Persistence of Avian Influenza H5N1 Virus in Surface and Sea Water

The present study aimed to test the persistence of avian influenza H5N1virus (Egyptian isolate) in water with different environmental conditions (temperature and pH) and to test the possible transmission of the virus via aquatic animal Tilipia zillii. The persistence of the virus was assessed by using two types of water (Nile water and sea water) adjusted at different pH 6.5, 7.0, 7.5, 8.0 and different temperatures 20 and 34°C. The detection of low pathogenic avian influenza H5N1 virus in water samples was achieved by using real time reverse transcription PCR. Immunofluorescence assay and rt RT-PCR technique were used to detect H5N1 virus in fishes' tissue samples. The results revealed that the low pathogenic avian influenza H5Nl virus persisted for extended periods of time in Nile water than in sea water. In general real time reverse transcription PCR showed that the most optimum pH was 7.0 and the most optimum temperature was 20°C for the persistence of the virus. By using rt RT-PCR and immunofluorescence assay, H5N1 virus was found in the intestine of the fishes that was sampled at 4 and 8 days. Moreover, the viral RNA was detected in gills that were sampled at 4 days only. In conclusion, prevention and control measures can be suggested to minimize, if not eliminate the risk from the consumption of virus-contaminated water.