It is known that infectious diseases or infectious diseases (also called infection for short) are transmitted directly or indirectly to humans by pathogens. So, medically speaking, transmission means infection. Medical science understands this to mean the settlement and reproduction of microorganisms in a higher organized host organism. However, infection does not necessarily mean an infectious disease.

Overview of infectious diseases

According to abbreviationfinder, an infectious disease will come about all the more easily, the greater the number and the greater the attacking power of the invading pathogens, which attack people unprepared. With most types of pathogens, the human body will be able to cope with a certain amount.

Anyone can be infected at any time, i.e. colonized with microorganisms, without becoming ill. Among other things, there are completely healthy carriers of diphtheria pathogens and healthy excretors of germs that could trigger an intestinal infection. We are all surrounded by a multitude of microorganisms, of which only a small proportion can make us ill.

Some microorganisms do not even enter us, they cannot exist in the human environment. Others are harmless lodgers of our body, on which we even depend. A number of them cause diseases in plants and animals without harming humans, or vice versa. What this species specificity is based on, we do not yet know down to the last detail.

Different forms of pathogens

We distinguish four large groups of pathogens: First, the fission fungi, which occur in various forms, namely in the form of rods as bacilli (bacteria), such as the causative agent of dysentery, typhus, tuberculosis and others, in spherical form as the pus-causing agent in grape or Chain arrangement, in the form of a bun as the causative agent of pneumonia, meningitis and gonorrhea, as fungi, such as the common causative agent of athlete’s foot, or in the form of a corkscrew, among other things as the causative agent of syphilis.

Another group of pathogens are the virus species, which are very common and so small that they cannot be seen with a standard microscope. They pass even the finest filters. They can only be grown on living cells and can be visualized with an electron microscope. They prefer to attack certain tissues, for example the jaundice virus the liver cells, the polio virus certain nerve cells, the flu virus cells of the upper respiratory tract.

The rickettsia, another group of microorganisms, are in the order of magnitude between virus species and fission fungi. For example, they cause typhus. The fourth group of pathogens, the protozoa, cause a tropical form of dysentery and malaria as unicellular animals.

Infectious diseases have always been of great importance in the life of all peoples, especially when they spread like epidemics. None of the past periods of human history can be imagined without these diseases. The type, severity and point in time of an infectious disease that has been overcome are also important factors for the mental and physical development of individuals and for their integration into society. Severe infectious diseases in childhood, for example a disease of the brain and the rest of the nervous system, often leave a lifelong mental and physical disability.

History of Virus & Bacteria Discovery

At all times people have dealt with the experience of infectious diseases in different ways. If their interpretation was originally based on the belief in demons, the believing and fatalistic person later thought that an illness that had occurred was the direct intervention of a higher power, a punishment sent by God, a rewarding or avenging hand. In the 19th century, knowledge of living pathogens gradually spread, but this made it seem like a coincidence whether and when a person could ingest the pathogens and become ill from them.

Today, the co-creating influence of the environment is a well-known factor. Man is practically not separated from the environment by his outer skin, but everything around him belongs to him, including the smallest creatures. We even depend on them to some extent. They live with us in a community, a symbiosis, especially on the mucous membranes of the body cavities that are open to the outside, such as the mouth, the intestines and the female sexual organs. Even pathogenic microorganisms are part of our environment. But when does their presence lead to illness?

Infection by germs, viruses & bacteria

A number of factors play a role here, factors that are partly human-related, but also partly dependent on the pathogens. An infectious disease will come about all the more easily, the greater the number and the greater the attacking power of the invading pathogens, which attack people unprepared. With most types of pathogens, the human body will be able to cope with a certain amount. If, for example, typhus germs got into the food from the unclean hand of a cook in tropical countries, eating the soup, for example, will not yet cause illness. However, if this soup has stood for hours and the typhoid pathogens in the soup have multiplied rapidly, typhoid fever can occur after eating the soupdevelop.

With some viral diseases, however, it is sufficient to ingest a small amount of infectious substance. So it is, for example, with measles, chickenpox and smallpox. If germs are particularly vital or virulent, i.e. if they multiply quickly and quickly form toxic metabolic products, so-called toxins, then an infectious disease will develop quickly.

The ability of the human body to react to pathogens is decisive for the development of an infectious disease. A strong, healthy, reasonably living person is more likely to dismiss an infection than an ailing homebody. An exhausted, stressed organism will be more vulnerable than a fresh, rested one. Doctors and laypeople often see hypothermia as the cause of a cold, bronchitis or pneumonia, which in reality are real infectious diseases. Cause and effect are easily confused by shivering, freezing or even a chill, which indicate the beginning of an infectious fever, can be related to an external cooling.

However, we do not want to deny that hypothermia can significantly disrupt the body’s responsiveness, since blood circulation in the mucous membranes and limbs worsens under the influence of cold and wet conditions. A condition that favors the development of infections when the appropriate germs are present. However, humans are able to form defense bodies, the so-called immune bodies, against certain pathogens or toxins. Immunity is the increased defensive readiness of an organism against certain germs.

The newborn gets these immune bodies for a short period of time from the mother’s organism. For later times, each organism must develop these immune bodies itself, either by surviving an infectious disease – after measles there is generally lifelong immunity – or by vaccinations, which force the body to form these immune bodies – at least temporarily – by means of a weakened or shortened course of infection.

Symptoms, Ailments & Signs

Typical symptoms of an infectious disease are fever, pain and swelling as well as inflammation-related redness and itching. In addition, the affected organs react with defense reactions such as runny nose, cough and hoarseness as well as cramp-like symptoms or nausea. The severity of the symptoms depends on the individual immune system and age.

In the case of a bacterial infection and a viral infection, symptoms such as diarrhea, difficulty swallowing and headaches can occur, as can body aches. In addition, a noticeable urge to urinate with urine discoloration is possible. You may also experience chills, a rash, tiredness and difficulty breathing. Timely attribution of these symptoms can be problematic.

In the case of certain infectious diseases, the signs only appear with a very long delay after infection with pathogens such as Lyme disease. In some of the infectious diseases, the classic symptoms are only mildly pronounced, making classification difficult. In other cases, the symptoms are more helpful for an initial assessment of the disease.

Coughs, runny noses and sore throats as well as hoarseness and difficulty swallowing are clear indications of infections of the respiratory tract. Diarrhea, malaise and vomiting are also typical symptoms of stomach and intestinal infections. If an unpleasant burning sensation occurs when urinating, these symptoms indicate a urinary tract infection. Symptoms of an infectious disease can be limited to certain parts of the body or can be found throughout the body.


It is usually not possible to universally predict whether infectious diseases will lead to severe symptoms or even complications. In many cases, infectious diseases can be limited relatively well with the help of antibiotics and other medications, so that no particular complications arise from them. However, these can occur if treatment is not started quickly enough.

This can cause irreversible damage to the patient’s internal organs. Most of those affected suffer from severe fever and exhaustion due to the infectious diseases. The patient’s resilience drops drastically and there is also a severely reduced quality of life. As a rule, the patient’s immune system is also significantly weakened, so that other infections or inflammations can also occur.

In most cases, infectious diseases are treated with medication. However, whether there are complications depends on the disease in question. A positive course of the disease does not occur in every case. There may be damage to the internal organs, so that the patient is dependent on a transplant. Life expectancy can also be reduced by infectious diseases.

When should you go to the doctor?

Many common infectious diseases, such as a cold or gastrointestinal infections, will go away on their own within a short period of time and do not require medical treatment. However, high fever, circulatory problems, impaired consciousness or severe abdominal pain should give reason to see a doctor. A medical examination is also advisable if the symptoms do not improve over the course of days or if you have a cold and a severe cough with shortness of breath. Other infectious diseases begin insidiously and show only non-specific symptoms: A doctor should be consulted if the body temperature has been elevated over a long period of time or fever attacks occur without any recognizable cause, as well as constant tiredness, a drop in performance,

Some childhood diseases are accompanied by characteristic skin rashes: Due to the high risk of infection, unvaccinated children should be presented to a pediatrician as soon as possible if such skin changes appear together with fever or a general feeling of illness. In adults, a doctor’s visit is recommended for painful redness and swelling that spreads quickly. Antibiotic therapy is necessary to treat Lyme disease: Typical of this is a flat reddening of the skin that occurs some time after a tick bite and is often accompanied by flu-like symptoms. If headaches are accompanied by fever and stiff neck, there is a suspicion of life-threatening meningitis, which must be treated immediately.

Treatment & Therapy

If one asks about the nature of an infectious disease, starting from the clinical point of view, one imagines a disease that generally progresses in a relatively short time, usually has a favorable outcome and shows symptoms that are repeated from case to case. What is characteristic of an infectious disease, however, is its transmissibility. From the time of infection to the outbreak of the disease, there is a certain period of time that we call the incubation period. During this time there is already a possibility of infection.

In scientific research, two epochs have been significant for the recognition and treatment of infectious diseases: First, the time of Robert Koch with the discovery of pathogens, the knowledge of epidemiology and the first experiments with medicinal serums, and second, the time of the discovery of chemical and antibiotic ones remedies that are closely associated with the names Domagk and Fleming. The introduction of antibiotics has also initiated a change in the appearance of infectious diseases, since with timely and correct use of such substances the infection cannot spread in the organism and is therefore temporarily much shorter and milder.

When it comes to containing infectious diseases, we have two important tasks to fulfill: firstly, to treat the diseases that have occurred and, secondly, to protect healthy people from possible infections. Therapy and prophylaxis must be understood as a unit, because isolating and treating infectious patients eliminates a possible source of infection. This is the best way to contain an epidemic that has occurred. A prerequisite for successful treatment is always the determination of the pathogen and its reaction to applicable remedies.

All measures to combat contagious diseases that are part of the epidemic law are the responsibility of the state health and hygiene authorities and the Federal Ministry of Health. Control measures can only be initiated if the health care facilities mentioned are informed immediately of the outbreak of such diseases. Therefore, there is a general obligation to report various infectious diseases. Most infectious diseases require isolation, which means the sick person must be admitted to a hospital ward where they are isolated from the general public and treated appropriately. In general, he may only be released from this hospital treatment if, after his recovery, according to medical judgment, there is no longer any risk of infection for those around him.

In the case of illness and especially in the case of epidemics, quarantine measures in the vicinity of the sick person are extremely important so that the germs are not spread further. Vaccinations are precautionary measures that should be carried out as completely as possible in order to protect children and vulnerable people from the outset. Vaccination brings about the longest possible immunity of the vaccinated person, as a result of which some diseases, such as polio and smallpox, have almost completely disappeared in our country. Recommended vaccinations for children are vaccination against diphtheria, polio, whooping cough and tetanus. Furthermore, vaccination againstMeasles and in flu times an additional comprehensive flu vaccination is planned.

Our modern healthcare system is constantly striving to contain or even eradicate epidemics of all kinds. In this endeavor, it is supported by the Health and Hygiene Offices and by the Federal Ministry of Health, whose core areas of epidemic protection directs scientific research in the field of infectious diseases and epidemic protection, the aim of which is comprehensive protection of our population from contagious diseases and whose success depends on the insight and willingness of the population.

Outlook & Forecast

Infectious diseases usually have a favorable prognosis. Although the risk of infection is very high, in many patients the symptoms gradually heal without the use of medical care. If you have a mild flu or other common illnesses, you will be free of symptoms within a few weeks. In the case of mild infections in particular, a doctor is not always required.

As the disease progresses, the organism becomes severely weakened. The use of medicines prevents the pathogens from multiplying. The immune system is additionally supported so that the germs ultimately die off within a few days or weeks and are transported out of the body. Afterwards, a recovery can also be expected.

People whose body’s own defense system is already weakened often experience a chronic development of the disease. The infectious disease further weakens the general health of the patient and can lead to a worrying condition. There is a possibility of permanent impairments. In addition, the relief of the symptoms can often only occur after several months. In particularly serious cases, the person concerned is at risk of premature death.

The prognosis is worse in patients who suffer organ damage due to the infectious disease. Lifelong dysfunctions are possible here. In addition, there may be a failure of organ activity and the need for a transplant.


Infectious diseases often need good follow-up care after they have healed. It aims to strengthen the immune system, regenerate those affected and, above all, to prevent the disease from flaring up again. Depending on the area of ​​the disease, the follow-up care after infectious diseases looks a little different and is ideally discussed with the doctor treating you.

In the case of superficial infections, such as wounds, care must be taken to ensure that the affected skin area remains free of dirt. This is accomplished by carefully covering the area, but also by leaving a scab on the skin until it falls off on its own.

In the area of ​​internal infections, which mainly affect the gastrointestinal area or the respiratory tract, the body’s defenses can be strengthened by a number of measures that are in the hands of the patient. This includes a healthy diet, drinking enough water and getting enough sleep. It is also important not to start sporting activities too early if the person concerned is not fit enough for it.

The function of the intestine is often impaired by medication given as part of the infection. This applies in particular to the administration of antibiotics. A non-stressful diet helps with follow-up care. Yoghurt products are often able to rebuild a disturbed intestinal flora.

You can do that yourself

An infectious disease does not always have to be treated by a doctor. A common infection can be treated independently through physical rest and a temporary change in diet.

If you have a cold or flu, classics such as chicken soup and rusks are just as good as herbal tea (e.g. fennel, camomile or lime blossom) and a diet rich in vitamins. If you have a fever, rest in bed and be warm. Chills can be counteracted, for example, by wearing warm clothing or blankets. Gentle inhalation (e.g. salt water or essential oils) helps against a sore throat). Coughs and colds can also be treated with menthol or camphor essential oils applied to the chest and back overnight. A good alternative are neck wraps or wet wraps. Various natural remedies have proven their worth for flu-like infections: Linden blossoms and willow bark against inflammatory pain and marigold blossoms to strengthen the immune system.

After the acute phase of the disease, the following applies: slowly get the weakened organism used to regular exercise again. Light gymnastics or a walk in the fresh air strengthen the circulation and increase well-being. Depending on the type of infection, there are a number of other measures that can be taken. However, it is always up to the general practitioner to decide what people who are infected with an infectious disease can do themselves.

Infectious Diseases

Infectious Diseases Guide