NOSOCOMIAL INFECTIONS
(24)� Biological vector
(b) See Figure 15.11,
Modes of disease transmission
(c) ["modes of transmission" infectious disease (Google Search)] [index]
(19) Horizontal transmission
(a) Transmission of a pathogen can be either horizontal or vertical
(b) Horizontal means transmission between individuals specifically who are not related as a parent is to its offspring
(c) [horizontal transmission (Google Search)] [index]
(20) Vertical transmission
(a) Vertical transmission occurs from parent to offspring, e.g., in utero, during passage down the birth canal, or in breast milk
(b) Typically pathogens that have evolved for vertical transmission cannot be as virulent as those that have evolved for horizontal transfer since the recipient of the transfer must survive until reproductive maturity to pass on the pathogen
(c) However, note that not all (nor even most) pathogens that may be transmitted vertically have evolved for that mode of transmission (so, just as hybridomas and monoclonal antibodies typically are not made by employing recombinant DNA technology, don't leave this discussion thinking that all pathogens that may be passed from parent to offspring are harmless--most are instead just in the wrong place at the wrong time so far as the poor baby is concerned)
(d) [vertical transmission (Google Search)] [index]
(21)
Contact transmission
(a) Contact transmission requires either the direct or indirect contact with a reservoir of infection
(b) ["contact transmission" and disease (Google Search)] [index]
(22)
Direct contact transmission
(a) Direct contact transmission requires direct contact between individuals
(b) [direct contact transmission (Google Search)] [index]
(23)
Direct fecal-oral transmission
(a) Direct fecal-oral transmission is an example of direct contact transmission where inappropriate hygiene (or kinky sexual practices) result in the direct contact between an individual and another individual's feces
(b) Fecal-oral contact can also occur via indirect routes as discussed below
(c) Fecal-oral contact, direct or not, is how pathogens with oral portals of entry and fecal portals of exit (many gastrointestinal diseases) get passed from individual to individual
(d) [direct "fecal-oral", fecal-oral (Google Search)] [index]
(24)
Indirect contact transmission
(a) Indirect contact transmission does not involve direct contact between individuals
(b) Instead, contact is made between a healthy individual and the disembodied body fluid of a carrier (or diseased individual)
(c) [indirect contact transmission (Google Search)] [index] Indirect contact transmission
(a) Indirect contact transmission does not involve direct contact between individuals
(b) Instead, contact is made between a healthy individual and the disembodied body fluid of a carrier (or diseased individual)
(c) [indirect contact transmission (Google Search)] [index]
(25) Fomites
(a) Indirect contact transmission typically occurs via fomites which are inanimate objects upon which a pathogen has been deposited
(b) Indirect contact transmission occurs via contact between a healthy individual and a pathogen-carrying fomite
(c) E.g., bed sheets, eating utensils, etc., just about any inanimate object a person can come into contact with can serve as a fomite, though some fomites serve as less hostile environments for the pathogen than others
(d) Note that fomites are not vehicles of transmission and that vehicles of transmission are not fomites
(e) [fomites (Google Search)] [CDC hospital infections program: laundry] [index]
http://mansfield.osu.edu/~sabedon/bl...t_transmission
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