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 task of the specialty is also the study of microbes and parasites, the immune system and the development of new therapies and drugs.
What is infectious diseases?
Infectiology is the study of diseases caused by microbes and parasites. Infectiology is the science of diseases caused by biological agents of inflammation. The pathogens are bacteria, viruses, fungi, and parasites. The clinical infectiologist is a medical doctor who takes care of the diagnosis and elimination of the infestation with the causative organisms. He is a specialist with additional training regulated by law. The research infectiology is devoted to the basic knowledge. This branch is dominated by microbiology and molecular biology. The microbiological branch is further specialized into bacteriology, virology and mycology (science of fungi). Molecular and cellular immunology are the branches dedicated to the study of the body’s defenses. These subspecialties of infectious diseases are also treated by biochemists and biologists. Within immunology, serology (the study of blood plasma) forms another specialty. In clinical practice, the disciplines of infectiology intermingle. Thus, the medical microbiologist is a basic researcher by training. However, he often assists the medical infectiologist when it comes to diagnostics. This is because the microbiologist can identify the microorganisms that have caused an infectious disease.
Treatments and therapies
Bacterial infections are a common problem that infectiologists have 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 one of the bacterial infections. On the rise is Lyme disease, which is transmitted by ticks. The Borrelia bacteria affect the nervous system and the joints. Bacterial infections also include many venereal diseases. Viral infectious diseases include rhinitis caused by rhinoviruses and other respiratory diseases. Adenoviruses cause leukocytosis, an increase in the number of white blood cells (leukocytes) as a reaction of the immune system. Viruses from this family are responsible for influenza, conjunctivitis, as well as diarrheal diseases. Childhood diseases such as mumps, measles, chickenpox and polio as well as rubella are also viral infections. Highly contagious are viral diseases that cause hemorrhagic fever. Causes include Ebola, Lassa, and yellow fever viruses. This syndrome is characterized by life-threatening bleeding. Mycoses are infections with fungi, whereby yeasts or higher fungi can be involved. Physicians distinguish between surface mycoses of the skin and systemic or invasive mycoses that affect internal organs. Pathogens enter the body through the lungs and can affect the spleen and liver as is the case with histoplasmosis (infection with histoplasma). Systemic mycoses can be fatal. Between the two groups of mycoses is the infestation with Candida albicans. The yeast fungus colonizes the oral and intestinal mucosa and also the lung epithelium (epithelium: closing tissue). Surface mycoses occur as dermatomycoses on the skin and onychomycoses on the nails. Parasites of humans include protozoa (single-celled animals) such as Plasmodium (malaria pathogen). The microbes invade erythrocytes (red blood cells). Multicellular organisms such as tapeworms and the small liver fluke are also parasitic in humans.
Diagnosis and examination methods
Diagnosis in infectious diseases begins with the patient interview. The symptoms described, such as fever, fatigue, vomiting, or diarrhea, provide the physician with the first clues for identifying the disease. During the physical examination, the physician will detect classic signs of inflammation (heat, swelling, redness, pain). Blood testing reveals an increase in leukocytes and molecular markers of inflammation. Identification of antigens in the blood serum is used to directly identify the pathogens.Antigens are surface molecules of microbes to which the immune system reacts by forming antibodies. The serological test can also detect these highly specific proteins. This is then a sign that an immune response has already taken place. Using cell cultures, the microbiologist identifies the causative agents of the infection. The evaluation is carried out both macroscopically-optically and microscopically. Biochemical detection methods complement the visual findings. Antibiotics provide the infectiologist with an effective means of eliminating a bacterial infestation. Providing effective antibiotics is a major research challenge. This is because microbes tend to develop resistance to single or multiple of the antibacterial drugs. Therefore, the development of new antibiotics is like a constant race against time. Antiviral drugs are only available for a few viral infections. To prevent bacterial as well as viral infections, doctors use specific active immunizations (vaccinations). The physician injects the patient with attenuated pathogens, whereupon the immune system becomes active. The body’s defenses have thus acquired the ability to respond quickly to an infection. Passive immunization is used to fight an acute infection. Antibodies are administered to the patient with an injection. Pharmaceutical companies produce these immunoglobulins from the blood of infected animals. Antimycotics help against fungal infections. The form of application is either an ointment for surface mycoses or oral tablets for systemic mycoses. Sometimes an injection is also necessary. There are no protective vaccinations for parasitoses yet. Limited protection against malaria is provided by chemoprophylaxis; in the case of acute infestation, drugs developed from ingredients of the mugwort herb help. The physician removes roundworms endoscopically from the gastrointestinal tract (stomach and intestines).