Download Infectious & Non-Infectious Diseases

 Infectious diseases are caused by
pathogenic microorganisms, such as
bacteria, viruses, parasites or fungi; the
diseases can be spread, directly or
indirectly, from one person to another.
Droplet Contact
Also known as the respiratory route, it is a typical
mode of transmission among many infectious
agents.
 If an infected person coughs or sneezes on
another person the microorganismsmay enter the
body through the nose, mouth or eye surfaces.
 Diseases that are commonly spread by coughing or
sneezing include (at least):
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Bacterial Meningitis
Chickenpox
Common cold
Influenza
 Mumps
 Strep throat
 Tuberculosis
 Measles
 Rubella
 Whooping cough
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Direct contact is rare for this route, for humans at least.
More common are the indirect routes
 When food or water become contaminated
 (by people not washing their hands before preparing food, or untreated
sewage being released into a drinking water supply) and the people who
eat and drink them become infected.
 Happens in less developed countries
Examples of Oral Transmission
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Cholera
Hepatitis A
Polio
Rotavirus
Salmonella
This refers to any disease that can be caught during sexual activity with
another person, including vaginal or anal sex or (less commonly) through oral
sex. Transmission is either directly between surfaces in contact during
intercourse (the usual route for bacterial infections and those infections causing
sores) or from secretions (semen or the fluid secreted by a female) which carry
infectious agents that get into the partner's blood stream through tiny tears in
the penis, vagina or rectum (this is a more usual route for viruses).
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Some diseases transmissible by the sexual route include:
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HIV/AIDS
Chlamydia
Genital warts
Gonorrhea
Hepatitis B
Syphilis
Herpes
Diseases that can be transmitted by direct contact are called contagious . These
diseases can also be transmitted by sharing a towel (where the towel is rubbed
vigorously on both bodies) or items of clothing in close contact with the body (socks,
for example) if they are not washed thoroughly between uses.
 For this reason, contagious diseases often break out in schools, where towels are
shared and personal items of clothing accidentally swapped in the changing rooms.
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Some diseases that are transmissible by direct contact
include:
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Athlete's foot
Impetigo
Syphilis (on rare occasions, if an uninfected person touches a chancre)
Warts
 A vector is an organism that does
not cause disease itself but that
transmits infection by conveying
pathogens from one host to
another.
 Examples include mosquitoes,
deer ticks, animal bites, etc.
Non-infectious diseases (also called Noncommunicable diseases ) are those diseases that are
not caused by a pathogen and cannot be shared from
one person to another.
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Non-infectious diseases may be caused by either the
environment, nutritional deficiencies, lifestyle choices,
or genetic inheritances. Unlike infectious diseases, noninfectious diseases are not communicable or
contagious, although some kinds can be passed down
genetically to the children of a carrier.
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 Historically, infectious diseases were the main
cause of death in the world and, indeed, in
some developing regions this may still be the
case. With the development of antibiotics and
vaccination programs, infectious disease is no
longer the leading cause of death in the western
world. Non-infectious disease is now
responsible for the leading causes of death in
both developed and some developing countries.
 Causes of non-infectious disease are
categorized into genetically inherited
diseases and environmental diseases.
Non-infectious diseases that are not
genetic disorders are environmental
diseases, although many diseases are
affected by both genetic and
environmental factors.
Environmental disease is a very broad category. It includes
avoidable and unavoidable conditions caused by external
factors, such as sunlight, food, pollution, and lifestyle choices.
The diseases of affluence are non-infectious diseases with
environmental causes. Examples include:
 Many types of cardiovascular disease
 Chronic obstructive pulmonary disease caused by smoking
tobacco
 Type 2 Diabetes
 Malnutrition caused by too little food, or eating the wrong
kinds of food (e.g. scurvy from lack of Vitamin C)
 Skin cancer caused by radiation from the sun
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