Infection studies with two highly pathogenic avian influenza strains (Vietnamese and Indonesian) in Pekin ducks (Anas platyrhynchos), with particular reference to clinical disease, tissue tropism and viral shedding.

Pekin ducks were infected by the mucosal route (oral, nasal, ocular) with one of two strains of Eurasian lineage H5N1 highly pathogenic avian influenza virus: A/Muscovy duck/Vietnam/453/2004 and A/duck/Indramayu/BBVW/109/2006 (from Indonesia). Ducks were killed humanely on days 1, 2, 3, 5 and 7 after challenge, or whenever morbidity was severe enough to justify euthanasia. Morbidity was recorded by observation of clinical signs and cloacal temperatures; the disease was characterized by histopathology; tissue tropism was studied by immunohistochemistry and virus titration on tissue samples; and viral shedding patterns were determined by virus isolation and titration of oral and cloacal swabs. The Vietnamese strain caused severe morbidity with fever and depression; the Indonesian strain caused only transient fever. Both viruses had a predilection for a similar range of tissue types, but the quantity of tissue antigen and tissue virus titres were considerably higher with the Vietnamese strain. The Vietnamese strain caused severe myocarditis and skeletal myositis; both strains caused non-suppurative encephalitis and a range of other inflammatory reactions of varying severity. The principal epithelial tissue infected was that of the air sacs, but antigen was not abundant. Epithelium of the turbinates, trachea and bronchi had only rare infection with virus. Virus was shed from both the oral and cloacal routes; it was first detected 24 h after challenge and persisted until day 5 after challenge. The higher prevalence of virus from swabs from ducks infected with the Vietnamese strain indicates that this strain may be more adapted to ducks than the Indonesia strain.

Alopecia Universalis in a Horse.

Abstract- Alopecia universalis was diagnosed in a 3-year-old brown Percheron mare. Clinical and histo-pathologic findings in this previously unreported condition in the horse are described.

Control of pandemic (H1N1) 2009 influenza virus infection of ferret lungs by non-adjuvant-containing pandemic and seasonal vaccines.

The pandemic H1N1 2009 influenza virus caused relatively mild disease in most infected people but some suffered extensively from primary lung infection, many more than would have occurred with seasonal influenza infection. Early commercially available pandemic H1N1 vaccines did not contain adjuvant, as did many of the subsequent vaccines, and could not stop infection with the pandemic virus in vaccinated ferrets. Nevertheless, we showed that virus loads in the lungs were greatly diminished in ferrets vaccinated once with an unadjuvanted pandemic vaccine and challenged with 10(6)EID(50) wildtype A/California/07/2009 (H1N1). In addition, a single inoculation with seasonal vaccine showed beneficial reduction in pandemic pulmonary virus loads in the absence of any detectable cross-reactive serological responses. Ferrets primed with either seasonal or pandemic vaccine and then boosted with pandemic vaccine also showed less extensive lung infection when challenged with a tenfold higher dose of pandemic virus. These results implicate non-classical protective mechanisms that prevent severe pulmonary disease but not viral shedding and imply that particular non-adjuvanted vaccines may have retained the ability to induce these responses.

Hendra virus: what do we know?

Hendra virus infection is an emerging infectious disease that is not well understood. Most cases of Hendra virus infection have occurred in Queensland, with one case in a horse in NSW. Hendra virus infection has a high mortality rate in horses and humans and as cases could occur anywhere in Australia it is important to be ready for prompt action should an outbreak occur in NSW. This paper: reviews the current knowledge on Hendra virus infection including methods for preventing the disease; explains the animal health and human health response for an outbreak within NSW; and discusses possible future avenues for post-exposure prophylaxis and prevention by vaccination.