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.