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Büscher, P.

Magnus, E.

Meirvenne, N. Van

Tibayrenc, R.

Verloo, D.

English

OAK Obihiro University Archives of Knowledge

J．ハ・（舶こ川）／．ノ～f～†，．1マ，ノ．り†ノ 7且ブりソ卿J  L’叩1・Jセ／7／便〕Jり瑚，r／7P／～ど－㌣〔汀√ノー〔「p川P′■．♪げけ「〟〃二′フ仁川＝nJ‘ノ川／βrJ仰7川〃r〃〃て1■  Performanぐe OrEcologlCalTests n汀rりp〟〟∂∫〃椚〟g川〃∫fIn鮎ctiomsim  Camels什omNiger  D．VERLOOl．R，T旧Al・′RLNC2，E．MAGNUSl、P．BCscHERl  and N．VANMEIRVENNEl  〃〃沼川／′′可■7叫函■√′／ル九ノr／／√、／肛／）叩〃′J′′′川J√ゾ■川r√雨J（）／〃g．V一入加わ／J〃／‘，■†け（刷ノ55，／ブ加ハIT‘ノ甲州．  〃ぐ／g血′仇Ji・ノJ・2J．ノし榊7〃√丁－′押〆〟ル（ノ’√ノ√ん′・r／れJ▼ナ√川＝ノ  lくtミく  ▲（一っ（l＼岬l」ヽtlL）リH  l，TNTRODUCTION  SurraisawidespreadirlreC†ious diseaseresFX，nSible forimportant econc・micalLosses・  ●LlleCauSingagentistheproIozoanparasile Thtp（”l（・・附枇（Tl）e一／Iu，”idlichisnleChanicaLly  transmi（（edbydifferentvectors suchasrlies（TManidLLe，S［（，m（，Yr．y・一．”）andvampire bats  （0日／〃r′血＼rrイ〃〃血．り（Hoare、】972）．  The parasile caninfecla varie†y of hos（S and causes a speCies－SPeCific pathology・  CarneLsandhorsesarever）lSenSiIive（OT，eV（LnVianddeathcanoccu‥血hinthreen10nlhs・］n  waterbuffaloesandcattle，theinfectiollratherseems toinduceimmunosuppression whkh  may belhe cause of vaceination faiLure（e・g・rinderpest，PaSLeureltosis）andincreased  SuSCePtibilitytootherdiseases（e・g・CIosLridialinfeclions，anthrax，haemorrhagicsep（icemia  etc・）（Stephen，1986）・  Thediagnosisof■surracan beachievedindifferent ways・Trypanosone detection tests  】acksufficien†sensi（ivltyandhavetokconduetedimmediateLyaftersampllng．  SerologJCaltestsare much more sensitiveandcan beexecuted groupwiseon silmPLes  Which can be stored ror a］ong time・Serolog．caltests combined with parasitologLCaJ  exarninationareuseful10OIsrorepidemiologlCalsurveys．Howevcrthe上）reSentantibodyor  antLgendetectiontestsrernainlobeimprovedL   In our］aboratory（lTMAS），SeVeraIan（ibody detection assays，based on the  Predominantvariableantigenlype（VAT）RoTarl・2．have beendeveloped・Theseinc］ude  directandindirec暮agglutinatio一一teS（S（CAllT／7’LeVanSiandL＾TEX／T・eVanSi），Whichcanbe  conducted under field conditions as welL as varian暮 SpeCificimmune trypanoJys］S and  ELISA，Whichneedra（hersophis（icatedlaboratoryequpmentandreagentsL   ln；lpreVious study（Ver】oo etaL】997）、CATT／T・押LlnSi，［．ATIIX／T・e，l：enS．ELISA／1二  evan．血Lldimmunetrypanolysishave beenevaluatedwith serarrom rabbiLs，eXPerimenIaLly  inrected with T．et、anLVipopuJations orlg】nating rrom The PhiJipplneS，CoLombia、  SouthAmerica，China，Kenya．KazaksLan，Lndonesiaandisolatedfromdifferenthostspecies  （Waterbuffalo，dog，CaPybara，Came］，horse）．  OverallsensitivltyOf allthese antitxx］y de（ection tests was】00％from day3O on・  Pre－infeclion sera yielded negative resl山s・Only diree（agg］utination CATTy／Ilれ■unLdhas  beenevaLuatedinthefieLd（Dri11etal．1994：Dialetal．19｛）7）．   1n thepresent s（udy CATT／T・eV（EnYi．LATEX／T・e川n付andimmunetrypanolys・S（es†s  Were Performed on a random scTies of dromedary camcL serum samples from 24  p乙IraSi10loglCa）lyconfirmeda一一d76puta（ivelynon－infecTed animaLsong］natingfrom Niger・   2．M＾TtくRl＾l．S＾ND METHOJ）S  之．1．Fieldsampling：  SampIesong［natefromcameLsin（hePrahouadistrictinNiger．ParasiloJoglCal  examinationbybloodsmearsandrninihenlalocrilcentrifugation technique（Woo7969），   丁71Y［，AN〃SnMA T：YANS［INFECTtONtNCAMELS FROM NTGER  ro11owed by serum sampling and screenlng雨th CATTrT，eVCmSiatlkldilution were  COnducledinthefieLd・Serawerekeptfrozenunti］expeditionondryiceatlTMASwhere  furTherstoragewasaト70℃・TwentyfourparasitoIoglCallypositiveand76parasitologlCally  negativeanimals（Singleexamination）were randomlyselectedwithouttakinginto account  theCATT／T・eVun・，1iresultsobtainedinNiger・  2．2．CATT／γ．即α〝射：   TheCATT／TevansiwasarapiddirectagglutinationtestwhichusedCoomassiestained，  freeze－dried（rypanosomesofr・eVanLVivariab】eantigentype（VAT）RoTatl・2（Bajyanand  Hamer1988）・TwofoldserumdilutionsinPBS（phosphatebufferedsalirLeO．01M，pH7．4）  WereteSted】Twenty fivelLIwas mixed wi（h451LLorreagen10na reaCtionzoneof／the  agglutinationcard・Thecard wasrocked for5minutesonaCATTrotatorat70rpm．A  reae暮ionwasseored positivewhenTTlaCrOSCOP．CaggIutination wasvisible・Theend tilreis  definedasthehighestdilutionofthetestserumStillshowingaFK）Sltiveresul（．  2．3．LATtこWr．ビyα柁g上：   LATEX／Tevunsiisarapidindirectagglutination（estinwhichtheantlgenCOnSistsof  Purifiedvariablesuげaceglycoprolein（VEG）（LqjonetalL1998）of TlevansIVAT RoTat  l・2cova）entIyCOuP［edtolatex partielesaccordingtoBuscheretaL・（1991）・Thereagentis  Stabilizedbylyophylisationa71drehydrated with purified H20before use．TwentyJLlof  lwofe＞Ld dilutions jn PBSis mixed雨th20 FLlof reagent on a tes（Card．Further  ■Ⅵamlpu】ationsarethesameasforCAITノr．evα郡上 ヱ■4．Trypamolys誌：   Tmmune trypanolysis wasperformed according tovanMeirvennee（al．（1995）wi（hTl  evaJ7SIVATRoTatl・2．The serawere testedata用diJution．Live trypanosomesofwell  definedvaTiablea11tigentype（inthiscaseRoTatl．2）wereincubatedfor（60minutes雨th  testserumandgu）neaplgSerumaSthesourceofcomplement・Ifvariantspecificantibodies  Were preSentin the serum，1ysed trypanosomeswere observed under thephase coTltraSt  microscope．   3．RESULTS  3．1．CATT／r．gyα那古曲ndLATEX／r．gy〃〝ざJ：   The evaluatjon parameters used weredefined asfollows（Dukes et al．J984），Where  TFヒtruepositive，TN＝trueneBative，FP＝falseposi柚eandFN＝falsenegative．lnthiscasethe  nurnber of parasito］ogicalIy confirmed（TP＋FN）cases was 24 and the number of  parasitoIogicallynonconfirmedcaseswhichareconsiderednoninfected（TN＋FP）Ⅶ76．  Sensitivity（％）＝TPxIO叫TP＋FN）and specificity（％）＝TNx）OO／（TN＋FP）・Sensitivity and  SpeCificityofCATT／T evanLTiand LATEX爪evansiwere calculatediTlfunctionofserum  dilutior）andresuJtsareg）VeninTat）lesland2．  Tablel：Scnsitivltyandspeclicily theCATT／T・eVanSiatdifferenLserumdilution・  Senmldilutionsusedin theCATT／T，eVL7／びj  1／1  1／4  1侶  】／16   1／3ヱ  ＊Ni騨rl／4  Sensitiヽ1恒’（√苑）   100  ウコ  紺  7（－  28  96   Speci」■ic叫′（′芹り  49  69  79  84  9コ  72  好Niger114＝CATT／T・eVa17SiscreenlngteStCOnductedlnNigerbyRobertTibayrencatal／4dilution 丁署YPAN（）S（）MAllTVANLV］rN「L（二rr［ON＝NCAMELS FROM N7GER  Table2：Setlnti、山and叩eしIihLlily（，lPLher－ATEX／r・‘）lI（JJIL，jこ11dirTererlLherumdj】u110nト‘  SerumdiLuti（lnSuSCdin theLATEX／r．FV（lfLLYi  ＝4  ト′H  ‖h  ト′3ユ  ト′桐  l．廿隷  Se耶i山・iL）’（W′）  96  ％  84  6H  3ユ  4  Specil■icit）イ弄）  65  73  7ト  ド】  肖り  堀   3・2・Immunetrypan（Ilysts：   A”24 sera from parasitologlCally confirmed camds were positiveinimmune  trypano】ysis．Ofthe76supposed】ynoninfectedcamels23wereaLso［ested positive・glV］ng  atotalof47tx）SLtiveand53negativecases・Takingtheresu［tsoftheimmunetrypano（ys■SaS  reference，SenSitiⅥty and specifici（y of CATTrTlどl，anSiand LATEX／T・eVanSIwas then  Calculatedasfollows．Sensitivity（％）＝TPxIOOKa］Jimmune（rypanolysisposi（ives）・l血h’’all  immune trypa†10Lysis positivesr’＝47．specificity（％）＝Tex］00ぺaLlimmune trypano］ysis  negatives）而th a11”immune trypanolysis negatives■l＝53・Resultsin function of serum  dilution are summarizedinTables3and4．  Tilblc3：Sen血豆LtyandspeCieAalCilvol■lhcCATT／r．eJV（t（tSidLdirrercntdilutiorLaSCOmPiu．edlいthe  resLlll＝l「thcimmuneLr）rPiLnOlysISteSt．  Serunldilulionsu腫d血LheCATT／1．どり（拙1・J  ‖  】・ノ4  】佃  りIh  lノ3二三 ＊NiぎCr】／4  Sensjtil7il〉ノ（侃）   l（≠）  り6  引  f清  二肖  りh   Spec】t’ic11y（′斉）  7（）  （朔  】（）い  …）   l川）   川（1  ＊Niger）／4＝CATT／T・eVE71LiliscreenlngLestconductedinNigerbyRobertTibavrencatl／一4di】ution・   Tilb】e4：Senくj1日巾PilnJ叩eCiF、jcjl＼OflheLA’rEX／丁．伸一JIILYiとItdirrerenLscnlmdj】l山川l”uL，mPdreし1to  therestlJIso＝heimmlLnetrypanOlysistes（．  ScT・um diLuti（）nt，uHCdin Lhc L＾TEX／r．t・vLLTZ．Yi  lノ4  1ノH  】ノ】6  】／′3ヱ  1ノ64  】ノ】コH  Sc¶けilJl′巾r（像）  9H  93  R3  輔  34  4   Spcしicf’icil）‘（√方）  R9  】（）（）  m（）   【（Y）   1川）   l川）  4．DISCUSSl（｝N   Thediagr．osticperformanceofCA111／T・eVan・Yitestinnaturalcamelinfectionshasbeen  invest】gatedandpub】ishedbyDial］eIil］・（1994）andDiaetal．（1997）．DialLeta］．obtaineda  SenSitiv］tyOf89％anda speCificityof73％at aL／5serumdilution．T）ialetal＿Obtained a  SenSiti、′L（yof帥％anda specifici（Y Of77％a［al舟serum dilulion・Resu11s［or CATT／T・  evaTZSlandLATEX／T・eVanSlobtainedwithinthepresen（Studyaresimi1ar．   C＾Tll／r evanLY［results obtainedh Nigerand atlTMASon thesarne batchof scrum  Samplesa（1Adilutionshowminordifferences■TTleSlightlylowersensitivltyandspeCificity  Observed atlTMAS can be due to variouslechnica］faetors＿  Positiveimmune trypanolysLSreSults areindica（iveforthe presenceofRoTa（I．2variant   TR押AN（）SnMA FVANSIINFECTTONINCAMELSFROMNIGER  SPeCifjcantjbodies・Earlier，in rabbits experimenta］］yinfectedwilh T・eV朗SE orlglrLatlng  fromdifferentpartsofthewortd（VerlooetaL・1997），WeO♭servedthatRoTatl・2specifie  aT］tibodiesappearedina11rabbit各面thinonemonthofinfection・Bo抽resultsstrengthenthe  StatemerltロfBqjyanaandHamcr（1988）tha（RoTa11・2isawide－SPreadpredominanLVAT  i．e．aVAT thatappearsearlylntheinfectionandthaIisexpressed bymanyifnolallTl  どl′α〃JエpOPulations・   A”serum samples rrom parasi10logLCally co11firmed animals were FK）Sltiveinimmune  trypano）ysIS，WhereLaSSOmeWerenegativeinCATT／Tevu椚iandLATEX仇evansievenata  lkldilution．ThisdifferencebetweentheimmunetrypanoLysLSandagglutjnationtestresults  SuggeStlhatdifftrentantibodiesareinvoIved・   Twen暮ythreeoutof76（30％）serafrorn supposedlyparasitologically nega（iveanimals  WereP（）5itiveinimmunetrypanolysis・Atl侭dilution5bothagg］utinationassaysweTelOO％  SPeCifica畠COmparedtotheresultsorthcimmunetrypanolysISteS（S・Thelowerspecificityof  lheagglulinationtestswithreferencetotheparasito［oglCalresultscanbeexp）ainedby the  lowsensitiv］tyOraSlng［eparasiToLoglCalexamiElationandk）rbyperSistenceof（rypano）ytlC  antibodiessIillcircuJa（lng】n Cured host．Ano（herexplanationmight be the presence of  SpeCifictrypanolyticactivlty tn SOmeCameL sera・Thisremainstobechecked withother  VATs．At（］B dilulions the agg】utination assays give some false positive resu］ts v血en  COmPared toimmune（rypano‡ysis・Cryptic VSGepi［ome that become exposed on the  surfaceinCATT／Tevan．YiandLATEX／Tevan3ireagentsorevennonVSGan暮igenswhich  arenotexposedatthece11surhceoflivlngtryPanOSOmeSCanl光reSEX）nSibleforthis・   Both CATl’／7二evan．viand LATEX／r．evansilesIs are curTently being evaluatedin  experimenlalandfieldinfectionsindifferen暮COuntriesandwithdifferenta扁maIspecies・   5．ACKNOWLEDGl乙MENTS   TIlisinvestlgationreceivedfinancialsupportfromlLRl，Nairobi・   6．REFERENCES  B毎yama，S・E・＆Hamer，R・1988・A肌ぶ据・βどな・ルねd・作叩・6おご2・ヲj・  BiJSCher、P．、Draelants，E．，Magnus，E．，Vervoort，T．＆VanMeirveTlne，N・］991・A肌Soc・   駄句．抽d．什叩．7J■■2／i7．  DiaL，M．L．，VanMeirvenne，N．，Magnus，E・，Lackins，A・G・，Diop，C・，Thiam，A・，Jacquiet，P・＆   Hamer，R．】997．尺ビl，〟g仇，β．〟gd．V〟．Pαγ9什り－5〃ご2り・  Diall，0・，Banyana，S・E・，Magnus，E・，Kouyate，B‥Dia］oglB・1VanMeirvenne，N・＆Hamer，   R．】994．尺ピー・．．一山．JビC力．〔鮮血．句症．ノjニ7ら〉j．  Dukes，P．，Rickman，L．R．，Kimck－Kendrick，R．，Kakoma†L帆rapa，F・K・，DeRaadt．P・＆  Morr（）W，R．1984．汁叩どJl肌ed．Pαr（如才ビ・J5ニノヰノ・  Hoare，C，A．I972．ThetrypanosomesofmammalsrO4，rd：βkzckwe［［ScE・PubLicafions］r  749．  1Jejon，V．，BilSheer，P．，Magnus，E・，Moons，A・，Outers，1・＆VanMeirvenne，N・1998・Acta  Ⅳ呼・β9J／5J・  Stephen，L且1986∴11けPanOSOmiasis・A相加血町＝刑Y胤■加ピ，αゆr（ゴノー5jリ・  VanMeirvenne，N．，Magnus，E■＆Biisheer，P・Ⅰ995・AcJαⅣ叩・d仇ノぎ9・  VerLoo，D．，VanMeirvenne，N．，l」再on，V．，Magnus，E，＆Bilscher，P・1997・Abs（rwts24th   〟ビゼf．r！／■Jんビル眈ぶぐJ・C√ノ〟乃Cfブルr7ナ〝朗〃∫√ノ〝∽j山鮎†gα′ぐカα〃dC‘｝′脾OJ，几血p〟れ   故jこα椚以可〟ピアヰ・  Woo，P．rK．1969．C（J′几ノ．みノ（ノm．ヰ7ごリ2ノ．  ．Jリ、1   

Performance of Ecological Tests for Trypanosoma evansi Infections in Camels from Niger

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Performance of Ecological Tests for Trypanosoma evansi Infections in Camels from Niger

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