what is droplets infection ?????
Answers
Answer:
the term “droplet”, as used in this context, consists mostly of water with various inclusions, depending on how it is generated.
Naturally produced droplets from humans (e.g. droplets produced by breathing, talking, sneezing, coughing) include various cells types (e.g. epithelial cells and cells of the immune system), physiological electrolytes contained in mucous and saliva (e.g. Na+, K+, Cl-), as well as, potentially, various infectious agents (e.g. bacteria, fungi and viruses).
With artificially generated droplets in a health-care setting (e.g. suction of respiratory tract), the main constituent will also be sterile water, with various electrolytes (e.g. “normal” or physiological saline, including Na+, Cl-) and often the molecules of a drug (e.g. salbutamol for asthmatics).
Both these naturally and artificially generated droplets are likely to vary in both size and content. Droplets >5 μm tend to remain trapped in the upper respiratory tract (oropharynx — nose and throat areas), whereas droplets ≤5 μm have the potential to be inhaled into the lower respiratory tract (the bronchi and alveoli in the lungs).
Currently, the term droplet is often taken to refer to droplets >5 μm in diameter that fall rapidly to the ground under gravity, and therefore are transmitted only over a limited distance (e.g. ≤1 m). In contrast, the term droplet nuclei refers to droplets ≤5 μm in diameter that can remain suspended in air for significant periods of time, allowing them to be transmitted over distances >1 m (Stetzenbach, Buttner & Cruz, 2004; Wong & Leung, 2004). Other studies suggest slightly different definitions, with ranges for “large” droplets, “small” droplets and droplet nuclei being >60 μm in diameter, ≤60 μm in diameter and <10 μm in diameter, respectively (Tang et al., 2006; Xie et al., 2007). The concept is that the naturally and artificially produced aerosols will contain a range of droplet sizes, whose motion will depend significantly on various environmental factors, such as gravity, the direction and strength of local airflows, temperature and relative humidity (which will affect both the size and mass of the droplet due to evaporation).
There have been several studies on the number and size of droplets of saliva and other secretions from respiratory activities (Jennison, 1942; Duguid, 1945; Hamburger & Roberston, 1946; Loudon & Roberts, 1967; Papineni & Rosenthal, 1997; Fennelly et al., 2004) and excellent reviews have been written (Nicas, Nazaroff & Hubbard, 2005; Morawska, 2006). These studies and reviews note that the size of droplet nuclei due to sneezing, coughing and talking is likely to be a function of the generation process and the environmental conditions. The actual size distribution of droplets also depends on parameters, such as the exhaled air velocity, the viscosity of the fluid and the flow path (i.e. through the nose, the mouth or both) (Barker, Stevens & Bloomfield, 2001). There is also a great individual variability (Papineni & Rosenthal, 1997; Fennelly et al., 2004).
Humans can produce respiratory aerosols (droplets) by several means, including breathing, talking, coughing (Figure C.1, A), sneezing (Figure C.1, B) and even singing (Wong, 2003; Toth et al., 2004).
Figure C.1. (A) Schlieren image (visualization using light refraction caused by differences in air density) of a human cough, and (B) flash photo of a human sneeze.
Figure C.1
(A) Schlieren image (visualization using light refraction caused by differences in air density) of a human cough, and (B) flash photo of a human sneeze. Source: Photographs reproduced with the kind permissions of (A) Prof Gary S Settles, Department of (more...)
Answer:
infection transmitted by airborne droplets of saliva or sputum containing infectious organisms.
Explanation:
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