Detection and quantification of infectious avian influenza A (H5N1) virus in environmental water by using real-time reverse transcription-PCR

Routes of avian influenza virus (AIV) dispersal among aquatic birds involve direct (bird-to-bird) and indirect (waterborne) transmission. The environmental persistence of H5N1 virus in natural water reservoirs can be assessed by isolation of virus in embryonated chicken eggs. Here we describe development and evaluation of a real-time quantitative reverse transcription (RT)-PCR (qRT-PCR) method for detection of H5N1 AIV in environmental water. This method is based on adsorption of virus particles to formalin-fixed erythrocytes, followed by qRT-PCR detection. The numbers of hemagglutinin RNA copies from H5N1 highly pathogenic AIV particles adsorbed to erythrocytes detected correlated highly with the infectious doses of the virus that were determined for three different types of artificially inoculated environmental water over a 17-day incubation period. The advantages of this method include detection and quantification of infectious H5N1 AIVs with a high level of sensitivity, a wide dynamic range, and reproducibility, as well as increased biosecurity. The lowest concentration of H5N1 virus that could be reproducibly detected was 0.91 50% egg infective dose per ml. In addition, a virus with high virion stability (Tobacco mosaic virus) was used as an internal control to accurately monitor the efficiency of RNA purification, cDNA synthesis, and PCR amplification for each individual sample. This detection system could be useful for rapid high-throughput monitoring for the presence of H5N1 AIVs in environmental water and in studies designed to explore the viability and epidemiology of these viruses in different waterfowl ecosystems. The proposed method may also be adapted for detection of other AIVs and for assessment of their prevalence and distribution in environmental reservoirs.

Surgical Treatment of Gastric Impaction in Farmed Ostriches

Partial or complete impaction of the proventriculus and/or the ventriculus is usually seen in juvenile ostriches. Common impaction materials include stones, sand, hay stems and leaves, and even plastic and metallic objects. Six live ostriches showing signs of impaction and three dead ones suspected to have impacted stomachs were presented to the Department of Clinical Sciences of the Faculty of Veterinary Medicine of the Aristotle University of Thessaloniki. The birds manifested anorexia, whitish and decreased urine output, scant defecation, unwillingness to rise and consume water. Clinical examination revealed distended and firm proventriculi, while radiographs showed foreign objects in the proventriculi of all birds and the ventriculus of one of them. The living birds were successfully treated surgically and medically. Autopsy of the three dead ostriches revealed severe dehydration and impaction of the stomachs. Bacteriological and parasitological examination was negative. Amendments in management practices were important to minimize losses caused by impaction of the stomachs in ostriches, while proventriculotomy remains the most effective approach to the problem.