Transmission of Infectious Diseases
The process through which a disease moves from one host to another is called transmission.
Infections and diseases can spread in a variety of ways. It can spread directly from person to
person or by certain viruses, bacteria, protozoa, or fungi. There are two different modes of
transmission of diseases:1
Direct transmission – when the pathogen is directly transferred from an infected
individual. For example, an individual with an open wound may become infected
with hepatitis B if their blood comes into touch with the wound.
Indirect transmission – indirect transmission occurs when viruses spread via vectors
like dogs, flies, mosquitoes, ticks, and so on rather than directly from the sick
individual.
Direct Transmission
Disease Transmission Modes of Disease Disease Caused
Transmission
Direct Transmission Spread through droplets Cold, cough
Spread by skin Conjunctivitis, chickenpox
Spread through blood or HIV, hepatitis
bodily fluids
Person to person Gonorrhoea
Indirect Transmission
Disease Transmission Modes of Disease Disease Caused
Transmission
Indirect Transmission Airborne transmission Measles, Influenza
Contaminated objects Cold, syphilis
Vector-borne transmission Malaria, Lyme disease
Transmission through food and Cholera, Diarrhoea
water
Transmission through animals Rabies, anthrax
Environmental factors Hookworm, Legionnaires’
disease
Transmission of infectious disease
1
MODES OF TRANSMISSION OF DISEASES, https://byjus.com/biology/modes-of-transmission-of-diseases/#:~:text=Transmission%20is
%20the%20process%20by,viruses%2C%20protozoa%2C%20or%20fungi., 16/05/2024
,When germs come into contact with bodily fluids like blood or mucus membranes – the
thin, moist lining of many body parts like the nose, mouth, throat, and genitalia – they can
spread through the air as tiny droplets (droplet spread) or tiny aerosol particles (airborne
spread). They can also spread through contact with faeces (poo) and then the mouth
(faecal-oral spread).2
Indirect transmission of germs occurs when an infected individual comes into contact with
contaminated toys, door handles, bench tops, bedding or toilets, and then another person
comes into contact with the contaminated environmental source. Germs can enter the body
through the:
Mouth
Respiratory tract
Eyes
Genitals
Broken skin
Some infections can be spread in several different ways.
There are various widely accepted ways to explain the spread of germs. Sexual contact can
transfer germs, typically through body fluids like semen and vaginal secretions, but it can
also happen when mucous membrane come into touch. Water and food can harbour
bacteria. Contact with faeces followed by the mouth is one method of germ transmission,
though one (faecal-oral). Additionally, a mother’s blood or other bodily fluids can transfer
germs to her foetus. Skin or mucous membrane contact during childbirth is another
common way.
Parvovirus, chlamydia, and COVID-19 are all examples of infectious disease caused by direct
transmission.3
COVID-194
The SARS-CoV-2 virus is the infectious agent that causes coronavirus illness (COVID-19).
When an infected person cough, sneezes, speaks, sings, or breathes, tiny liquid particles
from their mouth or nose might spread the virus. These particles can be tiny aerosols or
bigger respiratory droplets. It’s crucial to follow respiratory etiquette, such as coughing into
a bent elbow, and to remain at home and take care of yourself until you feel better.
The majority of virus-infected individuals will recover from mild to moderate respiratory
infection without the ned for additional care. Nonetheless, a small percentage will get really
sick and need medical care. Serious sickness is more likely to strike the elderly and those
2
WAYS INFECTIOUS DISEASES SPREAD, https://www.sahealth.sa.gov.au/wps/wcm/connect/public+content/sa+health+internet/
conditions/infectious+diseases/ways+infectious+diseases+spread#:~:text=Germs%20can%20spread%3A,with%20the%20contaminated
%20environmental%20source., 16/05/2024
3
MANAGING SPECIFIC INFECTIOUS DISEASES: A TO Z, https://www.gov.uk/government/publications/health-protection-in-schools-and-
other-childcare-facilities/managing-specific-infectious-diseases-a-to-z, 23/05/2024
4
CORONAVIRUS DISEASE (COVID-19), https://www.who.int/health-topics/coronavirus#tab=tab_1, 23/05/2024
, with underlying medical disorders such as diabetes, cancer, cardiovascular disease, or
chronic respiratory diseases.
With COVID-19, anyone can get sick, get very sick, or pass away at any age. Being
knowledgeable about the illness and the virus’s mode of transmission is the strongest
defence against it and a mean of reducing its spread. By keeping a minimum of one metre
between people, wearing a mask that fits properly, and often washing your hands or using
an alcohol-based rub, you can prevent infection in both yourself and other people. Get
vaccinated when it’s your turn and follow local guidance.
Parvovirus5
When an infected individual coughs or sneezes, respiratory secretions from that person are
the main route that parvovirus B19 spreads. When an infection first manifests as the
common cold, people are most contagious. People are less infectious after developing a
rash or joint pain. Parvovirus can also be spread through blood contact and from a pregnant
woman to her infant.
Since there is no vaccination for parvovirus B19, preventative measures include avoiding
close contact with ill people, washing your hands frequently, and avoid touching your face.
It is important to stay inside, cover your mouth and nose, and keep your hands away from
contaminated bodily fluids. Prenatal check-ups, blood tests, and ultrasounds should be used
to monitor the infection in pregnant women exposed to B19. Testing for immunity or
infection should be discussed. Less than 5% of cases of result in miscarriage and severe
anaemia in the affected new-born.
Chlamydia6
Men and women can contract chlamydia, a commonly sexually transmitted infection. The
bacteria that causes it is known as chlamydia trachomatis. Antibiotics are a simple
treatment and cure for it. Chlamydia can lead to major issues like ectopic pregnancy and
infertility if left untreated. It may result in an early birth of the child (prematurity) in
pregnant women. The best method of preventing chlamydia is to use condoms during
intercourse correctly and consistently.
Syphilis, MRSA and Legionnaires’ disease are all examples of infectious disease caused by
indirect transmission.7
Syphilis8
A sexually transmitted infection (STI) called syphilis can spread through vaginal, anal, or oral
sex with an infected person. It is brought on by a bacteria. Antibiotic drugs are used to treat
syphilis. If left untreated, syphilis can cause blindness as well as harm towards the heart,
5
PARVOVIRUS B19 (FIFTH DISEASE), https://health.hawaii.gov/docd/disease_listing/fifth-disease-parvovirus-b19/#:~:text=Parvovirus
%20B19%20is%20primarily%20spread,people%20are%20not%20as%20contagious., 23/05/2024
6
CHLAMYDIA, https://www.who.int/news-room/fact-sheets/detail/chlamydia, 23/05/2024
7
MANAGING SPECIFIC INFECTIOUS DISEASES: A TO Z, https://www.gov.uk/government/publications/health-protection-in-schools-and-
other-childcare-facilities/managing-specific-infectious-diseases-a-to-z, 23/05/2024
8
SYPHILIS, https://my.clevelandclinic.org/health/diseases/4622-syphilis, 23/05/2024
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller dahliablush. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $13.68. You're not tied to anything after your purchase.