Primary Survey Of AIV And NDV Infections In Wild Birds In Some Areas Of Hei Longjiang Province

Avian influenza(AI) and Newcastle disease(ND), which were contagious and widespreadavain disease affecting most species of birds, are two most serious infectious disease of poultry.Most recently, the outbreaks of NDV appears new characteristic. The reports of immunizationfailing occurred increasingly. Avian influenza is a serious disease in poultry that can causesevere economic losses in many countries, also can directly infect human, so, the governmentsin the world attach importance to this disease. Wild birds are considered a potential reservoirand may therefore play a role in the epidemiology of economically important or zoonoticdisease. Studing the prevalence of this two diseases, we may find out the role of wild birds inthe two viruses spreading. Furthermore, it is very important for the two diseases that we couldprevent and control them more effectively.One hundred and eighty-three wild birds were captured in Hei Longjiang province, thentracheal and cloacal swabs were taken from each bird using commercial swabs. For thedetection of AIV and NDV, viruses were isolated by two or three passages using embryonated,specific-pathogen-free(SPF) eggs. Positive samples were further tested by haemagglutinationinhibition(HI) and RT-PCR. Results showed the overall separation rate of AIV seropositivesamples was 11.5% which were 21. And comprising 16 samples that were seropositive forNDV(prevalence=7.8%). Next, twelve specific primers for the eight gene segments of AIVwere designed on the basis of published AIV nucleotide sequence data with the aid of primerpremier software. And then eight gene segments of AIV from waterfowl was amplified byRT-PCR which HA, PA, PB1, PB2 were amplified by dividing two parts. The PCR productswere purified, directly cloned into the vector pMD18-T, transformed into E.coli and obtainedthe positive plasmids for sequence confirmation. Finally, we edited nucleotide sequences,analysis, prediction of amino acid sequences and alignments were conducted using thebiological software. Amino acid analysis and phylogenetic tree were constructed with H6N2.Sequence results showed that the eight gene segments of AIV all containing completeopen reading frame and 5'-3'-untranslated regions. BLAST compare indicated this strainorigined from Eurasia which may be homology with Hokkaido strains. Nucleotide sequence ofHA gene pointed that it has the same cleavage site with low pathogenic AIV HA gene whichamino acid is ³⁴⁰PQIETR↓G³⁴⁶. Based on H6N2 subtype has no HPAI reports so far, weconclude that A/Mallard/SanJiang/151/06(H6N2) strain is not high pathogenic avain influenza.