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.
Paragonimiasis is a zooanthroponotic disease from the group of biohelminthiasis caused by a pulmonary fluke, usually parasitizing in the lungs, less often in the brain and other organs. Disease can be manifested by abdominal syndrome, itching of the skin, bronchopneumonia, hemoptysis, pulmonary bleeding, symptoms of meningitis, convulsive seizures, decreased visual acuity. The diagnosis is established…
Acute respiratory infections are various acute infectious diseases that occur as a result of damage to the epithelium of the respiratory tract by RNA and DNA–containing viruses. Usually accompanied by fever, runny nose, cough, sore throat, lacrimation, symptoms of intoxication; may be complicated by tracheitis, bronchitis, pneumonia. The diagnosis of ARI is based on clinical…
Acute diarrhea is a polyetiological syndrome accompanying the course of a number of infectious and non–communicable diseases, characterized by frequent loose stools. With acute diarrhea, the stool becomes profuse, watery or mushy, it may contain impurities of undigested food, mucus; its frequency is more than three times a day. To determine the causes of the…
Monkey pox is an acute viral disease related to natural focal infections. The main sign is a rash on the skin and mucous membranes, generalized lymphadenopathy, fever, arthralgia, myalgia, pronounced weakness. Less common is dry cough, sore throat. Diagnosis consists in the isolation of the pathogen using microscopic and virological methods, detection of antibodies in…
Opisthorchiasis is a helminthic disease caused by flat parasitic worms of the fluke class and occurring with damage to the hepatopancreatobiliary system. The course of opisthorchiasis is characterized by fever, abdominal pain, impaired appetite, skin rashes, jaundice, hepatosplenomegaly, dyspepsia, asthmatic bronchitis, asthenovegetative syndrome. Diagnosis of opisthorchiasis is based on the detection of opisthorchis eggs in…
Psittacosis is a chlamydial infection that occurs with a predominant lesion of the respiratory system. Clinical manifestations include fever-intoxication syndrome, pneumonia, conjunctivitis, hepatolienal syndrome, signs of neurotoxicosis and meningism. The diagnosis of psittacosis is confirmed by the data of serological studies (IFA, IFT, HI, ELISA), sputum microscopy, lung radiography. Etiotropic therapy of psittacosis is carried…
Opportunistic infections are a large group of infectious diseases that develop in patients with various types of immunodeficiency and are uncharacteristic for people with normal immune status. Pathologies affect any organ system and cause the corresponding symptoms. Common clinical manifestations include prolonged subfebrility, lymphadenopathy, asthenic syndrome. Diagnosis of opportunistic infections includes serological, molecular genetic, bacteriological…
Onchocerciasis is a helminthic invasion from the group of filariatoses, leading to damage to the skin, lymph nodes and eyes. Dermatological changes in onchocerciasis are characterized by the formation of dense fibrous nodes, itchy rash, slowly healing ulcers, depigmentation sites. The defeat of the lymphatic system is accompanied by sclerosis of lymph nodes, the development…
Omsk hemorrhagic fever is a naturally focal transmissible viral infection characterized by hemorrhagic reactions, predominant damage to the respiratory system and the central nervous system. Disease occurs with high fever, intense headache, myalgia, increased bleeding, frequent development of bronchitis, pneumonia, cerebral and meningeal phenomena. Diagnosis is based on clinical and epidemiological history, laboratory and instrumental…
Omicron is the official WHO name for the SARS-CoV-2 B.1.1.529 mutation that causes coronavirus infection. Among the hypotheses of its appearance are changes in the virus in the body of people with immunodeficiency, circulation between the population of animals and humans, insufficient coverage of the population with immunization. The symptoms of omicron are similar to…
