SWINE

Senecavirus A testing update   

Jim Fairles, Josepha DeLay, Davor Ojkic

Senecavirus A (Seneca Valley virus A, SVV) has become a concern for the Ontario swine market as our neighbours in the US continue to diagnose cases.

https://www.aasv.org/aasv%20website/Resources/Diseases/SenecaValleyVirus.php

The Ontario Animal Health Network (Swine) has links to bulletins outlining the disease.

http://oahn.ca/resources/networks/swine/

Testing for SVV is dependent on the clinical syndrome:

Þ For cases with vesicular lesions, CFIA must be contacted in order to exclude Foot-and-mouth disease virus infection.

Þ In herds experiencing a sudden increase in neonatal mortality but with no apparent vesicular lesions, samples can be submitted to the Animal Health Laboratory (AHL).

The PCR test for SVV has been recently validated by the CFIA and the protocol distributed to the Canadian Animal Health Surveillance Network labs, of which the AHL is a member.

Test cost is $31 (Ontario clients) and the short code is “svvpcr”.

Typing of influenza viruses in 2014 and 2015   

Davor Ojkic

Hemagglutinin and neuraminidase genes were identified for 86 influenza viruses detected in swine samples submitted to the AHL in 2014 and 2015. There was a noticeable increase in both the number of submissions and the number of influenza A positives: 18 influenza A viruses from 2014 and 68 viruses from 2015 were subtyped (Table 1).

In 2014, almost three-quarters (72%) of typed viruses were H3N2 subtype; 28% were H1N1 subtype. All 13 H3N2 viruses were cluster 4-related (94-97% amino acid sequence identity). Four of 5 subtyped H1N1 viruses were related to the “pandemic 2009” H1N1 cluster; one was related to the contemporary “swine” influenza virus alpha cluster.

In 2015, the situation had changed, and 50% of typed influenza viruses were H1N1 subtype, while the proportion of H3N2 viruses had decreased to 37%. Again the majority (29) of H1N1 viruses were related to the “pandemic 2009” H1N1 cluster, whereas 9 samples had beta-cluster viruses, and 3 contained alpha-cluster viruses. H3N2 viruses in 2015 were 94-97% identical to cluster 4 viruses.

In 2014, H1N2 viruses were not detected, but H1N2 represented 6% of viruses typed in 2015. The frequency of detection of mixed infection (2 influenza viruses detected in the sample) has also increased from 0% in 2014 to 7% in 2015.   

Table 1. Influenza A viruses of swine origin typed at the AHL in 2014 and 2015.