BVDV sequence analysis as an aid to eradication

George Russell, Dawn Grant, Claudia Bachofen

Bovine viral diarrhoea

• BVD is an important disease of cattle with both economic and welfare costs

• Causes diarrhoea, infertility, abortion and death • National eradication scheme in Scotland • Voluntary schemes rest of UK • Persistent infection drives BVDV epidemiology

BVDV is a pestivirus

• Single strand RNA • 12.5 kb genome • diverse group • Similar biology • Range of

pathogenicity • Error-prone

replication 5‘UTR 3‘UTR

Erns Npro C E1 E2 p7 NS 2 NS 3 NS4A NS4B NS5A NS5B

BVDV persistent infection • Acute infection generally mild in adults • Infection of a pregnant cow can transfer to foetus • Consequence can be abortion, immunity or PI

Persistently infected (PI) animal

Insemination Birth Month ~2-4

Abortion immunity

Where can infection come from?

Molecular tracing?

http://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=0ahUKEwiUgKnG7ZDWAhUE6xQKHbNbD2YQjRwIBw&url=http://www.clipartpanda.com/categories/green-tractor-art&psig=AFQjCNELZywroUT3wRxWkyzlb7hNph9WhQ&ust=1504797413793746http://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjMi7qQ7pDWAhVGWRQKHf8SD_gQjRwIBw&url=http://www.joesboots.com/p/MOV18006.html&psig=AFQjCNG33TwrOnCe5wedrq_q60KTe6adaQ&ust=1504797551528480https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjpnvXF9JDWAhUB2hQKHQqdASIQjRwIBw&url=https://shannonclarkefinalyearproject.wordpress.com/author/shanclarke23/page/15/&psig=AFQjCNGCziS_Yfe3n16unNsRlt-BBt2eKQ&ust=1504799212833129

5‘UTR Npro

Genotyping BVDV PI samples • Sequence-based • Uses 5’UTR (or Npro) • RT-PCR from serum • Compared with reference strains • Many subtypes of BVDV type 1

BVDV Biobank status

• >3000 5’UTR sequences • >1200 different

sequences • Over 80% BVDV1a • identical sequences at

multiple locations

• Are they identical viruses?

Identical 5’UTR sequences = strains?

• Two groups identical 5’UTR • BVDV1a & BVDV1b • Analysed Npro sequences • More resolution

5‘UTR Npro

BVDV1b

BVDV1a

MRI0203 MRI0262 MRI0263 MRI0270 MRI0278 MRI0279 MRI0467 MRI2323 MRI2324 MRI2325 MRI2326 MRI2327 MRI2329 MRI2350 MRI2356 MRI2887 MRI2888 MRI2890 MRI2893

MRI0238 MRI0243 MRI0348 MRI0688 MRI0689 MRI2128 MRI2281 MRI2510 MRI2577 MRI2625 MRI2780 MRI2781 MRI2790 MRI2792 MRI2812 MRI2814 MRI2815 MRI2947 MRI2990 MRI2999 MRI3000 MRI5001

Some identical sequences

Npro sequences vary Core of identical sequences

Adding other data

PhyloViz analysis • sequence network • coloured by premises • locally related strains

BVDV1b

BVDV1a

How can sequencing help eradication?

• Understanding chains of infection – Animal movements – Local contacts – Carriage via people/vehicles

• Need to evaluate risk – Sequences – Movements – Other contacts

Acknowledgements

• Samples & data sources – Paul Burr @ Biobest – George Caldow @ SAC – Moredun VSU

• EPIC colleagues – Ruth Zadoks – Sam Lycett – George Gunn

SAC Consulting

http://www.roslin.ed.ac.uk/http://www.ed.ac.uk/http://www.sruc.ac.uk/http://www.bioss.ac.uk/http://www.gla.ac.uk/http://www.moredun.org.uk/http://www.hutton.ac.uk/

www.moredun.org.uk

BVDV sequence analysis as an aid to�eradicationBovine viral diarrhoeaBVDV is a pestivirusBVDV persistent infectionWhere can infection come from?Genotyping BVDV PI samplesBVDV Biobank statusIdentical 5’UTR sequences = strains?Some identical sequencesAdding other dataHow can sequencing help eradication?AcknowledgementsSlide Number 13