Health and Wellness 2
 We will get a chance to study…
 What is disease
 What are the types of disease
 What is an infection?
 How do we get infected?
 How does our body protect itself from infection?
 What are some diseases that we could come in contact with and
how do we prevent and recognize each disease.
 i.e. hepatitis, tetanus, polio, chicken pox, measles, flu, the cold, mono
and others.
What is health? What is disease?
Health is the state of physical, mental and social
well-being. It is not just being free from disease.
A disease is a disorder that affects an
organism's body, organs, tissues or cells.
Primary disease vs Secondary disease
Primary is a disease that is not associated with or
helped along by a previous injury or disease,
meaning this is a disease that just occurred on its
own and that's it. For example, if you were happy
and healthy and got infected with the flu, that would
be called a primary disease.
Secondary disease is a disease that results after and
as a consequence of a primary disease.
Local vs Systemic
Local disease is a disease that is confined to a
certain area or system of the body. For example,
if you have something like an abscess on your
leg, that's a manifestation of a local disease
process. Or, if you have a broken wrist, that's also
a manifestation of a local problem.
Systemic disease is a disease that affects the body as
a whole. For example, the flu is a systemic disease
since it causes you aches and pains all over your
body. Diabetes is a systemic disease since it affects
multiple organ systems and functions all over the
place
Congenital disorder is a medical condition that is
present at the time of birth
(majority are related to heart).
Inherited by a child from its parents (not in all cases)
Acquired diseases can occur during the lifetime
of an individual and also are not present from
birth. It can be developed after birth
Acquired in some other forms or the other
Types of Acquired Disease
1. Communicable disease
2. Non communicable disease
Communicable disease are caused
by pathogens and can be
transferred from one person to
another, or from one organism to
another,
ex in humans, these include
measles, food poisoning and
malaria
Pathogens – microorganisms that’s causes the
disease (agents of disease)
Direct – physical contact or through droplets
Indirect – spread through ;
 Waterborne - contaminated water,
 Airborne – aerosol transmission, droplet
nuclei
 Foodborne – contaminated food or beverages
 Fomite borne – infected inanimate object
 Vector borne – flies & insects
Viruses
Bacteria
Fungi
Protozoa
Parasitic Worms
Smallest pathogen
Can only replicate on living host
Cannot reproduce on their own – takes over body cell and tells it to
produce new viral particles… then released to other cells. It is
truly dependent to host to thrive and multiply
Difficult to fight viruses…why?
https://www.nbcnews.com/science/science-news/why-areviruses-hard-kill-virologists-explain-why-these-tiny-n1202046
…because some drugs will harm the host and the virus.
Some examples:
Influenza (flu) viruses
Hepatitis viruses (liver)
Retroviruses (backwards sequence) – HIV
AIDS
What is DNA? –
 “Blueprint” of the cell
 Contains the genetic code
What is RNA? –
 Similar structure to DNA
 Contains sugar (ribose)
 Single stranded
Coronavirus is an RNA-based virus with
unique repair mechanisms, or proofreading
proteins that other RNA-viruses lack. Its
structure is hardy and rugged; if a drug
tries to damage the cell—or kill it—it has
the ability to repair itself.”
 Simple one-celled organisms
 Larger than virus. Often shaped as rods, spheres or spirals
 “second wave of attack” they love to attack after a virus has
attacked first.
 Examples = Tuberculosis, tetanus, gonorrhea, Meningitis, strep
throat
 Antibiotics can kill the bacteria without harming the cells
 Downsides = side effects, allergic reactions, frequent expose to
bacteria and antibiotic use can cause the bacteria to build up
resistance to the antibiotics = loss of effectiveness
 Single or multi-celled organisms
 Made of thread-like fibers and reproductive spores.
Microorganism that include yeast, mushrooms and mold.
 Fungi release enzymes that digest cells – most likely on hair-
covered areas of the body
 Treatment = antifungal drugs
 Examples – athletes foot
 Single-celled
 They live in a wide variety of moist habitats including fresh water,
marine environment and the soil.
 They are able to multiply in humans, which contributes to their
survival and also permits serious infections to develop from just a
single organism.
 Common examples = malaria, giardiasis (contaminated drinking
water from animal and/or human feces)
 Treatment = symptom relief treatments and protozoa specific
treatments
 An organisms that derive a benefit from their host without giving
one back.
 Type of pathogens that hurts us. Some attack specific tissues or
organs. These include ectoparasites like mosquitoes, fleas, lice and
ticks. “ecto”means something on the outside., so they live outside
the host.
 Another example is “endo parasites”, where endo refers to
something within. It infest our body from within such tapeworms,
roundworms, flukes and much more. These endoparasites are often
caught from eating uncooked meat or contaminated beef, pork and
fish
 Treatment = specific medication
Infection is a complex
process triggered by
various pathogens
(disease causing
organisms)
Host vs. Agents in an
environment
i.e. I get the flu. I am the
host and the flu virus is
an agent in an
environment
Epidemiology is a process used in the
medical field to study diseases.
 Pathogen  Host (your body)  Process of
infection begins  Incubation period 
Infection period  Recovery
 Incubation period = could be days, weeks or
even years
 Infection period = variety of symptoms
 Recovery = length depends on type of
pathogen
Diseases of this kind can't be spread
from person to person. Genetic
mutations or environmental factors may
cause them. Cancer and heart disease
are examples.
Risk factor
1. Age
2. Gender
3. Genetics
4. Pollution
5. Unhealthy behaviors
6.Physical inactivity
7. Hypertension
8. Obesity
9. Viruses