H.
BTEC L3 EXTENDED DIPLOMA IN APPLIED SCIENCE
Unit 12: Diseases and Infection
Assignment 12A: Infectious and non-infectious disease
Disease and infection
The term disease relates to a condition that negatively impacts the
functioning/structure in an organism such as in humans, animals, and plants (1).
In comparison, infection refers to a condition where disease-causing
bacteria/viruses invade the body resulting in a disease (2).
In this assignment, different types of disease, infectious and non-infectious, are
researched to discuss the causes and the relationship between disease
progression and the effects on human health. From the research carried out, a
set of different case studies are produced to assess the physiological effects of
diseases and the progression over time.
Infectious agents
There are different types of infectious agents that lead to disease in humans:
- Bacteria
- Viruses
- Parasites
- Fungus
- Protozoa
These infectious agents are also referred to as pathogens- a microorganism that
causes disease. Each of these pathogens are responsible for causing diseases
and a specific named example will be explained for each pathogen including the
factors that lead to this specific disease. In addition to this, the features and the
life cycle of each pathogen will be explored along with the specific biological
mechanisms.
Bacteria
Bacteria are prokaryotic single-celled microorganisms that contain a nucleoid,
plasmid, cytoplasm, cell membrane, cell wall, capsule, ribosome, pilus and
flagellum (some may not contain a flagellum). They are classed as infectious
agents since they are microorganisms that cause disease, for example,
meningitis is caused by many types of bacteria including (3):
- E.coli
- Group B strep
- Listeria monocytogenes
- Haemophilus influenzae
- Neisseria meningitidis
- Streptococcus pneumoniae
There are factors that lead to the development of meningitis such as being
unvaccinated, travelling, dealing with animals, going to school, living in a shared
living space, having a weak immune system along with being diagnosed with an
STD (7). There are many vaccinations for meningitis that individuals can take (8):
1
, H.
BTEC L3 EXTENDED DIPLOMA IN APPLIED SCIENCE
Unit 12: Diseases and Infection
- Meningitis B vaccine
- 6-in-1 vaccine
- Pneumococcal vaccine
- Hib/MenC vaccine
- MMR vaccine
- Meningitis ACWY vaccine
These vaccinations make individuals less susceptible to meningitis and decrease
the development of meningitis (7). Individuals who are unvaccinated will have a
higher risk of developing meningitis and can therefore spread it to other
individuals. This disease can impact any individual however it has been found
that babies, young children, and adults are commonly affected by meningitis.
Travelling is a developmental factor of meningitis since exposure to uncommon
bacteria that you have not been previously exposed to increases if an individual
travels to an area where the bacteria is more common (7). This results in a
higher risk of developing meningitis as an individual can come across the other
types of bacteria that cause meningitis (as listed before). Another developmental
factor for meningitis is dealing with animals as meningitis can be zoonotic- this
refers to the spread from animal to human (7). Animals could have the bacteria
that causes meningitis and by dealing with animals, this increases the likelihood
of developing meningitis as the bacteria can travel from animals to humans
(zoonotic). Going to school also is a factor in developing meningitis as younger
children are in close distance with other children and teachers (7). This, overall,
increases the likelihood of developing meningitis for both the children and
teachers. Moreover, the sharing of equipment and other items at school can
further increase the likelihood of developing meningitis by spreading infection.
Living in a shared space can also lead to the development of meningitis since
areas are shared so infection can spread easier from person to person as they all
are in close distance of each other (7). By having a weak immune system,
individuals are more susceptible to developing meningitis since their immune
system will find it harder to fight bacteria that cause meningitis resulting in the
development of meningitis (7). Additionally, if individuals are diagnosed with an
STD, e.g. syphilis, it could potentially lead to the development of meningitis as it
can affect the immune system, causing it to be more susceptible to bacteria
causing meningitis (7).
Bacteria can be classified into different types: gram-positive bacteria and gram-
negative bacteria (9). This classification is based on the technique, Gram
staining, which is used to identify different bacteria. For gram-positive bacteria,
the stain is purple as they have a thick cell wall made of peptidoglycan, causing
the stain to be retained within the cell walls (9) (10). However, for gram-negative
bacteria, the stain is red since they have a thin cell wall made of peptidoglycan
that cannot retain all the components of the stain, only the safranin- this causes
the stain to appear red on gram-negative bacteria (9) (10). In terms of
meningitis, gram-negative bacteria are responsible for causing this illness since
when performing the Gram staining technique, the bacteria turn red/pink (78),
showing it is gram-negative.
These different types of bacteria can be further classified into shapes (9):
2
BTEC L3 EXTENDED DIPLOMA IN APPLIED SCIENCE
Unit 12: Diseases and Infection
Assignment 12A: Infectious and non-infectious disease
Disease and infection
The term disease relates to a condition that negatively impacts the
functioning/structure in an organism such as in humans, animals, and plants (1).
In comparison, infection refers to a condition where disease-causing
bacteria/viruses invade the body resulting in a disease (2).
In this assignment, different types of disease, infectious and non-infectious, are
researched to discuss the causes and the relationship between disease
progression and the effects on human health. From the research carried out, a
set of different case studies are produced to assess the physiological effects of
diseases and the progression over time.
Infectious agents
There are different types of infectious agents that lead to disease in humans:
- Bacteria
- Viruses
- Parasites
- Fungus
- Protozoa
These infectious agents are also referred to as pathogens- a microorganism that
causes disease. Each of these pathogens are responsible for causing diseases
and a specific named example will be explained for each pathogen including the
factors that lead to this specific disease. In addition to this, the features and the
life cycle of each pathogen will be explored along with the specific biological
mechanisms.
Bacteria
Bacteria are prokaryotic single-celled microorganisms that contain a nucleoid,
plasmid, cytoplasm, cell membrane, cell wall, capsule, ribosome, pilus and
flagellum (some may not contain a flagellum). They are classed as infectious
agents since they are microorganisms that cause disease, for example,
meningitis is caused by many types of bacteria including (3):
- E.coli
- Group B strep
- Listeria monocytogenes
- Haemophilus influenzae
- Neisseria meningitidis
- Streptococcus pneumoniae
There are factors that lead to the development of meningitis such as being
unvaccinated, travelling, dealing with animals, going to school, living in a shared
living space, having a weak immune system along with being diagnosed with an
STD (7). There are many vaccinations for meningitis that individuals can take (8):
1
, H.
BTEC L3 EXTENDED DIPLOMA IN APPLIED SCIENCE
Unit 12: Diseases and Infection
- Meningitis B vaccine
- 6-in-1 vaccine
- Pneumococcal vaccine
- Hib/MenC vaccine
- MMR vaccine
- Meningitis ACWY vaccine
These vaccinations make individuals less susceptible to meningitis and decrease
the development of meningitis (7). Individuals who are unvaccinated will have a
higher risk of developing meningitis and can therefore spread it to other
individuals. This disease can impact any individual however it has been found
that babies, young children, and adults are commonly affected by meningitis.
Travelling is a developmental factor of meningitis since exposure to uncommon
bacteria that you have not been previously exposed to increases if an individual
travels to an area where the bacteria is more common (7). This results in a
higher risk of developing meningitis as an individual can come across the other
types of bacteria that cause meningitis (as listed before). Another developmental
factor for meningitis is dealing with animals as meningitis can be zoonotic- this
refers to the spread from animal to human (7). Animals could have the bacteria
that causes meningitis and by dealing with animals, this increases the likelihood
of developing meningitis as the bacteria can travel from animals to humans
(zoonotic). Going to school also is a factor in developing meningitis as younger
children are in close distance with other children and teachers (7). This, overall,
increases the likelihood of developing meningitis for both the children and
teachers. Moreover, the sharing of equipment and other items at school can
further increase the likelihood of developing meningitis by spreading infection.
Living in a shared space can also lead to the development of meningitis since
areas are shared so infection can spread easier from person to person as they all
are in close distance of each other (7). By having a weak immune system,
individuals are more susceptible to developing meningitis since their immune
system will find it harder to fight bacteria that cause meningitis resulting in the
development of meningitis (7). Additionally, if individuals are diagnosed with an
STD, e.g. syphilis, it could potentially lead to the development of meningitis as it
can affect the immune system, causing it to be more susceptible to bacteria
causing meningitis (7).
Bacteria can be classified into different types: gram-positive bacteria and gram-
negative bacteria (9). This classification is based on the technique, Gram
staining, which is used to identify different bacteria. For gram-positive bacteria,
the stain is purple as they have a thick cell wall made of peptidoglycan, causing
the stain to be retained within the cell walls (9) (10). However, for gram-negative
bacteria, the stain is red since they have a thin cell wall made of peptidoglycan
that cannot retain all the components of the stain, only the safranin- this causes
the stain to appear red on gram-negative bacteria (9) (10). In terms of
meningitis, gram-negative bacteria are responsible for causing this illness since
when performing the Gram staining technique, the bacteria turn red/pink (78),
showing it is gram-negative.
These different types of bacteria can be further classified into shapes (9):
2
