Infectious diseases include an extensive group of diseases caused by specific pathogenic (pathogenic) pathogens and transmitted from an infected individual to a healthy one. The peculiarities of infectious diseases are their contagiousness (contagiousness), the ability to mass epidemic spread, the cyclical course and the formation of post-infectious immunity. However, these features are expressed to varying degrees in different diseases.
This type of disease develop as a result of a complex biological process of interaction of a pathogenic microorganism with a susceptible macroorganism under certain conditions. There are several periods in the development of infectious diseases: incubation (latent), prodromal (the period of precursors), the period of development of clinical manifestations, the period of the outcome of the disease. The outcome of the infectious process can develop in several ways: convalescence (recovery), lethality, bacterial carrier, transition to a chronic form.
Infectious diseases account for 20 to 40% of the total structure of human diseases. Many medical and microbiological disciplines are engaged in the study, treatment and prevention of infections: actually infectious diseases, epidemiology, venereology, urology, gynecology, therapy, phthisiology, otolaryngology, immunology, virology, etc.
The number of infectious diseases known to science is constantly increasing and currently has more than 1,200 units. During his life, a person comes into contact with a huge number of microorganisms, but only 1/30000 of this community is capable of causing infectious processes. Viruses, rickettsias, bacteria, fungi have pathogenicity properties.
Depending on the location of the predominant localization of the process and a certain mechanism of transmission, infectious diseases are divided into intestinal (dysentery, cholera, salmonellosis, escherichiosis, paratyphs A and B, typhoid fever, food toxicoinfections); respiratory tract infections (ARVI, influenza, chickenpox, measles, mycoplasma respiratory infection); external integuments (erysipelas, anthrax, scabies); blood infections (HIV infection, malaria, yellow fever, recurrent and typhus); infections with multiple transmission routes (enterovirus infections, infectious mononucleosis).
By the nature of the pathogen, infectious diseases are distinguished: viral (viral hepatitis A, B, D, E and C, influenza, rubella, measles, cytomegalovirus and herpes infections, HIV infection, meningococcal infection, hemorrhagic fevers); bacterial (staphylococcal and streptococcal infection, cholera, salmonellosis, plague, dysentery); protozoal (malaria, trichomoniasis, amoebiasis); mycoses or fungal infections (aspergillosis, candidiasis, epidermophytia, cryptococcosis).
Infectious diseases are divided into anthroponotic and zoonotic. Anthroponoses include infections peculiar exclusively to humans and transmitted from person to person (smallpox, diphtheria, typhoid fever, measles, dysentery, cholera, etc.). Zoonoses are animal diseases that can also infect humans (foot-and-mouth disease, anthrax, rabies, tularemia, plague, listeriosis, leptospirosis, brucellosis).
Diseases caused by pathogens of animal origin – parasites (ticks, insects, protozoa) are called invasive or parasitic.
Among infectious diseases, there is a group of particularly dangerous (quarantine) infections with a high degree of contagion, a tendency to rapid spread, a severe epidemic course and a high risk of death in the shortest possible time from the moment of infection. Plague, smallpox (considered eradicated in the world since 1980), cholera, yellow fever (and similar epidemiology of Marburg fever and Ebola) are classified as particularly dangerous infections by the World Health Organization. Tularemia and anthrax are also classified as particularly dangerous infections in our country.
Treatment of patients with infectious diseases is carried out in specialized hospitals or departments, in mild cases – at home. A prerequisite for the successful treatment of infections is compliance with a strict anti-epidemic regime. The prevention of most infectious diseases is the observance of sanitary and hygienic rules and specific immunization.
The medical directory of diseases posted on the website “Medic Journal” contains a special section – where you can find useful information about the causes, mechanisms of development and clinical manifestations of infections, as well as about modern diagnostic and therapeutic techniques used in this field of medicine.
Norovirus infection is an acute viral disease, manifested mainly by gastroenteritis syndrome. The main symptoms are nausea, vomiting, pain, rumbling in the stomach and liquid watery stools, less often – a pronounced temperature reaction of the body, respiratory manifestations. Diagnosis of the disease consists in the detection of the virus in biological materials, antibodies to…
Nocardiosis is a deep pseudomycosis, the causative agent of which causes purulent granulomatous lesion of the lungs, skin and internal organs. The pulmonary form of nocardiosis occurs in the form of bronchopneumonia, empyema of the pleura. With septic nocardiosis, brain abscesses and purulent meningitis usually occur. Nocardiosis of the skin is characterized by the development…
Nematodes are helminthiasis caused by roundworms of the Nematoda class. They occur when infected with parasites by fecal-oral or transmissible means. The most common representatives of this group of diseases include enterobiosis, ascariasis, strongyloidosis. Symptoms of nematodoses include toxic-allergic syndrome, dyspeptic disorders, organ lesions, taking into account the parasitizing sites of mature individuals. To diagnose…
Neuroinfections are a group of infectious pathologies that are caused by bacteria, viruses, fungi or protozoa, characterized by the predominant localization of the pathogen in the central nervous system and signs of damage to its departments. Clinical manifestations are represented by meningeal, intoxication, liquorodynamic syndromes, vegetative-vascular disorders. In the process of diagnosis, anamnestic data, the…
Naegleriasis is an acute infectious disease caused by a free–living pathogenic amoeba, nongleria. It is a very rare fatal pathology. It is characterized by the presence of a general intoxication syndrome, symptoms of damage to the nervous system with the development of primary amoebic meningoencephalitis. Diagnostic measures provide for the detection of the parasite in…
Smallpox is an infectious human disease related to particularly dangerous infections caused by the Orthopoxvirus variola virus, characterized by fever, intoxication and specific rashes on the skin and mucous membranes. The spread of smallpox occurs by aerosol, while the pathogen is so stable in the air that it can cause infection of people who are…
Human monocytic ehrlichiosis is an infectious disease transmitted by ticks. The main symptoms are myalgia, rashes, fever. Nausea, abdominal pain, signs of damage to the respiratory and urinary, as well as the central nervous system are less common: photophobia, vomiting at the peak of cephalgia, impaired consciousness, rigidity of the occipital muscles, paresis, paralysis. Diagnosis…
Mycetoma of the foot is a chronic infectious disease of the feet caused by fungi and bacteria. Specific to the pathology is the formation of granuloma with subsequent damage to fascia, muscles, bones and ligaments. Deformities of bones and joints, painless edema, formation of fistulous passages are characteristic. Diagnostic procedures include examination of biopsy and…
Mycotoxicosis is food intoxication (less often respiratory and dermal lesions) caused by mycotoxins of mold fungi. The symptoms depend on the type of mycotoxin and the way it enters the body. There may be signs of gastroenteritis, headaches, mental disorders, leukopenia, sore throat, convulsions, gangrene of the extremities, etc. anamnesis, cultural isolation of the fungus…
Mycoplasma respiratory infection is an acute respiratory tract infection characterized by the development of bronchopneumonia. Respiratory mycoplasmosis is a very common disease. There is a wave-like rise in morbidity with a frequency of 1 every 2-4 years. There is seasonality: the peak incidence occurs during the cold season. Mycoplasmoses account for 6-22% of all acute…
