Pigeon circovirus infection is an immunosuppressive disease of pigeons carried on by the widely recognized virus known as Pigeon circovirus (PiCV). Additionally, due to PiCV’s immunosuppressive activity, a group of diseases collectively known as the “young pigeon disease syndrome” (YPDS) occurs. This study aims to provide information about pigeon circovirus infection transportation throughout the world, the symptoms that have been identified as the disease has progressed, and the diagnostic methods that have been recently developed for the detection of pigeon circovirus. Pigeons of all ages may develop the disease affecting meat and racing pigeons. PiCV-infected pigeons exhibit symptoms such as ruffled feathers, depression, anorexia, weight loss, regurgitation, poor racing performance, diarrhea, and polydipsia. However, asymptomatic PiCV infection has been reported. Most typical and characteristic pathological lesions were the presence of massive basophilic intracytoplasmic inclusion bodies in the thymus, spleen, bursa of Fabricius, and other lymphoid tissues, which are diagnostic. Real-time quantitative and digital droplet PCR techniques have been developed lately for viral detection and quantification.