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.
Cholera is an acute intestinal infection that occurs when a person is infected with cholera vibrio. Cholera is manifested by pronounced frequent diarrhea, copious repeated vomiting, which leads to significant loss of fluid and dehydration of the body. Signs of dehydration are dryness of the skin and mucous membranes, a decrease in tissue turgor and…
Yaws is a chronic non–venereal endemic treponematosis with a predominantly contact transmission mechanism. The clinical picture is characterized by lesions of the skin, less often – mucous membranes with the presence of characteristic rashes. At the secondary and tertiary stages, damage to the osteoarticular system is added. When making a diagnosis, the epidemiology of the…
Filariasis is a group of transmissible helminthic diseases caused by filariasis – nematodes that parasitize the lymphatic system and subcutaneous tissue. Common symptoms of filariasis include fever, lymphadenitis, lymphangitis, skin rashes, lymphostasis with the development of elephantiasis of the hands, feet, scrotum, eye damage, etc. The diagnosis of filariasis is confirmed when microfilariae are detected…
Fascioliasis is a parasitic invasion caused by hepatic or giant fluke and characterized by a predominant lesion of the hepatobiliary system. The course of fascioliasis is accompanied by malaise, fever, urticaria, nausea, pain in the right hypochondrium, an increase in the size of the liver, jaundice. In the diagnosis of fascioliasis, serological methods (ELISA, RPH),…
Tungiasis is a parasitic disease caused by fleas. Pathognomonic symptoms are the presence of extensive inflammatory infiltrate at the site of introduction of the pathogen, severe itching and pain. Often the disease is accompanied by impaired walking function, edema of the lower extremities and fever. Diagnostics is based on the detection of flea eggs, insects…
Intestinal tuberculosis is a chronic infectious disease caused by mycobacteria; characterized by the formation of specific granulomas in the intestinal wall with further melting of the focus, the formation of a cavity and fibrosis during sanitation. The clinical picture is characterized by the absence of specific symptoms; pain syndrome, dyspeptic phenomena, intoxication are typical. For…
Tuberculosis is a chronic infection caused by Mycobacterium tuberculosis complex bacteria. When affected by tuberculous mycobacteria, respiratory organs most often suffer, in addition, tuberculosis of bones and joints, genitourinary organs, eyes, peripheral lymph nodes occurs. Diagnosis consists in conducting a tuberculin test, X-ray examination of the lungs, detection of mycobacterium tuberculosis in sputum, flushing from…
Whipworm is an intestinal invasion caused by the parasitization of the round helminth – whipworm and occurring with a predominant violation of the function of the digestive tract and nervous system. Gastrointestinal dysfunction in whipworm is characterized by decreased appetite, salivation, nausea, vomiting, abdominal pain, diarrhea or constipation; central nervous system damage leads to headache,…
Trichinosis is an acute infection caused by roundworms. Characteristic symptoms are a variety of allergic reactions and severe muscle pain. Edematous syndrome and fever are often observed. Diagnosis of trichinosis includes serological techniques and detection of the pathogen in biopsies of the affected muscle tissue. Etiotropic methods of treatment involve the use of anthelmintic drugs,…
SARS is an inflammatory pathology of the lung tissue of viral etiology. It is characterized by increasing severe respiratory failure due to respiratory distress syndrome. The clinical picture also includes fever, dry cough, severe shortness of breath. Diagnosis is carried out using molecular genetic methods (identification of the pathogen) and serological studies (search for antibodies).…
