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.
Food poisoning are acute intestinal infections caused by eating foods containing microorganisms and their toxins. Food poisoning are characterized by a sudden onset, bouts of nausea and repeated vomiting, diarrhea, cramping abdominal pain, fever and symptoms of intoxication. Diagnostics is carried out by bacteriological examination of vomit, gastric lavage, feces, food products. In case of food…
Pyroplasmosis is a transmissible protozoal disease of humans and animals caused by intracellular protozoa of the genus Babesia, parasitizing in erythrocytes. The disease develops in individuals with a reduced immune response. The course of pyroplasmosis is accompanied by fever, chills, headaches and muscle pains, arthralgia, hepatomegaly, anemia. The diagnosis of pyroplasmosis is confirmed by the…
Pinta is an infectious bacterial disease with a predominant lesion of the skin and mucous membranes. Pathognomonic symptoms are the stages of skin lesions from pinto chancre to vitiligination of the site of penetration of the pathogen. Lymphadenitis, lymphangitis, fever are characteristic. The diagnosis of pinta is based on the data of the bacterioscopic method…
Pasteurellosis is an acute zoonotic infectious disease of bacterial origin. It proceeds with the involvement of the skin, subcutaneous tissue, joints and bones. The condition is manifested by high fever, severe intoxication, damage to internal organs; cases of chronic course are described. Diagnosis of pathology is carried out mainly by bacteriological methods, serological techniques are…
Parvovirus is an anthroponotic disease caused by a DNA-containing virus. It is often asymptomatic. It can manifest as a general intoxication syndrome, catarrhal phenomena, dyspeptic symptoms and rash. For adults, the presence of signs of arthritis is characteristic. With transplacental transmission of the pathogen, nonimmune fetal dropsy develops, miscarriages are possible in the early stages. Diagnosis…
Paratyphoid fever A and B are acute infectious diseases similar in clinical course to typhoid fever caused by intestinal bacteria of the genus Salmonella. The paratyph A clinic is characterized by a febrile syndrome, catarrhal phenomena, an abundant roseolous rash on the body; paratyph B proceeds with an increase in body temperature, skin rashes, signs…
Paratyphoid fever C is an acute bacterial intestinal infection. Characteristic signs of pathology are nausea, vomiting, copious loose stools, enlargement of the liver and spleen. The disease is accompanied by severe fever and intoxication. Diagnosis involves the detection of the pathogen in the body’s biological fluids, an increase in the titer of antibodies to bacterial…
Parapertussis is an acute respiratory tract infection caused by Bordetella parapertussis. Clinically resembles a mild form of whooping cough, manifested by rhinitis, pharyngitis, paroxysmal cough (sometimes with reprises), subfebrility. Etiological diagnosis is performed by the cultural method, using PCR analysis and serological tests (RPH, ELISA). Paracoccus therapy is carried out by symptomatic means: expectorants, antihistamines,…
Parasitic liver diseases are a group of heterogeneous diseases caused by parasites and helminths. The most common liver parasitoses are ascariasis, echinococcosis, amoebiasis, opisthorchiasis, etc. Common symptoms include exhaustion, dystrophic changes in the skin and hair, increased fatigue, sleep disorders, bad breath. In diagnostics, duodenal probing, examination of duodenal contents, analysis of feces for helminth…
Parainfluenza is an acute viral disease of the upper respiratory tract. Pathognomonic symptoms of the disease are inflammation of the trachea, larynx, the formation of false croup in children. Symptoms of intoxication, fever, nasal congestion, enlarged lymph nodes are also detected. The diagnosis of pathology is based on the detection of the parainfluenza virus in…
