Editorial: Immunosuppressive disease in poultry

Phylodynamic reconstruction of major chicken infectious anemia virus clades epidemiology, dispersal, and evolution

Introduction

Immunosuppressive diseases, such as chicken infectious anemia virus (CIAV), pose a major threat to livestock farming due to reduced disease resistance, poor vaccine response, and overall poor productivity. CIAV, recognized globally for decades, shows a significant genetic diversity, but its implications remain underexplored.

Methods

This study analyzed over 1,000 VP1 sequences and examined CIAV's epidemiology, evolution, and spread with various phylodynamic and phylogeographic approaches.

Results

Findings suggest that CIAV likely originated in Japan in the early 20th century, followed by worldwide diversification in two main clades. Both clades exhibited no significant competition and similar global patterns, characterized by a progressive increase until about 2000, when a transient decline was observed for some years, potentially reflecting the increasing use of vaccines. Accordingly, although significant selective pressures were shaping viral evolution, comparable strengths were estimated in the two viral populations. The phylogeographic analysis identified several connections involving also distantly related regions, and more generally, multiple introduction events occurred in several countries and were followed by local evolution, indicative of unconstrained viral circulation.

Discussion

Overall, the study highlights the ongoing circulation and evolution of different CIAV variants worldwide, where biosecurity measures and vaccination appear insufficient to prevent viral presence and dispersal.

Phytochemicals: a promising approach to control infectious bursal disease

Infectious bursal disease (IBD) is one of the dangerous diseases of poultry that affects the bursa of Fabricius, which is an important organ of the bird's immune system. IBD virus is resistant to many drugs, making its control difficult. Vaccination of IBD is in practice for a long time worldwide to control IBD, but secondary issues like vaccine failure and lower efficacy lead to their reduced use in the field. Multiple medicines are currently used, but the phytochemicals have emerged as promising agents for controlling IBD. The drugs to be developed should possess direct antiviral properties by targeting viral entry mechanisms, enhancing the host immune response, and inhibiting viral protein synthesis. Phytochemicals have potential to contribute to food security by minimizing the possibility of disease outbreaks and ensuring that consumers worldwide obtain healthy poultry products. It has been now claimed that direct and indirect activities of phytochemicals can be effective in the control of IBDV. Although available evidence suggest that the phytochemicals can contribute in controlling occurrence IBDV, there is a definite need of focused studies to gain more insight and develop rational strategies for their practical use. This review highlights the disease caused by IBDV, inhibition of viral replication, boosting the immune system, disruption of viral membrane, and important phytochemicals showing antiviral activities against IBDV.

Cytokine and immunoglobulin profiles of Arbor Acres broiler chickens at different stages of physiological development

Background and Aim

Modern scientific research focuses on a detailed study of the immune system, the mechanisms of immunosuppression, and the search for an effective means to restore disturbed immune homeostasis in farm animals. The present study examined the cytokine and immunoglobulin (Ig) profiles of healthy broiler chickens during physiological development.

Materials and Methods

Arbor Acres broilers (n = 28) were used in the study to achieve this objective. The immune status of broiler chickens was assessed on 7, 14, 28, and 42 days of age, including serum levels of cytokines, Igs, and lysozyme by enzyme immunoassay.

Results

We observed a decrease in the efficiency of immune system functioning of birds with increasing age. The most pronounced immunological deficiency in the body of broiler chickens is noted at the age of 7-14 days, which is associated with immaturity of the immune system and is characterized by the fact that non-specific humoral and specific cellular defense factors are at a rather low level. The levels of lysozyme, interleukin (IL)-2, IL-10, and IgA in blood serum at this age were minimal; starting from 28 days of age, there is a specific humoral immune deficiency, which is compensated by strengthening of cellular defense factors. The serum level of IgY intensively decreases against the background of an increase of lysozyme, IL-2, IL-4, and IL-10.

Conclusion

During postnatal ontogenesis, the immune system of broiler chickens undergoes dynamic changes that have an age direction and phase character. Changes in the immune system may affect immunocompetence, disease susceptibility, and, consequently, productivity.