Fowl adenovirus serotype-4 (FAdV-4) infection, also known as hydropericardium-hepatitis syndrome (HHS), is one of the most prevalent diseases in the Korean poultry industry. Therefore, an effective vaccination against FAdV-4 should be developed for prevention of HHS infection. However, a standard animal model with significant pathologic characteristics has not been established for evaluation of HHS vaccine efficacy. In this study, we comparatively evaluated FAdV-4 pathogenicity from specific- pathogen-free (SPF) chickens using FAdV-4 strain (ADL091024) isolated in laying chickens in Korea according to chicken age, passage number and virus titers. In brief, FAdV-4 passaged four times in yolk sac of SPF eggs with the highest viral titers could induce the most severe clinical signs in 1-day-old chickens, similar to natural HHS outbreaks. Furthermore, the efficacy of a newly developed attenuated live FAdV-4 vaccine candidate was successfully determined using the established 1-day-old SPF chickens. There was no significant pathogenicity based on the criteria such as mortality, body weight, gross lesions, histological lesions and virus detection rates in the vaccination and non-challenge control groups. However, the challenge group without vaccination showed significant pathogenicity including hepatic necrosis, histological lesion scores in the liver and heart, virus replication and decreased body weight gain. In conclusion, the chicken challenge model established in this report was proposed for consistent and reliable evaluation of FAdV- 4 vaccine efficacy.

This report describes the different responses to dapsone treatment in two cases of sterile nodular panniculitis (SNP). Two dogs were presented with ulcerative skin lesions, painful and erythematous papules, and nodules. History and physical examination revealed systemic signs such as pyrexia, lethargy, depression, and anorexia, in addition to ulcerated and ruptured nodules on the skin. The dermatological diagnostics included clear taping, trichogram, skin scraping, impression smears, fungal and bacterial cultures, and histopathology and special stainings of multiple punch biopsies obtained from the skin lesions. Based on the clinical and histopathologic findings, the absence of microbiological infection, and the positive response to immunosuppressive therapy, both the dogs were diagnosed with SNP. Although both dogs had been treated with various immunosuppressive drugs including prednisolone, cyclosporine, azathioprine, and triamcinolone, therapy was switched to dapsone due to recurrent dermatological signs and presumed steroidinduced hepatotoxicity. The clinical responses to dapsone were opposite in the two cases. In the first case, combination therapy with prednisolone and cyclosporine was effective in attenuating ulcerative lesions, while dapsone alone did not control the clinical signs. In contrast, in the second case, the therapeutic response to the common immunomodulatory drugs such as prednisolone, triamcinolone, and azathioprine was inadequate. Interestingly, dapsone alone was effective in controlling the clinical signs without causing undue side effects. Although the usefulness of dapsone for the treatment of canine SNP is unknown, it may be considered in mild to moderate cases of SNP when the use of steroids is not recommended due to its low efficacy or side effects.

Korea had experienced second epidemic highly pathogenic avian influenza (HPAI), and there were the seven affected farms, including two breeder duck farms, from 22nd November 2006 to 6th March 2007. Here, we reported the clinico-pathological characteristics of domestic breeder ducks farms naturally infected with HPAI virus (H5N1). Clinically, the most ducks showed various signs from depression, decreased egg production and feed consumption to even, death. The most commonly gross changes were hepatomegaly, splenomegaly, petechial and ecchymotic hemorrhage on the liver surface, a white stripe on the cardiac muscle, and severely hemorrhagic and deformed eggs. The most significant histopathological changes were necrosis of various cells such as neuron, lymphocytes, cardiac myocytes, hepatocytes, blood vessels and pancreatic acinar epithelium. The viral antigen was mainly detected in the endothelium of blood vessels of various organs and tissues, peripheral nerves and neuronal cells. Based on the above results, we identified that HPAI H5N1 induced systemic infection in the adult breeder ducks.