Negative influence of suboptimal quality of drinking water on avian coronavirus pathogenesis and immune response: A...

This study investigated the impact of poor drinking water quality on infectious bronchitis virus (IBV) pathogenesis. Drinking water samples from Alberta layer farms were assessed based on physical, chemical, and microbiological properties. The highest-scoring field water (FW), which is suboptimal with higher pH, hardness and bicarbonate concentration was selected, transported in clean containers, and used in this control experiment. Forty-eight specific pathogen free White Leghorn chicks were divided into four groups: Tap water non-infected (TW-control), field water non-infected (FW-control), tap water infected (TW-infected), and field water infected (FW-infected). They were maintained on their respective water types for 7 weeks. The IBV genome load was significantly higher in the lungs of the FW-infected when compared to TW-infected group at 4 days post-infection (dpi). The histopathological lesion scores in the trachea and lungs were higher in the FW-infected birds when compared to the uninfected controls at observed time points. However, the histopathological lesion scores in the trachea and lungs of the TW-infected birds were not different when compared to that of FW-infected group. In the lungs, the CD4 + and CD8 + T cell populations were significantly higher in the TW-infected group at observed time points when compared to uninfected controls. However, the CD4 + and CD8 + T cell populations in lungs of the FW-infected birds were not different when compared to that of TW-infected group. In the spleen, CD4 + and CD8 + T cell populations were significantly higher in TW-infected and FW-infected birds when compared to uninfected controls depending on the observed time point and we did not observe differences in CD4 + and CD8 + T cell populations in spleen between TW-infected and FW-infected birds. These findings suggest that sub-optimal drinking water can exacerbate IBV infection by weakening immune responses and increasing disease severity. Further studies are necessary to observe the effect of suboptimal water quality on the development of vaccine-mediated immune response. Understanding these interactions is key for improving water management strategies for maintaining poultry health and productivity.