Following an announcement by the Animal Health and Veterinary Laboratories Agency (AHVLA) at the end of 2013 regarding an increase in swine influenza diagnoses in the UK, Merial Animal Health is urging pig farmers to consider vaccination against the disease. Writing in its October report, the AHVLA indicated that there had been an increase in incidences of swine influenza.
Cases highlighted included one in Bury St. Edmunds where an 1,800 head herd was moved indoors after being housed under tents. Thirty percent of the animals showed signs of respiratory disease, malaise and recumbency and 25 were found dead. Swine influenza was detected by polymerase chain reaction (PCR) in three portions of the lungs and was the most likely cause of the upsurge in respiratory problems and mortality. It is thought that by moving the pigs into finishing sheds, the spread of infection among the herd escalated.
Swine influenza was also detected in a separate case of the sudden death of three pre-weaned piglets with Glässer's disease, and was believed to have pre-disposed them to concurrent disease.
Findlay MacBean, head of Large Animal Business for Merial Animal Health, said: "The benefits of taking a preventative approach to swine influenza, rather than simply treating outbreaks of the disease, are becoming more apparent.
"We advise producers to talk to their vets about vaccination to reduce both the economic impact and the associated welfare problems of the disease. Not only does it affect the vigor of the current herd, but can significantly increase herd replacement rates. Swine influenza increases the likelihood of both abortion and still births. The disease can also affect conception rates and decrease lactation, both of which add to a decrease in herd output."
The main subtypes of swine influenza affecting pigs in the UK and Europe are H1N1, H3N2, and H1N2. The disease can be sub-clinical and therefore the productivity of the herd can fall before the disease is detected. The presence of Influenza is often not detected until there is a clinical outbreak. By this point, treatment can be costly and pigs' health severely compromised.
Many vets are now integrating flu vaccination into herd health plans for UK pig producers. Gripovac 3 is the only approved swine influenza vaccine on the UK market and is approved for all three of the main subtypes of swine influenza.