safe and successful for reducing mosquito populations, thereby preventing mosquito-borne disease spread.

History, epidemiology and diagnostics of dengue in the American and Brazilian contexts: a review

Dengue virus (DENV), an arbovirus transmitted by mosquitoes, has become a major threat to American human life, reaching approximately 23 million cases from 1980 to 2017. Brazil is among the countries most affected by this terrible viral disease, with 13.6 million cases. DENV has four different serotypes, DENV1-4, which show a broad clinical spectrum. Dengue creates a staggering epidemiological and economic burden for endemic countries. Without a specific therapy and with a commercial vaccine that presents some problems relative to its full effectiveness, initiatives to improve vector control strategies, early disease diagnostics and the development of vaccines and antiviral drugs are priorities. In this study, we present the probable origins of dengue in America and the trajectories of its spread. Overall, dengue diagnostics are costly, making the monitoring of dengue epidemiology more difficult and affecting physicians' therapeutic decisions regarding dengue patients, especially in developing countries. This review also highlights some recent and important findings regarding dengue in Brazil and the Americas. We also summarize the existing DENV polymerase chain reaction (PCR) diagnostic tests to provide an improved reference since these tests are useful and accurate at discriminating DENV from other flaviviruses that co-circulate in the Americas. Additionally, these DENV PCR assays ensure virus serotyping, enabling epidemiologic monitoring.