dr. naresh jindal college of veterinary sciences lala lajpat rai university of veterinary and animal...

Dr. Naresh JindalCollege of Veterinary Sciences

Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar -125 004 (INDIA)

Enteric viruses in chicken enteritis

Introduction Clinical findingsNecropsy findingsPresent situationEconomic lossesFuture research

Outline

Enteritis is an infectious multifactorial disease of young chicks with clinical signs of diarrhea, depression, lethargy and gross lesions of pale intestines and/or ceca with watery contents.

Introduction

Chicken Runting stunting syndrome (RSS) Maldigestion syndrome Malabsorption syndrome Infectious stunting syndrome Helicopter syndromeTurkeys Poult enteritis complex Poult enteritis syndrome Poult enteritis mortality syndrome Light turkey syndrome

Multifactorial Bacteria:

◦Salmonella ◦Escherichia coli◦Enterococcus◦Clostridium

Protozoa:o Coccidia and Cryptosporidia

Viruses

Cast of characters

Viral causesRNA

- Rotavirus (RV) - Reovirus (ARV)- Astrovirus (AstV)- Picornavirus- Picorna-like virus

DNA -Adenovirus (CAdV)- Parvovirus (CPV)

Reovirus - Pathogenic and non-pathogenic- Limited homology with turkey isolates

Rotavirus - Group A: Mammals and birds

- Group D: Exclusive to birdsAstrovirus - Avian nephritis virus (ANV)

- Chicken astrovirus (CAstV) - Turkey astrovirus-1 (TAstV-1) & -2 (TAstV-2)

Picornavirus - Cause transmissible viral proventriculitis Adenovirus - Ubiquitous in all avian speciesParvovirus

- Induces RSS in broilers - Important determinant in the complex

etiology of enteric diseases of poultry

Virus variationRNA viruses are unstableMutation and recombination are commonGenotype – serotype – pathotype

Differences in antigenicity and pathogenicity:◦Disease presentation◦Problems for diagnosis◦Epidemiology◦Potential vaccines

Implications of virus variation

Watery faecesPasty ventPoor growth / retarded feather developmentLameness in some of the affected birdsMortality

Clinical findings

Pasty vent

Watery feaces

Necropsy findings

Pale and thin-walled intestines Watery and frothy intestinal contents Distended caeca with watery and foamy

contents

Watery contents

Gross lesions- Duodenum

▪ Undigested feed

▪ Erythema of villi

Gross lesions- Jejunum

▪ Watery contents▪ Undigested feed▪ Increased mucus

USACAstVs in 86% (19/22) of the samples (Pantin-

Jackwood et al., 2006)

43 commercial broiler chicken flocks Astroviruses detected in 86% of the flocks (Pantin-Jackwood et al., 2008)

Present situation

Occurrence of various pathogens in PES-affected flocks (n=151)

Pathogen No. (%) of PES flocksRotavirus 73 (48)Small round virus 26 (17)Reovirus 1 (0.6)Adenovirus 1 (0.6)Salmonella 85 (56)E. coli 54 (36)Enterococcus 16 (11)Eimeria 44 (29)Unknown 9 (6)

Jindal et al. (2009).

Detection of enteric viruses from poult enteritis syndrome (PES)-affected cases

Method Number (%) of cases positive for Rotavirus TAstV-2/SRV1 Reovirus

EM 25 (58) 13 (30) 0 RT-PCR 40 (93) 36 (84) 17 (40)

TAstV-2 = turkey astrovirus-2 (detected by RT-PCR); SRV = small round viruses (detected by electron microscopy).EM = electron microscopy; reovirus and coronavirus were not detected in any of the PES cases by EM.RT-PCR = reverse transcription-PCR; none of the PES cases were positive for coronavirus by RT-PCR.

Jindal et al. (2010)

Detection of enteric viruses alone or in combination from poult enteritis syndrome (PES)-affected cases

Method Number (%) of cases positive for 1 virus 2 viruses 3 viruses

EM 16 (59) 11 (41) 0RT-PCR 8 (19) 20 (46) 15 (35)

TAstV-2, Rotavirus or reovirus alone or in combination None of the PES cases were positive for coronavirus by RT-PCR.


- Tested 34 commercial flock (2010 and 2012) - 85.3% flocks positive for enteric viruses- Detected combinations of two or more enteric

viruses simultaneously in 51.7% of enteric virus-positive chicken farms

- ANV, CAstV, RV, ARV major enteric viruses detected (Koo et al., 2013)

Korea

280 intestinal contents samples from chicken111 samples (39.6%) positive for one virus while

115 (41.1%) samples for two or more enteric viruses

Combination of two viruses detected in 74 samplesANV, CAstV, RV, FAdV, and ARV were the major

viruses detected (Mettifogo et al., 2014)

Brazil

Pathogen(s) Number (%) of samples positive for indicated viruses

CAstV alone 31 (47.69)ANV alone 04 (6.15)CAstV + ANV 26 (40.98)Total 61 (93.84)

India - Intestinal contents from 65 enteritis-affected chicken

flocks (2014-2015) were examined.- Samples collected from birds of 1-3 weeks of age.

All samples were negative for ARV and RV

CAstV/22330/2014/HR(India)/Chicken_(KT386334) CAstV/23724/2014/HR(India)/Chicken_(KT386336) CAstV/1089/14/HR(India)/Chicken_(KT386338)

CAstV/22397/2014/HR(India)/Chicken_(KT386332) CAstV/23893/2014/HR(India)/Chicken_(KT386327)



CAstV/4175/2006/USA/Chicken_(JF832365) CAstV/GA2011/2007/USA/Chicken_(JF414802) CAstV/GA-SEP-A364-05/USA/Chicken(DQ324839)


CAstV/Indovax/APF/1319/2013/India/Chicken(KC865608) CAstV/Indovax/EI/1078/2013/India/Chicken(KC855215)

CAstV/PDRC/588/North_zone/2011/India/Chicken(JX945881) CAstV/PDRC/447/South_zone/2012/India/Chicken(KC633178)

CAstV/Indovax/SH/1079/2013/India/Chicken(KC855214) CAstV/PDRC/1803/South_zone/2012/India/Chicken(KC633179) CAstV/PDRC/580/West_zone/2011/India/Chicken(JX945880) CAstV/PDRC/579/West_zone/2011/India/Chicken(JX945879)

CAstV/USP358-4/2009/Brazil_(GU014472) CAstV/USP337-2/Brazil/2009/Brazil/Chicken(GU585496)

CAstV/USP238-1/2010/Brazil/Chicken(JF309118) CAstV/USP388-3/2010/Brazil/Chicken(JF309117)

CAstV/GA-SEP-A368-05/USA/Chicken(DQ324842) CAstV/PDRC/1804/South_Zone/2012/India/Chicken(KC633180)

CAstV/PDRC/589/North_zone/2011/India/Chicken(JX945882) CAstV/23324/2014/HR(India)/Chicken_(KT386337)

CAstV/PDRC/200/East_zone/2011/India/Chicken_(JX945868) CAstV/325004/2008/Italy/Chicken(JN048401)

CAstV/327845-1/2008/Italy/Chicken(JN048402) CAstV/324595/2008/Italy/Chicken(JN048391)

CAstV/324996-4/2008/Italy/Chicken(JN048400) CAstV/ADL122057/2012/S.Korea/Chicken(KC593414) CAstV/ADL102655-1/2010/S.Korea/Chicken(JN635502)

CAstV/ADL110638/2011/S.Korea_(KC593405) CAstV/CAstV/CRO-443/2011/Croatia/Duck(JQ946070)

CAstV/MO-SEP-A799-05/2005/USA/Chicken(DQ324850) CAstV/GA-SEP-A792-05/USA/Chicken(DQ324849)

CAstV/_GA-SEP-A450-05/2005/USA/Chicken(DQ324844) CAstV/DE-SEP-A654-05/USA/Chicken(DQ324848)

CAstV/ADL121238/2012/S.Korea/Chicken(KC593413) CAstV/11672/2004/UK/Chicken_(EU668998)

CAstV/324169/2008/Italy/Chicken_(JN048393)

0.05

Gp I

Gp II

Gp III

Phylogenetic analysis based on polymerase gene of chicken astrovirus

Amino acid from

Amino acid to Position No. of strains showing the change

Isoleucine Valine 256 9/12Lysine Aspartic acid 257 8/12

Valine Glycine 262 2/12Leucine Glutamic acid 310 3/12

Serine Phenylalanine 330 3/12

Glycine Cysteine 331 2/12

Amino acid changes in polymerase gene of chicken astrovirus

Phylogenetic analysis based on polymerase gene sequences of ANV

Sichuan80/2011_(HQ603055) Sichuan87/2011_(HQ603056) 2009/Sichuan_(HM029238)

255554-3/2009_(JN048380) ADL120915/2012_(KC593401)

ADL110638/2011_(KC593390) ADL120886/2012_(KC593400)

ANV/1043/2014/HR(India)/Chicken_(KT376414) GA-CK-SEP/364-2005_(HQ188698)

GA-CK-SEP/451-2005_(HQ188696) ADL111234/2011_(KC593391)

DE-CK-SEP/811-2005_(HQ188693) GA-CK-SEP/458-2005_(HQ188699)

ANV/1105/2012/HR(India)/Chicken_(KT376416) ANV/1301/2015/HR(India)/Chicken_(KT376415)




GA/SEPA368/05/2010_(HM017850) CRO-799/2011_(JQ692619)

VIC3b/2010_(KM985697) NSW4/2010_(HM017855) VIC-4a/2010_(KM985694)

NSW3/2010_(HM017854) VIC-6a/2010_(KM985702)

VIC-5c/2010_(KM985701) VIC-5b/2010_(KM985700)

G4260/1999_(AB033998) NSW_1a_(KM985690)

TK/G145/08/2008_(HQ317722) NC-TK-SEP/537-2005_(HQ188695) NC-TK-SEP/670-2005_(HQ188697)

0.02

Amino acid from

Amino acid to Position No. of ANV strains showing the change

Arginine Tryptophan 1271 8/9Threonine Alanine 1289 8/9Arginine Lysine 1302 2/9Phenylalanine Valine 1347 8/9

Amino acid changes in polymerase gene of avian nephritis virus

- Conducted a study in five breeder flocks- Flocks sampled for nine weeks- Maximum viral load upto 3 weeks of age

Age in weeks1 2 3 4 5

Viral load

6


Estimated losses from growth depression due to poult enteritis between US$300 and US$400 million annually considering 10% -15% growth depression throughout the turkey industry in the US

(Barnes et al., 2000)Experimental studies revealed growth depression

upto 31% in turkey poults (Jindal et al., 2009, 2010)

Economic losses

20000 birds broiler chicken farm Necrotic enteritis resulted in a 12% reduction in

body weight and a 10.9% increase in feed conversion ratio compared to healthy birds

Final body weights ranged from 4.63 to 7.94 lbLoss to producer ranged from US$878.19 to

US$1480.52 per flock due to weight lossIncreased feed cost ranged from US$370.49 to

US$739.38 per flock ( Skinner et al., 2010)

Economic losses contd…

Current scenario of poultry industry in India

Second largest egg (65 billion eggs) and third largest broiler chicken meat (3.8 million tonnes) producer in the world as in 2015.

Market is estimated to be worth about Rs 90,000 crore (equal to 900 billion USD).

By 2016 total chicken meat consumption forecast at 4.19 million tons, up by approximately 8% over 2015.

Future studies▪ Experimental reproduction of the disease▪ Surveillance studies▪ NGS study▪ Potential pathogens and viral interactions▪ Economic losses▪ Prevention and control measures

Acknowledgements

1.Prof. Sagar M. Goyal2.Dr. Andre F. Ziegler3.Dr. Devi P. Patnayak4.Dr. Sunil K. Mor5. Dr. Babita Kaithal6. Dr. Pawan Bagri

Thanks

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