Deformation of eggshell by infectious bronchitis
The infectious bronchitis virus has a strong tropism for the respiratory mucosal tissue, kidney tissue and the mucosa of the oviduct. As a consequence of infection of the mucosa of the oviduct hidrosalpingitis may occur (if the right atrophied oviduct is affected) and salpingitis (if developed oviduct is affected). In the latter case the inflammation causes fibrosis and as a result of this it affects the form and subsequent calcification resulting in poorly calcified shells and ribs that are casts of the mucosal lesions of the oviduct.
The deformations of the shell may appear together with or without renal and respiratory injuries. When the vaccination program adequately protects birds, and there is a confrontation with the field virus (probably from migratory birds) hidrosalpingitis is a very common and exclusive lesion and also the presentation of deformed shells.