scholarly journals Humidity and respiratory virus transmission in tropical and temperate settings

2014 ◽  
Vol 143 (6) ◽  
pp. 1110-1118 ◽  
Author(s):  
S. PAYNTER
Keyword(s):  
Influenza Virus ◽  
Respiratory Virus ◽  
Virus Transmission ◽  
Indirect Contact ◽  
Environmental Survival ◽  
Contact Transmission ◽  
Dry Conditions ◽  
Syncytial Virus ◽  
The Tropics ◽  
Virus Survival

SUMMARYInfluenza and respiratory syncytial virus (RSV) are similarly structured viruses with similar environmental survival, but different routes of transmission. While RSV is transmitted predominantly by direct and indirect contact, influenza is also transmitted by aerosol. The cold, dry conditions of temperate winters appear to encourage the transmission of both viruses, by increasing influenza virus survival in aerosols, and increasing influenza and RSV survival on surfaces. In contrast, the hot, wet conditions of tropical rainy seasons appear to discourage aerosol transmission of influenza, by reducing the amount of influenza virus that is aerosolized, and probably also by reducing influenza survival in aerosol. The wet conditions of tropical rainy seasons may, however, encourage contact transmission of both viruses, by increasing the amount of virus that is deposited on surfaces, and by increasing virus survival in droplets on surfaces. This evidence suggests that the increased incidence of influenza and RSV in tropical rainy seasons may be due to increased contact transmission. This hypothesis is consistent with the observation that tropical rainy seasons appear to encourage the transmission of RSV more than influenza. More research is required to examine the environmental survival of respiratory viruses in the high humidity and temperature of the tropics.

scholarly journals High Temperature (30°C) Blocks Aerosol but Not Contact Transmission of Influenza Virus

2008 ◽  
Vol 82 (11) ◽  
pp. 5650-5652 ◽  
Author(s):  
Anice C. Lowen ◽  
John Steel ◽  
Samira Mubareka ◽  
Peter Palese
Keyword(s):  
Influenza Virus ◽  
Influenza Season ◽  
Virus Transmission ◽  
Tropical Regions ◽  
The World ◽  
Contact Transmission ◽  
Dry Conditions ◽  
Range Spread ◽  
Guinea Pig Model ◽  
The Tropics

ABSTRACT Influenza causes significant morbidity in tropical regions; however, unlike in temperate zones, influenza in the tropics is not strongly associated with a given season. We have recently shown that influenza virus transmission in the guinea pig model is most efficient under cold, dry conditions, which are rare in the tropics. Herein, we report the lack of aerosol transmission at 30°C and at all humidities tested. Conversely, transmission via the contact route was equally efficient at 30°C and 20°C. Our data imply that contact or short-range spread predominates in the tropics and offer an explanation for the lack of a well-defined, recurrent influenza season affecting tropical and subtropical regions of the world.

scholarly journals Overview of Viral Pneumonia Associated With Influenza Virus, Respiratory Syncytial Virus, and Coronavirus, and Therapeutics Based on Natural Products of Medicinal Plants

2021 ◽  
Vol 12 ◽  
Author(s):  
Ziwei Hu ◽  
Jinhong Lin ◽  
Jintao Chen ◽  
Tengxi Cai ◽  
Lixin Xia ◽  
...  
Keyword(s):  
Natural Products ◽  
Influenza Virus ◽  
Medicinal Plants ◽  
Respiratory Virus ◽  
Herbal Medicines ◽  
Viral Pneumonia ◽  
Screening Tools ◽  
Current Status ◽  
Clinical Effects ◽  
Syncytial Virus

Viral pneumonia has been a serious threat to global health, especially now we have dramatic challenges such as the COVID-19 pandemic. Approximately six million cases of community-acquired pneumonia occur every year, and over 20% of which need hospital admission. Influenza virus, respiratory virus, and coronavirus are the noteworthy causative agents to be investigated based on recent clinical research. Currently, anaphylactic reaction and inflammation induced by antiviral immunity can be incriminated as causative factors for clinicopathological symptoms of viral pneumonia. In this article, we illustrate the structure and related infection mechanisms of these viruses and the current status of antiviral therapies. Owing to a set of antiviral regiments with unsatisfactory clinical effects resulting from side effects, genetic mutation, and growing incidence of resistance, much attention has been paid on medicinal plants as a natural source of antiviral agents. Previous research mainly referred to herbal medicines and plant extracts with curative effects on viral infection models of influenza virus, respiratory virus, and coronavirus. This review summarizes the results of antiviral activities of various medicinal plants and their isolated substances, exclusively focusing on natural products for the treatment of the three types of pathogens that elicit pneumonia. Furthermore, we have introduced several useful screening tools to develop antiviral lead compounds.

scholarly journals The Disappearance of Respiratory Viruses in Children during the COVID-19 Pandemic

2021 ◽  
Vol 18 (18) ◽  
pp. 9550
Author(s):  
Anna Chiara Vittucci ◽  
Livia Piccioni ◽  
Luana Coltella ◽  
Claudia Ciarlitto ◽  
Livia Antilici ◽  
...  
Keyword(s):  
Respiratory Virus ◽  
Respiratory Infections ◽  
Virus Transmission ◽  
Tertiary Hospital ◽  
Virus Infections ◽  
Epidemic Period ◽  
Syncytial Virus ◽  
Viral Respiratory Infections ◽  
Respiratory Virus Infections ◽  
The Impact

Background: Social distancing measures are used to reduce the spreading of COVID-19. The aim of this study was to assess the impact of local restrictions on the transmission of respiratory virus infections. Methods: we retrospectively analyzed the nasopharyngeal samples of all patients (0–18 years old) admitted with respiratory symptoms in a large Italian tertiary hospital during the last three seasons from 2018 to 2021. Results: A strong reduction in all viral respiratory infections was observed in the last season (2020–2021) compared to the two previous seasons (−79.69% and −80.66%, respectively). In particular, we found that during the epidemic period 2018–2019 and 2019–2020, the total number of Respiratory Syncytial Virus (RSV) cases was, respectively 726 and 689, while in the last season a total of five cases was detected. In the first months of 2018–2019 and 2019–2020, the total flu infections were 240 and 354, respectively, while in the last season we did not detect any influenza virus. As other viruses, the presence of Rhinovirus declined, but to a lesser extent: a total of 488 cases were assessed compared to the 1030 and 1165 cases of the two previous respective epidemic seasons. Conclusions: Public health interventions and distancing (including continuous use of face masks) settled to counter the pandemic spread of COVID-19 had a macroscopic impact on all respiratory virus transmission and related diseases, with a partial exception of Rhinovirus. The absence of viruses’ circulation could result in a lack of immunity and increased susceptibility to serious infections in the next seasons.

scholarly journals Comparison of xTAG Respiratory Virus Panel and Verigene Respiratory Virus Plus for Detecting Influenza Virus and Respiratory Syncytial Virus

2014 ◽  
Vol 29 (2) ◽  
pp. 116-121 ◽  
Author(s):  
Sang Mee Hwang ◽  
Mi Suk Lim ◽  
Minsuk Han ◽  
Yun Ji Hong ◽  
Taek Soo Kim ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Respiratory Syncytial Virus ◽  
Respiratory Virus ◽  
Syncytial Virus

scholarly journals Significant impact of nationwide SARS-CoV-2 lockdown measures on the circulation of other respiratory virus infections

2020 ◽  
Author(s):  
Monika Redlberger-Fritz ◽  
Michael Kundi ◽  
Stephan W Aberle ◽  
Elisabeth Puchhammer-Stöckl
Keyword(s):  
Respiratory Syncytial Virus ◽  
Respiratory Virus ◽  
Public Life ◽  
Virus Transmission ◽  
Human Metapneumovirus ◽  
Virus Infections ◽  
Virus Surveillance ◽  
Syncytial Virus ◽  
Respiratory Virus Infections ◽  
Short Time

Abstract Since the worldwide spread of SARS-CoV-2, different European countries reacted with temporarily nationwide lockdowns with the aim to limit the virus transmission in the population. Also Austria started a lockdown of public life in March. In this study we investigated whether the circulation of different respiratory virus infections in Austria, as assessed by using the established respiratory virus surveillance system, is affected by these measures as well and may reflect the success of the lockdown in limiting respiratory virus transmission. Sentinel data obtained for influenza virus, respiratory syncytial virus, human metapneumovirus and rhinovirus cases were analyzed and compared between the season 2019/ 2020 and the five previous seasons. We observed a rapid and statistically significant reduction of cumulative cases for all these viruses within short time after the lockdown in March 2020, compared to previous seasons (each p<0.001). Also, sentinel screening for SARS-CoV-2 infections was performed and a decrease of SARS-CoV-2 was seen after the lockdown. While for the seasonally occurring viruses as influenza, respiratory syncytial virus or human metapneumovirus the lockdown led to the end of the annual epidemics, a re-increase of rhinovirus infections was observed after liberalization of numerous lockdown measures. Our data provide evidence that occurrence of different respiratory virus infections reflect not only the efficiency of lockdown measures taken against SARS-CoV-2 but also the effects of their release on respiratory transmission.

scholarly journals Respiratory Virus Shedding in Exhaled Breath and Efficacy of Face Masks

2020 ◽  
Author(s):  
Nancy HL Leung ◽  
Daniel KW Chu ◽  
Eunice YC Shiu ◽  
Kwok-Hung Chan ◽  
James J McDevitt ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Respiratory Virus ◽  
Virus Transmission ◽  
Respiratory Illness ◽  
Source Control ◽  
Exhaled Breath ◽  
Virus Infections ◽  
Virus Shedding ◽  
Human Coronaviruses ◽  
Respiratory Droplets

Abstract There are few studies describing the presence of respiratory viruses in respiratory droplets and aerosols in the exhaled breath of infected persons, and the efficacy of facemasks as a source control to prevent respiratory virus transmission. Here, we recruited children and adults with acute respiratory illness and collected respiratory droplets and aerosols, with and without surgical facemasks. We identified human coronaviruses, influenza virus and rhinovirus from both respiratory droplets and aerosols. Surgical face masks reduced detection of coronavirus RNA in both respiratory droplets and aerosols, but only respiratory droplets and not aerosols for influenza virus RNA. Our results provide mechanistic evidence that surgical facemasks could prevent transmission of human coronavirus and influenza virus infections if worn by symptomatic individuals.Authors Donald K Milton and Benjamin J Cowling are joint senior authors.

scholarly journals Thapsigargin Is a Broad-Spectrum Inhibitor of Major Human Respiratory Viruses: Coronavirus, Respiratory Syncytial Virus and Influenza A Virus

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 234
Author(s):  
Sarah Al-Beltagi ◽  
Cristian Alexandru Preda ◽  
Leah V. Goulding ◽  
Joe James ◽  
Juan Pu ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Respiratory Syncytial Virus ◽  
Influenza A Virus ◽  
Broad Spectrum ◽  
Influenza A ◽  
Respiratory Viruses ◽  
Influenza Viruses ◽  
Virus Challenge ◽  
2009 H1n1 ◽  
Syncytial Virus

The long-term control strategy of SARS-CoV-2 and other major respiratory viruses needs to include antivirals to treat acute infections, in addition to the judicious use of effective vaccines. Whilst COVID-19 vaccines are being rolled out for mass vaccination, the modest number of antivirals in use or development for any disease bears testament to the challenges of antiviral development. We recently showed that non-cytotoxic levels of thapsigargin (TG), an inhibitor of the sarcoplasmic/endoplasmic reticulum (ER) Ca2+ ATPase pump, induces a potent host innate immune antiviral response that blocks influenza A virus replication. Here we show that TG is also highly effective in blocking the replication of respiratory syncytial virus (RSV), common cold coronavirus OC43, SARS-CoV-2 and influenza A virus in immortalized or primary human cells. TG’s antiviral performance was significantly better than remdesivir and ribavirin in their respective inhibition of OC43 and RSV. Notably, TG was just as inhibitory to coronaviruses (OC43 and SARS-CoV-2) and influenza viruses (USSR H1N1 and pdm 2009 H1N1) in separate infections as in co-infections. Post-infection oral gavage of acid-stable TG protected mice against a lethal influenza virus challenge. Together with its ability to inhibit the different viruses before or during active infection, and with an antiviral duration of at least 48 h post-TG exposure, we propose that TG (or its derivatives) is a promising broad-spectrum inhibitor against SARS-CoV-2, OC43, RSV and influenza virus.

scholarly journals The efficacy of live and inactivated vaccines of Hong Kong influenza virus in an industrial community: A report to the Medical Research Council Committee on Influenza and other respiratory virus vaccines

1973 ◽  
Vol 71 (4) ◽  
pp. 641-647 ◽  
Author(s):  
D. Hobson ◽  
F. A. Baker ◽  
R. L. Curry ◽  
A. S. Beare ◽  
P. M. O. Massey
Keyword(s):  
Influenza Virus ◽  
Hong Kong ◽  
Medical Research ◽  
Research Council ◽  
Respiratory Virus ◽  
Medical Research Council ◽  
Influenza Viruses ◽  
Protective Efficiency ◽  
Industrial Community ◽  
Inactivated Vaccines

Intranasal vaccines of inactivated or living attentuated A2/Hong Kong influenza viruses were compared for clinical acceptability, serological effects and protective efficiency against natural epidemic influenza in a large industrial and clerical population.

scholarly journals Droplets and aerosols: An artificial dichotomy in respiratory virus transmission

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Yannis Drossinos ◽  
Thomas P. Weber ◽  
Nikolaos I. Stilianakis
Keyword(s):  
Respiratory Virus ◽  
Virus Transmission
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