What are the main transmission routes of exogenous infection?

Exogenous infection refers to infection caused by pathogenic bacteria outside the host. The sources of infection mainly include patients with infectious diseases, convalescent patients, healthy carriers, as well as sick animals, infected animals and vector insects.

The main routes of transmission are:

1. Contact transmission? It is the main transmission route of exogenous infection.

(1) Direct contact transmission: infected individuals directly transmit pathogens to susceptible hosts, such as mother-to-child transmission of herpes virus, chlamydia trachomatis and coxsackie virus.

(2) Indirect contact transmission: pathogens are transmitted to susceptible hosts through media. The most common media are the hands of doctors and nurses, as well as the same media (such as water, food, medical equipment) and biological media (such as insects).

2. airborne? Airborne infection is caused by air, and particles with pathogenic microorganisms in the air flow with the airflow. There are three forms of air transmission.

(1) droplet transmission: The droplets discharged from the infectious source are large and suspended in the air for a short time, and infection will only occur when the susceptible person or patient is in close contact.

(2) Droplet Nucleus Transmission: Before the droplets of the infectious source fall to the ground, the surface water evaporates to form droplet nuclei containing pathogens, which can float for a long time and spread over a long distance.

(3) the spread of bacterial dust: the infectious substances on the surface of the object dry to form bacterial dust, which is inhaled or falls on the wound, causing direct infection; Or bacterial dust falls on the surface of indoor objects, causing indirect transmission.

3. Injection and blood transfusion? Spread hepatitis B and C viruses, HIV, plasmodium, etc. Through contaminated liquid drugs and blood.

4. Drinking water and food transmission? Food not only causes bacterial food poisoning in hospitals, but also often contains various conditional pathogens, which can be colonized in patients' intestines and increase the chance of infection.

5. Biological vector transmission? Refers to animals or insects that carry pathogenic microorganisms as intermediate hosts for human transmission. Such as malaria and Japanese encephalitis transmitted by mosquitoes.