ZOONOTIC DISEASE PREVENTION

Although it is not common for personnel to "catch" a disease from pigs, or any other animal, which is termed a "zoonotic" disease, the risk is ever present.

The primary method to protect oneself is to practice good personal hygiene, especially the steps listed below: this module highlights only a few, common zoonotic diseases; for an extensive review of the various pathogens with zoonotic potential, please consult one of the listed references.

STEPS TO PREVENT DISEASE TRANSMISSION FROM PIGS TO MAN

Wear gloves whenever caring for pigs, handling their wastes (feces, urine and dirty bedding), or handling any body product such as: blood, meat, viscera, nasal discharges, or fluids draining from wounds. After removing your gloves, wash your hands with soap and water.
Never eat or drink in areas where pigs, their wastes, or body products are handled. Absolutely no eating, drinking, or smoking is allowed in areas where pigs are housed.
Report all suspected sick pigs as soon as possible, so the veterinarian may determine the cause of the illness and implement any additional protective steps. When the veterinarian does post signs, telling everyone to wear special, protective clothing such as masks, gowns, rubber boots or shoecovers, be sure to follow these procedures. If you don't, you increase your chances of getting sick, but also, you may expose other people by transmitting the disease pathogen on your clothes or hands!
Although a normal, healthy adult person may have only mild symptoms when they become infected with a zoonotic disease, that person may spread the disease to others. Cases of animal handlers "carrying home" zoonotic diseases to their infants, with fatal consequences are common! Therefore, good hygiene is not only to protect the person working directly with pigs, but all persons with whom they have contact. At special risk are persons who may have a suppressed immune system, such as: infants, the elderly, people who have had their spleens removed, and people with long-term or debilitating conditions such as cancer, diabetes, AIDS or renal failure.
For personnel at the farms, wear a designated pair of shoes and jeans, or coveralls, while working at the farm and don't wear these clothes anywhere else! Wash the designated clothing separate from the family wash, or have the farm unit do the washing to reduce chance of contamination.
Before leaving the farm, either change to another clean pair of shoes, or clean the "farm" shoes before getting into your vehicle. Use a brush to remove manure and mud, then spray with a commercial disinfectant.

ALLERGIC SENSITIVITIES

Allergic skin and respiratory reactions are common in personnel working with pigs, or with other kinds of animals and birds. Consult your physician, who may advise you to wear protective clothing, e.g., gloves, masks, or gowns.

Balantidium coli

is a protozoan normally found in the cecum and large intestine of the pig. If the normal, gut bacterial flora becomes unbalanced, this organism may reproduce in greater numbers and then cause anemia, enteritis and poor growth. In man, the organism causes a severe colitis, with ulcers and sloughing of intestinal mucosa. Transmission to man is by fecal contamination. Always wash your hands after handling pigs, their wastes or body tissues. Remember, even normal pigs will have this protozoan in their feces and observing good hygiene is a must!

BRUCELLOSIS

B. suis is the main species found in pigs. The majority of infected swine herds show no symptoms, but the classic signs are abortions, infertility, weak piglets at birth, infection of the testes and arthritis due to joint infection. Transmission to man is by direct contact with tissues, blood, urine, vaginal discharges, or aborted fetuses and placentas from infected animals. The disease in man is life threatening with severe fever and disabling lesions of the spine. Men may become sterile from testicular infections. Prevention is by observing good hygiene, particularly wearing masks and gloves, as well as hand washing. Although treatment is available, lifelong antibiotic therapy is required.

CAMPYLOBACTERIOSIS

C. jejuni is considered to be one of the principal bacterial agents causing enteritis and diarrhea in man. Transmission is usually from an handler not washing their hands after handling a pig which has diarrhea caused by this organism.

COCCIDIOSIS

In pigs, these protozoan parasites may cause mucoid or bloody diarrhea, dehydration, anemia and weakness. Although the risk of infection to humans is fairly low, pigs infected with this parasite should be isolated from other pigs and treated.

COLIBACILLOISIS

Certain strains of E. coli are responsible for a syndrome called Edema disease, wherein pigs show neurologic symptoms and edema of the eyelids and sometimes, edema of the entire neck and belly area. The disease may be discovered when large numbers of weanling pigs suddenly die, without any previous signs of ill health. In man, the bacteria can cause profuse and watery diarrhea, abdominal colic and vomiting; a few strains of E. coli may cause rapid disease and death! Transmission is controlled by wearing protective clothing (gloves) when handling pigs, their wastes or body tissues.

ERYSIPELAS

is a disease caused by the bacteria Erysipelothrix rhusiopathiae. Infected pigs show high fevers, painful movement due to infected joints and often, there is a skin rash of raised, pink to purple, squarish lesions which range in size from pinpricks to about four inches across. Similar lesions may be seen in man, although the bacteria can also spread to the blood and cause damage to the heart valves, or, sudden death. In man, as in pigs, arthritic changes can occur from joint infection. Wear protective clothing (gloves) when handling pigs, their wastes or body tissues and afterwards, wash your hands!

LEPTOSPIROSIS

Infected pigs usually show no symptoms from this bacteria, although within a herd there may be an increase in abortions and small, weak piglets. Since apparently healthy pigs may be secreting huge numbers of these bacteria in their urine for months, persons caring for pigs must routinely observe good personal hygiene.

SALMONELLOSIS

S. typhimurium is a common bacteria of the intestinal tract of many animals, including pigs and man. Contamination of the environment by fecal material is the most common source for infection. A watery, profuse diarrhea for about 10 days is the typical symptom in man, but persons with a suppressed immune system may die.

TAPEWORM

The worm, Taenia solium, can infect man if they eat insufficiently cooked pork containing the larval stage of the worm, or, by eating food or water contaminated with infective, human feces (as when farm workers choose to relieve themselves in the field, or, in nations where human waste is used as fertilizer). This parasite causes severe problems in man, including: brain seizures, muscle pain and weakness, heart failure and sometimes, sudden death. The parasite is uncommon in America, but found in about 5% of the pigs tested in Mexico. Successful control is achieved by inspecting pork carcasses, properly cooking pork, and properly disposing of human feces.

TRICHINOSIS

The worm, Trichinella spiralis, circulates throughout the body and encapsulates within muscle. In the pig, it usually causes no problems. Most human cases result from eating homemade sausage, or other pork, which was insufficiently cooked. Never eat pork which has not reached temperatures above 171o F and wash hands after handing raw meat.

TUBERCULOSIS (TB) or MYCOBACTERIOSIS

Pigs are susceptible to three agents, M. bovis, M. avium and M. tuberculosis. Symptoms may or may not be evident in the live pig but lesions are an important cause for carcass condemnation at the time the meat is processed. Transmission to man occurs by inhalation and ingestion. Prevention is based on avoiding contaminated meat, observing good hygiene and having annual intradermal skin tests performed at Student Health, office of immunization.

EXTERNAL PARASITES

Any pig noted to be infected with mites or lice should be immediately treated. Notify the facility supervisor if you suspect a problem! To eliminate external parasites, all pigs housed in a particular room must be treated at the same time and there must be repeated treatments, as well as cleaning of the housing area.

SARCOPTIC MANGE MITE

The mite which causes mange is found on swine throughout the world. It is barely visible to the naked eye, but only if placed on a dark background. The clinical signs are skin lesions, itching and rubbing. The mite is found in very high numbers on the inner surface of the ear, so skin scrapings from the ear are used for diagnosis. Treatment consists of ivermectin injections and steam cleaning the housing facilities.

PEDICULOSIS (louse infestation)

Lice are the most common external parasite of pigs and are easily seen with the naked eye; being quite large. Infected pigs are often seen rubbing and itching. The louse cannot live for more than a few days off the pig, and normally they are spread from pig to pig by direct contact. Injections of ivermectin are useful in controlling this parasite.

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Last updated: 01/02/2008 gea