Newcastle disease virus immunization with I-2 vaccine: a case study of local free range chickens in rural communities in Morogoro, Tanzania

摘要

Thisstudyevaluatestheimmunizationstatusoffree-rangelocalchickens(FRLC)followingamassvaccinationprogramagainstNewcastlediseasevirus(ND)thatwascarriedoutinMvomerodistrict,Morogoro,Tanzania.Sixvillagesfromtwowards(onetrialandonecontrolward)wereinvolved.Atotalof819chickensfromthetwowardsweretestedbyhaemagglutinationinhibition(HI)forNDantibodiesfollowingI-2vaccinationinthetrialward.ThevaccinewasadministeredtoFRLCbyeyedropintrialvillagesbytrainedcommunityvaccinatorswhilechickensinthecontrolvillageswerenotvaccinated.BirdswithHIantibodytitresequalorgreaterthan23(HI#8805;23)wereconsideredimmune.ThepercentageofbirdsineachagecategorywithprotectiveNDVantibodiesinthetrialwardwerechicks(25.3%),growers(53.3%)andadults(84.8%),whilethepercentageinthecontrolwardwerechicks(14.0%),growers(30.1%)andadults(40.4%).Thepercentageofimmunechickensbyagecategoriesinthetrialwardweresignificantlyhigher(p0.05)comparedtoimmunebirdsinthecontrolward.ThecurrentstudyindicatesthattheNationalvaccinationregimeismoresuccessfulingrowersandadultsversuschicks.InordertoimproveflockprotectionagainstND,thevaccinationprogramshouldcoverchicks.Thiscanbeachievediffarmersscheduleaspecialvaccinationprogramforchicksandharmonizehatchingtoconformtothevaccinationregime.