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.
Sleeping sickness is a protozoic, the causative agent of which is the simplest genus Trypanosoma, and the carriers are blood–sucking tsetse flies. The symptoms are characterized by the formation of primary affect at the site of the bite (trypanosomal chancre), wave-like fever, lymphadenitis, skin rashes, local edema, increasing drowsiness, paralysis, mental disorders, coma. Diagnosis is…
Rat bite fever is a disease of the spirochetosis group that develops when bitten by mouse–like rodents, occurring with recurrent fever and skin manifestations. Symptoms include primary affect (infiltrate with an expression at the bite site, lymphangitis), as well as recurrent attacks of fever, polymorphic rash, regional lymphadenitis. The methods of specific diagnosis are microscopy…
Scarlet fever is an acute infection with a predominant lesion of the oropharynx, severe intoxication and characteristic exanthema. The causative agent of scarlet fever is group A streptococcus, which is transmitted from the patient by contact or airborne droplets. The scarlet fever clinic includes general intoxication and fever, scarlet fever, regional lymphadenitis, crimson tongue, small-point…
Pseudomonas infection is an infectious disease caused by the invasion of Pseudomonas aeruginosa. It is the leading nosocomial infection. Chronic forms are characterized by damage to the respiratory tract with the formation of “biological films”, for acute course – bacteremia and damage to internal organs. Diagnosis is based on the detection of the pathogen in…
Ciguatera is a disease that occurs when eating certain types of reef fish. The most common symptoms are neurological manifestations, such as paresthesia of the face, limbs, hallucinations, headache, loss of consciousness, delirium. Neuropsychological, cardiovascular, gastrointestinal disorders are not uncommon. Diagnosis consists in the detection of a toxin in food, characteristic symptoms of the disease.…
Anthrax is an acute, especially dangerous infectious disease that occurs in humans and animals when infected with Bacillus anthracis, occurring with the formation of specific carbuncles on the skin, or in septic form. The source of infection is wild animals and cattle, infection occurs by contact. The incubation period of anthrax is on average 3-5…
Septicopyemia is a form (phase) of the course of sepsis, which is characterized by the appearance of pyemic metastatic foci in various organs due to hematogenous infection. It proceeds with the phenomena of severe intoxication, aggravated by the formation of abscesses in soft tissues, liver, the development of abscessing pneumonia, purulent meningitis, osteomyelitis, endomyocarditis, etc.…
Swine flu is a highly contagious disease of animals and humans caused by the influenza virus serotype A (H1N1) and prone to pandemic spread. In its course, disease resembles the usual seasonal flu (fever, weakness, body aches, sore throat, rhinorrhea), but differs from it in some features (the development of dyspeptic syndrome). Diagnosis is based…
Glanders is a severe bacterial disease of a septic-pyemic nature caused by Glanders bacillus – Burkholderia mallei. With disease, intermittent fever, lymphadenitis, muscle abscesses, abscessing pneumonia, purulent arthritis, osteomyelitis, multiple purulent-hemorrhagic pustules on the skin and mucous membranes, turning into glanders ulcers, are noted. The diagnosis is confirmed by microscopic, bacteriological, serological studies, biological and…
Salmonellosis is an infectious disease of the digestive system resulting from infection with bacteria of the genus Salmonella, accompanied by severe intoxication and dehydration, sometimes occurring as typhus, or with septicemia. The most dangerous in terms of salmonellosis are thermally poorly processed eggs, dairy and meat products. The course of salmonellosis can occur according to…
