dr. daniel linhares - seneca-associated diseases, clinical presentation and epidemiological...
TRANSCRIPT
Seneca-Associated Diseases:
Clinical Presentation and
Epidemiological Distribution
Daniel Linhares1, Chris Rademacher1, Fabio Vannucci2, David Barcellos3
1Iowa State University, 2University of Minnesota, 3Universidade Federal do Rio Grande do Sul
Acknowledgements
• US team – Drs Rademacher, Yoon, (JQ)
Jianqiang, Zimmerman, Gauger, Derscheid,
Pineyro, Schwartz, Bates, Canon, Canning,
Karriker, Holtkamp, Baum, Madson, Arruda,
Maine, Halbur
• Brazil team – Drs Barcellos, Paladino, Guedes,
Rosa, Assayag, Heck, Zanella, dos Santos, Reis
• Funding:
Definition of ETNL
E
Epidemic
Suddenonset, up to
70%
T
Transient
Self-limiting (7-10 days)
NL
Neonatal Losses
<3 and <7 days old
Vannucci et al., 2015
Timeline
"shift" from ETNL to IVD
Timeline of onset of Epidemic Transient Neonatal Losses (ETNL) and Idiopathic Vesicular Disease (IVD) in Brazil
Linhares, Barcellos, Vannucci 2015 (in prep)
We estimate that 70-80% of Brazilian swine industry has experienced ETNL or IVD
We are not aware of re-breaks Mortality on ETLN cases took 4-10
days to return to baseline Pigs affected with DVI healed lesions
in 10-15 days
Seneca & US…
• Circulating since 1988 (USDA data)
• Summer 2015: increase in number of reports
– IA, MN, IL, SD, MO
– Exhibit pig cases (8 fairs)
– Finishing sites (~15 cases)
– Sow farms (~40 cases)
• Retrospective sampling (UMN, ISU, NC):
– Low prevalence of Seneca RNA detection by
PCR
Epidemic transient neonatal mortality
Most piglets had stomachs full of milk, lethargic
~50% cases: piglet diarrhea (mesocolonic edema)
~70% cases: reported VD in sows
Linhares & Teixeira, 2015 in prep
No apparent reproductive impact on sows
Sampling…
• Finishing pigs
– Clinical signs (lameness, VD lesions)
– (#1) Swab lesions, (#2) Oral fluids, also nasal rectal, and/or tonsil swabs, serum (transient viremia)
• Sow farms
– Clinical signs (sudden increase in neonatal mortality, VD-like lesions)
– (#1) Swab lesions, (#2) piglet nasal/rectal swabs
Summary
• Vesicular disease– High morbidity (> 50%)
– ~Zero mortality
– Healing/recovery ~ 2 weeks
– Still shedding additional 2-3 weeks
– Key: communication with health officials/power plant
• Epidemic Transient Neonatal Losses– High morbidity within litters (>70% farrowing)
– High mortality (up to 70% young litters: 1-4 days age)• Litters with 0-1 days old: high mortality.
• Litters 5+ days old: not clinically affected
– Back to baseline mortality: 4-10 days
– Do piglets w/o clinical signs carry virus? yes
Thoughts
• SVV– Consistency on association with VD
– ETNL?: most cases with VD, also SVV by PCR
– If SVV is causing, which SVV? Alone or with something else? If something else, infectious?
• Assuming infectious agent (SVV, or SVV+?)– Highly transmissible
– Highly immunogenic
– Quick establishment of protective, long lasting immunity
– If Seneca, has it changed? How to define new vs old (markers)?
Thoughts on transmission
(assuming Seneca Disease)
• Extremely high transmission rate
– Quick onset, quick natural “whole herd”
exposure??
• Highly immunogenic, long lasting immunity
– After 7 days: infection is gone
– No rebreaks after ~10 months (BR experience)
• Easily transmitted indirectly (air? mosquitoes?
other animals, truck, feed ingredients, vaccines?)
– BR experience: clustered time & space
Moving forward…
• Sow farm and growing pig longitudinal shedding studies
• Infection models: understand dynamics of infection,
seroconversion and immunity
• Koch’s postulates (assess Seneca’s role on both clinical
syndromes)
• Dx tools & Epidemiological studies (molecular
comparisons, looking for virus & antibodies in the swine
industry, finding triggers of vesicular disease/neonatal
mortality syndromes)
Daniel Linhares, DVM, MBA, PhD
Assistant Professor, Dept of Vet Diagn & Production Animal Medicine
Director of Graduate Education
Iowa State University College of Veterinary Medicine
Office: (515) 294-9358
Mobile: (515) 357-1044
http://field-prrs.blogspot.com/
Google:(ISU) James McKean Swine Disease Conference
Thursday, November 5 - Friday, November 6, 2015. Ames, IA.
Thank you very much!