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Prevalence and Molecular Detection of Edwardsiella tarda in Cultured Tilapia Species of Fish Farms of Punjab in Pakistan and their Postmortem Examination
Kashif Manzoor1, Fayyaz Rasool2, Noor Khan3, Khalid Mahmood Anjum4 and Shakeela Parveen5
1Department of Fisheries and Aquaculture, University of Veterinary and Animal Sciences Lahore, Pakistan; 2Department of Zoology, Faisalabad Campus, University of Education Lahore, Pakistan; 3Institute of Zoology, University of the Punjab Lahore, Pakistan; 4Department of Wildlife and Ecology, University of Veterinary and Animal Sciences Lahore, Pakistan; 5Department of Zoology, Wildlife and Fisheries, University of Agriculture Faisalabad, Pakistan
*Corresponding author:


Edwardsiellosis caused by an emerging fish pathogen Edwardsiella tarda, is one of the major problems in aquaculture, associated to massive economic losses due to high mortality of a wide variety of fish species worldwide. In the current study, we isolated, identified, detected E. tarda and performed phylogenetic tree analysis of its 16SrRNA gene. Postmortem examination of infected fish revealed skin depigmentation, exophthalmia, swollen abdomen, enlarged liver, white bacteria filled nodules in liver, kidney and intestine. Biochemical identification of E. tarda showed negative results in citrate, lactose, amylase and arginine tests while methyl red, H2S, catalase, indole and glucose tests showed positive results. Amplification of esrB, gadB, gyrB, blaTEM, qnrA, and sul3 gene by PCR revealed bands at 312, 585, 414, 801, 654, and 444bp respectively. We recorded maximum 18% prevalence in intestine with respect to organs, 32.3% in male with respect to fish sex, 38.8% in O. niloticus with respect to fish species, 37.8% at fish farm FMG-10 of Muzaffargarh with respect to sampling site and 38.9% in summer at 37°C with respect to season. Overall 27.2% prevalence of E. tarda was recorded at all selected fish farms resulting 4.7% mortality. Chi-square test of independence showed significant difference (P<0.05) with respect to sampling sites. Our all isolated E. tarda strains showed 100% similarity with E. tarda strain isolated in USA. We concluded that virulence genes of E. tarda and high temperature in association with high stocking density and pollutant water also increase prevalence of E. tarda and cause mortality in fish.

To Cite This Article: Manzoor K, Rasool F, Khan N, Anjum KM, Parveen S, 2023. Prevalence and molecular detection of Edwardsiella tarda in cultured tilapia species of fish farms of Punjab in Pakistan and their postmortem examination. Pak Vet J, 43(2): 309-314.


ISSN 0253-8318 (Print)
ISSN 2074-7764 (Online)