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.
Dermatobiasis is a parasitic human disease caused by a gadfly larva. Typical manifestations of the disease include single or multiple skin lesions in the form of tumor-like formations with infiltrates around them, sensations of a foreign body, symptoms of intoxication. Mucous membranes and internal organs are much less often involved. Diagnosis of parasitosis is based…
Influenza is an acute viral respiratory infection caused by RNA–containing influenza A, B and C viruses, manifested by fever, intoxication and damage to the epithelial lining of the upper respiratory tract. Influenza is included in the group of acute respiratory viral infections – ARVI. The greatest infectious danger of a person with influenza is in…
Granulocytic anaplasmosis is an infectious disease with a transmissible transmission pathway. The main symptoms are prolonged fever with pronounced general intoxication manifestations. Disorders of the gastrointestinal tract, cough, myalgia and skin rashes are much less common. Diagnosis of anaplasmosis is carried out by PCR and dark-field microscopy of stained blood smears to identify the pathogen,…
Hong Kong flu is an acute respiratory disease caused by the H3N2 serotype of the influenza A virus. The clinical features of the disease are damage to the respiratory and digestive systems, as well as poorly controlled high fever. Symptoms of this type of flu are dry cough, sore throat, headache, nasal congestion, pronounced weakness,…
Purulent-resorptive fever is a pathological process that occurs during secondary wound healing. The main symptoms are local complications (purulent congestion, abscesses, phlegmons), fever and general intoxication manifestations. With a prolonged course, traumatic exhaustion develops, a fatal outcome occurs. Diagnosis of the disease is based on anamnesis data, clinical symptoms, detection of pyogenic flora. Treatment is…
Histoplasmosis is a deep mycosis caused by the dimorphic yeast fungus Histoplasma capsulatum, which affects tissue macrophages of the lungs, liver, spleen, lymph nodes, skin and mucous membranes. Among the various forms of the disease, acute histoplasmosis of the lungs prevails, characterized by fever, chest pain, cough, weakness, lymphadenopathy, X-ray changes. In the diagnosis of…
Hirudiniasis is a disease of humans and animals associated with the suction and penetration of leeches into the body. The manifestations are different, depending on the localization of the parasite. Nasal, intestinal and other bleeding, hemoptysis, hoarseness of voice, weakness, headaches, dizziness, hearing loss are more often detected. Diagnosis of pathology is carried out in…
Hymenolepiasis is a helminthic disease caused by tapeworms (dwarf or rat tapeworm) parasitizing in the small intestine. Often the disease has a subclinical course; the clinic of the manifest form is characterized by pain, dyspeptic, asthenoneurotic and allergic syndromes. The diagnosis is confirmed by the detection of eggs or individuals of helminths in the stool.…
Herpes is a chronic recurrent infection caused by the herpes simplex virus and characterized by a predominant lesion of the integumentary tissues and nerve cells. The main route of transmission of herpes infection is contact, but airborne and transplacental transmission of the virus is possible. A distinctive feature of herpetic infection is the ability of viruses…
Hepatitis C is a viral infectious liver disease transmitted by transfusion, characterized by a mild, often subclinical, rarely moderate course in the phase of primary infection and a tendency to chronization, cirrhosis and malignancy. In most cases, hepatitis C has an inanimate, low-symptom onset. In this regard, it may remain undiagnosed for several years and…
