Renal tuberculosis itself is not contagious, as the main route of transmission of tuberculosis is through airborne droplets. The main cases of infection with renal TB itself include primary and secondary. Primary cases are rare and are seen in areas with severe tuberculosis epidemics, mainly due to transmission of other pulmonary tuberculosis leading to the first infection with the tubercle bacilli causing renal tuberculosis. Secondary renal tuberculosis develops mostly due to endogenous reinfection after exogenous tuberculosis infection is the main source of this secondary tuberculosis disease. When the body is first infected with the tuberculosis bacillus, the bacillus is able to spread slowly and unrestrictedly throughout the body because the body has no specific immunity. The majority of TB bacilli in latent foci can remain latent for life without developing disease. In a few cases, when the body’s resistance decreases, combined with malnutrition, anemia, trauma, diabetes, etc., latent TB bacilli multiply and lead to the development of renal TB disease. Tuberculosis usually forms a confined space in the kidney, resulting in strong local tissue reaction, caseous necrosis and cavities, and even invasion from one kidney to the other, but it is not contagious, although some of it is excreted in the urine.