Airborne virus transmission under different weather conditions.

The COVID19 infection is known to disseminate through droplets ejected by infected individuals during coughing, sneezing, speaking, and breathing. The spread of the infection and hence its menace depend on how the virus-loaded droplets evolve in space and time with changing environmental conditions. In view of this, we investigate the evolution of the droplets within the purview of the Brownian motion of the evaporating droplets in the air with varying weather conditions under the action of gravity. We track the movement of the droplets until either they gravitationally settle on the ground or evaporate to aerosols of size 2 µm or less. Droplets with radii 2 µm or less may continue to diffuse and remain suspended in the air for a long time. The effects of relative humidity and temperature on the evaporation are found to be significant. We note that under strong flowing conditions, droplets travel large distances. It is found that the bigger droplets fall on the ground due to the dominance of gravity over the diffusive force despite the loss of mass due to evaporation. The smaller evaporating droplets may not settle on the ground but remain suspended in the air due to the dominance of the diffusive force. The fate of the intermediate size droplets depends on the weather conditions and plays crucial roles in the spread of the infection. These environment dependent effects indicate that the maintenance of physical separation to evade the virus is not corroborated, making the use of face masks indispensable.

The deployment of mobile diagnostic laboratories for Ebola virus disease diagnostics in Sierra Leone and Guinea.

BACKGROUND: Ebola virus emerged in West Africa in December 2013. The ease of mobility, porous borders, and lack of public health infrastructure led to the largest Ebola virus disease (EVD) outbreak to date. INTERVENTION: The 2013 EVD outbreak signalled the need for laboratory diagnostic capabilities in areas without strong public health systems. As part of the United States' Department of Defense response, MRIGlobal was contracted to design, fabricate, equip, deploy, and operate two mobile diagnostic laboratories (MDLs). The first laboratory analysed blood samples from patients in an adjacent Ebola Treatment Centre (ETC) and buccal swabs from the deceased in the community in Moyamba, Sierra Leone. The second laboratory was deployed to support an ETC in Conakry, Guinea. The Department of Defense provided real-time quantitative reverse transcription polymerase chain reaction assays that were deployed and validated on-site. LESSONS LEARNT: Prompt and accurate molecular diagnostics reduced sample turn-around times from over 24 h to under 4 h. Experienced laboratory staff tested up to 110 samples per day and on-site engineering proved necessary for MDL setup and operation. As the Ebola response slowed, the sustainment of the MDLs' operations was prioritised, including staff training and the transition of the MDLs to local governments. Training programmes for local staff were prepared in Sierra Leone and Guinea. RECOMMENDATIONS: The MRIGlobal MDL team significantly contributed to establishing increased laboratory capacity during the EVD outbreak in West Africa. Using the MDLs for molecular diagnosis is highly recommended until more sustainable solutions can be provided.

Sustainable Laboratory Capacity Building After the 2014 Ebola Outbreak in the Republic of Guinea.

Background: The 2014-2016 West Africa Ebola virus disease outbreak heavily impacted the Republics of Guinea, Sierra Leone, and Liberia. The outbreak uncovered the weaknesses of the public health systems, including inadequately trained and insufficient health personnel as well as limited and poorly equipped health infrastructures. These weaknesses represent significant threats to global health security. In the wake of the outbreak, affected countries made urgent requests for international engagement to help strengthening the public health systems. Methods: This work describes the successful multi-year implementation of a laboratory capacity building program in the Republic of Guinea. The program integrated biorisk and quality management systems training, infectious diseases diagnostic training, facility engineering and maintenance training, and mentorship to strengthen Guinea's bio-surveillance capacity. Results: The major outcome of these efforts was an established and local staff-operated public health laboratory that performs disease surveillance and reporting and diagnostic of priority diseases and pathogens of security concerns. Conclusions: This work has improved the Guinea country's capabilities to address country public health issues and preparedness to respond to future infectious disease threats.

Transmission of airborne virus through sneezed and coughed droplets.

The spread of COVID19 through droplets ejected by infected individuals during sneezing and coughing has been considered a matter of key concern. Therefore, a quantitative understanding of the propagation of droplets containing the virus assumes immense importance. Here, we investigate the evolution of droplets in space and time under varying external conditions of temperature, humidity, and wind flow by using laws of statistical and fluid mechanics. The effects of drag, diffusion, and gravity on droplets of different sizes and ejection velocities have been considered during their motion in air. In still air, we found that bigger droplets traverse a larger distance, but smaller droplets remain suspended in air for a longer time. Therefore, in still air, the horizontal distance that a healthy individual should maintain from an infected one is based on the bigger droplets, but the time interval to be maintained is based on the smaller droplets. We show that in places with wind flow, the lighter droplets travel a larger distance and remain suspended in air for a longer time. Therefore, we conclude that both temporal and geometric distance that a healthy individual should maintain from an infected one is based on the smaller droplets under flowing air, which makes the use of a mask mandatory to prevent the virus. Maintenance of only stationary separation between healthy and infected individuals is not substantiated. The quantitative results obtained here will be useful to devise strategies for preventing the spread of other types of droplets containing microorganisms.

A Comparative Study of Byssinosis in Jute Industries.

BACKGROUND: Byssinosis is an acute respiratory difficulty that is caused usually following exposure to cotton and hemp dust. Occurrence of such similar acute symptoms had been reported following exposure to jute dust/fiber also. With passage of time, Jute industries have modernized themselves for increased quality and productivity, which has lessened workforce and thereby provided more working space. However, occupational health benefit due to such changes has rarely been explored. This study was initiated to understand whether this modernization can protect the health of workers. METHODOLOGY: This study was carried out in two jute mills manufacturing jute clothes, jute bags, and so on. Interview of the workers for their occupational and morbidity details, medical examinations, as well as pre-shift and post-shift pulmonary function tests was carried out. RESULTS: It was observed that chest tightness was significantly more in the industry with old technologies. Breathlessness was also more in this industry. As far as pulmonary function status is concerned, it was noted that greater than 5% cross-shift change in forced expiratory volume in one second was more common in the industry with old technology. Obstructive feature on lung function test was also observed in workers of both industries. CONCLUSION: The study concluded that exposure to jute dust has contributed to both acute and chronic respiratory health effects in the jute industry workers. Modernized industry showed lesser prevalence of acute symptoms and changes related to byssinosis. Modernization of processes in jute industries may prove fruitful in lowering the respiratory problems of workers.

Exposure to varying concentration of fungal spores in grain storage godowns and its effect on the respiratory function status among the workers.

Grain storage depot workers suffer from different respiratory problems after getting the exposure to storage grain dust. Which is a mixture of pesticides, fungi, silica, bacteria, spores, storage mites, animal hairs, pollens etc. The present study was undertaken to evaluate the fungal spore concentration in summer and winter season as well as the pulmonary function status of the workers; studies are limited in our country. In summer and winter seasons, air sampling was done to measure the airborne fungal spore concentration inside the godowns by Rotorod sampler, UK. Aspergilla, Alternaria, Drechslera, Epicoccum, Nigrospora, Periconia were very much common and found higher in winter compared to summer. The respiratory functional status was assessed in two groups of workers of the same storage grain depot (total n=316) in summer (n=136) and in winter (n=180). List of the workers was collected from the authority and randomly selected every alternate worker and divide them for the studies in summer and winter seasons. Slow Vital Capacity (SVC), Forced Vital Capacity (FVC), and Peak Expiratory Flow Rate (PEFR) were recorded and Forced Expiratory Volume in one second (FEV1), FEV1% and different flow rates were calculated. The Immunoglobulin- E (IgE) level in the blood serum was assessed on post shift pulmonary function tests (PFT) decreased workers. The age, height and weight of the same categories of workers of both studies are highly comparable. Mean PFT values in summer found higher than winter. A gradual decrement of values were found as age was increased but not with duration of exposure. Post-shift PFT was carried in 21.8% (69) workers of which 46.4% (32) workers showed the decrement of values. The serum IgE level of the post-shift PFT decreased subjects was found more than 250 IU/ml in 53.1% (17) workers. Restrictive, obstructive and combined types of respiratory impairments were noticed among the workers. Presence of different spores in varying concentration in the working atmosphere may be responsible for the post shift decrement of PFT, allergic symptoms, high IgE level and respiratory impairments among the workers.

Comparison of pulmonary function test abnormalities between stone crushing dust exposed and nonexposed agricultural workers.

OBJECTIVES: The aim of this study is to examine the effects of stone crushing in West Bengal, India, by comparing pulmonary functions of stone crushing workers with those of nonexposed agricultural workers. METHODS: Two hundred seventy two stone crushing workers and 123 nonexposed workers were analyzed in terms of occupational and personal histories, radiological findings, and pulmonary function test (PFT) results including slow vital capacity (FVC), forced vital capacity (FVC) and peak expiratory flow rate (PEFR). Different lung volumes i.e. FEV(1), FEV(1%), and flow rates i.e. FEF(200-1200ml), FEF(25-75%) and FEF(75-85%), were analyzed with regard to sex, smoking habit, work status, age and work duration. RESULTS: Contrary to our expectations, the incidences of suspected (2.94%) and definite (1.84%) pneumoconioses were very low and the results of some PFT such as those for FVC and FEV(1%), in the exposed group were better than those in the nonexposed group, although a gradual decline the performance in PFT was observed with age and work duration. There was a higher prevalence of restrictive impairment among the exposed group and a higher prevalence of obstructive impairment in the nonexposed group. CONCLUSIONS: Some of the results were unexpected. Possible reasons for these include (i) undetectable concentrations of free silica in the stone dust in the work environment of the exposed workers and (ii) factors, such as climate, in the work environment of the nonexposed agricultural workers that could cause pulmonary impairment. Further protective measures should be undertaken to prevent pulmonary impairment in both groups of workers.

Respiratory health status of the roadside school children at Kolkata.

School students in metro cities are often exposed to vehicle exhausts as their schools are situated mostly on the high traffic roadside. Acute exposure to automobile exhaust is associated with increased respiratory symptoms and may decrease and impair lung function in children. The lung functioning performance of the city school children was compared with rural school children where there is no pollution and automobile exhausts. In Kolkata, two schools for boys (n = 210) and two schools for girls (n = 200) and in rural area one school for boys (n = 99) and the other school for girls (n = 95) were investigated. City schools are situated on the main roadside, nearer to the traffic junction. The detail histories about health status of children, if they have any subjective feelings of health related problems during the school hours or after returning from the school, and the family histories were taken by questionnaire method. The pulmonary function tests (PFT) were carried out by Spirometric method by Spirovit-Sp-10 and Wright's Peak flow meter. The mean PFT values of the students found in the normal range. Boys were having higher values compared to the girls in both city and rural schools. Lung volumes and flow rates were significantly higher in rural students. Symptomatic changes like breathlessness, cough and other problems (sneezing, eye irritation, running nose etc.) among city schoolboys found 13%, 7% and 15% and in girls found 12%, 6% and 7% respectively. In symoptomatic students, mean PFT values were significantly lowered compared to non-symptomatic. PFT values were presented in relation to age and height. It has been found that a number of city school students are having different types of respiratory symptoms. Long-term effect of exposure into such environment may develop lung functional impairments.

Effect of examination stress on blood cell parameters of students in a Pakistani medical college.

BACKGROUND: Physiological studies show that stress can alter the blood cells parameters in healthy individuals. We tried to determine whether exams in medical schools are stressful enough to produce such changes. METHODS: A randomized selection of female students from Women Medical College, Abbottabad, Pakistan, was carried out. After preliminary medical checkup blood samples were taken before and during exams. Students having temperature or high blood pressure at the start of study were excluded. Finally 37 students were included. Estimations of red blood cells, hematocrit, neutrophils, lymphocytes, eosinophils, monocytes, basophils and platelets were carried out. RESULTS: Compared with pre-examination results the blood samples taken during exams showed a significant decrease in eosinophil, basophil, lymphocyte and monocyte count. An increase in platelet and neutrophil count was also observed. No significant changes were observed in red blood cell and hematocrit readings. CONCLUSION: It is concluded that examinations in medical schools are stressful enough to produce changes in blood cells parameters which include increase in neutrophils, and platelets, while eosinophils, monocytes basophils and lymphocytes decreased in number.