Table of ContentsView AllTable of ContentsDropletAirborneDirect ContactBloodborneIndirect ContactFecal-OralVector-Borne
Table of ContentsView All
View All
Table of Contents
Droplet
Airborne
Direct Contact
Bloodborne
Indirect Contact
Fecal-Oral
Vector-Borne
Knowing how germs are transmitted is key to preventing disease, and it varies for different bacteria, viruses, and other pathogens. In some cases, you have to come into direct contact with an infected person to be infected. In others, the germ may be aerosolized (for instance, when someone sneezes) and find its way into your body when you simply take a breath. Some diseases can be spread in more than one way.
Understanding these and other modes of germ transmission can help you protect your health and that of the people around you.
Ellen Lindner / Verywell
Some examples of diseases spread through droplet transmission include:
Respiratory droplets can be spread as far as 6 feet away from their source.
Cold and flu viruses can remain infective on surfaces for hours and up to a few days.If someone touches the surface and then touches their mouth, nose, or eyes, they may become infected.
Precautions
To prevent or reduce droplet transmission,cough or sneeze into a tissue or your elbow. Then, wash your hands so you don’t pass your germs on. Likewise, to protect yourself from germs you may pick up,wash your hands frequently, use hand sanitizer when you don’t have soap and water available, and try not to touch your face.
Germs capable of airborne transmission can reach the lower respiratory tract when inhaled. It may not take many germs for an infection to occur.
There is scientific debate as to whether influenza can beairborne, although most agree that droplet transmission is the usual route.
When there is an outbreak of a novel pathogen, such as the coronavirus disease COVID-19 and Middle East respiratory syndrome (MERS), researchers look closely at transmission patterns to see if it can be airborne, as this has many implications for controlling its spread.
It is much more difficult to prevent transmitting or catching airborne infections. Isolating those who are sick is an important way to control the spread.
In a medical setting, negative pressure isolation rooms ensure that air is drawn into the room from the outside, so it is not recirculated to/from other patients. The use ofN95 respirators rather than surgical masksis needed to protect healthcare personnel from airborne diseases.
N95 respirators are expensive and must be properly fitted, and users must be trained to use them. For this reason, it is important to know when they are truly needed. In the case of influenza (where there is debate about airborne spread), studies have shown that wearing surgical masks is as effective for protecting healthcare personnel as N95 respirators.
Vaccination can prevent the spread of chickenpox and measles, but vaccines for tuberculosis are not used in the U.S.
Close physical contact is required to transmit some diseases, as these germs can’t survive for any time away from a host (the body).They are spread via saliva, wound secretions, sexual contact, etc.Sexually-transmitted diseasesare in this category. For other germs, this can be an additional mode of transmission (e.g., passing a cold via kissing).
In daily life,safer sex practicesare steps that can be taken to prevent direct contact transmission. In healthcare settings,standard precautionsincluding wearing gloves, masks, and washing hands can prevent direct transmission.
Some diseases spread through contact with blood. Examples include:
Bloodborne transmission is a type of direct contact transmission. It can occur when someone’s blood enters an open wound or mucous membrane. It can also happen through shared personal objects that contain trace amounts of blood, such as hypodermic needles.
Avoid sharing items that have been in contact with someone else’s blood, such as a razor or hypodermic needle. In a healthcare setting, providers should wear gloves and additional equipment such as a mask, gown, and eyewear if there’s a possibility of blood splash.
Some germs can live a shorter or longer time on a contaminated surface. They may be spread to surfaces via droplets or transfer of mucus, blood, saliva, feces, or wound secretions. The objects that harbor these germs are called fomites.
Contaminated food and water are the modes of transmission of many bacteria and viruses that infect the digestive system and are shed in the feces. Some examples of diseases spread this way include:
Waterborne illness may result from ingesting, bathing, or swimming in contaminated water. While municipal water supplies in developed countries are rarely a risk, you might be exposed when traveling, in times of disaster, or when swimming in a river, stream, or pond.
Foodborne illness is often due toimproper hygiene. Failure to wash your hands thoroughly after using the restroom can transfer germs to food you are preparing or serving.
As well, improper hygiene can transfer fecal bacteria and viruses to surfaces, where others can pick them up and transfer them to the mouth (hence, the name fecal-oral route).
How are bacteria transmitted?Bacteria can be transmitted in several different ways, including via droplets, airborne, bloodborne, vector-born, and direct contact such as sexual transmission.
How are bacteria transmitted?
Bacteria can be transmitted in several different ways, including via droplets, airborne, bloodborne, vector-born, and direct contact such as sexual transmission.
Vector-borne diseases are transmitted from human to human or from an animal to a human through an insect such as a mosquito or tick. In these cases, the germmustpass through the vector host before it can infect humans, such as withmalaria.
Examples of vector-borne illnesses include:
What Is the Difference Between a Vector-Borne Disease and a Zoonotic Disease?A zoonotic disease is a disease that can be passed from an animal to a human in various ways such as droplet transmission or through a bite or scratch. Some examples of zoonotic diseases include:Avian influenza (bird flu)Hantavirus pulmonary syndrome (HPS)Rat bite feverLeptospirosisRabiesVaccination of dogs and cats can prevent the spread of rabies.
What Is the Difference Between a Vector-Borne Disease and a Zoonotic Disease?
A zoonotic disease is a disease that can be passed from an animal to a human in various ways such as droplet transmission or through a bite or scratch. Some examples of zoonotic diseases include:Avian influenza (bird flu)Hantavirus pulmonary syndrome (HPS)Rat bite feverLeptospirosisRabiesVaccination of dogs and cats can prevent the spread of rabies.
A zoonotic disease is a disease that can be passed from an animal to a human in various ways such as droplet transmission or through a bite or scratch. Some examples of zoonotic diseases include:
Vaccination of dogs and cats can prevent the spread of rabies.
Summary
Diseases can spread through various modes of transmission, including droplets, direct contact, and indirect contact. Pathogens can also become airborne, and some can spread through the fecal-oral route.
10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Centers for Disease Control and Prevention.Influenza (flu): How flu spreads.
Tellier R, Li Y, Cowling BJ, Tang JW.Recognition of aerosol transmission of infectious agents: a commentary.BMC Infect Dis. 2019;19(1):101. doi:10.1186/s12879-019-3707-y
Seto WH.Airborne transmission and precautions: facts and myths.J Hosp Infect. 2015;89(4):225-8. doi:10.1016/j.jhin.2014.11.005
ARadonovich LJ Jr, Simberkoff MS, Bessesen MT, et al.N95 respirators vs medical masks for preventing influenza among health care personnel: A randomized clinical trial.JAMA. 2019;322(9):824–833. doi:10.1001/jama.2019.11645
Centers for Disease Control and Prevention.Section 10: Chain of infection.
Centers for Disease Control and Prevention.Norovirus illness: Key facts.
The Centers for Disease Control.Appendix A: How Infections Spread.
World Health Organization.Sexually transmitted infections.
World Health Organization.Vector-borne diseases.
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