The Enteritis Complex

L. P. DOYLE AND L. M. HUTCHINGS.

A GROUP of diseases having similar manifestations is called a complex. Several ailments that cause inflammation of the digestive tract of swine make up the enteritis complex as enteritis means an inflammation of the intestine.

Inflammation of the gut is often accompanied by necrosis, or death, of tissues in the gut wall. The word "necrosis" has been shortened to "necro" and is used widely in referring to disease of the intestine. The term has little definite value because it does not distinguish between the various intestinal diseases.

Some diseases, such as swine dysentery, affect the intestine without causing much change in other organs. Other diseases, such as hog cholera, seriously affect other organs as well as the intestine. Other specific diseases in the enteritis complex are swine dysentery and transmissible gastroenteritis (TGE). Other diseased conditions of the gut are less well defined.

SWINE DYSENTERY is one of the important diseases of the intestinal tract.

Several common names have been given to it, such as bloody diarrhea, bloody or black scours, and bloody flux.

Dysentery affects swine of all ages. The death rate may vary from less than 10 percent to 90 percent of the herd. Death losses average about 25 percent unless treatment is effective.

The disease is caused by a germ, which is given off in the bowel discharge from infected animals. A small amount of bowel discharge may infect a large number of healthy animals. Brood sows and boars may be carriers of infection even if they appear to be healthy.

The lesions of dysentery are in the large intestine. The small intestine is usually normal. The lining of the stomach frequently is inflamed, but a similar inflammation occurs in several other diseases. Early in dysentery the lining of the large intestine shows small, red spots and diffuse reddening. The intestine content consists of bloody mucus mixed with feces. Later there is sloughing of exudate and of the bowel lining. This sloughed material mixes with the intestinal content, giving a "rice-water" appearance. Usually mucus exists in the intestine in all stages of the disease.

After several days the large gut lining shows necro. The necrosis is superficial instead of being deep, as in hog cholera.

Dysentery is usually brought to a farm by hogs that have recently been in an infected herd or in an infested sale barn or stockyard. Animals that went through an outbreak several weeks or months previously may bring the disease into a healthy herd.

The first symptoms usually appear 5 to 14 days after contact with infection, although a longer period may pass before symptoms are seen. The symptoms are usually easily recognized. Diarrhea, or scours, probably always occurs. The bowel discharge may not differ at first from what occurs in relatively harmless scours. Soon (usually not later than 2 or 3 days) blood or mucus, or both, appear in the bowel discharge. Blood in the bowel discharge is one of the most reliable signs of dysentery. Occasionally hogs that have other diseases, such as cholera, also bleed from the bowels.

Affected animals may quickly become gaunt and lose considerable weight. Individuals that have the disease can often be detected by sunken sides. In many cases there are surprisingly few symptoms, except scours.

The animals may remain on feed while scouring profusely. Sometimes the disease runs such a rapid course that death occurs before diarrhea is noticed. Return of scours is likely in hogs that recover temporarily.

When dysentery starts in a herd, promptly moving the healthy hogs away from the infection helps reduce losses. If the healthy animals are ready for market, it is usually advisable to market them for immediate slaughter. If the healthy animals are kept for a time, they should be moved to a clean place and divided so as to reduce the spread of infection.

It is doubtful whether any animal that has passed through the disease should be kept for breeding because of the danger from carriers. Affected hogs should be fed lightly on easily digested feed. Milk seems to help recovery.

Yards and houses where dysentery has been should not be used for hogs for a while after all the hogs have been removed. The houses and yards and all the equipment should be carefully cleaned. The interior of the houses and equipment should be sprayed with a disinfectant.

Direct sunlight soon kills the germs in a clean yard, but the germs may live for a longer time when protected by manure or in some other way.

Some antibiotics, given in large doses, reduce the severity of symptoms temporarily and lower the death losses. The antibiotics do not definitely cure the disease and prevent it from recurring. Arsenic, properly used, reduces losses but fails to effect a final cure. These drugs should be used by a veterinarian or under his supervision. Arsenic is always potentially dangerous.

The experience with treatments and so-called cures has emphasized the importance of depending upon fundamental control measures quarantine to prevent introducing the disease into a herd, sanitation for preventing its spread, and disposing of the infected herd and restocking with hogs from a healthy herd in order to eradicate it.

THE TRANSMISSIBLE GASTROENTERITIS (TGE) is a destructive disease among young pigs. It is highly contagious and affects swine of all ages, but the death losses are limited mostly to pigs less than 3 or 4 weeks old. Shoats and breeding animals usually recover from an attack in about 7 or 10 days. Younger pigs that survive may be stunted for some time.

The cause is a virus.

Symptoms may be seen within 18 hours after pigs are exposed to infection. Practically all the animals may become sick within 2 or 3 days. Scours always occurs, and some of the sick animals vomit. The scouring is watery and profuse in older swine. Scouring and some loss of weight may be the only symptoms in older hogs. Vomiting may occur. Some of the older animals may die.