Could giant viruses be considered as a biotechnological tool for preventing and controlling Acanthamoeba infections?

AIM: The aim of the study was to evaluate the efficiency of mimivirus as a potential therapeutic and prophylactic tool against Acanthamoeba castellanii, the etiological agent of Acanthamoeba keratitis, a progressive corneal infection, that is commonly associated with the use of contact lenses and can lead to blindness if not properly treated. METHODS AND RESULTS: Mimivirus particles were tested in different multiplicity of infection, along with commercial multipurpose contact lenses' solutions, aiming to assess their ability to prevent encystment and excystment of A. castellanii. Solutions were evaluated for their amoebicidal potential and cytotoxicity in MDCK cells, as well as their effectiveness in preventing A. castellanii damage in Madin-Darby canine kidney (MDCK) cells. Results indicated that mimivirus was able to inhibit the formation of A. castellanii cysts, even in the presence of Neff encystment solution. Mimivirus also showed greater effectiveness in controlling A. castellanii excystment compared to commercial solutions. Additionally, mimivirus solution was more effective in preventing damage caused by A. castellanii, presented greater amoebicidal activity, and were less cytotoxic to MDCK cells than commercial MPS. CONCLUSIONS: Mimivirus demonstrates a greater ability to inhibit A. castellanii encystment and excystment compared to commercial multipurpose contact lens solutions. Additionally, mimivirus is less toxic to MDCK cells than those commercial solutions. New studies utilizing in vivo models will be crucial for confirming safety and efficacy parameters.

The impact of viral infections on childhood central nervous system infections.

BACKGROUND: Viruses are a common cause of central nervous system (CNS) infections. However, studies of CNS viral pathogens in pediatric patients are poorly explored because viral infections are often erroneously diagnosed as bacterial infections. METHODS: 299 CNS samples were collected from pediatric patients aged from one month to 14 years old. A total of 140 viral meningitis cases that met the inclusion criteria were included in this study. In 38 of the 140 cerebral spinal fluid (CSF) samples (27.1%), conventional and real-time PCR were used to identify viruses commonly associated with CNS infections. RESULTS: Among them, 23 patients (16.5%) tested positive for flaviviruses such as dengue, Zika, and yellow fever virus, eight patients (5.7%) were positive for enterovirus (ENTV), and six patients (4.3%) were positive for human herpesvirus 1/2. We also identified one case of dengue virus and ENTV co-infection. CONCLUSIONS: A correlation between clinical symptoms and laboratory findings for the viruses was identified. Our study also reinforces the importance of including viruses in the laboratory diagnosis of CNS infections especially flaviviruses, which assists public health authorities in implementing early interventions.

Detection of SARS-CoV-2 RNA on public surfaces in a densely populated urban area of Brazil: A potential tool for monitoring the circulation of infected patients.

The world is experiencing the worst global health crisis in recent decades since December/2019 due to a new pandemic coronavirus. The COVID-19 disease, caused by SARS-CoV-2, has resulted in more than 30 million cases and 950 thousand deaths worldwide as of September 21, 2020. Determining the extent of the virus on public surfaces is critical for understanding the potential risk of infection in these areas. In this study, we investigated the presence of SARS-CoV-2 RNA on public surfaces in a densely populated urban area in Brazil. Forty-nine of 933 samples tested positive (5.25%) for SARS-CoV-2 RNA, including samples collected from distinct material surfaces, including metal and concrete, and distinct places, mainly around hospital care units and public squares. Our data indicated the contamination of public surfaces by SARS-CoV-2, suggesting the circulation of infected patients and the risk of infection for the population. Constant monitoring of the virus in urban areas is required as a strategy to fight the pandemic and prevent further infections.

Silent Circulation of the Saint Louis Encephalitis Virus among Humans and Equids, Southeast Brazil.

Saint Louis encephalitis virus (SLEV) is a mosquito-borne flavivirus that occurs throughout the Americas, and is considered a public health threat. In Brazil, SLEV has been detected from human cases associated with dengue-like disease, but no neurological symptoms were reported. Furthermore, the epidemiology of SLEV in human populations is still poorly explored in the country. We reported serological and molecular detection of SLEV in a healthy population of equids and humans from rural areas in Southeast Brazil. A plaque reduction neutralization test was applied, and neutralizing antibodies were detected in 11 individuals (4.6%) and 60 horses (21.5%). A qPCR targeting the 5'UTR region and reverse transcription-PCR (RT-PCR) targeting the non-structural protein (NS5) gene were performed and three individuals tested positive in both assays. Subsequent phylogenetic analysis confirmed SLEV circulation and its findings suggest the occurrence of an asymptomatic or subclinical presence in human and animal cases, correlating with the risks for outbreaks and consequently burden of SLEV infections to public health. Preventive strategies should include improved surveillance in regions with a high probability of SLEV occurrence, improvement in diagnostic methods, and evaluation of exposure/risk factors that can favor SLEV emergence.

Meningitis Associated with Simultaneous Infection by Multiple Dengue Virus Serotypes in Children, Brazil.

To determine the causes of viral meningitis, we analyzed 22 cerebrospinal fluid samples collected during the 2014-2015 dengue epidemics in Brazil. We identified 3 serotypes of dengue virus (DENV-1, -2, and -3), as well as co-infection with 2 or 3 serotypes. We also detected the Asian II genotype of DENV-2.