biology infectious disease/disease transmission- year 11

be precise

what is disease transmission?

•Disease transmission is the spread of pathogens from a reservoir or infected person to a new host.

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•This can occur through direct contact (touching, bodily fluids), indirect contact (contaminated surfaces, air), or vectors (insects).

what is an example of direct contact?

touching and intercourse

what is an example of indirect contact?

contaminated surfaces

what is an example of vehicle transmission?

faeces, food and water, air and dust

what are examples of vectors?

mechanical and biological

what is direct contact?

•Direct transmission means that the disease is passed directly from one infected person or animal to another person or animal.

•This can occur through actions such as:

•Touching

•Kissing

•Sexual contact

•Droplet sprays that land on nearby people

•Mother to baby during pregnancy

•Examples of diseases spread via direct contact: common cold, chickenpox and genital herpes

what is indirect contact?

•Indiret transmission occurs when a disease is passed from an infected person to another person, even though the two people have not had direct contact.

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•Involves inanimate objects called fomites that become contaminated by pathogens from an infected individual or reservoir.

•Transmission occurs indirectly when a new susceptible host later touches the fomite and transfers the contaminated material to a susceptible portal of entry.

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•For example, an individual with the common cold may sneeze, causing droplets to land on a fomite such as a tablecloth or carpet, or the individual may wipe her nose and then transfer mucus to a fomite such as a doorknob or towel.

•Fomites can also include objects used in clinical settings that are not properly sterilized, such as syringes, needles, catheters, and surgical equipment. 

what is vehicle transmission?

•The term vehicle transmission refers to the transmission of pathogens through vehicles such as water, food, and air.

•Water contamination through poor sanitation methods leads to waterborne transmission of disease.

•Dust and fine particles known as aerosols, which can float in the air, can carry pathogens and facilitate the airborne transmission of disease.

Although droplet transmission over short distances is considered contact transmission, longer distance transmission of droplets through the air is considered vehicle transmission

what is the vector transmission: mechanical transmission?

•Diseases can also be transmitted by a mechanical or biological vector, an animal (typically an arthropod) that carries the disease from one host to another. 

•Mechanical transmission is facilitated by a mechanical vector, an animal that carries a pathogen from one host to another without being infected itself. 

what is the vector transmission: biological transmission?

•Biological transmission occurs when the pathogen reproduces within a biological vector that transmits the pathogen from one host to another .

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•Examples of biological transmission to humans:

•Mosquitoes transmitting malaria

•Ticks transmitting lyme disease

•Fleas transmitting the plague

Animals transmitting rabies

how are pathogens transmitted through the air?

when an infected person coughs or sneezes, the air particles contain tiny droplets containing pathogens which are then released into the air which allows the pathogen to enter a new host causing infection.

what is the transmission of pathogens through air called?

airborne, examples are covid - 19, influenza

how are pathogens transmitted through dust particles?

pathogens can attach themselves to the dust particles in the environment, and when the dust particles become airborne they can be breathe in causing infection.

how are pathogens transferred through faeces?

pathogens in an infected person or animal faeces can contemned food, water or surfaces and they may become infected if they swallow these things or touch them. the pathogens from faeces can also be transferred through mechanical transmission by which flies land on faeces and then carry that pathogen to other surfaces.

how are pathogens transmitted through animals?

animals can carry pathogens from eating foods or drinking water which has been infected by these pathogens, which if they bite humans, they can then become infected

how can pathogens be transferred through food?

pathogens can contaminate food during handling or if stored in unsanitary places, and if eaten can cause infections.