Gut Susceptibility to Viral Invasion: Contributing Roles of Diet, Microbiota and Enteric Nervous System to Mucosal Barrier Preservation.

The gastrointestinal lumen is a rich source of eukaryotic and prokaryotic viruses which, together with bacteria, fungi and other microorganisms comprise the gut microbiota. Pathogenic viruses inhabiting this niche have the potential to induce local as well as systemic complications; among them, the viral ability to disrupt the mucosal barrier is one mechanism associated with the promotion of diarrhea and tissue invasion. This review gathers recent evidence showing the contributing effects of diet, gut microbiota and the enteric nervous system to either support or impair the mucosal barrier in the context of viral attack.

Nutritional status, diet and viral respiratory infections: perspectives for severe acute respiratory syndrome coronavirus 2.

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was recognised by the WHO as a pandemic in 2020. Host preparation to combat the virus is an important strategy to avoid COVID-19 severity. Thus, the relationship between eating habits, nutritional status and their effects on the immune response and further implications in viral respiratory infections is an important topic discussed in this review. Malnutrition causes the most diverse alterations in the immune system, suppressing of the immune response and increasing the susceptibility to infections such as SARS-CoV-2. On the other hand, obesity induces low-grade chronic inflammation caused by excess adiposity, which increases angiotensin-converting enzyme 2. It decreases the immune response favouring SARS-CoV-2 virulence and promoting respiratory distress syndrome. The present review highlights the importance of food choices considering their inflammatory effects, consequently increasing the viral susceptibility observed in malnutrition and obesity. Healthy eating habits, micronutrients, bioactive compounds and probiotics are strategies for COVID-19 prevention. Therefore, a diversified and balanced diet can contribute to the improvement of the immune response to viral infections such as COVID-19.

Nutritional Risk Screening Tools for Older Adults with COVID-19: A Systematic Review.

Coronavirus disease 2019 (COVID-19) is associated with high risk of malnutrition, primarily in older people; assessing nutritional risk using appropriate screening tools is critical. This systematic review identified applicable tools and assessed their measurement properties. Literature was searched in the MEDLINE, Embase, and LILACS databases. Four studies conducted in China met the eligibility criteria. Sample sizes ranged from six to 182, and participants' ages from 65 to 87 years. Seven nutritional screening and assessment tools were used: the Nutritional Risk Screening 2002 (NRS-2002), the Mini Nutritional Assessment (MNA), the MNA-short form (MNA-sf), the Malnutrition Universal Screening Tool (MUST), the Nutritional Risk Index (NRI), the Geriatric NRI (GNRI), and modified Nutrition Risk in the Critically ill (mNUTRIC) score. Nutritional risk was identified in 27.5% to 100% of participants. The NRS-2002, MNA, MNA-sf, NRI, and MUST demonstrated high sensitivity; the MUST had better specificity. The MNA and MUST demonstrated better criterion validity. The MNA-sf demonstrated better predictive validity for poor appetite and weight loss; the NRS-2002 demonstrated better predictive validity for prolonged hospitalization. mNUTRIC score demonstrated good predictive validity for hospital mortality. Most instruments demonstrate high sensitivity for identifying nutritional risk, but none are acknowledged as the best for nutritional screening in older adults with COVID-19.

COVID-19, Obesity, and Undernutrition: A Major Challenge for Latin American Countries.

In March of 2020, the World Health Organization declared the SARS­Cov2 2019 (COVID­19) outbreak a global pandemic after documenting community scale transmission in every region, including Latin America. The risk factors associated with severity of disease include older age, diabetes, hypertension, cardiovascular and lung diseases, and immune suppression. Additional evidence strongly suggests that obesity is also a risk factor for severe forms of COVID­19 disease, while other types of malnutrition increase the risk of hospitalization from influenza­like diseases, regardless of the causative agent of the illness (1). Although detailed data are not yet available on the impact of under nutrition in the evolution of COVID­19, given the known inflammatory response caused by this condition, it is reasonable to expect a suboptimal immune response and higher risk of severity, as found with obesity (2).

Congenital Zika syndrome is associated with maternal protein malnutrition.

Zika virus (ZIKV) infection during pregnancy is associated with a spectrum of developmental impairments known as congenital Zika syndrome (CZS). The prevalence of this syndrome varies across ZIKV endemic regions, suggesting that its occurrence could depend on cofactors. Here, we evaluate the relevance of protein malnutrition for the emergence of CZS. Epidemiological data from the ZIKV outbreak in the Americas suggest a relationship between undernutrition and cases of microcephaly. To experimentally examine this relationship, we use immunocompetent pregnant mice, which were subjected to protein malnutrition and infected with a Brazilian ZIKV strain. We found that the combination of protein restriction and ZIKV infection leads to severe alterations of placental structure and embryonic body growth, with offspring displaying a reduction in neurogenesis and postnatal brain size. RNA-seq analysis reveals gene expression deregulation required for brain development in infected low-protein progeny. These results suggest that maternal protein malnutrition increases susceptibility to CZS.

Factors Associated with Dengue Virus Infection and Reinfection in Asymptomatic Children in Two Colombian Municipalities.

Dengue is the most important arbovirosis in the world. In this study, we assessed the knowledge, attitudes, and practices (KAP) regarding dengue in parents from two small Colombian municipalities in the Cundinamarca Province. Parents and their healthy children from 4 to 14 years of age were included in some public elementary schools. After a medical examination, blood samples were taken for diagnosis of dengue using enzyme-linked immunosorbent assays (capture immunoglobulin M and capture immunoglobulin G [IgG], indirect IgG and detection non-structural viral protein 1) and detection of viral RNA by reverse transcription polymerase chain reaction. In addition, a KAP survey was applied to the children's parents or tutors. The indirect IgG test determined that of the 347 examined children, 87.9% had a previous infection with the dengue virus (DENV), 12.7% of them were positive for viral RNA (asymptomatic infection), and 32.0% presented reinfections. Risk factors evaluation showed that children aged 8 years and older living in the municipalities for more than 7 years were more likely to be infected or reinfected by DENV. In the same way, poor nutrition, lack of water supply, sewer service, or waste disposal services could raise the likelihood of dengue infections. The surveys indicated that parents have unhealthy practices and a low knowledge about the transmission of the disease, which could result in an increase of mosquito breeding sites, allowing sustained dengue transmission.