STRATEGIES TO CONTROL THE ORAL TRANSMISSION OF DISEASE IN FARM ANIMALS

Oral transmission of disease occurs when pathogenic organisms are present in or on any object that can be licked or chewed, e.g., food, water, dishes, toys, paws, fencing, etc. The source of contamination is commonly feces or urine, but may also be aborted fetuses, placentas, milk, semen, other body fluids or infected tissue. In addition to adhering to standard practices for hand hygiene and the use of personal protective equipment, there are a number of additional precautions that can be used to reduce the risk of oral transmission of pathogens in veterinary practice and animal care settings.

Small Animals————

Waste management: —-

Animal kennels and cages, parking lot areas, animal play areas, waiting room areas, etc. should be cleaned on a regular basis to remove feces and urine. A separate area for exercise should be used for animals with known or suspected infectious disease. Patients with diarrhea should be isolated and handled separately to avoid the potential contamination of others with infectious feces. Likewise patients with potentially infectious urine (e.g., Leptospirosis) should be isolated and handled separately. Prompt clean-up of diarrhea and potentially infectious urine, followed by thorough disinfection of the area, especially common use areas, is warranted. Use a disinfectant product that has EPA-approved activity against the specific contaminating organism at the appropriate dilution.

Food and water: ———

Food and water dishes should be removed from cages after feeding, then cleaned, disinfected and thoroughly dried prior to reuse. Disposable feeding trays may be used for animals with known or suspect infectious disease. Feed and storage areas should be clean and secured from rodents, wildlife and insects. Store animal feed in bins with tight fitting lids to keep rodents, wildlife and insects out. Spilled food should be cleaned up promptly. Stored food should be rotated on a first-come, first-used basis. New feed should not be added on top of old feed. Raw meat diets should be avoided except when absolutely necessary, e.g., wild exhibit animals.

Large Animals-————–

Waste management: ——-

Waste should be removed at least once to several times a day, depending on the weather and stocking density. It should be moved to a designated area away from animal contact. For smaller volumes, the storage area should be level and well-drained. Composting is recommended to destroy bacteria and parasite eggs. For larger volumes of waste, manure should be stored in a well-constructed lagoon. Use equipment that is dedicated solely for use of manure management, i.e., do not use the same equipment for hauling feed, managing crops, etc.

Feedlots and corrals can also be dragged to disperse manure and expose it to heat, sunlight and wind. Dragged lots should be left vacant an ample amount of time to allow killing of infectious organisms. Local, state and federal regulations for waste removal may vary, so be familiar with the regulations for your area.

Food and water: ———–

Protect feed from rodents, wildlife, pets and insects. Feed storage areas should also be protected from weather as excessive heat and moisture can spoil feed. Spilled feed should be cleaned up promptly. Feed produced on site should be evaluated for risk of introducing and/or transmitting disease. Purchased feed should be documented and approved by an acceptable quality assurance program. If contamination is suspected, a sample should be collected and frozen for testing.

Situate feed so that it is not easily contaminated while animals feed, e.g., so that animals cannot defecate or urinate in it and people cannot walk or drive through it. Push the feed up as animals eat to reduce waste and decrease chance of spoilage. Remove old feed before putting down new feed. Use feed containers with smooth surfaces, e.g., plastic liner in troughs, to avoid crevices into which feed can pack and spoil. Clean feeding containers regularly. If animals are fed in an open area, rotate the feeding area regularly. Group animals by age and minimize the stocking density at each feeding location.

Artificial water sources (e.g., troughs) are preferred over natural water sources (e.g., streams) for improved water quality and less risk of contamination. Whatever the water source is, it should be protected as much as possible from potential sources of contamination, e.g., situated such that animals cannot defecate, urinate or stand in the water. Watering containers should be examined and cleaned regularly.

Water should be tested yearly for horses and every six months or more frequently for cattle. Tests for water solids should be less than 1000 ppm. A coliform bacterial count should also be performed to check for contamination from manure or septic tank.

Pasture management:———-

Avoid using high-risk fertilizers such as non-composted manure on pastures where animals graze. Do not allow overgrazing as this forces the animals to graze close to the ground near fecal piles. Drag the pasture area on a regular basis to break up manure piles and expose fecal material to heat, sunlight and wind. Only unoccupied pastures should be dragged, then left vacant for at least two weeks.

Orally Transmitted Zoonotic Diseases—————–

There are a number of zoonotic diseases that can be transmitted orally, including:

• Anthrax (Bacillus anthracis)

• Baylisascariasis (Baylisascaris procyonis)

• Bovine spongiform encephalopathy (Mad cow disease)

• Brucellosis (Brucella melitensis, B. abortus, B. suis, B. canis)

• Campylobacteriosis (Campylobacter jejuni, C. fetus, C. coli)

• Cryptosporodiosis (Cryptosporidium parvum)

• Cysticercosis (Taenia saginata, T. solium)

• E. coli infection (E. coli O157:H7)

• Echinococcosis (Echinococcus granulosus, E. multilocularis)

• Giardiasis (Giardia intestinalis [G. lamblia])

• Larval migrans – roundworm (Toxocara canis, T. cati)

• Leptospirosis (Leptospira spp)

• Listeriosis (Listeria monocytogenes)

• Lymphocytic choriomeningitis (Arenavirus – Lymphocytic choriomeningitis virus)

• Mycobacteriosis, nontuberculous (Mycobacterium aviumcomplex, M. marinum)

• Plague (Yersinia pestis)

• Psittacosis (Chlamydophila psittaci)

• Q fever (Coxiella burnetti)

• Salmonellosis (Salmonella spp)

• Streptococcosis (Streptococcus ssp)

• Toxoplasmosis (Toxoplasma gondii)

• Trichinellosis (Trichinella spiralis)

• Tuberculosis (Mycobacterium bovis)

• Tularemia (Francisella tularensis)

• Whipworm (Trichuris suis, T. trichiura, T. vulpis)

• Yersiniosis (Yersinia enterocolitica)

By adopting and consistently enforcing standard veterinary precautions, infection control practices and biosecurity measures that reduce the transmission of any one of these diseases, we can significantly reduce the risk of transmission of multiple diseases spread by the same route of infection, including zoonotic, foreign animal and emerging “as-yet-undefined” diseases, to our country.

Reference-on request