Kategorie: Uncategorised
Zugriffe: 519

Es stellen sich Fragen, auf die es noch keine gesicherten oder widersprüchliche Antworten gibt:


18. Mai 2020: Sollten geschlossene Kinderrutschen (Rutschröhren) aufgrund möglicher Tröpfchen- oder Aerosol-Übertragungen weiterhin gesperrt bleiben?


16. Mai 2020: Aerosol - Können die im Nasensekret enthalten Polysacharide um ein Corona-Virus ein stabiles Korset bilden, so dass dieses auch im "quasi-trockenen" Zustand funktional überdauern kann?

virulence 4:8, 847–858; November 15, 2013; © 2013 landes Bioscience

Particle size and pathogenicity
in the respiratory tract
Richard James Thomas
Defence Science and Technology laboratories (Dstl); Salisbury, wiltshire, uK

The situation in relation to deposition is more complex due
to evaporation. Atmospheric relative humidity (RH) and temperature are generally lower than that of the body. Once the particles are in the atmosphere evaporation occurs at rates according
to their original size and composition of the particle to reach
equilibrium with atmospheric conditions. Hence, the aerosol

produced is dynamic, changing with distance from the initial
point of generation. Particles produced from sneezing and coughing will contain varying amounts of saliva and mucus comprising
inorganic and organic ions plus glycoproteins.
33,38 Many aerosol
transmission modeling studies are based on assumptions e.g.,
settling velocities and/or evaporation parameters of pure water
droplets within a vacuum and droplet distributions from healthy
21,22 It is probable that irrespective of composition due
to the small droplet sizes originating from a cough or sneeze that
evaporation will be rapid unless the presence of solutes greatly
retards evaporation, for example, a 5
μm water droplet will
evaporate within 0.8 s in 97% RH.
21 However, extrapolating
to natural situations where the droplet composition will be very
different and turbulence will exert a large effect on how rapidly
particles deposit requires care. Indeed, one recent study demonstrated that infected individuals generated larger aerosol particles
than healthy counterparts.
41 This could be attributable to differences in mucus (composition, quantity, and viscosity) produced
during infection affecting evaporation and the location of the
33,42 The closer an individual is situated to an aerosol
source then the greater the likelihood of large particles being
inhaled prior to complete evaporation.

Source: R. J. Thomas, Particle size and pathogenicity in the respiratory tract.Virulence4, 847858 (2013).


27. April 2020: Maskenpflicht - Gibt es einen Zusammenhang zwischen dem Tragen einer einfachen Stoff- oder OP-Maske (Mund-Nasen-Schutz) und dem "Schweregrad" eines Covid-19-Krankheitsverlauf?