الفهرس 
Introduction
Overview on Pasteurella sppOnly 14 pages are availabe for public view
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Abstract
The present investigation was carried out in El-Minia governorate, for studying pasteurella infections in waterfowl particularly to ducks and geese. 230 samples were collected via nasal swabs (nasal cleft) and eye swabs of diseased bird or tissue (liver and heart blood) from recently dead birds which had a history of respiratory tract affection, diarrhea, C.N.S. manifestations and high mortalities.
In this revealed the followingresults were revealed;
1) Out of 230 examined cases, 42 isolates (18.26%) form ducks and geese proved morphologically and biochemically to be pasteurella organisms followed by serological identification using ELISA, which revealed only 15 strains out of 42 isolated strains. Nine isolates being classified as serotype A:1 (60%), 3 as serotype A:3 (20%%), 2 as serotype A:4 (13.3%) and one untypable strain (6.6%) .
2) Thirteen isolates were recovered from ducks (7.22%) in relation to number of duck samples. According to age they segregated into 4 isolates (2.22 %) were recovered from duckling (1-7 wks.), 8 isolates (4.44 %) from ducks (≥ 8wks.),one isolates (0.55%) from white pekin (≥ 10 wks.).
3) The Balady breeds of duck have the high incidence rate of isolation (4.44%) in comparisonto white pekin breeds (0.55%).
4) Two isolates were recovered from geese with percentage of (4%) in relation to number of geese samples.
5) In this work, trials for isolation of other pasteurella organisms from the examined samples disclosed no other Pasteurellae species were detected.
6) Experimental infection of duck with the isolated serotypes A: 1, A: 3, A: 4 and untypable strains via intramuscular and intranasal routes pointed out to the following results:
a –P.multocida strains isolated from duckswere of variable pathogenicityand the highest morbidity and mortality rates were observed with serotype A: 1.
b-The intramuscular route of inoculation was more effective with high mortalityrate in comparison with the intranasal route of inoculation. The most showedclinicalsigns and macro morphological features were dullness, greenish diarrhea,pastyvent and huddlingtogether.The postmortem findings werecongestionof theliver,mottled spleen, catarrhal to severe haemorrhagic enteritiswithenlargementofthe liver inadvancedstage of infection, pale areas of focalnecrosison the liversurface andlungsappeared,fibrinousperihepatitisandpericarditis .
7) Results of in-vitro sensitivity test of the isolated P. multocida strains to various chemotherapeutic agents indicated thatthe majority of our P. multocidaisolates from duck and geese were susceptible to multiple antibiotics in descending manneras norfloxacin, ciprofloxacin,gentamicin, ampicillin, amoxicillin, doxycyclineand Streptomycin .And exhibited absolute (100%) resistance to Sulfadiazine.P. multocidaA: 1 strains(7) isolates recovered from ducks were most sensitive to norfloxacinfollowed by ciprofloxacin and with a variable sensitivity to the other tested drugs. P. multocidaA: 3, A: 4 and untypable strains showed the same pattern of sensitivity tonorfloxacinfollowed by ciprofloxacin and gentamycin and intermediate sensitivity to chlortetracycline and tetracycline. In regarding to the serotype A: 1 strains isolated from geesewere sensitive to norfloxacin followed by ciprofloxacin,doxycycline and streptomycine.While intermediate to ampicillin and oxytetracycline and fully resist to sulfadiazine and chlortetracycline.
from the results obtained in this workwe could concluded the following:
1) Trials for isolation of other pasteurella organisms from the examined samples were failed to detected other Pasteurellae species.
2) The isolation rate of P. multocida from ducks and geese was 7.2%and 4% respectively.
3) The most isolated and predominant serotype is serotype A: 1(60%), followed by A: 3 (20%),A: 4 (13.3%) and untypable strain (6.6%).
4) The occurrence of unclassified Pasteurella spp. in duck samples could indicate the possible presence of new taxa of Pasteurella spp. Thus, subsequent characterization by molecular techniques is required to decide thetaxonomic position of these organisms.
5) The Balady breeds of ducks have the high incidance rate of isolation in comparable to white pekin breeds.
6) This study has documented on experimental infection with 0.2 ml x 108 organisms of the P. multocida type strain that highest morbidity and mortality rates were observed with serotype A: 1.
7) The proper use of the antimicrobial agents for treatment of P. multocida infections is important to avoid the development of drug resistant among field strains. Thus the antibiotic sensitivity pattern of isolated strains from ducks were carried out and the most effective antibioticswere Norfloxacin (85.72%), Ciprofloxacin (71.44%) Gentamycin(66%), Doxycycline (62%) and the highest level of resistance detected was to Sulfadiazine 100%.
8) Future research studies will be intended to hold on the molecular pathogenesis of the isolated strains and what is the effective gene(s) that played a role in the pathogenicity and if it is deleted could the wild strain be attenuated and used as a living vaccine having the advantage of crossprotectio