Gonadal pathogenicity of an infectious bronchitis virus strain from the Massachusetts genotype

Abstract

An outbreak of infectious bronchitis caused by the IBVPR03 strain of the Massachusetts genotype affected H-120 vaccinated laying hens in South Brazil. We investigated the cross protection of the vaccine by assessing the traqueal ciliostasis, virus recovery, and histopathological changes typically observed in the respiratory tract. Although the IBVPR03 strain is S1genotyped as Massachusetts with a high genomic similarity to the H-120 vaccine strains, surprisingly, we found no tropism or pathogenicity to the trachea in birds infected with this strain. On the other hand, we observed ovarian and testicle lesions. Here, we show that, despite belonging in the Massachusetts genotype, the IBVPR03 pathotype differs from the expected respiratory pattern, causing instead marked histopathological changes in the gonads, so far not associated with this group.

Pathogenicity of the Canadian Delmarva (DMV/1639) Infectious Bronchitis Virus (IBV) on Female Reproductive Tract of Chickens

“…Our interesting finding of multi-focal heterophilic infiltrations in the ovary (Figure 7e) supports the reoccurrence of acute infections in the persistently infected birds. A similar finding of intense heterophilic infiltration in the ovary was observed 4 to 7 days post infection with a Mass type strain of IBV [50].…”

“…Various Mass type and QX-like strains have been shown to cause no substantial microscopic ovarian lesions [24,25,52]. On the other hand, lesions similar to our findings in the ovary have been described following infection with other IBV strains belong to Mass and QX genotypes [40,50]. The differences in the observations might be due to the difference in the sampling time.…”

Infectious Bronchitis: A Moving Target for Commercial Poultry Industry

“…Deleterious effects of infectious bronchitis on the reproductive health of roosters and cockerels need serious attention and are lacking. Testicular histopathological findings depicted micro-bleeds, tubular degeneration, focal necrosis and vascular congestion [20]. In some reports, the live attenuated and killed IBV vaccine increased the incidence of epididymal stones, decreasing sperm and testosterone concentration [21,22].…”

Infectious Bronchitis Coronavirus Infection in Chickens: Multiple System Disease with Immune Suppression

“…Histologically, deciliation of the epithelium and a reduction in the height of the epithelial cells, along with epithelial desquamation and degeneration, are common in infected oviducts between 7 and 21 dpi [ 66 ] with occasional follicular destruction and microbleeding [ 15 , 68 ]. Fibroplasia and edema of infected lamina propria are also evident [ 66 ].…”

“…Gallardo and colleagues observed IBV replication in cells of the seminiferous tubule (i.e., Sertoli cells) infected with Arkansas (Ark) and Mass IBV strains; moreover, they demonstrated IBV transmission to layers via infected semen, indicating the possibility of venereal transmission of IBV [ 70 ]. IBV-induced changes including mononuclear cell and heterophil infiltration, necrosis and microbleeding of testes have been documented [ 68 ].…”