Preventing
Disease Spread
by Dr. Bob Wright and Dr. Dan Kenney
Keep strangles and rhino in check with proper hygiene and management
When bacterial
and viral outbreaks, such as strangles and rhinopneumonitis respectively,
occur in barns, owners commonly ask:
• How long
will the bacteria, virus, or other disease agent stay in the barn?
• How do
I stop the agent from spreading from horse-to-horse or from barn-to-barn?
• How can
I disinfect the barn?
Many disease agents
(bacteria, such as Streptococcus equi which causes strangles, viruses,
and parasites) can remain in a barn for considerable time. They can
be harboured in the horses themselves, in the fecal and organic matter
which has been ground into the wood and cement of the barn, in the
soil in the pasture and in rodents or birds that live in the barn.
Horse handlers can also be a reservoir or source of the disease agent,
either by harbouring disease agents such as salmonella or methicillin-resistant
Staphylococcus aureus (MRSA) or by carrying the agent on their clothing
and shoes.
Personal Hygiene
The horse industry is very lax when it comes to personal hygiene as
a means of preventing the spread of disease. To prevent the spread
of disease, the swine and poultry industries require that their employees
“shower in and shower out” of their facilities. Horse people,
however, commonly go from barn to barn and from a show to home without
any concern for disease spread.
Horse handlers
should dedicate boots and clothing for use only on that farm. If this
is not possible, boots should be cleaned prior to entering the premise
and freshly laundered clothing should be worn. A freshly laundered
pair of coveralls would also suffice. This is also true when returning
from a horse show. Handlers should be encouraged not to wear the same
clothing home as there is the potential for them to carry a problem
back to their farm.
Hand Washing
Hand-washing facilities should be suitably located around the barn/farm
to encourage the frequent washing of hands. Research at a human hospital
showed that, as the access to a hand- washing facility increased,
the hand-washing compliance increased (1). Thorough hand washing with
soap is adequate in most cases. Antiseptic soaps (e.g., chlorhexidine)
or iodophor shampoo/washes (e.g., Betadine scrub) may also be used
and should be located at the sink in an easy dispensing container.
The use of alcohol-based hand gel disinfectant may be an alternative
or adjunct to hand hygiene in horse barns. Dispensers could be attached
to the handler’s belt or outside of the stalls, allowing horse
handlers the opportunity to disinfect their hands after working with
an individual horse. These products require 15 seconds for the disinfectant
to dry and provide good hand disinfection. They reduce the overall
time required to disinfect one’s hands. Choose a product that
doesn’t dry out the skin or cause skin irritation.
Hand washing is
also important to prevent chemical contamination of the work place
when working with horse medicines. Products such as the progesterone
product, Regumate, and the horse dewormer, Eqvalan®, are commonly
used around horse barns. They should be washed off immediately if
they come in contact with bare skin. If workers are required to walk
a long distance and open doors to reach a sink, the hand washing won’t
occur and door handles and other objects will become contaminated.
Cleaning of
the Barn and Stalls
The number one rule for disease control is cleaning. Clean means free
of dirt and organic matter such as manure. This means the removal
of all manure and feed, followed by washing, scrubbing and rinsing,
or pressure washing, all surfaces with hot water and detergent. This
is followed by the use of a disinfectant according to label directions.
(Complete label details for many of the common disinfectants are included
in the Compendium of Veterinary Products, available in your veterinarian’s
office.) Thorough cleaning will remove most of the contamination and
allow disinfectants to penetrate surfaces and kill micro-organisms.
Thorough cleaning is a must. This is difficult to accomplish in many
horse barns due to the presence of wooden walls, dirt floors, open
ceilings and lack of drains. When building a new barn, choose a design
and materials that will make cleaning easier. Incorporate drains in
appropriate locations. In barns with sand or other porous floors,
thorough cleaning may entail replacing the sand or clay from the stalls.
A disinfectant
is a chemical or substance that kills micro-organisms and is applied
to objects. Disinfectants are too toxic, irritating or corrosive for
use on living animals, including people. Disinfectants kill micro-organisms
but may not kill bacterial spores which are a dormant form of some
bacteria, e.g., Clostridia.
Types of Disinfectants
The “Active Ingredients” section of the label on the container
of disinfectant will identify the type of product. Most commonly,
they fall into the chemical categories as listed in the chart shown
at left, on this page.
The presence of
organic material, including bedding, manure, blood, and pus, interferes
with the action of most disinfectants. This is the reason that the
directions on most disinfectants recommend thorough cleaning of the
surface to be disinfected before applying the product. Some products
include the use of both a detergent and a disinfectant. Thorough cleaning
will remove the majority of the organisms and expose the rest to the
action of the disinfectant. Follow the label directions before using.
The product label will often state a dilution rate when being used
either as a germicidal cleaner (killing micro-organisms) or as a sanitizer
(reducing the number of micro-organisms). A minimum contact time is
normally stated on the label. The minimum contact time is the time
required to kill micro-organisms. The kill time is affected by the
presence of organic matter, temperature, pH, hardness of water and
concentration of disinfectant.
Special Uses
for Some Types of Disinfectants
For sterilizing needles and syringes, use alcohol, quaternary ammonium
products labeled for this purpose, glutaraldehyde or chlorhexidine
(but change solution if contaminated with blood).
For washing animals
or washing your hands, use chlorhexidine or iodophor surgical scrub,
shampoo or washes (e.g., Betadine scrub).
As a skin antiseptic
prior to a surgical procedure, chlorhexidine or iodophor skin antiseptic,
e.g., Betadine solution, is applied.
Example: Strangles
and recommended critical action points
A new horse arrives
in the barn and, within one week of arriving, has developed swellings
under the jaw suggestive of strangles. Strep. equi, the causative
agent of strangles, is suspected and strangles is a highly contagious
disease which can remain in the barn for many months.
1. Remove the
infected horse from the main barn to an isolation area. If this
is not possible, create a quarantine area at one end of the barn,
separated from the rest of the horses by a visible barrier (e.g.,
plastic sheet or caution rope draped across the alleyway) to remind
handlers to take extra precautions when entering and leaving the area.
Do not use an outdoor run-in shelter as a quarantine area during fly
season if the infected horse has open abscesses. Flies can transmit
the micro-organism within a 600-yard radius.
2. Check with
your veterinarian regarding the immunity and vaccination status of
other potential contact horses. Vaccinate contact horses if recommended
by your veterinarian.
3. With your
veterinarian, develop a protocol for the treatment of the infected
animal, the test(s) necessary to determine if the animal is a carrier
and guidelines by which the horse should be allowed back into
the main horse population.
4. Develop
and follow a protocol for fly and insect control.
5. Develop and
follow a protocol for disposal of infected material such as
bandages and bedding.
6. The quarantine
area should be equipped with the following:
• rubber
boots and coveralls.
• wash area
with water, paper towels, skin disinfectant and a garbage container.
• disposable
gloves if treating infected areas.
• supplies
of bandages, needles, syringes, and a sharps disposal container.
7. Clean all
surfaces of the infected stall(s). Dispose of bedding in a way
that will prevent horses and flies from becoming contaminated. Disinfect
pitch forks, shovels and brushes which may have been in contact with
the infected horse. Use separate equipment for cleaning stalls of
affected animals and non-affected animals. Clean stalls of non-infected
animals first.
Don’t get
over-stressed by strangles. Remember, strangles is like head-lice
and chicken pox in school age children. At some point in its life,
your horse will come in contact with strangles, influenza and the
(respiratory) virus. Most horses do not have any permanent, long-term
consequence as a result of strangles.
References and
Reading Material
1. Boyce JM. Antiseptic Technology: Access, Affordability, and Acceptance.
Emerging Infectious Diseases Journal. Centers for Disease Control
and Prevention website www.cdc.gov/ncidod/eid/vol7no2/boyce.htm
2. Swine Medicines
Course Swine Medicines Manual, 1st ed. Ontario Pork Producers’
Marketing Board, 2000. ISBN 0-9687896-0-9.
3. Bayley A. Compendium
of Veterinary Products. 7th ed. Hensall , Ontario , Canada : North
American Compendiums Ltd., 2001.
Reprinted with
permission of HorseCanada
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