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.

Fever of Unknown Origin

Fever of unknown origin (FUO) – clinical cases characterized by a persistent (more than 3 weeks) increase in body temperature above 38 ° C, which is the main or even the only symptom, while the causes of the disease remain unclear, despite intensive examination (conventional and additional laboratory techniques). Fevers of unclear genesis can be…

Ebola Virus

Ebola virus is a particularly dangerous viral infection caused by the Ebola virus and occurring with severe hemorrhagic syndrome. The initial clinical signs of Ebola virus include high fever and severe intoxication, catarrhal phenomena; during the peak period, indomitable vomiting, diarrhea, abdominal pain, hemorrhages in the form of skin hemorrhages, external and internal bleeding are added.…

Chikungunya Virus

Chikungunya virus is an acute viral infectious disease with a transmissible transmission pathway caused by the arbovirus of the same name. A specific manifestation of fever is inflammation of the joints ‒ polyarthritis. The clinic of the disease is also characterized by high fever, symptoms of intoxication (weakness, fatigue, decreased performance, moderate headache) and rashes.…

Ross River Virus

Ross River virus is an acute viral disease with a transmissible pathway of infection. The main symptoms are polyarthritis, tendovaginitis and rash. The disease is also manifested by fever, moderate intoxication syndrome, a violation of the psycho–emotional state, less often – lymphadenopathy, paresthesia of the extremities. The diagnosis of pathology is reduced to the detection…

Sadfly Fever

Sadfly fever is an acute natural focal infection caused by a filtered arbovirus and occurring with a short–term febrile syndrome. Disease is accompanied by febrile fever, headaches and muscle pains, eye reactions (symptoms of Peak and Taussig), hyperemia of the face and neck, hemorrhages, meningeal phenomena, prolonged asthenic syndrome. Recognition is carried out on the…

Lassa Fever

Lassa fever is a naturally focal viral infection occurring with capillarotoxicosis and multiple organ disorders. Clinical manifestations of Lassa fever include fever, intoxication, diarrhea, bleeding, ulcerative pharyngitis, kidney failure, etc. Laboratory diagnostics of Lassa fever is based on the isolation of the virus from the biological materials of the patient, as well as the determination…

Q Fever

Q fever is a rickettsiosis infection that occurs with a febrile syndrome and lung damage, in particular, with the development of atypical pneumonia. The initial period is characterized by general toxic manifestations; during the peak period, symptoms of tracheitis, bronchitis, and pneumonia dominate. The diagnosis is based on a complex of clinical, epidemiological and laboratory…

Zika Virus

Zika virus is an acute infectious disease with a predominantly transmissible transmission mechanism. The disease is asymptomatic or is manifested by an increase in body temperature, general intoxication syndrome, pain in muscles, joints, conjunctivitis, rash. The main danger of infection is the formation of microcephaly and various neurological disorders in the fetus in case of…

west nile virus

West Nile Virus

West Nile virus is an acute infectious viral disease with predominantly transmissible human infection. Specific symptoms are damage to the central nervous system, blood vessels, and mucous membranes. Characterized by cephalgia, prolonged fever with terrific chills, severe muscle pain, arthralgia. Diagnosis involves the detection of the pathogen and antibodies to it in the blood and liquor…

Rift Valley Fever

Rift Valley fever is an acute arbovirus infection. The main symptoms of the disease are lesions of the central nervous system, eyes and liver, various hemorrhagic manifestations. The disease is accompanied by severe intoxication and fever. The diagnosis is based on the methods of virus isolation from the biological substrates of the patient and the…