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