Route of infection

The path of infection is the characteristic way in which pathogens of infectious diseases spread, i.e. in particular bacteria (→ bacterial infection ), viruses (→ viral infection ), fungi (→ mycosis ) and parasites (→ human parasites ). The best protection against infection is to avoid these routes of infection and to adhere to basic hygiene measures . This applies to all people who come into contact with infected people, especially medical personnel.

overview

Infections can be classified according to various criteria. The number of pathogens necessary for an infection ( infection dose ) depends, among other things, on the type of pathogen.

→ For a more detailed description of the types of infection, see Infection # Criteria for Classification

Types of infection according to the origin of the pathogen

• Endogenous infection (auto-infection): The pathogen comes from the body's own flora of the skin or mucous membrane and is transmitted to organs or the bloodstream. So z. B. Intestinal bacteria enter the urinary bladder via the urethra and cause cystitis there; If the pathogens rise through the ureter into the kidney pelvis, they can possibly get into the bloodstream and cause sepsis there .

• Exogenous infection: The pathogen comes from the environment and is transmitted by droplet or smear infection (contact infection).

Types of infection according to the pathogen's portal of entry

• Enteral infection: The pathogens enter the organism through the intestines. The entire digestive tract (mouth, throat, esophagus, stomach and the entire intestine) is viewed as the inside of a tunnel that is not itself part of the body. The intestine, from which the infectious agents penetrate the actual interior of the body, is considered here as the gateway.
  • Faecal-oral infection: pathogens from faeces enter the organism through the mouth, e.g. B. from contaminated drinking water.

• Parenteral infection: In the literal sense, it is an infection in which the pathogens “past the intestine”, ie did not enter the organism via the digestive tract. In medical usage, parenteral is synonymous with “directly into the blood”.
  • Percutaneous infection: The pathogens enter the organism through the skin.
  • Permucous infection: The pathogens enter the organism via the mucous membranes.
  • Inhalation infection: The pathogens enter the organism via the respiratory tract.
  • Urogenital infection: The pathogens enter the organism via the urinary tract.
  • Genital infection: The pathogens enter the organism via the sexual organs.
  • Intrauterine infection: The pathogens enter the body of the unborn child during pregnancy.

Direct and indirect infection

• Direct infection: through droplet infection or through contact with the skin or mucous membrane; as endogenous pathogen transmission or from person to person without intermediate steps

• Indirect infection: Transmission using various vehicles such as objects and materials (e.g. door handles, toys, food, water) or vectors such as blood-sucking insects .

Important routes of infection

Droplet infection

→ Main article : droplet infection

Droplet infection can transmit respiratory diseases, but also infectious diseases in other organ systems. Secretion containing pathogens is transferred to the new host via splashes, small droplets or extremely fine particles, for example by sneezing or shaking hands. Most of the time, the pathogens cannot survive long on objects, outdoors or on the skin.

Smear infection

With smear infection or direct contact infection, the pathogen is transmitted by touching the skin or mucous membrane. If contaminated material - dirt , contaminated water, feces , mucus , sputum , pus , blood , etc. - gets on the skin, the pathogens first have to overcome the skin barrier. Even a very small wound makes it easier for the pathogen to enter. An infection via the mucous membranes is easier because they are more permeable to pathogens. The exchange or ingestion of contaminated body fluids is also a direct contact infection. These include blood , breast milk , saliva , sweat , ejaculate and vaginal secretions . The pathogens it contains cannot survive long without a host organism.

Ticks and blood-sucking insects

Ticks and blood-sucking insects can act as vectors (carriers) and transmit various pathogens from the host to the victim. A well-known example is the plague , which is transmitted from the rat (main host, reservoir host) via the rat flea (vector and intermediate host) to humans.

• A basic distinction must be made between biological transmission and mechanical transmission, see vector .
• For information on individual tick species and the pathogens and diseases they transmit, see tick bite .
• For information on individual groups of insects and the pathogens and diseases they transmit, see blood-sucking insects .

Individual evidence

1. ^ Christian Jassoy, Andreas Schwarzkopf: Hygiene, Infectiology, Microbiology. Thieme, Stuttgart 2018, p. 32f, ISBN 978-3-13-241368-9
2. ^ Christian Jassoy, Andreas Schwarzkopf: Hygiene, Infectiology, Microbiology. Thieme, Stuttgart 2018, p. 33, ISBN 978-3-13-241368-9 .
3. ^ Christian Jassoy, Andreas Schwarzkopf: Hygiene, Infectiology, Microbiology. Thieme, Stuttgart 2018, p. 32.

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !