Infectious diseases can spread rapidly in a herd. Once a disease is suspected or identified, immediate steps must be taken to contain it:
- Isolate the animal showing clinical signs of disease.
- Implement movement restrictions until situation is evaluated: restrict movement of all animals until exposed animals can be identified and a perimeter is established.
- Contact your veterinarian.
- Inventory other animals in the herd, identify and isolate potentially exposed animals, and immediately implement health monitoring- take temperature twice daily and observe for clinical signs.
- Communicate with employees, service providers, visitors and other parties if involved about your biosecurity measures to contain the disease spread.
Questions to Consider Before a Disease Outbreak
Planning ahead for a livestock disease outbreak will help you to anticipate issues/barriers that will arise:
- How well are you equipped to handle large-scale mortality (more than 25 percent of your livestock) on your farm?
- If more than 25 percent of your animals were to suddenly die, how would this impact your operation?
- How prepared are you to deal with carcass disposal?
- How will you get feed to your livestock?
- How will you manage if restrictions on animal movement are put in place?
- What resources will you need to have available, or will be able to acquire during an emergency such as a disease outbreak?
- How will family and employees be affected by movement restrictions?
Creating a biosecurity plan will help you anticipate how to manage one sick animal or many.
Response for Larger Livestock Disease Outbreaks
When a quarantine is implemented, certain zones will be defined to determine the extent of movement restrictions and surveillance that will occur, depending upon the proximity to the index case, or first identified case of a disease outbreak. The two main types of zones surrounding the index case are the exposed zone and the surveillance zone. These zones may be adjusted daily. Zones may be expanded or other zones may be established if new exposed premises are identified.
The following factors will be taken into account when the exposed zone and the surveillance zone are defined:
- Characteristics of the pathogen.
- Epidemiology of the disease incident.
- Livestock species involved.
- Environmental factors.
- Wildlife involvement.
- Natural vs. artificial. barriers/boundaries.
- Geopolitical boundaries.
- Industries involved.
- Livestock movement patterns.
- Processing options (livestock and products).
The exposed zone (sometimes also called the infected zone) is defined as any area in which infection of animals has been presumed or confirmed. All premises within this area with susceptible animals and potentially contaminated materials are strictly quarantined and subject to constant surveillance.
The actual size of the zone in any one direction is determined by epidemiological factors such as terrain, the pattern of livestock movements, livestock concentrations, the weather and prevailing winds, the distribution and movements of susceptible wildlife, the estimated time elapsed since initial outbreak of disease, and known characteristics of the agent. This zone can extend several miles from the original infected farm.
The typical protocol for establishment and maintenance of exposed zones by the official agency in charge is as follows:
- Conduct epidemiological investigation to:
- Identify trace-ins and trace-outs
- Identify the source of infection
- Determine extent of disease spread
- Determine the time elapsed since initial outbreak of the disease
- Implement quarantine restrictions. Such quarantines should apply to all susceptible species and all conveyances or equipment that may have direct or indirect contact with susceptible species.
- Establish biosecurity and movement control checkpoints on avenues of transportation into and out of the exposed zone. At this point, producers will be asked to begin enforcing biosecurity measures that are more stringent than their routine practices.
- Restrict movement of all animals, humans, and vehicles departing the exposed zone by enforcing the following:
- Passage permitted only through biosecure travel corridors, through established biosecurity perimeters and movement control checkpoints.
- No animals or animal products can leave the zone.
- Vehicles, equipment and people may leave if strict biosecurity procedures are followed:
- Information concerning whereabouts and animal contacts is provided.
- All vehicles, equipment, and people are clean and disinfected.
- Personnel shower out.
- Human-to-animal contact policies are established and regulated, appropriate for the specific agent.
- Official permitting and permission is provided.
Local or regional hazmat teams may assist with decontamination as they have the equipment and expertise to decontaminate equipment and portable showers for personnel.
The surveillance zone is defined as the area surrounding an exposed zone in which movement of all susceptible animals and potentially contaminated materials are restricted and subject to aggressive surveillance.
This surveillance zone will surround the exposed zone. The exact boundaries of the zones will be established to optimize containment of the outbreak. In the early stages of the outbreak, all movement would likely be stopped. Once the extent of the outbreak is understood, susceptible livestock may be allowed to move within the surveillance zone with permits but not out of the zone. Non-susceptible livestock or poultry may be allowed to move within and outside of the surveillance zone with a permit.
The typical protocol for establishment and maintenance of surveillance zones by the official agency in charge is as follows:
- Ensure that all personnel working in the zone have access to appropriate and adequate personal protective equipment (PPE).
- Conduct activities to find infected animals and conduct trace backs.
- Increase awareness among all animal health professionals.
- Conduct surveillance at concentration points and epidemiologically suspect areas.
- Limit movement of non-susceptible livestock, poultry, commerce and products out of the zone to biosecure corridors and require appropriate biosecurity such as cleaning and disinfection of vehicles.
- Restrict public access to animals and wildlife.
- Implement quarantine of any suspected cases.
Implementing a Quarantine
Important activities official agencies may consider when implementing a quarantine:
- Eliminate human and animal traffic onto the quarantined farm except for essential personnel and dedicated service technicians. These individuals should not visit other farms for a minimum of 48 hours.
- Report all animal illness, deaths, and escapes.
- Prohibit all movement (including deliveries) into or out of the farm. Officials may set guidelines for deliveries (e.g. supply drop-offs at farm gate).
- Limit movement of the producer, family members, and employees to essential visits only.
- Establish cleaning and disinfection stations at the entrance to the farm.
- Clean and disinfect all vehicles entering or leaving the premises.
- Control essential service visits (e.g. feed deliveries):
- Visits to the farm under quarantine should be the last stop of the route.
- The driver should not enter animal housing facilities.
- The driver must wear plastic disposable boots.
- The driver must use hand sanitizer before leaving the farm.
- Upon leaving the farm, the vehicle must be thoroughly cleaned and disinfected.
- After leaving the farm, the driver should bathe and launder clothing prior to further stops or discard disposable clothing on site.
- Dispose of dead animals properly, according to rules of local environmental and public health officials and any guidelines established by veterinary officials during the quarantine.
- Dispose of animal products such as milk and eggs on-farm until the farm is released from quarantine.
Personal Protective Equipment (PPE)
Individuals working in an exposed zone around sick animals should wear appropriate personal protective equipment (PPE) to protect themselves and to reduce the risk of carrying the infectious agent off the farm. The US Department of Labor Occupational Safety and Health Administration (OSHA) has established standards for PPE.
Diseases that have the potential to infect humans are extremely hazardous and the highest level of protection should be utilized. Any plan involving a biological hazard should be based on relevant infectious disease or biological safety recommendations by the Centers for Disease Control and Prevention (CDC) and other experts, including emergency first responders, law enforcement, and public health officials. The need for decontamination or medical treatment of exposed farm personnel and first responders should be established after consultation with local public health authorities.
Chemical contaminants and other hazardous materials (e.g., radiological contamination) also pose a risk to the exposed people and emergency responders. The office of Hazardous Material Safety in the US Department of Transportation (DOT) developed the Emergency Response Guidebook (ERG2008) to assist responders in the identification of hazardous materials and to provide guidance on personal safety.
The establishment of decontamination facilities and the provision of personal protective equipment (PPE) are essential in handling all hazardous material incidents. Necessary decontamination equipment includes a safe water and air supply, shelter, decontamination stretchers, decontamination showers, water pump, and water tanks.
There are four levels of PPE (A through D with A being the highest protection level)1. It is recommended that rescue personnel use at least Level C. All staff members working in PPE should be required to attend training courses including setting up decontamination showers and proper use (don and doff) of PPE. The main focus is to train the staff to protect themselves from different routes of contamination, including skin, respiratory tract and eyes.
More about PPE can be found on the US Environmental Protection Agency, Emergency Response Program - Personal Protective Equipment website.
If PPE is not required for a response, protective clothing may still be needed to prevent personal contamination or injury. The type of protective clothing needed will depend upon the type of agent, concentration, and route of exposure. Disposable coveralls, plastic booties, gloves, and masks are examples of protective clothing. This type of gear will not protect the individual from adverse health effects, but on-site disposal of protective clothing can limit the spread of the agent outside the exposed zone.
Mortality Management/Carcass Disposal
Depending upon the incident—natural disaster or CBRNE agent (chemical, biological, radiation, nuclear, explosive)—local, state, and federal regulations may dictate the method of carcass disposal to be used (commonly burial, composting, rendering, or incineration). During disease outbreaks and hazardous material exposure, state and federal veterinarians will also be involved in the decision-making process.
Farm owners should be prepared for an emergency response by understanding local and state regulations for animal disposal, and identifying the availability of rendering facilities, landfills, incineration plants and carcass transportation in the area.
If you want to compost your deadstock, follow the steps listed below:
1. Decide what method you will use.
- Composting methods include static piles, turned windrows, turned bins, and contained systems.
- Static piles with minimum dimensions of 4 feet long x 4 feet wide x 4 feet deep are by far the simplest to use.
- Turned windrows may be an option for farmers already composting manure in windrows.
- Turned bin systems are more common for handling swine and poultry mortalities.
- The EcoPOD® is a contained system developed by Ag-Bag, which has been used to compost swine and poultry mortalities.
2. Select an appropriate site.
- Well-drained with all-season accessibility.
- At least three feet above seasonal high ground water levels.
- At least 100 (preferably 200) feet from surface waterways, sinkholes, seasonal seeps, or ponds.
- At least 150 feet from roads or property lines—think about which way the wind blows.
- Outside any Class I groundwater, wetland or buffer, or Source Protection Area—contact NRCS for verification.
3. Select and use effective carbon sources.
- Use materials such as wood chips, wood shavings, coarse sawdust, chopped straw or dry heavily bedded horse or heifer manure as bulking materials. Co-compost materials for the base and cover must allow air to enter the pile.
- If the bulking materials are not very absorbent, cover them with a 6-inch layer of sawdust to prevent fluids from leaching from the pile.
- Cover the carcass two feet deep with high-carbon materials such as old silage, dry bedding (other than paper), sawdust, or compost from an old pile.
- Plan on a 12' x 12' base for an adult dairy or beef animal. The base should be at least two feet deep and should allow two feet on all sides around the carcass.
- When composting smaller carcasses, place them in layers separated by two feet of material.
4. Prepare the carcass.
- After placing the carcass on the base, lance the rumen of adult cattle.
- Forget this once and you'll never forget again! Explosive release of gasses may uncover the pile releasing odors and attracting scavengers.
5. Protect the site from scavengers.
- Adequate depth of materials on top of the carcass should minimize odors and the risk of scavengers disturbing the pile.
- Scavengers may be deterred by the temperatures within the pile, but if not, an inexpensive fence of upside down hog wire may be adequate to avoid problems.
6. Monitor the process.
- Keep a log of temperature, carcass weight, and co-compost materials when each pile is started. Weather and starting materials will affect the process.