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.
Intestinal worms is a helminthic disease caused by helminths – round and flat, less often annular and spiny-headed parasitic worms. Disease is characterized by a chronic course and systemic effects on the body with the development of abdominal, allergic, anemic syndromes, chronic toxicosis; lesions of the lungs, liver, biliary tract, brain, organ of vision. Laboratory…
Haff disease is an acute food poisoning associated with toxic products accumulating in the insides of fish. Pathognomonic symptoms of nosology are recurrent attacks of muscle pain and symptoms of kidney failure. Fever and signs of intoxication are moderately pronounced. Diagnosis is based on the detection of laboratory criteria for organ dysfunction, the results of a…
Vuhereriosis is an anthroponotic natural focal biohelminthiasis with a transmissive transmission mechanism. Characteristic symptoms of the disease are allergic reactions, the presence of lymphangitis, lymphadenitis with the gradual formation of elephantiasis mainly of the lower extremities and scrotum. Diagnosis is based on the detection of the parasite itself, as well as its antigens and antibodies…
Trench fever is an acute bacterial vector–borne infection. Pathognomonic signs of pathology are severe joint, muscle pain and abundant rash on the body. The disease is accompanied by paroxysmal fever, pronounced symptoms of general intoxication. Diagnosis of the disease consists in the isolation of the pathogen by sowing on nutrient media and molecular genetic methods;…
Recurrent typhus is a disease of the spirochaetosis group, including epidemic (lice) and endemic (tick-borne) recurrent fevers. The main signs are multiple febrile attacks alternating with intervals of apyrexia. There is also marked intoxication, skin rashes, hepatosplenomegaly, mild jaundice of the skin and sclera. The detection of spirochetes in the patient’s blood is crucial for…
Nosocomial infections are various infectious diseases that have been infected in a medical institution. Depending on the degree of spread, generalized (bacteremia, septicemia, septicopiemia, bacterial shock) and localized forms of nosocomial infections (with lesions of the skin and subcutaneous tissue, respiratory, cardiovascular, urogenital system, bones and joints, central nervous system, etc.) are distinguished. Identification of…
HIV is a disease caused by the human immunodeficiency virus, characterized by acquired immunodeficiency syndrome, which contributes to the occurrence of secondary infections and malignancies due to the deep suppression of the protective properties of the body. HIV infection has a variety of course options. The disease can last only a few months or last up…
Visceral leishmaniasis is a chronic infectious protozoal disease with damage to the liver and spleen, the development of anemia and cachexia. Other symptoms are fever, enlarged lymph nodes, skin manifestations. Diagnostics includes the identification of the pathogen from blood and biopsies of internal organs, less often by biopsy on rodents, the search for antibodies to…
Epstein-Barr virus is a pathogen that causes a variety of diseases, the most common of which is infectious mononucleosis. Clinical manifestations range from fever, sore throat, enlarged lymph nodes, difficulty in nasal breathing to symptoms of severe lesions of the nervous system and induction of malignant associated processes. The diagnosis of EBV infection is carried…
Nipah virus is a pathogen that causes an infectious disease with a wide range of symptoms. It is possible that there are no clinical manifestations, as well as signs of respiratory infection or brain damage. Encephalitis is especially often registered. Diagnostic methods used to isolate the virus and antibodies to it are PCR, isolation of…
