How do illnesses spread

Only a small portion of germs are known to cause infection. An infection occurs when germs enter the body, increase in number, and cause a reaction of the body. A Source is an infectious agent or germ and refers to a virus, bacteria, or other microbe.

In healthcare settings, germs are found in many places. People are one source of germs including:. People can be sick with symptoms of an infection or colonized with germs not have symptoms of an infection but able to pass the germs to others.

Germs are also found in the healthcare environment. Examples of environmental sources of germs include:. A susceptible person is someone who is not vaccinated or otherwise immune, or a person with a weakened immune system who has a way for the germs to enter the body. Devices like IV catheters and surgical incisions can provide an entryway, whereas a healthy immune system helps fight infection.

When patients are sick and receive medical treatment in healthcare facilities, the following factors can increase their susceptibility to infection. Transmission refers to the way germs are moved to the susceptible person. There are a few general ways that germs travel in healthcare settings — through contact i. Get the resource book. Flu is the 1 cause of death from a vaccine-preventable illness. Your best defence is to get your flu shot every year. Get flu protection. Health Professionals Page.

Many germs spread in more than one way. Some are spread through the air, by contact with an infected person, through blood or body fluids, contaminated food or water, or by insects and animals.

Not all germs cause disease. Some germs even help us to stay healthy. Some germs can lead to infection or disease. A communicable disease is an infection caused by a germ that is spread from person to person, or from the environment to a person. The influenza virus can be spread in droplets in the air or by contact with a tissue that someone with the flu has used to blow their nose.

Usually in droplets that are coughed, sneezed or breathed into the air by a person who is infected. Some germs such as the cold, influenza and mumps germs travel short distances.

Others such as measles and chickenpox stay in the air longer and can travel longer distances. Some diseases need direct person-to-person contact with an infected person. In other cases, germs are spread by contact with an object that has germs on it.

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The Government of South Australia may revise this disclaimer at any time by updating this posting. Users are advised to confirm the application or payment by other means. Do you have an emergency? Close overlay Button to close overlay. Ways infectious diseases spread On this page Germs can spread through: the air as small droplets droplet spread or tiny aerosol particles airborne spread contact with faeces poo and then with the mouth faeco-oral spread contact with the skin or mucus membranes the thin moist lining of many parts of the body such as the nose, mouth, throat and genitals contact spread blood or other body fluids for example, urine, saliva, breastmilk, semen and vaginal secretions.

Germs can spread: directly from person to person or indirectly from an infected person to the environment for example toys, door handles, bench tops, bedding and toilets and then to another person who comes in 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. Spread through the air by droplets Some infections are spread when an infected person talks, coughs or sneezes small droplets containing infectious agents into the air.

Examples of droplet spread diseases: common cold flu meningococcal disease rubella. Spread through the air by aerosol Some infections are spread when an infected person talks, breathes, coughs or sneezes tiny particles containing infectious agents into the air.

Examples of airborne spread diseases: chickenpox measles tuberculosis TB Spread through faeces and then the mouth faecal-oral spread Some infections are spread when microscopic amounts of faeces poo from an infected person with symptoms or an infected person without symptoms a carrier are taken in by another person by mouth.

The faeces may be passed: directly from soiled hands to the mouth indirectly by way of objects, surfaces, food or water soiled with faeces. Examples of diseases spread from faeces: Campylobacter infection Cryptosporidium infection Giardia infection hand, foot and mouth disease hepatitis A meningitis viral rotavirus infection Salmonella infection Shigella infection thrush viral gastroenteritis worms Yersinia infection.

Spread by skin or mucous membrane contact Some infections are spread directly when skin or mucous membrane the thin moist lining of many parts of the body such as the nose, mouth, throat and genitals comes into contact with the skin or mucous membrane of another person. Examples of diseases spread by skin or mucous membrane contact: chickenpox cold sores herpes simplex infection conjunctivitis hand, foot and mouth disease head lice molluscum contagiosum ringworm scabies school sores impetigo Staphylococcus aureus infection warts.

Spread through blood or other body fluids Some infections are spread when blood or other body fluids for example for example, urine, saliva, breastmilk, semen and vaginal secretions from an infected person comes into contact with: the mucous membranes the thin moist lining of many parts of the body such as the nose, mouth, throat and genitals , such as through kissing, breast-feeding or sexual contact or the bloodstream of an uninfected person, such as through a needle stick injury or a break in the skin.

Examples of diseases spread through blood or other body fluids: hepatitis B - blood, saliva, semen and vaginal fluids hepatitis C - blood human immunodeficiency virus HIV infection - blood, semen and vaginal fluids, breastmilk cytomegalovirus CMV infection - saliva, semen and vaginal fluids, urine, etc. Sexual contact means: genital to genital oral to genital genital to anal.

Examples of sexually transmitted infections: Chlamydia infection genital herpes genital warts gonorrhoea hepatitis B human immunodeficiency virus HIV infection non-specific urethritis NSU pubic lice crabs syphilis trichomoniasis.

Spread through food or water These diseases result from ingestion of water or a wide variety of foods contaminated with disease-causing germs or their toxins.

Examples of food or waterborne diseases: botulism Campylobacter infection cholera Cryptosporidium infection haemolytic uraemic syndrome Listeria infection Salmonella infection Shigella infection typhoid and paratyphoid Yersinia infection. Spread from a mother to her unborn child Some infections can be spread through the placenta from a mother to her unborn child or during delivery, or both.