Type I interferons are essential while type II interferon is dispensable for protection against St. Louis encephalitis virus infection in the mouse brain.

St. Louis encephalitis virus (SLEV) is a neglected mosquito-borne flavivirus that causes severe neurological disease in humans. SLEV replication in the central nervous system (CNS) induces the local production of interferons (IFNs), which are attributed to host protection. The antiviral response to SLEV infection in the CNS is not completely understood, which led us to characterize the roles of IFNs using mouse models of St. Louis encephalitis. We infected mice deficient in type I IFN receptor (ABR-/-) or deficient in Type II IFN (IFNγ-/-) and assessed the contribution of each pathway to disease development. We found that type I and II IFNs play different roles in SLEV infection. Deficiency in type I IFN signaling was associated to an early and increased mortality, uncontrolled SLEV replication and impaired ISG expression, leading to increased proinflammatory cytokine production and brain pathology. Conversely, IFNγ-/- mice were moderately resistant to SLEV infection. IFNγ deficiency caused no changes to viral load or SLEV-induced encephalitis and did not change the expression of ISGs in the brain. We found that type I IFN is essential for the control of SLEV replication whereas type II IFN was not associated with protection in this model.

Situação vacinal dos discentes da Faculdade de Medicina da UFJF-MG / Undergraduates' immunization status at the UFJF Medical School

Os profissionais da área de saúde estão expostos a vários tipos de riscos ocupacionais, sendo o de maior impacto o risco biológico, devido ao contato direto com material orgânico potencialmente contaminado. A manutenção da situação vacinal atualizada é uma das ferramentas que devem ser empregadas neste contexto, além da adoção de medidas universais de biossegurança, sendo a educação fundamental neste processo. Avaliamos a situação vacinal e a percepção sobre risco biológico dos discentes da Faculdade de Medicina da UFJF em estudo observacional transversal (n = 136 alunos). Oitenta e nove alunos (65,4 por cento) referiram estar com o cartão vacinal atualizado. Noventa e sete alunos (71,3 por cento) receberam o esquema da hepatite B, e 99 (72,8 por cento) o do tétano. Oitenta e seis 86 alunos (63,2 por cento) declararam ter recebido orientação sobre imunização durante o curso. Setenta e três alunos (53,7 por cento) já foram expostos a material potencialmente contaminado em suas atividades acadêmicas, e 97 deles (71,3 por cento) usam equipamentos de proteção individual (EPI) nestas. Identificamos falhas na imunização (hepatite B e tétano), expondo os discentes a riscos desnecessários. A orientação relativa à imunização se mostrou insuficiente. A significativa taxa de exposição a risco biológico e o insatisfatório uso de EPIs verificados demandam maior atenção, a fim de prevenir acidentes.

Health professionals are exposed to various occupational risks, with the greatest impact from biological hazards due to direct contact with potentially contaminated organic materials. Besides adopting universal biosafety measures, adequate immunization coverage must be achieved in this context, with educational initiatives playing a crucial role in the process. This was a cross-sectional observational study of undergraduates (n = 136) at the Medical School of the Federal University in Juiz de Fora to assess their immunization status and biological risk perceptions. Eighty-nine students (65.4 percent) reported a complete vaccination schedule. Ninety-seven (71.3 percent) had received full immunization against hepatitis B and 99 (72.8 percent) against tetanus. Eighty-six (63.2 percent) reported having received immunization advice during the course. Seventy-three (53.7 percent) had already been exposed to potentially contaminated material during their academic activities, and 97 (71.3 percent) used personal protective equipment (PPE) in these contexts. We identified missed immunization doses against hepatitis B and tetanus, a situation that exposes medical students to unnecessary risks. Immunization advice was insufficient. The significant rate of exposure to biological hazards and the unsatisfactory use of PPE call for greater attention to accident prevention.