EN
Circovirus infections are commonly found in birds and mammals. Today, two genuses: Gyrovirus and Circovirus occur within the Circoviridae family. In poultry pathology, especially on large commercial farms of hens and chickens, special attention is focused on Chicken Infectious Anemia Virus-CIAV of the Gyrovirus genus. The genus of Circovirus includes Psittacine Beak and Feather Disease Virus (PBFDV), pigeon circovirus, referred to as Columbid circovirus (CoCV), or Pigeon cicovirus (PiCV), goose circovirus (GoCV), canary circovirus (CaCV) and others described as circovirus-like diseases, isolated from other species of birds. The paper presents characteristics of circoviruses and the immunosuppressive effects on host cells as well as the diagnosis of infections in birds.