鸡群大肠杆菌病症状表现形式有很多种，根据鸡的年龄、抵抗力以及大肠杆菌的致病力、感染途径的不同，可表现为大肠杆菌败血症、肠炎、气囊炎、卵黄腹膜炎、输卵管炎、全眼球炎、大肠杆菌性肉芽肿、脐炎及滑膜炎等。当前危害最严重的是急性败血症，其次为气囊炎、卵黄性腹膜炎。
TherearemanykindsofsymptomsofColibacillosisinchickens.Accordingtotheageandresistanceofchickens,thepathogenicityandinfectionrouteofcolibacillosis,itcanbemanifestedascolibacillosissepsis,enteritis,ballooninflammation,yolkperitonitis,salpingitis,panophthalmitis,Escherichiacoligranuloma,umbilitisandsynovitis.Themostseriousharmisacutesepsis,followedbyballooninflammation,yolkperitonitis.
1、急性败血型和气囊炎：病菌通过血液循环或呼吸道进入气囊，引起气囊炎，出现咳嗽和呼吸困难；继而逐步发展成肠炎、纤维性心包炎、肝周炎、输卵管炎，出现全身败血症，病突然死亡或逐渐衰竭死亡，部分离群呆立或挤堆，羽毛逆立，食欲减退或废绝，拉黄、绿、白色稀粪，肛门周围羽毛污染，发病死亡率较高，是目前危害最大的一类病型。
1.Acutesepticemiaandballooninflammation:Bacteriaentertheballoonthroughthebloodcirculationorrespiratorytract,causingballooninflammation,coughanddyspnea;andthengraduallydevelopintoenteritis,fibropericarditis,perihepatitis,salpingitis,systemicsepsis,suddendeathorgradualfailureofthedisease,partofthegroupstoodstillorsqueezePiles,feathersinverted,lossofappetiteorabolition,yellowing,green,whitefeces,feathersaroundtheanuspollution,highmorbidityandmortality,isthemostharmfultypeofdisease.
病理变化：
Pathologicalchanges:
（1）纤维性心包炎，表现为心包积液、混浊增厚，有纤维性渗出物，与心肌粘连。
(1)Fibrouspericarditis,characterizedbypericardialeffusion,turbidthickening,fibrousexudates,andmyocardialadhesion.
（2）纤维性肝周炎，肝脏肿大，有不同程度的纤维素性渗出物覆盖。
(2)fibrouspericarditis,liverenlargement,withvaryingdegreesoffibrousexudate.
（3）纤维素性腹膜炎，腹腔有纤维素性渗出物。
(3)fibrousperitonitis,withfibrinousexudatesintheabdomen.
（4）气囊炎：气囊（胸、腹气囊）混浊、增厚，有泡沫状粘液，严重者有黄白或黄色干酪样渗出物，肠道及各脏器被渗出物充斥。这类病型主要发生于肉仔，发病高峰为3～6周龄，通常所讲的大肠杆菌病即指此类型。除死亡造成直接损失外，增加的料肉比和高昂的医药费也可导致损失惨重。
(4)Ballooninflammation:Balloon(thoracicandabdominalballoon)cloudy,thickened,withfoamymucus,seriouscaseshaveyellow-whiteoryellowcheese-likeexudates,intestinesandorgansarefullofexudates.Thistypeofdiseasemainlyoccursinmeatoffspring,thepeakincidenceof3-6weeksold,usuallyreferredtoasE.colidiseaseisthistype.Inadditiontodirectlossescausedbydeath,increasedfeedtomeatratioandhighmedicalexpensescanalsoleadtoheavylosses.
2、卵黄性腹膜炎：产蛋输卵管感染大肠杆菌而产生炎症，导致输卵管伞部粘连，排卵时无法打开，卵泡不能进入输卵管，跌入腹腔而引发广泛的腹膜炎，并产生大量毒素，引发母外观腹部膨大，继而死亡。病理变化：产蛋腹腔中充满淡黄色卵黄，腹腔器官表面覆盖着一层淡黄色凝固的纤维素渗出物，肠道相互粘连，肠浆膜上有针尖状大小的出血点，卵泡变形、变色，有的卵泡皱缩，积留在腹腔中的卵黄时间较长即凝固成硬块，切面呈层状，输卵管粘膜发炎，管腔中有黄白色纤维素性凝固分泌物。产蛋发生本病，除死亡造成直接损失外，产蛋下降和死淘率增加，防治成本提高。
2.Yolkperitonitis:InflammationcausedbyE.coliinfectionofoviductleadstoadhesionofoviductumbrella,failuretoopenovulation,folliclescannotentertheoviduct,fallintotheabdominalcavityandcauseextensiveperitonitis,andproducealargenumberoftoxins,causingmaternalappearanceabdominalenlargement,andthendeath.Pathologicalchanges:theegg-layingabdomenisfullofyellowishyolk,theabdominalorgansurfaceiscoveredwithalayerofyellowishcoagulatedcelluloseexudates,intestinaltractadhesion,intestinalserosaonthesizeofaneedle-likebleedingpoint,folliclesdeformation,discoloration,andsomefolliclesshrinkage,accumulatedintheabdominalcavityforalongtimethattheyolksolidifiesintoalump.Thesectionisstratified,theoviductmucosaisinflamed,andthereareyellowandwhitecellulosecoagulatingsecretionsinthelumen.Inadditiontothedirectlosscausedbydeath,eggproductiondecreasedandtherateofdeadpanningincreased,andthecostofpreventionandcontrolincreased.
3、脐炎：是指雏的脐孔不能正常愈合，雏多数在出壳后2～3日内死亡，临诊上可见病雏衰弱，挤推，拉稀，病腹部膨大，仔细检查可发现脐部感染，脐孔愈合不良，呈蓝黑色，有臭味，腹腔中有未吸收的卵黄，有时发生腹膜炎，感染的雏难以治愈，死亡率可达10%～12%。
3.Umbilitis:referstotheinfantumbilicalforamencannothealnormally,themajorityoftheinfantdiedwithin2-3daysaftertheshell,ontheclinicaldiagnosiscanbeseenweak,pushed,diluted,diseasedabdomenenlarged,carefulexaminationcanbefoundumbilicalinfection,umbilicalholehealingbad,blue-black,smelly,abdominalcavityhasnotabsorbedyolk,sometimesperitonitisTheinfectedchickensarehardtocure,withamortalityrateof10%to12%.
4、全眼球炎：舍内空气被大肠杆菌严重污染，感染后引起全眼球炎。急性败血性大肠杆菌后期也可出现，多数为单侧，少数为双侧。患侧眼睑粘连，外观肿大，内有黄白色豆腐渣样物质，切开眼睑可见眼球发炎，眼角膜浑浊，内脏器官无明显变化，病消瘦，生长不良，羽毛逆立，不喜活动。
4.Totaleyeballinflammation:theairinsidethehouseisseriouslypollutedbyE.coli,causinginfectionafterinfection.AcutesepticemiaEscherichiacolicanalsooccurinthelatestage,mostofwhichareunilateralandafewarebilateral.Theaffectedsideoftheeyelidadhesion,theappearanceofswelling,yellowandwhitetofu-likesubstances,incisioneyelidvisibleinflammation,cornealturbidity,visceralorgansnosignificantchange,weightloss,poorgrowth,feathersinverted,donotlikeactivity.
5、大肠杆菌性肉芽肿：病肝、心、十二指肠、盲肠及肠系膜上产生肉芽肿，外观和结核结节及马立克氏病的肿瘤结节相似。
5.Escherichiacoligranulomas:granulomasontheliver,heart,duodenum,cecumandmesentery,similarinappearancetotuberculousnodulesandtumornodulesinMareksdisease.
6、大肠杆菌性脑炎：病的主要症状为昏睡、精神沉郁，出现斜颈、转圈、共济失调等神经症状，剖检病脑膜充血、出血、发炎，病脑部可分离出大肠杆菌。
6.Escherichiacoliencephalitis:themainsymptomsofthediseasearesleeping,depression,appeartorticollis,circle,ataxiaandotherneurologicalsymptoms,dissectionofthediseasemeningescongestion,bleeding,inflammation,thediseasebraincanbeisolatedfromE.coli.