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.
Hepatitis E is a liver lesion of an infectious nature. The infection has a fecal-oral transmission mechanism, proceeds acutely, cyclically and is quite dangerous for pregnant women. The incubation period of viral hepatitis E can last up to 2 months. The clinical picture of the disease has a lot of similarities with the symptoms of…
Hepatitis TTV is an anthroponotic infection with a predominantly parenteral transmission mechanism caused by a hepatotropic DNA–containing virus. Among patients there is both asymptomatic viremia and manifest form of hepatitis (jaundice and itching of the skin, pain in the right side, dyspepsia, etc.). The only way to diagnose the disease is to determine the DNA…
Hepatitis G is an infectious lesion of liver tissue caused by the hepatotropic HGV virus. The leading symptom in the clinic of the disease is prolonged (up to three weeks) jaundice, associated, among other things, with the defeat of the biliary tract and the formation of intrahepatic stagnation of bile. Fever, increased fatigue and a…
Hepatitis D is an infectious liver lesion, coinfection or superinfection of viral hepatitis B, which significantly worsens its course and prognosis. Disease belongs to the group of transfusion hepatitis, a prerequisite for infection with hepatitis D is the presence of an active form of hepatitis B. Detection of hepatitis D virus is carried out by…
Hepatitis B is an infectious liver disease that occurs in various clinical variants (from asymptomatic carrier to destruction of the hepatic parenchyma). In hepatitis B, liver cell damage is autoimmune in nature. Sufficient concentration of the virus for infection is found only in the biological fluids of the patient. Therefore, hepatitis B infection can occur parenterally…
Hepatitis A is an acute infectious liver lesion characterized by a benign course, accompanied by necrosis of hepatocytes. Viral hepatitis A is included in the group of intestinal infections because it has a fecal-oral mechanism of infection. In the clinical course of viral hepatitis A, there are pre-jaundice and jaundice periods, as well as convalescence.…
Haemophilus influenzae is a group of bacterial infections caused by influenza bacillus (Pfeiffer). The respiratory organs, the brain, the musculoskeletal system are most often affected; sepsis occurs during generalization. About a third of those who have been ill remain permanently disabled or have persistent disorders of the central nervous system, joints, ENT organs. Diagnosis is…
Hemorrhagic fever are viral infections with a natural focal spread, occurring with hemorrhagic and acute febrile syndrome. The symptoms of hemorrhagic fever include severe intoxication, high body temperature, hemorrhagic rash, bleeding of various localization, multiple organ disorders. The form of hemorrhagic fever is determined taking into account clinical, epidemiological and laboratory data (PCR, ELISA, RIF).…
Hemorrhagic fever with renal syndrome is a zoonotic hantavirus infection characterized by thrombohemorrhagic syndrome and predominant kidney damage. Clinical manifestations include acute fever, hemorrhagic rash, bleeding, interstitial nephritis, in severe cases – acute renal failure. Specific laboratory methods for the diagnosis of hemorrhagic fever with renal syndrome include ELISA, PCR. Treatment consists in the introduction…
Marburg virus disease is an acute infectious disease caused by an RNA–containing filovirus (Marburg virus), occurring with severe capillarotoxicosis and high mortality. Symptoms include high fever, severe intoxication, severe diarrhea and vomiting, skin hemorrhages, internal bleeding, liver, heart, kidney, and central nervous system damage. The diagnosis takes into account epidemiological and clinical data, the results…
