Biological agents virulence

Infectious disease can be produced by any pathogen able to be aerosolized and subsequently transported into the respiratory tract at the appropriate concentration. Some common diseases which may result from airborne transmission in indoor environments are listed in Table 5. The rate of infection within any environment is a function of the viability and virulence of the pathogen, its concentration in the inhaled air, and characteristics, such as droplet size, of the carrier aerosol within which it is contained. Some biological agents produce disease at low concentrations, while others must accumulate to a higher level. Furthermore, individual susceptibility to infection depends on a number of factors, such as age and health, as well as concomitant exposure to chemical pollutants. 

Physical/chemical containment takes into account the toxicity, virulence, and potential for change and evolution of biological agents, and uses barriers, closed systems, and physical destruction by irradiation, chemicals and temperature to prevent the escape of viable agents. 

Biological agents vary in their virulence and risk of transmission. Virulence refers to an organism s ability to cause disease and relies upon several factors ... 

Puccinia chondrillina Bubak. Syd., a rust fungus from Europe, determined to be a virulent, host-specific, and safe biocontrol agent, was introduced into Australia in 1971 to control Chondrilla iuncea L., rush skeletonweed (27. 28). In 1976 it was introduced into California and later into other western states in the U.S. (29-31). The biology of this pathogen, weed control success, and assessment of the economic impact of controlling rush skeletonweed in Australia have been reviewed (23, 27-31). In summary, the... 

Pertussis toxin, produced by virulent strains of B. pertussis, the etiological agent of whooping cough, is a classical A-B type toxin comprised of an A subunit that possesses ADP-ribosyltransferase activity and is responsible for most of the biological effects of the toxin, and a B subunit with affinity for carbohydrates. The B subunit of the pertussis toxin is a pentamer composed of four different subunits (S2-S5). The toxin acts as a hemagglutinin and exhibits dual carbohydrate specificity, due to... 

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