Histopathological and immunohistochemical study of exocrine and endocrine pancreatic lesions in avian influenza A experimentally infected turkeys showing evidence of pancreatic regeneration

Potential of H1N1 influenza A virus as an air borne pathogen to induce infectivity in pancreas: a mouse model study

INTRODUCTION

H1N1 influenza virus, as an indoor/outdoor pathogen in air, can cause the flu-like illness and respiratory complication. The aim of this study was to evaluate the H1N1 influenza virus replication in pancreas and investigate the immune response against infected pancreas.

MATERIAL AND METHODS

First, mouse pancreas cell line was infected by H1N1 influenza A virus using intranasally and intravenously infection methods, and then the pancreas tissue was collected and pathology experiment was carried out. Next, the protein and genome of influenza virus were detected using immunocytochemistry and real-time PCR, respectively. In addition, serum cytokines and serum lipase were investigated using ELISA.

RESULT

The in-vitro results proved that the mouse pancreatic cell line can support influenza virus replication. The result also proved that influenza virus is capable to infect pancreas and induce pancreas damage. Further, the immune response in mice with infected pancreas exhibited a completely different pattern with that of mice infected through intranasal method.

CONCLUSION

It can be concluded that influenza virus can infect pancreas and change the influenza disease pathway, which might result in a pancreatic injury.

Age-dependent pathogenesis of clade 2.3.4.4A H5N2 HPAIV in experimentally infected Broad Breasted White turkeys

Highly pathogenic avian influenza (HPAI) is a viral disease with devastating consequences to the poultry industry as it results in high morbidity, mortality and international trade restrictions. In the present study, we characterized age-related differences in terms of pathology in commercial white broad breasted turkeys inoculated with A/turkey/Minnesota/12582/2015 (H5N2) HPAIV clade 2.3.4.4A, a virus from the largest HPAI poultry outbreak that affected the Unites States in 2014-2015. Turkeys infected at 6-weeks of age showed inapparent to little clinical signs with rapid disease progression, reaching 100% mortality at 3 days post infection (dpi). In contrast, turkeys infected at 16-weeks of age developed ataxia and lethargy and reached 100% mortality by 5 dpi. Infection in the 6-weeks old turkeys resulted in peracute lesions consistent of extensive hemorrhages, edema and necrosis, but inflammation was not prominent. In the 16-weeks old turkeys, necrosis and hemorrhages in tissues were accompanied by a more prominent subacute inflammatory infiltrate. Both age groups showed presence of avian influenza virus (AIV) nucleoprotein (NP) in multiple cell types including neurons, glial cells, ependymal cells, respiratory epithelial cells, air capillary epithelium and pulmonary macrophages, cardiac myocytes, smooth muscle fibers, pancreatic acini and ductal cells. Cells of the vascular walls stained strongly positive for viral antigens, but no positivity was found in the endothelial cells of any organs. These findings indicate that age is a determinant factor in the progression of the disease and delay of mortality during infection with the H5N2 clade 2.3.4.4A HPAI virus in naïve white broad breasted turkeys.

Diabetes Mellitus With Concurrent Cerebellar Degeneration and Necrosis in a Domestic Goose ( Anser anser domesticus)

A 5-year-old sexually intact male Toulouse goose ( Anser anser domesticus) was presented for ataxia, polyuria, and polydipsia. The goose was cachectic and exhibited head tremors. Results of plasma biochemical analysis and point-of-care glucometry revealed persistent hyperglycemia. Despite supportive care and oral glipizide, the goose died within 48 hours of presentation. Necropsy revealed severe pancreatic atrophy and fibrosis with regionally extensive cerebellar encephalomalacia and generalized Purkinje cell degeneration and necrosis. On a wet basis, hepatic zinc concentration was determined to be twice the reference interval by atomic absorption spectroscopy. Based on these findings, the pancreatic insufficiency with secondary diabetes mellitus was attributed to chronic zinc toxicosis. Despite birds' relative resistance to high blood glucose concentrations, prolonged hyperglycemia is suspected to have caused selective Purkinje cell degeneration and necrosis by glial activation, mitochondrial dysfunction, and glutamate toxicity, which resulted in the clinically observed motor deficits. This is consistent with experimental diabetic rat models. This case highlights the need for further investigation of the complex pathophysiology of diabetes mellitus in birds.

The outcome of experimentally induced inclusion body hepatitis (IBH) by fowl aviadenoviruses (FAdVs) is crucially influenced by the genetic background of the host

In the present study, inclusion body hepatitis (IBH) was experimentally induced by oral inoculation of two groups of specific pathogen-free (SPF) broilers and two groups of SPF layers at day-old with either a fowl aviadenovirus (FAdV)-D or a FAdV-E strain. A substantial variation in the degree of susceptibility was observed with mortalities of 100 and 96% in the FAdV-E and D infected SPF broiler groups, respectively, whereas in the groups of infected SPF layers mortalities of only 20 and 8% were noticed. Significant changes in clinical chemistry analytes of all infected birds together with histopathological lesions indicated impairment of liver and pancreas integrity and functions. Furthermore, significantly lower blood glucose concentrations were recorded at peak of infection in both inoculated SPF broiler groups, in comparison to the control group, corresponding to a hypoglycaemic status. High viral loads were determined in liver and pancreas of SPF broilers already at 4 days post-infection (dpi), in comparison to SPF layers, indicating a somewhat faster viral replication in the target organs. Overall, highest values were noticed in the pancreas of SPF broilers independent of the virus used for infection. The actual study provides new insights into the pathogenesis of IBH, a disease evolving to a metabolic disorder, to which SPF broilers were highly susceptible. Hence, this is the first study to report a significant higher susceptibility of SPF broiler chickens to experimentally induced IBH in direct comparison to SPF layers.