Upload
danielle-hopkins
View
12
Download
0
Embed Size (px)
Citation preview
Investigation of the potential relationship between influenza A virus (IAV) and Streptococcus suis infections in weanling piglets
Danielle HopkinsAdvisors: Zvonimir Poljak, Vahab Farzan, Helena Grgić, Robert Friendship
Department of Population Medicine, University of Guelph
The Interaction• A direct interaction
between these pathogens has been
proven in a cell culture study (Wang et al.
2013)
Streptococcus suis• a bacterium that colonizes in
the tonsils of all piglets: there are 35 serotypes; some serotypes are present in healthy pigs but a few
serotypes cause clinical disease
Influenza• a virus that causes piglets to become ill for a short period of time, leaving them susceptible
to secondary infection
BACKGROUND METHODOLOGY
1. Wang, Y., Gagnon, C.A., Savard, C., Music, N., Srednik, M., Segura, M., Lachance, C., Bellehumeur, C., and Gottschalk, M. (2013). Capsular salic acid of Streptococcus suis serotype 2 binds to swine influenza virus and enhances bacterial interactions with virus infected tracheal epithelial cells. Infection and Immunity, 81:4498-4508
Acknowledgements: This work is funded by Swine Improvement Porc, and the University of Guelph/OMAFRA Research Partnership. The participation of pork producers is greatly appreciated..
REFERENCES
1. Very important pathogens • S. suis and IAV are commonly present on swine farms and both are associated with production losses
2. Increased scientific and epidemiological knowledge• If a potential relationship between these pathogens exists, it could help explain why sporadic outbreaks of meningitis due to
Streptococcus suis occur
3.Implementation of control and prevention measures• Increased understanding of the interaction between these pathogens either on a pig level or farm level basis, will be beneficial in designing effective prevention and control methods
PRELIMINARY RESULTS
1: Case Selectio
n
• Identify case positive based on clinical signs for acute meningitis due to S. suis infection• Collect 1meningeal swab for bacterial culture, 2nasal swabs for detection of IAV, 3blood samples for
different assays related to historical and recent exposure to IAV, and 4tissue samples for genetic testing
2: Control
• Age-matched pen mate that appear healthy. Collect swabs and blood samples to determine IAV shedding and history, and genetic markers
3: Testing
• Confirm clinical cases are indeed due to S. suis by bacteriological culture and identify serotypes• Identify current IAV status of cases and controls by PCR* and virus isolation• Identify historical exposure to IAV by HI* and VN* tests and recent exposure by IgM ELISA
4: Analysis • Difference between cases and controls will be tested using logistic regression
Paddling piglet: http://www.nadis.org.uk/bulletins/glaessers
-disease.aspx
Heathy piglet: https://www.hiprofeeds.com/products/c
a/hog/
Growing virus to PCR : http://www.123rf.com
PRELIMINARY CONCLUSIONS AND BENEFITS TO SWINE INDUSTRY
Tonsil Meningeal 0
2
4
6
8
10
12
Case
Control
Bacterial Swabs
Num
ber
of p
igle
ts p
ositi
ve fo
r S.
suis
Fig 1. Represents the number of positive S. suis results following
culture analysis conducted by AHL at the University of Guelph. Positive results were based on meningeal and tonsil swabs collected from
cases and controls
Preliminary Analysis*• 92% (11/12) of bacterial swabs from cases positive for S.suis• 83% (10/12) of bacterial swabs from controls positive for S.suis• Currently undergoing serotyping and IAV status testing
* Key message- the accuracy of case selection and high prevalence of S. suis in both the cases and controls
Samples collected presently:• A total of 12 cases and controls were collected from single farm over a two
week period when S. suis was causing higher than average (>5%) mortality rates within the nursery, the following are the results of preliminary bacterial analysis: