Fortunately, the pig is subject to comparatively few serious diseases—save swine fever, swine erysipelas, and very occasionally anthrax, which are contagious or infectious, and all in the special charts of the veterinary department of the Board of Agriculture, and within the contagious Diseases Animals Acts. Prior to the stamping out of Foot and Mouth Disease or apthous fever and rabies, pigs suffered from these contagious and infectious diseases, particularly the former of the two, which caused immense losses, especially of young pigs, during the latter half of the past century.
Of the other ailments to which pig flesh is heir, the majority and the chief of them are mainly due to that want of knowledge or care in the feeding and in the housing of the pigs which renders them more susceptible to the sudden changes in the temperature or to the inclemency of the season. In former chapters some, if not all, of these ailments have been referred to, but it may be more convenient to our readers to include in one chapter a brief description of the ailments and the remedies and means of prevention.
Swine Fever
Some thirty years since the losses from this disease were of so serious a nature that the Board of Agriculture determined to attempt to stamp it out, as they had succeeded in stamping out pleura pneumonia in cattle, and foot and mouth disease. The success of their efforts was not at all commensurate with the outlay. The failure was attributed to many causes; amongst them the want of a complete knowledge of the disease, the impossibility of diagnosing it during the life of the patient, the absence of sympathy on the part of the local veterinary surgeons owing to certain steps taken by the then Veterinary Adviser of the Board, to which further reference is now inadvisable, and to the general opposition of pig-keepers who had as little faith in many of the post mortems and their results as in the power of the authorities to stamp out the disease which under various names had been more or less common in the country so long as they could remember. Doubts were also passed on the infectivity or contagiousness of swine fever, or as it was variously termed red soldier, spots, etc.
This disbelief was probably due in part to the fact that some of the external symptoms of swine fever, swine erysipelas, and heart disease, such as discoloration of the skin were of a similar character. In some instances this redness of the skin, which was looked upon as a sure sign that the pig had died from swine fever, did not prove to be infectious, as no other cases followed amongst the in-contact pigs. This led to the general belief that swine fever was not necessarily infectious. Dissatisfaction with the arbitrary manner in which the restrictions in movement, etc., were carried out did not mend matters, nor help to render the efforts of the Board more successful.
At the present time it is imperative on the part of the owner of an ill pig to report the fact to the nearest policeman. The owner then merely carries out the instructions supplied to him by the police so that it is almost unnecessary to state that the symptoms of swine fever are several. At times the attack is of so virulent a nature that a pig may take its food all right in the afternoon and be dead the next morning, no discoloration of the skin or other external symptoms being visible before or immediately after death.
As a rule when the pig is attacked the first symptom is loss of appetite, generally accompanied by a feverish condition of the skin which shows more or fewer red spots behind the shoulder, and inside the thighs, or in those portions of the body where the skin is the thinnest and most free from hair. The great desire of the affected pig is to burrow into the litter and to remain undisturbed, save when the feverish thirst impels it to seek moisture of any sort or kind, even urine which may have settled into any unevenness of the floor of the sty.
Many of the ailing pigs suffer from a dry, husky cough, a gummy discharge exudes from the eyes and forms a ring round them, the ankles become affected, and the muscles of the back become weakened so that the pig has difficulty in walking. The discoloration of the skin may or may not increase, but the weakness gradually becomes greater so that death may follow within a day or two from the first attack. Occasionally the affected pig will continue to live for several days, and eventually recover so much that it can be fatted, but there exists a great risk of the recovered pig being what is termed a "carrier" of the disease, and possessing the ability to infect other pigs with which it may come in close contact, although the germs of the disease which it carries do not affect its own health. Similar instances of human beings being "carriers" of the disease have been recorded. So difficult is it at times to discover the source of the infection of swine fever that certain persons who are not amongst the strongest believers in the practical knowledge of the members of the veterinary profession assert that swine fever need not necessarily be the result of infection, but that injudicious feeding or the neglect of sanitary arrangements will sometimes cause an outbreak. There does not appear to be the slightest ground for this belief, as there is a specific virus which when it obtains ingress into the body of the pig, whether by the mouth, nose, or in any other way, may result in an attack, more or less severe, of swine fever, unless the virus has become so attenuated that it is unable to affect the host sufficiently. This attenuation, which is due to causes which are probably not completely known, is commonly the cause of the absence of further cases of swine fever amongst one of a lot of pigs which has had a very mild attack. This variation in the virulence of most infectious diseases has been noticed and recorded.
At the present time the Board of Agriculture have suspended the slaughter order in cases where the owner of the pigs desires to inoculate the in-contact pigs with serum which is supplied from the Veterinary College. The experiment has not been in operation sufficiently long enough to express a confident opinion upon its results, but it is stated that in Denmark the inoculation of the pigs which have been in contact with diseased pigs has proved to be a success. The risks of carrying out the experiment are by no means slight, but appear to be worth running if there be any great probability of success.