Swine influenza in a third of Scotland, Northern Ireland herds

Aggregated data from surveys in Scotland and Northern Ireland show that more than a third of swine herds surveyed are positive for swine influenza, according to Merial Animal Health, maker of swine influenza vaccine Gripovac 3. Between the surveys just over 280 farms were assessed and serology demonstrated that 34 percent were positive.
This compares to research on pig farms in England carried out by the Royal Veterinary College (RVC) and the COSI Consortium in 2010, which showed that 59 per cent of herds were positive for one of the swine influenza strains.
The Scottish data is from figures collected by Quality Meat Scotland based on blood samples taken in 2012 and 2013. The Northern Irish data was gathered at the two main slaughter houses in the Province in 2011.
Callum Blair, Merial Animal Health said: “We would suspect that the results of blood tests at slaughter are an underestimate of the actual prevalence of swine influenza as antibodies from natural infection wane over time. Pigs that may have been affected, therefore, could still test negative at slaughter.  So it may be that the prevalence is even higher than a third of herds. The disease can be sub-clinical and the productivity of the herd can fall before the disease is detected. By this point, treatment can be costly and pigs’ health severely compromised.
 “In the case of the Northern Irish study there also seemed to be a link between the prevalence of swine influenza and pericarditis (infection around the heart) and pleuritis (infection around the lungs).”
Swine influenza can also significantly increase herd replacement rates. It increases the likelihood of both abortion and still births. The disease can affect conception rates and decrease lactation, both of which add to a decrease in herd output.

Early indications show swine influenza, PRRS cases on the rise in UK

The UK's Animal Health and Veterinary Laboratory Agency (AHVLA) has reported early indications show an upward trend in swine influenza and porcine reproductive and respiratory syndrome virus (PRRS). The agency noted there are more diagnostic submissions to investigate PRRS since the end of summer 2013.
PRRS survival is favored in cooler conditions. The survival of the PRRS virus on contaminated vehicles and pig accommodations is also more likely as effective cleaning, disinfection and drying of surfaces are harder to achieve in wet or cool conditions. Maintaining ideal ventilation and temperatures in pig buildings is also challenging as the weather becomes colder, especially when day and night temperatures fluctuate widely and these factors can also predispose to respiratory disease outbreaks. Where respiratory disease or increased mortality or poor growth is seen, it is worth discussing whether to submit pigs or plucks to an AHVLA post-mortem facility to investigate the causes and assist in making decisions on disease control measures and treatment.
Outbreaks of swine influenza are traditionally associated with autumn and winter months and this is attributed to the climatic conditions favoring survival of the virus and promoting transmission. If swine influenza infection is suspected, free testing for the virus is available through AHVLA.

Oral fluids help diagnose swine influenza

One possible tool to diagnose swine influenza is the analysis of oral fluids. "Although we have good evidence that swine influenza is widespread in the UK pig herd and that the disease affects production," says Nick Munce, pig business and technical manager at Merial Animal Health. "The symptoms may be sub-clinical, and producers may be unaware of the presence of the virus until such time as there is an actual outbreak that needs treating. A simple method that could be used to identify the presence of virus in the herd would be most welcome."
More should be done to encourage diagnosis of swine influenza, according to Munce.  "Vets are keen to explore a variety of options open to them for diagnosing the disease, and pig producers should be actively looking for symptoms and contacting their vets if they suspect that swine influenza is impacting the health and productivity of their herd."
Two papers presented at this year's 5th European Symposium of Porcine Health Management (ESPHM) in Edinburgh shed light on the use of the technique, which involves suspending a rope for the pigs to chew on, harvesting the oral fluids produced and then submitting them for laboratory analysis.
The first study¹ described a 130 farrow-to-finish operation in Brittany. Sows were displaying symptoms including anorexia, later or late abortions, early farrowings and weak new-born piglets. PRRS and PCV2 had both been eliminated. However, flu infection was evidenced in ill fatteners and, four days later, in weaned and suckling piglets. The research shows that 12mm ropes suspended in the pen for at least an hour every two days during weaning were a useful way of diagnosing the presence of swine influenza, although sub-typing was not possible.
Researchers in Spain have also used this technique successfully to detect PRRS and swine infl uenza on 97 farms where the pigs were experiencing respiratory signs, and fever, dullness, growth retardation or heterogeneity.² The study was able to successfully show which farms were positive for one or other of the diseases, for both, or for neither.
¹ Diagnosis of swine influenza virus in oral fluids samples in 20-day-old piglets: a field case. S. Turci (1), L. Mieli (2), G. Simon(3), S. Herve (3), J-B. Herin (4), B. Boivent (4), M. Bublot (5), F. Joisel (5), T. Vila (5), G. Perreul (4)
(1) Breizhpig, Plérin, France (2) LDA22, Ploufragan, France (3) ANSES, LNR Infl uenza Porcin, Ploufragan, France (4) MERIAL SAS, Ancenis, France (5) MERIAL SAS, Lyon, France
² Detection of the enzootic form of swine infl uenza by oral fl uid sampling. A. Callén (1), S. Cárceles (1),J. Gonzalez (1), A. Ferré (1), D. Arroyave (1), T. Vila (2), F. Joisel (2) (1) Merial Laboratorios S.A., Barcelona, Spain (2) Merial SAS, Lyon, France
(1) Merial Laboratorios S.A., Barcelona, Spain (2) Merial SAS, Lyon, France

UK pig producers encouraged to vaccinate against H1N1 strains

Most veterinarians agree that swine influenza or H1N1 is an increasing problem for pig producers, according to a survey recently conducted by Merial Animal Health. Only 8 percent of those interviewed said that in their experience the number of cases of swine influenza had stayed the same over the last five years, while 92 percent agreed that it had increased.
Views varied on the exact reasons for this apparent increase. These included better diagnostics, and increased reporting by pig producers. However, a number pointed at specific recent outbreaks which have driven the increase.
Most of those questioned - 60 percent - agreed that vaccination against swine influenza makes good economic sense. This was borne out by the number agreeing or agreeing strongly that the UK industry should take swine influenza more seriously, which amounted to 77 percent of the sample.
Nick Munce, Merial's Pig Business & Technical Manager said: "This survey demonstrates that the majority of veterinarians recognize the economic benefits of vaccination against swine influenza."
Some 77 percent of those interviewed agreed that swine influenza is a production disease that can affect reproduction, average daily weight gain and feed conversion ratios. In terms of controlling the disease biosecurity and a variety of vaccination strategies featured on most vets' lists.
Vets were asked to estimate the current prevalence of swine influenza in the English national herd and the average figure was around 44 percent. Research published in 2010 showed that 59 per cent of the 146 farms surveyed had at least one pig positive for the H1N1, H1N2 or H3N2 influenza viruses¹.
Gripovac 3 is currently the only swine influenza vaccine licensed for the UK. It provides protection against the most common influenza strains - H3N2, H1N1 and H1N2.

¹ Towards risk-based surveillance for swine influenza virus. Barbara Wieland*, Alexander Mastin*, Dirk U. Pfeiffer*, The COSI Consortium**
*Royal Veterinary College, Hatfi eld,
**Combating Swine Influenza Initiative Consortium, Cambridge, UK. 21st International Pig Veterinary Society congress, Vancouver, Canada, 2010.

Swine influenza in UK, Ireland may be higher than expected

The incidence of swine influenza in pig herds in the UK and Ireland could be higher than expected if the results of a recent survey are replicated across the national herds in these countries, according to Brian Rice, veterinary adviser at Merial Animal Health.
Routine diagnostic blood testing in these countries indicated most herds tested were positive for swine flu. “More than 70 percent of herds tested in Great Britain had one or more pigs that tested positive, while this figure increased to over 90 percent in Ireland," said Rice. "Historically, and with no vaccine available, the industry has tended to be reactive to swine influenza, managing outbreaks as they arose, but more and more producers are now realizing the benefits of vaccinating against the disease."
Previous research carried out in 2008–2009 by the Royal Veterinary College and the COSI Consortium across a broader sample of around 17 percent of the English herd showed that nearly six in 10 farms (59 percent) had pigs that were positive for one of the strains of swine influenza. “Many people may be surprised by just how widespread the disease is, but the real question is how they plan to mitigate the potential risks posed by swine influenza to the productivity of their herds,” said Rice.
According to Merial, the optimal route is for producers to investigate their herds' swine influenza status and put in place appropriate preventative measures.