What is infectious disease?
An infectious disease is a
disease that damages or injures the host that results from the presence
of one or more pathogenic microbial agents
including viruses, bacteria, fungi, protozoa, multi cellular parasites,
and aberrant proteins known as prions
also there is a contagious disease is an infectious disease that is
capable of being transmitted from one person or species to another.
What are kinds of pathogens?
Classified as either Primary pathogens or as
Opportunistic pathogens according to the status of host defenses
Primary pathogens cause disease as a result of their presence or
activity within the normal, healthy host, and their intrinsic virulence
Opportunistic pathogens Organisms which cause an infectious disease in a
host with depressed resistance
Opportunistic disease may be caused by microbes that are ordinarily in
contact with the host, such as bacteria or fungi in the gastrointestinal
or the upper respiratory tract
How does transmission of infectious disease occur?
||Sexually transmitted diseases
||Some infectious agents
|and meningitis are commonly acquired by
contact with aerosolized droplets, spread by sneezing, coughing & talking
||are often acquired by ingesting
contaminated food and water
||are acquired through contact with bodily fluids, generally as a result of sexual activity
||Some infectious agents may be spread as a result of contact with a
contaminated, inanimate object, such as a coin passed from one person to
another, while other diseases penetrate the skin directly
||Transmission of infectious diseases may also involve a "vector".
What does vector mean?
Vectors may be mechanical or biological.
|picks up infectious agent on the outside
of its body and transmits it in a passive manner. E.g. Housefly
||harbor pathogens within their bodies and deliver
pathogens to new hosts in an active manner, usually a bite are often
responsible for serious blood-borne diseases, such as malaria, viral
encephalitis, such as mosquitoes, ticks, fleas and lice.