Declan,
Myxomatosis is a highly contagious diease of rabbits, whilst hunting it would be difficult but not impossible to tell whether the animal was infected.
By far the commonest signs of myxomatosis are swollen eyes which can range from mild swelling to the eyes being fully shut. Other signs which you would be unable to see on the scope are swelling of the genitalia most obviously the vagina and snotty noses.
Nearly all infected rabbits are slower moving and easily seen as they feel so unwell that they cannot move around as much as a healthy rabbit.They are also generally in poor condition when severely affected.
It is worth noting that not all infected animals will show any signs of diease in the earliest stages.
Hope this is of some help to you
Victoria C Black
Veterinary Surge&on
special interests in dog breeding, clinical medicine and small animal surgical procedures.