Respiratory syncytial virus infection in children during SARS-CoV-2 pandemic at a referral center in Rio de Janeiro, Brazil

ABSTRACT Objective: In order to study the scenario of respiratory infections in pediatrics after the emergence of SARS-CoV-2 in Brazil, this study aimed to compare characteristics of children admitted for SARS or upper airway infection caused by either RSV or SARS-CoV-2. Methods: This was a cross-sectional study involving children up to 48 months of age admitted to a tertiary pediatric hospital with a diagnosis of SARS or upper airway infection between April of 2020 and April of 2021. Respiratory secretion samples were collected 2-5 days after hospitalization, and antigen/PCR tests for viral etiologies were performed. In this analysis, patients with laboratorial diagnosis of SARS-CoV-2 and/or RSV were selected, and their clinical and epidemiological characteristics were compared using logistic regression. Results: Our sample initially comprised 369 participants. SARS-CoV-2 and RSV infections were confirmed in 55 (15%) and 59 children (16%), respectively. Mean age was 12 months (0-48 months), and 47 were female. The following characteristics were significantly more frequent in patients with RSV when compared with those with COVID-19: younger age (OR = 0.94; 95% CI: 0.90-0.98); lower frequency of fever (OR = 0.18; 95% CI: 0.05-0.66); and more frequent upper airway symptoms: cough (OR = 7.36; 95% CI: 1.04-52.25); and tachypnea (OR = 6.06; 95% CI: 1.31-28.0). Conclusions: Children with RSV-related SARS were younger, had lower frequency of fever at admission, but had a higher frequency of signs of upper airway infection and lower systemic inflammation when compared with children hospitalized for COVID-19 during the first year of the pandemic.

An immunofluorescence test for diagnosis of ophthalmic herpes in a mouse corneal model

Herpes simplex virus type 1 (HSV-1) ophthalmic disease is the most common cause of corneal blindness in humans world-wide. Current culture techniques for HSV take several days and commercially available HSV laboratory based diagnostic techniques vary in sensitivity. Our study was conducted to evaluate the use of a quicker and simpler method to herpes ophthalmic diagnosis. Corneal smears were made by firm imprints of infected mouse eyes to glass slides, after smears were fixated with cold acetone, and an indirect immunofluorescence (IIF) method was performed using monoclonal antibodies in a murine model of ophthalmic herpes. Eye swabs from infected mice were inoculated in Vero cells for virus isolation. Cytology and histology of the eye were also performed, using hematoxylin-eosin routine. Mouse eyes were examined by slit-lamp biomicroscopy for evidence of herpetic disease at various times postinoculation. We made a comparative evaluation of sensitivity, specificity and speed of methods for laboratory detection of HSV. Our results indicate that this IIF method is quick, sensitive, specific and can be useful in the diagnosis of ophthalmic herpes as demonstrated in an animal model.

A doença oftálmica do vírus herpes simplex do tipo 1 (HSV-1) é a causa mais comum de cegueira córnea em humanos mundialmente. Técnicas de cultura atuais para HSV levam vários dias e laboratórios de HSV comercialmente disponíveis estabelecem que as técnicas diagnósticas variam em sensibilidade. Nosso estudo foi conduzido para avaliar a aplicação prática de um método mais rápido e simples para diagnosticar o herpes oftálmico. Decalques córneos foram feitos por impressões firmes de olhos de camundongos a lâminas de vidro, depois os decalques foram fixados com acetona fria, e um método de imunofluorescência indireta (IIF) foi executado empregando anticorpos monoclonais no modelo murino de herpes oftálmico. Swabs de córnea foram inoculados em células Vero para o isolamento de vírus a partir de camundongos infectados. A citologia e a histologia do olho foi feita pela rotina de hematoxilina e eosina. Os olhos de camundongos foram examinados através de oftalmomicroscopia para evidência de doença herpética em vários tempos pós-inoculação. A avaliação comparativa da sensibilidade, especificidade e velocidade de métodos para detecção laboratorial de HSV foi feita. Nossos resultados indicam que este método de IIF é rápido, sensível, específico e pode ser útil no diagnóstico de herpes oftálmico como demonstrado no modelo animal.