There are fears that African swine fever could hit the wild boar population in the Forest of Dean and then spread to other animals in the region.
It comes as the Forestry Commission brings in extra marksmen to cull the growing population of wild boar.
Pig farmer Richard Vaughan lives on the edge of the Forest of Dean and fears for his herd of middle white pigs. They are an endangered breed and much prized by top chefs. They are so rare that fewer than 250 exist in this country - he probably has half the population - and they could be wiped out if the virus takes hold.
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African swine fever is highly contagious and has slowly worked its way into Europe, where it has infected wild boar and domestic pig herds.
The Forest of Dean has - it is estimated - more than a thousand wild boar but in truth no one knows the exact number, despite attempts at counting them.
There is an annual cull of boar carried out by experienced wildlife rangers, but the Forestry Commission says that it is increasing the number of rangers in the Forest of Dean from four to six to bring them under more control.
There are concerns that the wild boar could contract the disease from infected pork products left behind after picnics and barbecues.
The Department for Environment, Food and Rural Affairs (Defra) is asking visitors and local residents to ensure that any waste food is disposed of securely to minimise the risk.
Experts confirm that this is the most likely way that the disease - which has such devastating consequences - is spread.