Introduction
In the case of a smear infection, pathogens or infections are passed on by touch. This is why they are also called contact infections. In a smear infection, the infection can be transmitted either directly or indirectly.
Infection carriers are the body secretions of the infected person, such as saliva, urine or stool. Direct transmission takes place from person to person. For example, if a flu patient coughs in his or her hand and then hands it to someone else, the pathogen is transmitted. In indirect smear infection, an object is located in the transmission line between the two people. This could be a door handle or a glass that is shared.
Causes
The most common cause of smear infections is lack of hygiene measures. The hands of a sick person or surfaces contaminated with germs are typically the sources of transmission. The pathogens can get there via different routes.
In most cases, smear infections are transmitted by germs that originate from the stool. These can be bacteria, viruses or parasites. The germs are passed on to another person from the hand of an infected person or from the surface to which he or she has transmitted them.
This happens when the healthy person touches the hand or the surface and thereby contaminates his own hand with the pathogen. Normally, the skin forms a natural protective barrier and prevents the pathogen from entering the body. However, even small injuries can quickly allow them to enter the body.
Even if the contaminated hand touches the eyes or mouth, this still provides an entry point for the pathogens. Although the immune system immediately takes action against the invading germs, it does not always manage to fight all pathogens. Diarrhoea pathogens such as rotaviruses or noroviruses are the main causes of smear infections.
Salmonella is also transmitted in this way. Influenza viruses that cause influenza and adenoviruses that can cause colds or conjunctivitis are also transmitted by contact infections. Less frequently occurring, but also transmissible by smear infections, are hepatitis A, cholera, typhoid fever and polio. The purulent secretion from chickenpox or herpes blisters contains viral pathogens that are transmitted via smear infections.
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