Tropical Conditions and Outbreak of COVID-19

Background: The new novel Coronavirus 2019 (nCOV-19 or COVID-19) has caused an unprecedented pandemic in humans. All nations have heightened their surveillances after the quick diagnosis of potential cases of the COVID-19. Objective(s): Recent statistics have mentioned that virus outbreak in tropical countries is relatively low compared to cold nations. To support this conclusion, we considered the six main tropical regions to investigate the pandemic distribution at the initial phase. Method(s): Chi-square test was applied to understand the correlation between outbreak and temperature changes. Significant probability P-value was set to P<0.01. P-values were calculated to both positive and death cases. Result(s): Out of 1211562 infected cases, 41776 cases (3.45%) were registered at hightemperature countries (P<0.0001) and 1161786 cases (96.55%) at other countries like European countries or the USA. Moreover, only 1433 mortality cases (2.2%) happened, and the remaining 97.8% of mortality happened among other nations. Conclusion(s): Similar to other respiratory viruses like flu and influenza, there is a low outbreak of COVID-19 in tropical nations compared to the other countries. Apart from weather conditions, it is also recommended to follow the serious preventive measures imposed by governments to survive this novel epidemic.Copyright © 2020

Modelling and Closed-Loop Control of Admissions in a Vaccination Center Through Tropical Algebra

This paper presents the development of a dynamical tropical algebra-based model of a vaccination center, which can be used to control and optimize the admission of users during center's operation. In addition, an analysis of closed-loop control methods designed to maximize the system performance in terms of service rate and minimize users' waiting time, while observing occupancy constraints due to social distancing protocols recommended by sanitary authorities due to Covid epidemic, is presented. © 2023, Brazilian Society for Automatics--SBA.

Assimilation of aircraft observations over the Indian monsoon region: Investigation of the effects of COVID-19 on a reanalysis

Since March 2020, the COVID-19 pandemic has significantly reduced the availability of global aircraft-based observations (ABOs), which has been restored later in 2021. This study focuses on the impact of ABOs on a regional reanalysis. Indian Monsoon Data Assimilation and Analysis (IMDAA) is a regional reanalysis for a period from 1979 to 2020 (originally up to 2018) over India and surrounding regions produced at the National Centre for Medium Range Weather Forecasting (NCMRWF), India, in collaboration with the UK Met Office. A comparison of the impact of ABOs on other conventional and satellite observations assimilated in the NCMRWF global model and IMDAA during 2019 and 2020 revealed the importance of ABOs, particularly in IMDAA, since it did not assimilate the latest satellite data as the IMDAA system was frozen in October 2016. A data denial experiment that removes all the ABOs from the IMDAA assimilation system for a period from March to November 2019 is designed. The results from the IMDAA reanalysis run, which assimilates ABOs during the same period, are compared with the data denial experiment. Assimilation of ABOs strengthened the upper tropospheric circulation, the Tropical Easterly Jet (TEJ), during the Indian summer monsoon compared to the data denial experiment. Analysis of the features of two cyclones that developed over the North Indian Ocean during the study period revealed that ABO assimilation played a key role in simulating the track and intensity of these cyclones when they were in the ‘severe' category. Since the sample is small, more cyclone cases need to be analysed to consolidate the result. © 2023 Royal Meteorological Society.

Dengue and COVID-19 co-infections: an important consideration in the tropics.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has affected >370 million individuals worldwide. Dengue is endemic in many countries and leads to epidemics at frequent intervals. In the tropics and subtropics, it is possible that individuals may be concurrently infected with both dengue and SARS-CoV-2. Differentiation between the two infections may be difficult from both a clinical and laboratory perspective. We have outlined the currently published findings (as of the end of December 2021) on patients with dengue and SARS-CoV-2 co-infections and have discussed the observed outcomes and management of such patients. Co-infections were more common in males >25 y of age, fever was not universal, 30-50% had medical comorbidities such as diabetes mellitus or hypertension and the case fatality rate was 16-28%.

Are we hunting bats to extinction? Worldwide patterns of hunting risk in bats are driven by species ecology and regional economics

Bats are routinely neglected in conservation, often regarded as uncharismatic and constantly maligned despite their provision of economic and ecosystem services. Yet many species are threatened, and while the loss of roosting and foraging habitat has been explored, the impacts of hunting on species survival are less well understood. Here, we analysed the hunting risk of 1320 bat species (of 1400 known) from around the world and explored the association between ecological traits and socioeconomic variables. Globally, at least 19 % of species are threatened by hunting. Large-bodied bats with narrow distributions are at increased risk of hunting, particularly in tropical regions. Multiple threats, such as habitat loss and modification, are likely to exacerbate the pressures experienced by hunted species. Furthermore, accessibility to bat habitats and low-income drive bat hunting in developing countries. With the global economic recession and the need for economic recovery following the pandemic, hunters may rely more on wildlife for subsistence and pose a threat to both biodiversity and public health. Achieving the balance between economics and conserving biodiversity is challenging due to socioeconomic factors, and the complex interplay of different forms of threat. Therefore, interventions to reduce bat hunting activities should include greater investment to facilitate sustainable livelihood development in the rural economy, and elevating public knowledge about bat ecosystem services, and their potential role in the transmission of zoonotic diseases.

In-House monitoring and measurement of respiration rate using Disposable Paper Sensor

This present work provides an easily disposable paper-based interdigitated sensor embedded inside the mask for the detection of respiration rate continuously without direct contact with the human body. In present COVID scenario, everyone needs to wear mask for preventing the unwanted spreading of the said virus. But in tropical countries like India, People always complain about a suffocating situation while wearing mask. In order to address this, we have designed a non-invasive paper sensor that can be placed inside the mask (beneath nostril) for measuring breathing rate regularly to find out a cost-effective device capable of monitoring breathing rate. In general, we prefer use and throw type mask, thus the proposed paper-based sensor gives a cost-effective solution compared to the Current appliances of breathing sensing as most of them are burdensome, bulky, inconvenient as well as exorbitant than a paper-based respiration sensor. Essentially, these current approaches undergo through a practical limitation of frequency and time span i.e. static measurement. It is known that the humidity level of a paper changes according to the moisture content. Thus, it can easily detect the inhalation and exhalation through this changing. Moreover, variation of moisture level that happens due to breathing cycle changes the ionic conductivity of the sensor. The interdigitated design is the most suited for achieving higher sensitivity and easy to fabricate. First, we have designed it in Finite Element Method (FEM) based platf orm and finally this design is implemented with graphite-based electrodes on cellulose paper. Microcontroller based electronic circuitry is used in order to monitor and record the real-time respiration rate. It has been observed that the breathing rate as well as pattern gives a significant variation along with physical conditions and obstructive pulmonary diseases.

Indonesian Medicinal Plants with Anti-inflammatory Properties and Potency as Chronic Obstructive Pulmonary Disease (COPD) Herbal Medicine

Indonesia is a tropical country with mega-biodiversity. Several medicinal plants locally have been recognized for their anti-inflammatory properties and are traditionally used to help treat respiratory diseases. Chronic obstructive pulmonary disease (COPD) is one of the diseases known as the high cause of death globally, and one of the treatment efforts is by using anti-inflammatory drugs. In developing alternative remedies for COPD, this review summarizes the potential of Indonesian medicinal plants and their ingredients known to have an anti-inflammatory activity to develop alternative remedies for COPD. Primarily, we focus on the medicinal plants that have been scientifically proven to pose some biological activities, such as legetan warak (Adenostemma lavenia), celery (Apium graveolens), pegagan (Centella asiatica), kenikir (Cosmos caudatus), and kersen (Muntingia calabura). This review is expected to provide more information about Indonesian medicinal plants and their potencies to be developed as COPD herbal medicine and, further, as a treatment to help patients suffering from coronavirus disease (COVID-19).

Impacts of Air Pollution and Dampness on Occupant Respiratory Health in Unplanned Houses: A Case Study of Bandung, Indonesia

This paper presents the results from field measurements and household surveys on the severity of indoor mold risk and its impact on respiratory health in a typical unplanned neighborhood of kampungs in Bandung, Indonesia. Mold risk was investigated using fungal risk detectors (n = 102), while air pollution levels were established with total suspended particulate (TSP) and particulate matter (PM2.5) (n = 38). The self-reported prevalence of respiratory diseases was obtained using a questionnaire form (ATS-DLD-78) (n = 599). The results showed that respiratory health problems were higher in the rainy season, particularly among children. Most houses suffered from severe mold risk, primarily due to extreme humid weather conditions, especially during rainy season (97%) where water leakage was prevalent (60%). In addition, the TSP and PM2.5 concentrations exceeded the WHO standards in most kampung houses, where around 58% of the houses recorded higher outdoor mean PM2.5 concentrations than indoors. Further, the path analysis showed that allergies followed by humidity rate and smell, which were affected by window-opening duration, directly impacted children’s respiratory health. Smoking behavior and building-related health problems, due to exposure to outdoor air pollution, affected the respiratory health of those aged 15 years old and over.

Using Genomics to Understand the Epidemiology of Infectious Diseases in the Northern Territory of Australia.

The Northern Territory (NT) is a geographically remote region of northern and central Australia. Approximately a third of the population are First Nations Australians, many of whom live in remote regions. Due to the physical environment and climate, and scale of social inequity, the rates of many infectious diseases are the highest nationally. Molecular typing and genomic sequencing in research and public health have provided considerable new knowledge on the epidemiology of infectious diseases in the NT. We review the applications of genomic sequencing technology for molecular typing, identification of transmission clusters, phylogenomics, antimicrobial resistance prediction, and pathogen detection. We provide examples where these methodologies have been applied to infectious diseases in the NT and discuss the next steps in public health implementation of this technology.

PCR, Tropical Arithmetic, and Group Testing

Polymerase chain reaction (PCR) testing is the gold standard for diagnosing COVID-19. Unfortunately, the outputs of these tests are imprecise and therefore quantitative group testing methods, which rely on precise measurements, are not applicable. Motivated by the ever-increasing demand to identify individuals infected with SARS-CoV-19, we propose a new model that leverages tropical arithmetic to characterize the PCR testing process. In many cases, some of which are highlighted in this work, tropical group testing is provably more powerful than traditional binary group testing in that it requires fewer tests than classical approaches, while additionally providing a mechanism to identify the viral load of each infected individual. © 2022 IEEE.

Near-Surface Atmospheric Behavior over Complex Tropical Topography in Puerto Rico Dominated by Seasonal Patterns Despite Frequent Environmental Changes

Understanding near-surface atmospheric behavior in the tropics is imperative given the role of tropical energy fluxes in Earth’s climate cycles, but this area is complicated by a land–atmosphere interaction that includes rugged to-pography, seasonal weather drivers, and frequent environmental disturbances. This study examines variation in nearsurface atmospheric behaviors in northeastern Puerto Rico using a synthesis of data from lowland and montane locations under different land covers (forest, urban, and rural) during 2008–21, when a severe drought, large hurricanes (Irma and Maria), and the COVID-19 mobility-reducing lockdown occurred. Ceilometer, weather, air quality, radiosonde, and satellite data were analyzed for annual patterns and monthly time series of data and data correlations. The results showed a system that is strongly dominated by easterly trade winds transmitting regional oceanic patterns over terrain. Environmental disturbances affected land–atmosphere interaction for short time periods after events. Events that reduce the land signature (reducing greenness: e.g., drought and hurricanes, or reducing land pollution: e.g., COVID-19 lockdown) were evidenced to strengthen the transmission of the oceanic pattern. The most variation in near-surface atmospheric behavior was seen in the mountainous areas that were influenced by both factors: trade winds, and terrain-induced orographic lifting. As an exception to the rest of the near-surface atmospheric behavior, pollutants other than ozone did not correlate positively or negatively with stronger trade winds at all sites across the region. Instead, these pollutants were hypothesized to be more anthropogenically influenced. Once COVID-19 lockdown had persisted for 3 months, urban pollution decreased and cloud base may have increased. © 2022, American Meteorological Society. All rights reserved.

The fatal fetal sting of Dengue: experience from a tropical country

Objectives: Dengue is a vector borne infectious disease, endemic in the tropical regions, that may be associated with significant maternal and fetal morbidity and mortality. However, literature is sparse on the rate and factors associated with stillbirths in women suffering from dengue. In this study, we aimed to explore the frequency of stillbirths in dengue infection in pregnancy during the COVID pandemic. We also studied the effect of severity of the disease on fetal morbidity and mortality. Design: Retrospective review of registers and case records Method: We reviewed the data of pregnant women admitted for dengue in the Obstetrics & Gynecology department in a tertiary care hospital of Northern India between September and December, 2021. Data collected included the age, parity, gestation at admission, severity of the maternal disease, other comorbities, maternal outcome, obstetrical outcome during the dengue disease and fetal outcome. Results: Twenty three pregnant women were admitted to the department between September and December 2021. The average age of the women was 26+/-5 years. Half of these women were primigravidas (12 out of 25). Most women were in the third trimester, while one woman each presented in second trimester and the postpartum period. Eleven mothers presented with severe dengue, 11 had dengue with warning signs and only one woman had dengue without warning signs. There were 7 maternal deaths. Three mothers died undelivered. There were 10 stillbirths of 20 deliveries and 22 babies. Majority of the woman delivered preterm. There were 2 twin deliveries. Of the babies who delivered at term, most were liveborn(6 of 7). The stillbirth rate was higher in the severe dengue group, dengue with warning signs and dengue without warning signs were 60%, 36% and nil respectively. Conclusions: The stillbirth rate is high in women with dengue in pregnancy, especially in the third trimester. The chances of stillbirth escalate with the severity of dengue. Maternal mortality is high in women admitted with dengue in pregnancy. Public health strategies to prevent dengue should be strengthened to avoid high stillbirth rates and maternal mortality. The data is limited by the retrospective design and skewed as women with only severe form of dengue would have been admitted.

Agri-food trade in 2020

The year 2020 marked one of the biggest recessions in global economic activity and world trade. During this period, the EU economy contracted by 6% and its international trade followed a similar downward trend - EU exports of goods decreased by 9% and imports by 12%, compared to 2019. By contrast, EU international trade in agri-food reported a slight growth. Over the course of 2020, the value of EU agri-food exports increased to 184.3 billion (a growth of 1.4% compared to 2019), while the value of imports rose to 122.2 billion (a growth of 0.5%). As a result, the EU further reinforced its leading position among the world's biggest exporters. On the import side, the EU has become the third largest importer after the US and China. The contraction in global trade was accompanied by increasing prices of food, including commodities as evidenced by the increases reflected in the FAO Global Price Index. The EU exports a wide range of products from all parts of the value chain which demonstrates the competitiveness of the EU agri-food sector in a variety of product classes ranging from commodities to highly processed food industry products. EU imports, on the other hand, are clearly dominated by basic agricultural food and feed products, which represent about 75% of all imports. Looking at product categories, exports of pig meat and wheat strongly contributed to the increase in EU overall agri-food exports. Conversely, spirits and liqueurs as well as wine are among the sectors that experienced a difficult period for a number of reasons (e.g. the COVID pandemic, US retaliatory tariffs). The growth in EU agri-food imports was mainly driven by increases in import values for oilseeds, other than soya beans;fatty acids and waxes, palm oil, fruit including tropical fruit, and soya beans. China, Switzerland and the Middle East and North Africa (MENA) region were the major growth destinations for EU agri-food exports in 2020. The value of EU exports fell most to the United States, Turkey, Singapore and Japan. In terms of imports, Canada grew significantly as a source for the EU imports. By contrast, EU imports declined most in value from the United Kingdom, Ukraine and the United States. In 2020, the UK has become the EU's most important partner in agri-food trade, with a share of 23% in total EU agri-food exports and 13% in total imports. With EU exports and imports both decreasing, its trade surplus with the US increased by 2% when compared to 2019, as falls on the imports side were stronger. China became the top destination for US agri-food exports. EU agri-food exports to China were primarily driven by continued record high sales of pig meat which increased by 74%. Pig meat and meat offal - the latter mainly comprised of products originating from pigs - accounted for over 40% of EU exports to China in 2020, demonstrating the importance of this market for the pig meat sector. Brazil's exports to China continued to increase in 2020, absorbing 35% of its total agri-food exports. Combined agri-food exports from Brazil to the EU and the US now account for half of Brazilian exports to China. In 2020, Brazil supplied 50% of extra-EU demand for soya beans and 40% for oilcakes. Wheat continued to be the leading EU export product to Africa with a 23% share of the EU's total export basket, whereas cocoa beans dominate in the EU imports from Africa, with the same share of 23%. Most African countries benefit from duty-free, quota-free access to the EU market under the "Everything But Arms" scheme and for many of them Economic Partnership Agreements (EPAs) or other trade agreements with the EU are applied, encouraging regional cooperation and trade. In 2020, the EU applied 45 free trade agreements (FTAs) with 77 partners. The share of agri-food trade under preferential agreements is also expanding and in 2021, it accounted for 31% and 41% of total EU agri-food exports and imports, respectively. The value of EU agri-food trade under preferential agreements expanded more in relative terms compared to total EU agri-food trade. EU agri-food ex

Tropical Conditions and Outbreak of COVID-19

Background: The new novel Coronavirus 2019 (nCOV-19 or COVID-19) has caused an unprecedented pandemic in humans. All nations have heightened their surveillances after the quick diagnosis of potential cases of the COVID-19. Objectives: Recent statistics have mentioned that virus outbreak in tropical countries is relatively low compared to cold nations. To support this conclusion, we considered the six main tropical regions to investigate the pandemic distribution at the initial phase. Methods: Chi-square test was applied to understand the correlation between outbreak and temperature changes. Significant probability P-value was set to P<0.01. P-values were calculated to both positive and death cases. Results: Out of 1211562 infected cases, 41776 cases (3.45%) were registered at hightemperature countries (P<0.0001) and 1161786 cases (96.55%) at other countries like European countries or the USA. Moreover, only 1433 mortality cases (2.2%) happened, and the remaining 97.8% of mortality happened among other nations. Conclusion: Similar to other respiratory viruses like flu and influenza, there is a low outbreak of COVID-19 in tropical nations compared to the other countries. Apart from weather conditions, it is also recommended to follow the serious preventive measures imposed by governments to survive this novel epidemic.

Beat back the health risks-and prepare for the looming economic crisis

This article presents a compilation of updates regarding the effect of the COVID-19 pandemic to the global timber industry, from manufacturing to international trade. The article cites the state of some countries regarding the current crisis, such as the hit on China's manufacturing due to slow export demand, US tropical hardwood imports dropping, hold in European timber imports, India's manufacturing shutdown, and the sharp drop on Japan's wooden door imports, among other things. Other subsequent effects on the timber crisis were cited as well, such as drops in housing sales, employee layoffs, temporary business suspension, and others. The consensus among analysts is that the global trade of wood products will be curtailed until at least mid-2021. The most severe declines are expected in the second and third quarters of 2020, with effects through to the first quarter of 2021, followed possibly by a slow recovery that could take as long as 2 years.

mRNA Vaccine: Determinants of Clinical Efficacy, and Optimization of Pharmacological Effects

The messenger ribonucleic acid (mRNA) vaccine has proven to be beneficial in containing the severe acute respiratory syndrome coronavirus. However, some school thought that it is not as effective as proposed, even though many others attest to its efficacy. The study employed scoping review on online journal and book publications to reveal the pharmacokinetics and pharmacodynamics of the mRNA vaccine. In this work, we have discussed the mechanism of action of the self-amplified messenger ribonucleic acid vaccines, the determinants of the clinical efficacy, and the possible reasons behind the varying efficacies that different populations may experience. We provided possible ways to tackle this challenge. In providing these solutions, we discussed pharmacogenetics viz-a-viz epigenetics. The study also used figures to elaborate on the factors that determine the clinical efficacy of mRNA vaccines. We are confident that caregivers and public health officials in the tropics would find the information interesting and invaluable.

Seasonal Variation of Influenza A Virus and Its Subtypes in Patients Attending Tertiary Care Hospital

Background:Influenza is an important respiratory infection, causing 250,000 to 500,000 deaths annually. Influenza virus A is the most virulent and associated with winter epidemics in temperate regions, more persistent transmission in the tropics, and occasional large-scale global pandemics. But, there is variability in the pattern, and the H1N1 pandemic of 2009-2010 was unusually with a large spike in spring and a sharp decline continuing throughout winter. Varying in pattern is due to antigenic shift and drift and reassortment of the virus. Methods:A prospective study was carried out in Advance Basic Sciences & Clinical Research Lab, Department of Micro- biology in SMS Medical College & Hospital, Jaipur for diagnosis of Influenza A virus as well as subtyping was done using RT-PCR technique over 1 year period (July 2019 to June 2020) and demographic data was noted. Results:Total of 7213 samples were tested, out of which 498 (6.90%) were positive for Influenza A which is less from the previous year’s 22.46%. Out of total positive cases Influenza a (H1N1) pdm09 was 24.9% and InfA H3N2 was 75.10%. InfA H3N2 was the prominent circulating strain in all months while Influenza a (H1N1) pdm09 was prominent strain pre- vious year. Majority of positive cases were found in March 2020 (43.17%), September 2019 (28.51%). Most of these cases 36.14% were from age group between 20 to 40 years. Conclusions: A decline in the positivity of influenza infection compared to last year is seen which could be in part due to circulation of SARS COV 2 and measures of prevention undertaken by community to prevent it. Demographic parame- ters and seasonal variation of Influenza A virus give ideas to create awareness and to improve control strategies to mini- mize the morbidity, mortality and spread of disease.

Assessment of Impact of Meteorology and Precursor in Long-term Trends of PM and Ozone in a Tropical City

Long-term trends of atmospheric pollutants, particularly ozone (O3) and particulate matter (PM) provide a direct evaluation of the response of the atmosphere to the environmental policies and the variability of anthropogenic and biogenic emissions. Here, we report the assessment of the temporal evolution of the air quality in a tropical urban city (Butuan) in the southern Philippines by evaluating the trends of meteorological conditions (i.e., temperature, R.H., boundary layer height), air pollutants (i.e., PM2.5, NO2, O3) and their precursors (Benzene, Toluene, and Xylene) from 2014 to 2020. During the seven-year measurement, the mean PM2.5 and PM10 mass concentrations were 8.7 ± 3.9 and 24.3 ± 12.0 µg m–3, with no single day exceeded the daily PM limit. The max concentrations of aerosol occurred during the dry season when the loss of particles through wet deposition was limited. Speciation of PM2.5 indicated that fine aerosol was dominated by sea salt and organic matter (OM). Analysis of the ratio of OM and sulfate indicated that the main source of pollution in the city was wildfire/biomass burning. The average O3 and NO2 mixing ratios during the same period were 22.3 ± 9.5 ppb and 8.1 ± 5.4 ppb while increasing at the rate of 0.409 ppb year–1 and 0.683 ppb year–1. The highest O3 concentration occurred during the summer months when photochemistry enhanced the formation of tropospheric O3. The increasing O3 trend was attributed to the contribution of anthropogenic VOCs (AVOCs), based on their ozone-forming potentials (OFPs). The seven-year measurement also showcased the variability of the atmospheric pollutants during the COVID-19 pandemic of 2020, when O3 substantially increased due to reduced vehicle transport activities. Overall, our results provide insights to better comprehend the sources of the variability of O3 and PM on a long-term temporal scale, as well as implications on relevant environmental policies in controlling air pollutants in a tropical developing region. © The Author(s).

Heat Health Management in a Quarantine and Isolation Facility in the Tropics.

INTRODUCTION: The Howard Springs Quarantine Facility (HSQF) is located in tropical Northern Australia and has 875 blocks of four rooms (3,500 rooms in total) spread over 67 hectares. The HSQF requires a large outdoor workforce walking outdoor pathways to provide individual care in the ambient climate. The personal protective equipment (PPE) required for the safety of quarantine workers varies between workgroups and limits body heat dissipation that anecdotally contributes to excessive sweating, which combined with heat stress symptoms of fatigue, headache, and irritability, likely increases the risk of workplace injuries including infection control breaches. STUDY OBJECTIVE: The purpose of this study was the description of qualitative and quantitative assessment for HSQF workers exposed to tropical environmental conditions and provision of evidenced-based strategies to mitigate the risk of heat stress in an outdoor quarantine and isolation workforce. METHODS: The study comprised two components - a cross-sectional physiological monitoring study of 18 workers (eight males/ten females; means: 41.4 years; 1.69m; 80.6kg) during a single shift in November 2020 and a subjective heat health survey completed by participants on a minimum of four occasions across the wet season/summer period from November 2020 through February 2021. The physiological monitoring included continuous core temperature monitoring and assessment of fluid balance. RESULTS: The mean apparent temperature across first-half and second-half of the shift was 34.7°C (SD = 0.8) and 35.6°C (SD = 1.9), respectively. Across the work shift (mean duration 10.1 hours), the mean core temperature of participants was 37.3°C (SD = 0.2) with a range of 37.0°C - 37.7°C. The mean maximal core temperature of participants was 37.7°C (SD = 0.3). In the survey, for the workforce in full PPE, 57% reported feeling moderately, severely, or unbearably hot compared to 49% of those in non-contact PPE, and the level of fatigue was reported as moderate to severe in just over 25% of the workforce in both groups. CONCLUSION: Heat stress is a significant risk in outdoor workers in the tropics and is amplified in the coronavirus disease 2019 (COVID-19) frontline workforce required to wear PPE in outdoor settings. A heat health program aimed at mitigating risk, including workplace education, limiting exposure times, encouraging hydration, buddy system, active cooling, and monitoring, is recommended to limit PPE breaches and other workplace injuries in this workforce.

Impaired performance of SARS-CoV-2 antigen-detecting rapid diagnostic tests at elevated and low temperatures.

Antigen-detecting rapid diagnostic tests (Ag-RDTs) can complement molecular diagnostics for COVID-19. The recommended temperature for storage of SARS-CoV-2 Ag-RDTs ranges between 2-30 °C. In the global South, mean temperatures can exceed 30 °C. In the global North, Ag-RDTs are often used in external testing facilities at low ambient temperatures. We assessed analytical sensitivity and specificity of eleven commercially-available SARS-CoV-2 Ag-RDTs using different storage and operational temperatures, including short- or long-term storage and operation at recommended temperatures or at either 2-4 °C or at 37 °C. The limits of detection of SARS-CoV-2 Ag-RDTs under recommended conditions ranged from 1.0×106- 5.5×107 genome copies/mL of infectious SARS-CoV-2 cell culture supernatant. Despite long-term storage at recommended conditions, 10 min pre-incubation of Ag-RDTs and testing at 37 °C resulted in about ten-fold reduced sensitivity for five out of 11 SARS-CoV-2 Ag-RDTs, including both Ag-RDTs currently listed for emergency use by the World Health Organization. After 3 weeks of storage at 37 °C, eight of the 11 SARS-CoV-2 Ag-RDTs exhibited about ten-fold reduced sensitivity. Specificity of SARS-CoV-2 Ag-RDTs using cell culture supernatant from common respiratory viruses was not affected by storage and testing at 37 °C, whereas false-positive results occurred at outside temperatures of 2-4 °C for two out of six tested Ag-RDTs, again including an Ag-RDT recommended by the WHO. In summary, elevated temperatures impair sensitivity, whereas low temperatures impair specificity of SARS-CoV-2 Ag-RDTs. Consequences may include false-negative test results at clinically relevant virus concentrations compatible with transmission and false-positive results entailing unwarranted quarantine assignments. Storage and operation of SARS-CoV-2 Ag-RDTs at recommended conditions is essential for successful usage during the pandemic.