Arshad, Siti Suri

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Agricultural SCiencesPathogenesis of nephropathogenic IBV MH5365/95 in SPF chickenSItI Sur! ArahadFacultyof Veterinary MedicineUniversiti Putra Malaysia43400 UPM, Serdang, SelangorMalaysiaTelephone Number of Corresponding Author: 03- 8946 8306E-mailolCorrespondingAuthor:suri@vet.upm.edu.myKey words: chicken, intestine, kidney, nephropathogenic IBV, tracheaIntroductionAvian infectious bronchitis virus (!BV) infects chicken and predominantly causes respiratory symptons. Other systemsaffected are the reproductive, gastrointestinal and urinary.The newly characterized nephropathogenic !BV strain MH5365/95 causes high mortalities and severe kidney lesion. The virusreplicates in renal epithelial cells, producing severe tubular damage and interstitial inflammation resulting in renal failure.Lesions described include pale parenchyma, swollen, mottled and uric acid deposits in the tubules and ureters. The objectiveof the work is to study the clinical signs, pathological changes and histopathological lesions of the respiratory tract and kidneyin chickens infected via intratracheal and intraocular routes with !BV-MH 5365195 strain.Materials and MethodsThe nephropathogenic !BV-MH5365195 of passaged two, was used in this experiment. Seventy-five of 21-day old SPFchickens were divided into 3 groups namely; Group I, Group 2 and Group 3 which consisted of 30,30, and 15 chickens,respectively.Each infected chicken received 0.2 ml of virus containing 105EID50/ml. Group I chicken received the virus intratracheallywhereas Group 2 chicken received the virus intraocularly. Control group was further divided into two subgroups (C I=7 andC2=8), receiving 0.2ml of PBS intratracheal and intraocular, respectively. During the 24-day course of post infection (pi.),clinical signs were recorded daily. About 4-5 chickens were killed at the interval of 3 days as follows; 3, 6, 9,12, 15, 18, 21,and 24 days. Those chickens, which were killed or died were necropsied and examined for the presence of gross lesions in thetrachea, lungs, air sacs, kidney, liver, gall bladder, spleen and gastro-intestinal tract (GIT). Selected tissues namely thetrachea, lung, kidney, and intestine were sampled. The tissues were fixed in 10% phosphate buffered formalin and processedfor for paraffin block using standard procedure before staining with haematoxylin and eosin,Results and DiscussionChickens infected with IBV by the two routes namely intratrachea and intraocular, showed essentially similar clinical signs ofruffled feathers, depressed, severe to moderate respiratory signs include gasping, sneezing, coughing and tracheal rales. Grosspathological changes include congested tracheas with excess mucus in the lumen at day 3, 6, and 9, pi. in both infected groups.However, some differences were observed in the time of onset of clinical signs, severity of clinical disease, and the rate ofrecovery. Chicken infected with IBV intratracheally showed faster onset of clinical sign, longer disease duration with severecondition, compared to those infected intraocularly. The latter group showed delayed onset of clinical signs, shorter diseaseduration with moderate disease condition. In both groups, although the respiratory sign disappeared by about 2 weeks pi, thereis no complete recovery from respiratory system. Among other pathological changes in the lung.. cloudiness of the air sacswere detected during the first week of infection, which is in accordance with the finding in Australian T-strain followingaerosal infection.Comparing between the two infected groups, incidence of nephritis-nephrosis did not differ between the groups. This is inagreement to earlier findings who noted that the birds infected by the in-contact route produced a similar pathogenesis to thoseinfected by other routes. Congestion of the GIT, whitish-green watery diarrhoea and congested liver and spleen observed inthis study have also been reported by others with different IBV strains. Lesion observed in these organs may indicate the widespectrum of the virus tissue tropism in chicken.The histological changes reported here were characterized by prominent lesions in the kidney, followed by respiratory tractinvolvement. These changes are compatible with those described previously. However, the dilation of Bowman's capsule is inagreement with Chen et al., (1996), but disagreement with others. The basophilic globules which looked-like inclusion bodiesseen in degenerated epithelium of trachea and renal, has been also reported by others. Upon close examination on the onset ofinterstitial lymphocytic reaction, infected chicken suffered from nephrosis initially, and late:' followed by nephrosis-nephritisbefore end-up with interstitial nephritis. The detail histopathological changes of degeneration and desquamation of enteric villiwith infiltration of-inflammatory cells observed in this study, have not been reported elsev..here. Thus, there is a speculationthat !BV-MH 5365/95 may multiply in the intestinal tract. The present study demonstrated that IBV-MH 5365/95 mayinduces a primary renal disease and moderate to severeeffects on the respiratory and intestinal tracts.213UPM Research Report 1997-2000. Vol II. Section 2-Extended AbstractsConclusionsInfectious Bronchitis Virus-MH5365/95 strain induces moderate to severe respiratory disease, diarrhoea and renal disease.Routes of inoculation did not significantly influence the pathogenesis of !BV. Lesion observed in many organs may indicatethe wide spectrum of the virus tissue tropism in chicken. In transmission studies, the virus was found to induce a primary renaldisease and moderate to severe effects on the respiratory and intestinal tracts.Benefits from the studyProviding new knowledge and information on the pathogenesis of the bronchitis disease virus in chicken and the expectedoutcome of the clinical sign. The involvement of many vital organ denotes the wide spectrum properties of the virus. Thisinformation is useful for field veterinarian to monitor the !B disease outbreak in the field.Patent(s), if applicable:NilStage of Commercialization, if applicable:NilProject Publications in Refereed Journals:NilProject Publications in Conference ProceedingsI. Arshad, S.S. and Al-Salihi, KA. 2001. The Effect Of Different Routes Of Infectious Bronchitis Virus Inoculation lnChickensHistopathology.In: Proceedings of the 13'"VAMCongress, Kuala Lumpur, 27-30 Oktober. 200 I; p 64-662. Arshad, S.S. and Al-Salihi, KA. 2001. The Effect Of Different Routes Of Infectious Bronchitis Virus Inoculation In Chickensf'linicalSigns And Gross Lesions. In: Proceedings of the 13'"VAMCongress, Kuala Lumpur,27·30 Oktober. 2001; p 62-63.3. Arshad, S.S. 2001. Avian Infectious Bronchitis Virus: In: Proceedings of the Persidangan Kebangsaan PenyelidikanDan Pembangunan[PTA.25-26 Oktober 2001, Kuala Lumpur.p 157.Graduate ResearchNameGraduateof Research Topic Field of Expertise Degree Awarded Graduation YearKarima AI-Salihi PathogenesisIBV inchicken:ofSPFAnimalbacteriologyPost-doctoralclinicalsign, gross lesionandimmunoperoxidaseIRPA Project numberOI-02-04-0305UPM Research Cluster :BAB214

Pathogenesis of nephropathogenic IBV MH5365/95 in SPF chicken

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Pathogenesis of nephropathogenic IBV MH5365/95 in SPF chicken

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