Airborne rhinovirus detection and effect of ultraviolet irradiation on detection by a semi-nested RT-PCR assay

BACKGROUND: Rhinovirus, the most common cause of upper respiratory tract infections, has been implicated in asthma exacerbations and possibly asthma deaths. Although the method of transmission of rhinoviruses is disputed, several studies have demonstrated that aerosol transmission is a likely method of transmission among adults. As a first step in studies of possible airborne rhinovirus transmission, we developed methods to detect aerosolized rhinovirus by extending existing technology for detecting infectious agents in nasal specimens. METHODS: We aerosolized rhinovirus in a small aerosol chamber. Experiments were conducted with decreasing concentrations of rhinovirus. To determine the effect of UV irradiation on detection of rhinoviral aerosols, we also conducted experiments in which we exposed aerosols to a UV dose of 684 mJ/m(2). Aerosols were collected on Teflon filters and rhinovirus recovered in Qiagen AVL buffer using the Qiagen QIAamp Viral RNA Kit (Qiagen Corp., Valencia, California) followed by semi-nested RT-PCR and detection by gel electrophoresis. RESULTS: We obtained positive results from filter samples that had collected at least 1.3 TCID(50 )of aerosolized rhinovirus. Ultraviolet irradiation of airborne virus at doses much greater than those used in upper-room UV germicidal irradiation applications did not inhibit subsequent detection with the RT-PCR assay. CONCLUSION: The air sampling and extraction methodology developed in this study should be applicable to the detection of rhinovirus and other airborne viruses in the indoor air of offices and schools. This method, however, cannot distinguish UV inactivated virus from infectious viral particles

Five insights from the Global Burden of Disease Study 2019

The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 provides a rules-based synthesis of the available evidence on levels and trends in health outcomes, a diverse set of risk factors, and health system responses. GBD 2019 covered 204 countries and territories, as well as first administrative level disaggregations for 22 countries, from 1990 to 2019. Because GBD is highly standardised and comprehensive, spanning both fatal and non-fatal outcomes, and uses a mutually exclusive and collectively exhaustive list of hierarchical disease and injury causes, the study provides a powerful basis for detailed and broad insights on global health trends and emerging challenges. GBD 2019 incorporates data from 281 586 sources and provides more than 3.5 billion estimates of health outcome and health system measures of interest for global, national, and subnational policy dialogue. All GBD estimates are publicly available and adhere to the Guidelines on Accurate and Transparent Health Estimate Reporting. From this vast amount of information, five key insights that are important for health, social, and economic development strategies have been distilled. These insights are subject to the many limitations outlined in each of the component GBD capstone papers.Peer reviewe

Exploration of the effects of classroom humidity levels on teachers’ respiratory symptoms

PURPOSE: Previous studies indicate that teachers have higher asthma prevalence than other non-industrial worker groups. Schools frequently have trouble maintaining indoor relative humidity (RH) within the optimum range (30-50%) for reducing allergens and irritants. However, the potential relationship between classroom humidity and teachers’ health has not been explored. Thus, we examined the relationship between classroom humidity levels and respiratory symptoms among North Carolina teachers. METHODS: Teachers (n=122) recorded daily symptoms, while data-logging hygrometers recorded classroom RH levels in 10 North Carolina schools. We examined effects of indoor humidity on occurrence of symptoms using modified Poisson regression models for correlated binary data. RESULTS: The risk of asthma-like symptoms among teachers with classroom RH >50% for five days was 1.27 (0.81, 2.00) times the risk among the referent [teachers with classroom RH 30-50%]. The risk of cold/ allergy symptoms among teachers with classroom RH >50% for five days was 1.06 (0.82, 1.37) times the risk among the referent. Low RH (<30%) for five days, was associated with increased risk of asthma-like [Risk Ratio (RR): 1.26 (0.73, 2.17)] and cold/allergy symptoms [RR: 1.11 (0.90, 1.37)]. CONCLUSIONS: Our findings suggest that prolonged exposure to high or low classroom RH was associated with modest (but not statistically significant) increases in the risk of respiratory symptoms among teachers