Unit 12: Diseases and Infection
B: Examine the transmission of infectious diseases and how this can be prevented
- P3: Explain how infectious diseases can be transmitted
Diseases brought on by harmful organisms like bacteria, viruses, fungi, and parasites are known as infectious
diseases. There are several ways that these pathogens can spread, and each one presents a different difficulty
in preventing the disease's spread. Preventing outbreaks and safeguarding public health require an
understanding of how infectious diseases spread. The various modes of transmission: air, water, food, physical
contact, vectors, and bodily fluids will be discussed in this section along with examples of diseases linked to
each method. We'll also talk about ways to lower the risk of transmission through prevention.
Airborne Transmission: Tiny droplets released when an infected person coughs, sneezes, or even speaks can
spread airborne diseases. These droplets have the potential to stay in the air and infect people if they are
inhaled.
For instance, tuberculosis (TB). The bacterial infection known as tuberculosis (TB) mainly affects the lungs.
When an infected person coughs or sneezes, the bacteria-containing droplets are released into the air, which is
how it spreads. It is possible to get TB without getting sick or spreading it to other people. Worldwide, 1.4
billion people suffer from tuberculosis. The majority are not ill. Globally, about 10 million people suffer from
active TB. The disease is most likely to strike those with compromised immune systems. After exposure,
symptoms may manifest within a few days. Some people don't activate for months or years. The lungs are
attacked by bacteria that grow quickly when the disease is active. It can travel to other organs, bones, or skin
through your lymph nodes and bloodstream.
Prevention: People should keep proper ventilation in crowded areas, cover their mouths when coughing or
sneezing, and wear protective face masks when needed to stop the spread of the disease through the air.
Although some TB strains are resistant to medications, there are medications that can treat and cure TB. Drug
resistance and symptom recurrence may result from not finishing the prescribed course of treatment.
https://www.facebook.com/Drugscom (2019). Tuberculosis. [online] Drugs.com. Available at:
https://www.drugs.com/health-guide/tuberculosis.html.
Mallick, A. (2021). A Survey on Face Masks: An Indispensable Textile Material in the Covid Times | Textile
Magazine, Textile News, Apparel News, Fashion News. [online] Textilevaluechain.in. Available at:
https://textilevaluechain.in/in-depth-analysis/articles/a-survey-on-face-masks-an-indispensable-textile-
material-in-the-covid-times
,Waterborne illnesses can arise from ingestion (eating) or contact with pathogens present in contaminated
water. This can be brought on by bathing in contaminated water, drinking contaminated water, or eating food
that has been cleaned with contaminated water. Waterborne illness is still a major issue in many parts of the
world. According to estimates from the World Health Organisation (WHO), over 500,000 deaths annually are
caused by drinking water that's contaminated.
For instance, the bacteria that causes cholera, Vibrio cholerae, is spread by tainted water from human waste.
Dehydration and severe diarrhoea are the results.
Waterborne illnesses can be avoided by installing water filtration systems, ensuring that everyone has access
to safe, clean drinking water, and practising good sanitation and hygiene.
Premiumtimesng.com. (2022). Available at: https://www.premiumtimesng.com/news/top-news/559429-ncdc-
calls-for-improved-water-sanitation-as-cholera-kills-233-in-2022.html?tztc=1.
GetDoc. (2017). What Is Cholera? | GetDoc Says. [online] Available at: https://www.getdoc.com/what-is-
cholera/.
Food Transmission: When food gets contaminated with pathogens, usually as a result of incorrect handling,
cooking, or storage, foodborne illnesses can be made. Any stage of the food production chain is vulnerable to
contamination. When bacteria, viruses, parasites, or chemicals enter the body through contaminated food,
they can cause foodborne illnesses, which are typically toxic or infectious. Serious poisoning or long-term
illnesses like cancer can result from chemical contamination. Many foodborne infections can result in death or
permanent disability.
Salmonella, for instance. Salmonella is usually found in raw meats, eggs, and occasionally vegetables.
Consuming contaminated or undercooked food can lead to infection.
Prevention: Hand washing before handling food, cooking meat to the right temperature, and properly storing
food to prevent cross-contamination are all important ways to lower the risk.
Limited, A. (n.d.). A collection Salmonella bacteria zoomed out surface cutting board raw chicken. Salmonella is
genus rod-shaped Gram-negative Stock Photo - Alamy. [online] www.alamy.com. Available at:
, https://www.alamy.com/stock-photo-a-collection-salmonella-bacteria-zoomed-out-surface-cutting-board-
52099555.html.
Physical Contact Transmission: Diseases that are spread through physical contact can spread when an infected
person comes into contact with another person or when people come into contact with contaminated objects
or surfaces. This may occur before they become aware of the illness. This is how gastrointestinal infections and
sexually transmitted diseases (STDs) are spread. Additionally, infectious diseases can be passed from pregnant
women to their foetuses through the placenta. During childbirth, some sexually transmitted diseases, such as
gonorrhoea, can be transferred from the gestational parent to the infant.
For instance, chickenpox. The varicella-zoster virus, which causes chickenpox, can be transferred by touching
contaminated objects or by direct skin-to-skin contact with an individual who has an active rash.
Prevention: The spread of diseases through physical contact can be stopped by avoiding close contact with
infected people, washing your hands frequently, and disinfecting surfaces.
Castaño, N., Cordts, S.C., Kurosu Jalil, M., Zhang, K.S., Koppaka, S., Bick, A.D., Paul, R. and Tang, S.K.Y. (2021).
Fomite Transmission, Physicochemical Origin of Virus–Surface Interactions, and Disinfection Strategies for
Enveloped Viruses with Applications to SARS-CoV-2. ACS Omega, 6(10), pp.6509–6527.
doi:https://doi.org/10.1021/acsomega.0c06335.
Barkley, S. (2020). Chickenpox: Symptoms, Causes, Treatment, and Prevention. [online] Power of Positivity:
Positive Thinking & Attitude. Available at: https://www.powerofpositivity.com/chickenpox/
Vectors are organisms that carry and transfer pathogens from one host to another, which is how some
diseases are spread. The pathogen is often spread by vectors, who bite or eat infected humans or animals.
Human illnesses brought on by bacteria, viruses, and parasites that are spread by vectors are known as vector-
borne diseases. Diseases like malaria, dengue, schistosomiasis, human African trypanosomiasis, leishmaniasis,
Chagas disease, yellow fever, Japanese encephalitis, and onchocerciasis cause over 700,000 deaths annually.
For instance, malaria. When an infected female Anopheles mosquito bites a human, the parasite Plasmodium
causes malaria. The parasite damages red blood cells and the liver after entering the bloodstream.
Preventing mosquito bites can be done by sleeping under mosquito nets, applying insect repellent, and getting
rid of standing water in which mosquitoes breed.
B: Examine the transmission of infectious diseases and how this can be prevented
- P3: Explain how infectious diseases can be transmitted
Diseases brought on by harmful organisms like bacteria, viruses, fungi, and parasites are known as infectious
diseases. There are several ways that these pathogens can spread, and each one presents a different difficulty
in preventing the disease's spread. Preventing outbreaks and safeguarding public health require an
understanding of how infectious diseases spread. The various modes of transmission: air, water, food, physical
contact, vectors, and bodily fluids will be discussed in this section along with examples of diseases linked to
each method. We'll also talk about ways to lower the risk of transmission through prevention.
Airborne Transmission: Tiny droplets released when an infected person coughs, sneezes, or even speaks can
spread airborne diseases. These droplets have the potential to stay in the air and infect people if they are
inhaled.
For instance, tuberculosis (TB). The bacterial infection known as tuberculosis (TB) mainly affects the lungs.
When an infected person coughs or sneezes, the bacteria-containing droplets are released into the air, which is
how it spreads. It is possible to get TB without getting sick or spreading it to other people. Worldwide, 1.4
billion people suffer from tuberculosis. The majority are not ill. Globally, about 10 million people suffer from
active TB. The disease is most likely to strike those with compromised immune systems. After exposure,
symptoms may manifest within a few days. Some people don't activate for months or years. The lungs are
attacked by bacteria that grow quickly when the disease is active. It can travel to other organs, bones, or skin
through your lymph nodes and bloodstream.
Prevention: People should keep proper ventilation in crowded areas, cover their mouths when coughing or
sneezing, and wear protective face masks when needed to stop the spread of the disease through the air.
Although some TB strains are resistant to medications, there are medications that can treat and cure TB. Drug
resistance and symptom recurrence may result from not finishing the prescribed course of treatment.
https://www.facebook.com/Drugscom (2019). Tuberculosis. [online] Drugs.com. Available at:
https://www.drugs.com/health-guide/tuberculosis.html.
Mallick, A. (2021). A Survey on Face Masks: An Indispensable Textile Material in the Covid Times | Textile
Magazine, Textile News, Apparel News, Fashion News. [online] Textilevaluechain.in. Available at:
https://textilevaluechain.in/in-depth-analysis/articles/a-survey-on-face-masks-an-indispensable-textile-
material-in-the-covid-times
,Waterborne illnesses can arise from ingestion (eating) or contact with pathogens present in contaminated
water. This can be brought on by bathing in contaminated water, drinking contaminated water, or eating food
that has been cleaned with contaminated water. Waterborne illness is still a major issue in many parts of the
world. According to estimates from the World Health Organisation (WHO), over 500,000 deaths annually are
caused by drinking water that's contaminated.
For instance, the bacteria that causes cholera, Vibrio cholerae, is spread by tainted water from human waste.
Dehydration and severe diarrhoea are the results.
Waterborne illnesses can be avoided by installing water filtration systems, ensuring that everyone has access
to safe, clean drinking water, and practising good sanitation and hygiene.
Premiumtimesng.com. (2022). Available at: https://www.premiumtimesng.com/news/top-news/559429-ncdc-
calls-for-improved-water-sanitation-as-cholera-kills-233-in-2022.html?tztc=1.
GetDoc. (2017). What Is Cholera? | GetDoc Says. [online] Available at: https://www.getdoc.com/what-is-
cholera/.
Food Transmission: When food gets contaminated with pathogens, usually as a result of incorrect handling,
cooking, or storage, foodborne illnesses can be made. Any stage of the food production chain is vulnerable to
contamination. When bacteria, viruses, parasites, or chemicals enter the body through contaminated food,
they can cause foodborne illnesses, which are typically toxic or infectious. Serious poisoning or long-term
illnesses like cancer can result from chemical contamination. Many foodborne infections can result in death or
permanent disability.
Salmonella, for instance. Salmonella is usually found in raw meats, eggs, and occasionally vegetables.
Consuming contaminated or undercooked food can lead to infection.
Prevention: Hand washing before handling food, cooking meat to the right temperature, and properly storing
food to prevent cross-contamination are all important ways to lower the risk.
Limited, A. (n.d.). A collection Salmonella bacteria zoomed out surface cutting board raw chicken. Salmonella is
genus rod-shaped Gram-negative Stock Photo - Alamy. [online] www.alamy.com. Available at:
, https://www.alamy.com/stock-photo-a-collection-salmonella-bacteria-zoomed-out-surface-cutting-board-
52099555.html.
Physical Contact Transmission: Diseases that are spread through physical contact can spread when an infected
person comes into contact with another person or when people come into contact with contaminated objects
or surfaces. This may occur before they become aware of the illness. This is how gastrointestinal infections and
sexually transmitted diseases (STDs) are spread. Additionally, infectious diseases can be passed from pregnant
women to their foetuses through the placenta. During childbirth, some sexually transmitted diseases, such as
gonorrhoea, can be transferred from the gestational parent to the infant.
For instance, chickenpox. The varicella-zoster virus, which causes chickenpox, can be transferred by touching
contaminated objects or by direct skin-to-skin contact with an individual who has an active rash.
Prevention: The spread of diseases through physical contact can be stopped by avoiding close contact with
infected people, washing your hands frequently, and disinfecting surfaces.
Castaño, N., Cordts, S.C., Kurosu Jalil, M., Zhang, K.S., Koppaka, S., Bick, A.D., Paul, R. and Tang, S.K.Y. (2021).
Fomite Transmission, Physicochemical Origin of Virus–Surface Interactions, and Disinfection Strategies for
Enveloped Viruses with Applications to SARS-CoV-2. ACS Omega, 6(10), pp.6509–6527.
doi:https://doi.org/10.1021/acsomega.0c06335.
Barkley, S. (2020). Chickenpox: Symptoms, Causes, Treatment, and Prevention. [online] Power of Positivity:
Positive Thinking & Attitude. Available at: https://www.powerofpositivity.com/chickenpox/
Vectors are organisms that carry and transfer pathogens from one host to another, which is how some
diseases are spread. The pathogen is often spread by vectors, who bite or eat infected humans or animals.
Human illnesses brought on by bacteria, viruses, and parasites that are spread by vectors are known as vector-
borne diseases. Diseases like malaria, dengue, schistosomiasis, human African trypanosomiasis, leishmaniasis,
Chagas disease, yellow fever, Japanese encephalitis, and onchocerciasis cause over 700,000 deaths annually.
For instance, malaria. When an infected female Anopheles mosquito bites a human, the parasite Plasmodium
causes malaria. The parasite damages red blood cells and the liver after entering the bloodstream.
Preventing mosquito bites can be done by sleeping under mosquito nets, applying insect repellent, and getting
rid of standing water in which mosquitoes breed.
