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.
Chickenpox is an acute infectious disease of viral etiology characterized by the appearance of a characteristic bubble rash against the background of a general intoxication syndrome. The causative agent of chickenpox is the herpes virus type 3, transmitted from the patient by airborne droplets. Chickenpox is one of the most common childhood infections. It is…
Vesicular rickettsiosis is an acute transmissible natural focal infection. Characteristic signs are primary affect with central necrosis and abundant rash on the body. Fever, symptoms of general intoxication and a relatively benign course are noted. The main method of diagnosis is the isolation of the rickettsia gene material (PCR), the detection of antibodies to the…
Bubonic plague is a quarantine natural focal infection. The main clinical symptom is the presence of plague bubo. Nosology is characterized by high fever, severe intoxication, with immunosuppression, visceral lesion, generalization of infection is possible. Diagnostics is based on the detection of the pathogen in biological materials (microscopy, seeding, PCR), serological methods are uninformative, practically…
Typhoid fever is an acute intestinal infection characterized by a cyclical course with a predominant lesion of the intestinal lymphatic system, accompanied by general intoxication and exanthema. Typhoid fever has an alimentary pathway of infection. The incubation period lasts on average 2 weeks. The typhoid fever clinic is characterized by intoxication syndrome, fever, rashes of…
Brucellosis is a zoonotic infection characterized by multiple organ pathologies and a tendency to chronization. An important pathogenetic component of brucellosis is allergic reactivity. Brucella transmission occurs mainly by food and water, most often through milk and meat of infected animals. In cattle breeders, an aerial and contact pathway of brucellosis transmission can be realized.…
Brugiosis is a chronic biohelminthiasis from the group of filarioses with a transmissive transmission mechanism. The clinical picture in the acute phase of the disease is characterized by the presence of signs of desensitization of the body, the development of lymphangitis and lymphadenitis. Repeated relapses of the pathological process lead to the formation of elephantiasis…
Botulism is an acute food toxicoinfection that develops as a result of ingestion of botulinum toxin into the human body. Infection occurs in an alimentary way, most often when eating canned food containing botulism spores. Botulism is characterized by damage to the nervous system as a result of blocking of acetylcholine receptors of nerve fibers…
Chagas disease is a transmissible protozoal infection, the causative agent of which is pathogenic Trypanosoma cruzi, and the carrier is triatom bugs. The acute form is manifested by fever, headache and muscle pain, edema, rash, lymphadenitis, hepatosplenomegaly, cardiomegaly and myocarditis, meningoencephalitis; chronic – heart failure, megaesophagus, megacolon. The diagnosis is based on the data of…
Whipple’s disease is a rare infectious disease that occurs with a predominant lesion of the lymphatic system of the small intestine and the synovial membranes of the joints. The main clinical signs are diarrhea, fever, polyarthritis and joint pain, multiple enlargement of lymph nodes, lung, heart and central nervous system damage. Diagnosis is made by…
Lyme disease is a vector–borne infection, the causative agent of which is the Borrelia spirochete, which enters the body when an ixod mite bites. The clinical course includes local cutaneous (chronic migrating erythema) and systemic (fever, myalgia, lymphadenopathy, neuritis of peripheral and cranial nerves, meningitis, encephalitis, myelitis, myocarditis, pericarditis, oligoarthritis, etc.) manifestations. Confirmation of the…
