As is well known, infectious diseases or infectious diseases (also known as infection for short) are transmitted directly or indirectly to humans by pathogens. In medical terms, transmission therefore means infection. Medical science understands this to mean the settlement and multiplication of microorganisms in a more highly organized host organism. However, infection does not yet necessarily mean infectious disease.
Overview of infectious diseases
Any human being can be infected at some time, that is, colonized with microorganisms, without becoming ill from them. Among other things, there are perfectly healthy carriers of diphtheria pathogens and healthy excretors of germs that could cause intestinal infection. We are all surrounded by a large number of microorganisms, but only a small proportion of them can make us ill. Some microorganisms do not even enter us, they cannot exist in the human environment. Others are harmless subtenants 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 to the last detail.
Different forms of pathogens
We distinguish four major groups of pathogens: First, the fission fungi, which occur in various forms, namely, in rod form as bacilli (bacteria), such as the causative agent of dysentery, typhoid fever, tuberculosis and others, in spherical form as pus pathogens in a grape or chain arrangement, in bread roll form as the causative agent of pneumonia, meningitis, and gonorrhea, as fungi, such as the common causative agents of athlete’s foot, or in corkscrew form as the causative agent of syphilis, among others. Another group of pathogens are the virus species, which are very common and so small that they cannot be seen in the usual microscope. They pass through even the very finest filters. They can only be grown on living cells and can be visualized under the electron microscope. They prefer to infect certain tissues, the jaundice virus, for example, the liver cells, the polio virus certain nerve cells, the flu virus cells of the upper respiratory tract. The rickettsiae, another group of microorganisms, are in the order of magnitude between virus species and fission fungi. They cause spotted fever, for example. The fourth group of pathogens, protozoa, are unicellular animal organisms that cause a tropical form of dysentery and malaria. Infectious diseases have always been of great importance in the life of all peoples, especially when they have spread epidemically. None of the past periods of human history can be imagined without these diseases. For the individual, too, the type, severity and timing of an infectious disease overcome are important factors for his mental and physical development and for his integration into society. Severe infectious diseases in childhood, such as disease of the brain and the rest of the nervous system, often leave mental and physical disability for life.
History of the discovery of viruses and bacteria
At all times, people have dealt with the experience of infectious diseases differently. If originally their interpretation was based on the belief in demons, later the believing and fatalistic person thought to recognize in an appeared disease the direct intervention of a higher power, a God-sent punishment, a rewarding or avenging hand. In the 19th century, the knowledge of animate pathogens gradually spread, which, however, made it appear to be a coincidence whether and when a person could ingest the pathogens and fall ill from them. Today, the co-shaping 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, so do the smallest creatures. We even depend on them to some extent. They live with us in a symbiotic community, 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. Pathogenic microorganisms are also part of our environment. But when does their presence lead to disease?
Infection by germs, viruses and bacteria.
There are a number of factors at play here, factors that depend in part on the individual, but also in part on the pathogens. An infectious disease will come about more readily the greater the number and attack power of the invading pathogens that attack humans unprepared. For most types of pathogens, the human body will be able to cope with a certain amount. For example, if typhoid germs have entered the food from the unclean hand of a cook in tropical countries during cooking, eating the soup, for example, will not yet cause illness. However, if this soup has stood for hours and the typhoid germs have multiplied rapidly in the soup, a typhoid disease may develop after the soup has been eaten. In some viral diseases, however, it is sufficient to ingest a small amount of infectious substance. This is the case, for example, with measles, chickenpox and smallpox. If disease germs are particularly vigorous or virulent, i.e., they multiply rapidly and they quickly form toxic metabolic products, so-called toxins, then an infectious disease will develop rapidly. For an infectious disease to develop, the human body’s ability to react to the pathogens is crucial. A strong, healthy, sensible person will be more likely to shrug off an infection than a sickly couch potato. An exhausted, strained organism will be more easily susceptible than one fresh from life and rested. Doctors and laymen not infrequently regard hypothermia as the cause of a cold, bronchitis, or pneumonia, but these are in fact true infectious diseases. Cause and effect are easily confused, in that shivering, chills or, even a chill, which indicate the onset of an infectious fever, are referred to an external chill. However, we do not want to deny that hypothermia can significantly disrupt the body’s ability to react, as the blood circulation of the mucous membranes and limbs deteriorates under the influence of cold and wetness. A condition that favors the occurrence of infections, if the corresponding germs are present. However, the human being is able to form defense bodies, the so-called immune bodies, against certain pathogens or toxins. Immunity is the increased readiness of an organism to defend itself against certain germs. The newborn child receives these immune bodies from the mother’s organism for a short period of time. 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 through vaccinations, which force the body by means of an attenuated or abbreviated course of infection to form these immune bodies – at least temporarily.
Symptoms, complaints, and signs
Typical symptoms of infectious disease include fever, pain, and swelling, as well as inflammation-related redness and itching. In addition, the affected organs react by defensive reactions such as rhinitis, cough, and hoarseness, as well as cramp-like discomfort or nausea. The degree of severity of the symptoms depends on the individual immune system as well as on age. In the case of a bacterial infection and a viral infection, symptoms such as diarrhea, difficulty swallowing and headaches may occur, as well as pain in the limbs. In addition, a noticeable urge to urinate with discoloration of the urine is possible. Chills, rash and fatigue may also develop, as well as breathing difficulties. Timely assignment 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, as in the case of Lyme disease. In some of the infectious diseases, the classic symptoms are only weakly pronounced, making it difficult to assign them. In other cases, the complaints are more helpful for an initial assessment of the disease. Indications of respiratory tract infections are predominantly clear from coughs, colds and sore throats as well as hoarseness and difficulty swallowing. Likewise, diarrhea, malaise and vomiting are typical symptoms of stomach and intestinal infections. If an unpleasant burning sensation occurs during urination, these symptoms indicate an infection of the urinary tract. Symptoms of an infectious disease may be limited to certain parts of the body or be detectable throughout the entire body.
Complications
Whether infectious diseases will cause severe discomfort or even complications cannot usually be universally predicted. 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 initiated quickly enough. This can result in irreversible damage to the patient’s internal organs. Most of those affected suffer from severe fever and fatigue as a result of the infectious diseases. The patient’s ability to cope with stress decreases drastically and there is also a greatly reduced quality of life. As a rule, the patient’s immune system is also significantly weakened, so that other infections or inflammations may also occur. In most cases, infectious diseases are treated with the help of medication. However, whether complications occur depends on the disease in question. A positive course of the disease does not occur in every case. Damage to the internal organs may occur, making the patient dependent on a transplant. Life expectancy may also be reduced by the infectious diseases.
When should you see a doctor?
Many common infectious diseases, such as the common cold or gastrointestinal infections, resolve on their own within a short time and do not require medical treatment. However, high fever, circulatory problems, impaired consciousness or severe abdominal pain should prompt a visit to the doctor. Medical clarification is also advisable if the symptoms do not improve over a period of days or if a cold is accompanied by a severe cough with shortness of breath. Other infectious diseases start slowly and show only unspecific symptoms: a doctor should be consulted if the body temperature remains elevated for a long time or if fever episodes occur without any apparent cause; constant fatigue, a drop in performance, physical weakness or an unwanted loss of weight may also indicate an infectious disease requiring treatment. Some children’s 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 visit to the doctor is recommended in the case of painful redness and swelling that spreads rapidly. An antibiotic therapy is necessary for the treatment of Lyme disease: typical for this is an extensive reddening of the skin, which occurs some time after a tick bite and is often accompanied by flu-like symptoms. If headaches are accompanied by fever and neck stiffness, a life-threatening meningitis is suspected and must be treated immediately.
Treatment and therapy
If one asks about the nature of an infectious disease, starting from the clinical view, one imagines a disease that generally runs its course in a relatively short time, usually has a favorable outcome, and shows manifestations that recur from case to case. Characteristic of an infectious disease, however, is its transmissibility. From the time of infection to the outbreak of the disease, a certain period of time passes for the individual diseases, which we call the incubation period. During this time, there is already the 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 the pathogens, the knowledge about epidemiology and the first experiments with curing serums, and second, the time of the discovery of chemical and antibiotic remedies, which is closely associated with the names Domagk and Fleming. The introduction of antibiotics also brought about a change in the appearance of infectious diseases, since if such substances are used correctly and in time, the infection cannot spread in the organism and therefore its course is at times much shorter and milder. In the control of infectious diseases, we have two important tasks to fulfill: first, to treat the diseases that have occurred and, second, to protect healthy people from possible infection.Therapy and prophylaxis must be seen as a unit, because isolating and treating infectious patients eliminates a possible source of infection. An epidemic that has occurred can best be contained in this way. A prerequisite for successful treatment is always the identification of the pathogen and its response to applicable remedies. All control measures against infectious diseases, which are the subject of the Epidemic Diseases Act, are the responsibility of the state health and hygiene offices and the Federal Ministry of Health. Control measures can only be initiated if the above-mentioned institutions of our health care system are immediately informed of the outbreak of such diseases. Therefore, there is a general obligation to report various infectious diseases. Most infectious diseases are subject to isolation, which means that the sick person must be admitted to a hospital ward where he is isolated from the general public and treated accordingly. In general, the patient may only be discharged from this hospital treatment if, after recovery, there is no longer any risk of infection for those around him, according to medical judgement. In the event of illness, and especially in the case of epidemics, quarantine measures in the vicinity of the sick person are extremely important to prevent the germs from being spread further. Vaccinations are preventive measures that should be carried out as completely as possible in order to protect children and people at risk from the outset. Vaccination induces the longest possible immunity in 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 against measles and in flu seasons an additional comprehensive flu vaccination is planned. Our modern health care system is constantly striving to contain or even eradicate epidemics of all kinds. In this endeavor, it is supported by the health and hygiene departments and by that of the Federal Ministry of Health, whose core areas for epidemic protection direct scientific research in the field of infectious diseases and epidemic protection, the goal of which is comprehensive protection of our population against contagious diseases, and the success of which depends on the insight and willingness of the population.
Outlook and prognosis
Infectious diseases normally have a favorable prognosis. Although the risk of infection is very high, many patients gradually heal even without the use of medical care. In the case of mild flu or other common illnesses, freedom from symptoms is achieved within a few weeks. Especially in the case of mild infections, a doctor is not always needed. With increasing courses of the disease, a strong weakening of the organism occurs. By taking medicines, the pathogens are prevented from multiplying. The immune system is additionally supported so that the germs ultimately die within a few days or weeks and are transported out of the body. Subsequently, recovery can also be expected. People whose body’s immune system is already weakened often experience chronic disease development. The infectious disease further weakens the patient’s general health and can lead to a worrisome condition. There is a possibility of permanent impairment. In addition, relief of symptoms may often take several months to occur. In particularly severe cases, the affected person is at risk of premature death. The prognosis is worse in patients who suffer organ damage due to the infectious disease. Here, lifelong functional disorders are possible. In addition, organ failure and the need for transplantation may occur.
Follow-up
Infectious diseases often need good aftercare after they are cured. It is aimed at strengthening the immune system, regenerating the affected person and, above all, preventing the disease from flaring up again. Depending on the area of illness, aftercare after infectious diseases looks somewhat different and is ideally discussed with the attending physician. In the case of superficial infections, for example wounds, care must be taken to ensure that the affected skin area remains free of contamination.This is achieved 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 or respiratory tract, the body’s defenses can be strengthened by a host of measures that are in the hands of the patients themselves. These include a healthy diet, sufficient drinking and enough sleep. It is also important not to start sporting activities too early if the patient is not yet well enough to do so. Often, the intestine is impaired in its function by medications given as part of the infection. This is especially true when antibiotics have been given. In this case, a non-stressful diet helps in the aftercare. Yogurt products are often able to rebuild a disturbed intestinal flora.
This is what you can do yourself
An infectious disease does not always need to be treated by a doctor. A common infection can be treated independently by physical rest and a temporary change in diet. For colds or flu, classics such as chicken soup and rusks are just as effective as herbal tea (e.g., fennel, chamomile or linden blossom) and a vitamin-rich diet. For fever, bed rest and warmth apply. Chills can be counteracted with warm clothing or blankets, for example. For sore throats, gentle inhalation (such as salt water or essential oils) helps. Coughs and colds can also be treated with menthol or camphor essential oils applied to the chest and back overnight. Throat compresses or moist compresses are a good alternative. For flu-like infections, various remedies from nature have proven effective: Linden blossoms and willow bark for inflammatory pain and marigold blossoms to strengthen the immune system. After the acute phase of illness, the weakened organism should slowly get 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 should always be the family doctor who decides what patients can specifically do themselves in the event of an infectious disease.
