An infectious disease that resolves within 2-3 weeks without symptoms or with very mild symptoms. In the absence of symptoms, a person is a constant source of infection for others who are unaware of his illness. People aged 30–49 years are most often affected; it is very rare in children and the elderly. From the first days of the disease, an admixture of blood in the sputum and more pronounced signs of intoxication and cough are detected. By the end of the 2-3rd week of the disease, the infectious phase ends, an inflammatory focus begins to form - focal shadows, pulmonary vascular ore, and pleural effusion are revealed on the radiograph during this period. Hidden infections are a special variant of infectious diseases. There are quite a lot of them, even among well-known diseases around the world. The most common latent infections are currently called: tuberculosis and measles; tuberculosis, herpes and hepatitis; gonorrhea and syphilis; rubella and HIV/AIDS; mononucleosis and hepatitis, etc. All these infections can occur without any manifestations, therefore, determining their true nature and danger to health becomes problematic. When the disease is in the incubation period (from 7 to 13 days), there are no signs at all. Pathology is detected at this stage only by a qualified doctor, so you need to see him immediately. The doctor also prescribes the correct treatment.