Infectiology

Infectiology is the study of diseases caused by microbes and parasites. The discipline includes diagnosis, therapy and prophylaxis of infestation with bacteria, viruses, fungi and parasites. The department is also responsible for research into microbes and parasites, the immune system and the development of new therapies and drugs.

What is the infectious disease?

Infectiology is the science of diseases caused by biological inflammatory agents. The pathogens are bacteria, viruses, fungi and parasites. The clinical infectiologist is a doctor and takes care of the diagnosis and the elimination of the infestation with the causative organisms. He is a specialist doctor with additional training regulated by law.

Research-based infectious diseases are devoted to basic knowledge. This sub-area is dominated by microbiology and molecular biology. The microbiological branch is further specialized in bacteriology, virology and mycology (science of fungi). Molecular and cellular immunology are the branches that serve to research the body's own defenses. These sub-subjects of infectiology are also treated by biochemists and biologists. Serology (examination of blood plasma) is another specialty within immunology.

In clinical practice, the disciplines of infectiology are mixed up. The medical microbiologist is a basic researcher by training. Often, however, he is at the side of the medical infectiologist when it comes to diagnosis. Because the microbiologist can identify the microorganisms that have triggered an infectious disease.

Treatments & therapies

Bacterial infections are a common problem that the infectiologist has to deal with. Salmonella is often the cause of diarrhea in the western hemisphere, while cholera is common in the developing world. Meningitis and pneumonia can also be caused by the protozoa. Tuberculosis is also a bacterial inflammation. Lyme disease, which is transmitted by ticks, is on the rise. Borrelia attack the nervous system and joints. Bacterial infections also include many sexually transmitted diseases.

The doctors count rhinoviruses caused by rhinoviruses and other respiratory diseases as viral infectious diseases. Adenoviruses cause leukocytosis, an increase in the number of white blood cells (leukocytes) in response to the immune system. The viruses from this family are responsible for the flu, conjunctivitis and diarrheal diseases. Childhood diseases such as mumps, measles, chickenpox and polio, as well as rubella, are viral infections. Viral diseases that cause hemorrhagic fever are highly contagious. The causes are, for example, Ebola, Lassa and yellow fever viruses. This syndrome is characterized by life-threatening bleeding.

Mycoses are fungal infections that may involve yeast or higher fungi. Doctors differentiate between surface mycoses of the skin and systemic or invasive mycoses that affect internal organs. The pathogens enter the body via the lungs and can affect the spleen and liver, as is the case with histoplasmosis (infection with histoplasm). Systemic mycoses can be fatal. The infection with Candida albicans stands between the two groups of mycoses. The yeast colonizes the oral and intestinal mucosa as well as the lung epithelium (epithelium: covering tissue).

Surface mycoses occur as dermatomycoses on the skin and onychomycoses on the nails. The parasites of humans include protozoa (single-celled animals) such as Plasmodium (malaria pathogen). The microbes invade the erythrocytes (red blood cells). Multicellular cells such as tapeworms and the little liver fluke are also parasitic in humans.

Diagnosis & examination methods

The diagnosis in infectious diseases begins with the patient consultation. The symptoms described, such as fever, exhaustion, vomiting or diarrhea provide the doctor with initial clues for recognizing the disease. During the physical examination, the doctor will determine classic signs of inflammation (heat, swelling, redness, pain).

The blood test reveals an increase in leukocytes and molecular markers of inflammation. The identification of the antigens in the blood serum serves to directly identify the pathogen. Antigens are surface molecules of the microbes to which the immune system reacts with the formation of antibodies. The serological test can also detect these highly specific proteins. This is then a sign that an immune response has already taken place.

The microbiologist uses cell cultures to identify who caused the infection. The evaluation is carried out both macroscopically and optically as well as microscopically. Biochemical detection methods complement the visual findings. With antibiotics, the infectiologist has an effective means of eliminating bacterial infestation. Providing efficient antibiotics is a major research challenge. This is because microbes tend to develop resistance to one or more of the antibacterial drugs. The development of new antibiotics is therefore a constant race against time. Antiviral drugs are only available for a few virus infections.

Doctors use specific active immunizations (vaccinations) to prevent bacterial and viral inflammation. The doctor injects the patient with weakened pathogens, which activates the immune system. The body's own defenses have thus acquired the ability to react quickly to an infection. Passive immunization is used to combat an acute infection. Antibodies are given to the patient with an injection. The pharmaceutical companies produce these immunoglobulins from the blood of infected animals.

Antifungal drugs help against fungal infections. The form of application is either an ointment for surface mycoses or oral intake of tablets for systemic mycoses. Sometimes an injection is also required. There are still no vaccinations for parasitosis. Chemoprophylaxis offers limited protection against malaria, and drugs that have been developed from the ingredients of mugwort help help with acute infestation. The physician removes roundworms endoscopically from the gastrointestinal tract (gastrointestinal tract).