Individual anthropometric, aerobic capacity and demographic characteristics as predictors of heat intolerance in military populations

Background and objectives: The Australian Defence Force (ADF) engages in combat-related activities in hot climatic conditions, which exposes ADF members to the threat of exertional heat illness (EHI). After an episode of EHI, the heat tolerance test (HTT) is conducted to determine heat tolerance. Heat intolerance is the inability to maintain thermal balance while exercising in a hot environment. This study investigated the predictive roles of individual characteristics (age, gender, aerobic capacity (VO2max) and body composition) on physiological responses to the HTT in a group comprising ADF personnel and civilian volunteers. Materials and Methods: A quasi-experimental design was used and 52 (38 males and 14 females) participants were recruited from the ADF and the general population for the HTT. Heat intolerance was defined following the standard criteria for the HTT (temperature and heart rate). Data were analysed using inferential statistics. Results: The mean age of the participants was 31.1 ± 11.6 years, and 44% (23 people: 19 males and 4 females) of the participants were heat intolerant. Independent samples T-test showed that body mass index (p = 0.011) and body fat% (p = 0.034) of heat-intolerant participants were significantly higher than their heat-tolerant counterparts. Body surface area to mass ratio (p = 0.005) and aerobic capacity (p = 0.001) were significantly lower in heat-intolerant participants. Regression analyses showed that age, gender, aerobic capacity and body fat% were significant (p < 0.001) predictors of heat tolerance outcomes, with R2 values ranging from 0.505 to 0.636. Conclusion: This study showed that aerobic capacity, body fat%, age and gender are predictors of heat intolerance among military and non-military populations. However, there may be a need for future studies to consider identifying other indicators such as clinical biomarkers of heat intolerance, which could be used to develop a more reliable HTT protocol

Functionality of physical activity referral schemes (PARS): a systematic review

Background: Physical activity (PA) is vital to maintaining good health. However, WHO estimates that 60% of the world’s population are inadequately active. To enhance PA, Physical Activity Referral Schemes (PARS) have been established by some countries. Objective: This study examined the functionality of the PARS process across different countries. Methods: This systematic review was performed and reported in accordance with the PRISMA guidelines. Sixteen electronic databases were searched from January 1990 to May 2020. PARS studies, published in English language and in peer-reviewed journals, that reported adherence, outcomes, disease conditions, interventions, facilitators and barriers, were included in this review. Results: Twenty-seven studies conducted across eight countries met the inclusion criteria. Most patients were referred for sedentary/inactivity reasons and supervised group-based activities was the most used intervention. Participants’ average adherence rate was 77.5%. Adherence was either facilitated or hindered by type of support provided during and after intervention period. Inclusion of PA allied health specialist in the intervention enhanced positive health outcomes. Conclusion: PARS is a key driver and motivator for individuals to undertake and adhere to PA interventions. Utilisation of guidelines on evidence-based interventional PA for different types of diseases, effective use of common group supervised activities and the involvement of PA specialists may aid PA adherence and foster positive health outcomes

Physical activity promotion: a systematic review of the perceptions of healthcare professionals

Physical activity (PA) is a cost-effective and non-pharmacological foundation for the prevention and management of chronic and complex diseases. Healthcare professionals could be viable conduits for PA promotion. However, the evidence regarding the effectiveness and benefits of the current forms of PA promotion are inconclusive. Healthcare professionals’ perceptions on key determinants impact on the optimum promotion of PA were explored in this review. Thirty-four (34) studies were identified after systematically searching seven databases for peer-reviewed articles published within the last decade. PA advice or counselling was the most recorded form of PA promotion, limited counselling time was the most reported obstacle while providing incentives was viewed as a key facilitator. There is widespread consensus among healthcare professionals (HCPs) on some aspects of PA promotion. Utilisation of all PA promotional pathways to their full potential could be an essential turning point towards the optimal success of PA promotional goals. Hence, strategies are required to broaden chronic disease treatment methods to include preventive and integrative PA promotion approaches particularly, between frontline HCPs (e.g., GPs) and PA specialists (e.g., EPs). Future studies could explore the functionality of GP to EP referral pathways to determining what currently works and areas requiring further development

Epidemiology of exertional heat illness in the military: a systematic review of observational studies

Exertional heat illness (EHI) is an occupational hazard among military personnel. This systematic review describes the incidence, risk factors, clinical manifestations, and biomarkers of EHI in the military. Six databases from inception to 28 May 2020 were systematically reviewed using the PRISMA guidelines. Forty-one articles met the inclusion criteria and the incidence of EHI ranged from 0.2 to 10.5 per 1000 person years, while the prevalence rates ranged from 0.3% to 9.3%. Intrinsic risk factors influencing EHI were gender, physical fitness, obesity, previous history of heat illness, and motivation, while the extrinsic factors included hot environmental conditions and service unit. Evidence suggests that loss of consciousness, absence of sweating and confusion were the common clinical features of exertional heat stroke (EHS). The mean core temperature ranged from 40 to 41.6°C, while elevated levels of creatine phosphokinase, liver enzymes, and creatinine were common biochemical markers of EHS. The findings of the review suggest a variation in the incidence of EHI among military populations possibly due to the varying definitions used. Although some risk factors of EHI were identified, more analytical studies are needed to investigate the association between EHI and other important factors such as acclimatisation and occlusive clothing

The ‘PRICE’ of Physical Activity Referral Schemes (PARS): stakeholders’ recommendations for delivering quality care to patients

Evidence-based strategies are needed to curb the growing cases of physical inactivity related morbidities. Delivering holistic care through collaborative shared decision making could boost the effectiveness of physical activity referral schemes (PARS) and foster the quality of care for patients with multimorbidity. A qualitative study involving semi-structured telephone interviews was utilised to gain insights from Australian PARS stakeholders (general practitioners, exercise physiologists, and patients). A pluralistic evaluation approach was employed to explore and integrate participants’ opinions and experiences of PARS and their recommendations were used to develop a model for quality care delivery in PARS initiatives. Five overarching themes: promote, relate, incentivise, communicate, and educate were identified as the ‘PRICE’ for developing effective and functional PARS programmes that foster quality patient care. It was evident that PARS programmes or policies aimed at optimising publicity, encouraging incentives, improving interdisciplinary information sharing and professional relationships between patients and healthcare professionals can transform healthcare delivery and provide top quality PARS care services to patients. Therefore, governments, healthcare systems, and PARS administrators can translate and leverage the insights from this study to optimise the delivery of high quality care to PARS patients

Broad Dengue Neutralization in Mosquitoes Expressing an Engineered Antibody

With dengue virus (DENV) becoming endemic in tropical and subtropical regions worldwide, there is a pressing global demand for effective strategies to control the mosquitoes that spread this disease. Recent advances in genetic engineering technologies have made it possible to create mosquitoes with reduced vector competence, limiting their ability to acquire and transmit pathogens. Here we describe the development of Aedes aegypti mosquitoes synthetically engineered to impede vector competence to DENV. These mosquitoes express a gene encoding an engineered single-chain variable fragment derived from a broadly neutralizing DENV human monoclonal antibody and have significantly reduced viral infection, dissemination, and transmission rates for all four major antigenically distinct DENV serotypes. Importantly, this is the first engineered approach that targets all DENV serotypes, which is crucial for effective disease suppression. These results provide a compelling route for developing effective genetic-based DENV control strategies, which could be extended to curtail other arboviruses

Correction: Broad dengue neutralization in mosquitoes expressing an engineered antibody.

[This corrects the article DOI: 10.1371/journal.ppat.1008103.]

Pathogenicity and immunogenicity of attenuated, nef-deleted HIV-1 strains in vivo

In efforts to develop an effective vaccine, sterilizing immunity to primate lentiviruses has only been achieved by the use of live attenuated viruses carrying major deletions in nef and other accessory genes. Although live attenuated HIV vaccines are unlikely to be developed due to a myriad of safety concerns, opportunities exist to better understand the correlates of immune protection against HIV infection by studying rare cohorts of long-term survivors infected with attenuated, nef-deleted HIV strains such as the Sydney blood bank cohort (SBBC). Here, we review studies of viral evolution, pathogenicity, and immune responses to HIV infection in SBBC members. The studies show that potent, broadly neutralizing anti-HIV antibodies and robust CD8+ T-cell responses to HIV infection were not necessary for long-term control of HIV infection in a subset of SBBC members, and were not sufficient to prevent HIV sequence evolution, augmentation of pathogenicity and eventual progression of HIV infection in another subset. However, a persistent T-helper proliferative response to HIV p24 antigen was associated with long-term control of infection. Together, these results underscore the importance of the host in the eventual outcome of infection. Thus, whilst generating an effective antibody and CD8+ T-cell response are an essential component of vaccines aimed at preventing primary HIV infection, T-helper responses may be important in the generation of an effective therapeutic vaccine aimed at blunting chronic HIV infection

Broad Dengue Neutralization in Mosquitoes Expressing an Engineered Antibody

With dengue virus (DENV) becoming endemic in tropical and subtropical regions worldwide, there is a pressing global demand for effective strategies to control the mosquitoes that spread this disease. Recent advances in genetic engineering technologies have made it possible to create mosquitoes with reduced vector competence, limiting their ability to acquire and transmit pathogens. Here we describe the development of Aedes aegypti mosquitoes synthetically engineered to impede vector competence to DENV. These mosquitoes express a gene encoding an engineered single-chain variable fragment derived from a broadly neutralizing DENV human monoclonal antibody and have significantly reduced viral infection, dissemination, and transmission rates for all four major antigenically distinct DENV serotypes. Importantly, this is the first engineered approach that targets all DENV serotypes, which is crucial for effective disease suppression. These results provide a compelling route for developing effective genetic-based DENV control strategies, which could be extended to curtail other arboviruses