By Lloyd Phillips
There are currently about 150 active cases of highly contagious foot-and-mouth disease (FMD) in KwaZulu-Natal alone – and experts warn that the disease is here to stay. The first and most important line of defence for livestock farms is a holistic, well-planned biosecurity strategy.
Unlike the deadly strains of FMD found in parts of Europe, the strains present in South Africa are rarely fatal to infected livestock. Infections can, however, still cause significant pain and distress. Animals that recover often suffer from long-term productivity losses, and livestock owners may face substantial veterinary costs, as well as major financial setbacks if their farms are placed under quarantine.
Dr Ariena Shepherd, a private veterinarian and head of the KwaZulu-Natal Animal Health Forum, says the province has long struggled with a growing number of FMD outbreaks. Contributing factors include the deliberate or accidental illegal movement of infected animals into and out of KwaZulu-Natal’s large FMD Disease Management Area.
This disease must now be regarded as a permanent threat that cannot be eradicated, Dr Shepherd said at BKB’s recent FMD Information Day in Dundee. Part of this district falls within the recently expanded Disease Management Area.
“The only solution left is for you to take care of yourself,” she said. “A holistic biosecurity programme for your livestock farm is the first and most important line of defence. It’s impossible to eliminate the risk of foot-and-mouth disease entirely, but good biosecurity can keep the risk low.”
There are various guidelines and checklists available to help farmers establish, implement and maintain biosecurity protocols tailored to their specific circumstances. Dr Shepherd warned, however, that some of these tools may not be comprehensive enough to address all potential risk factors for FMD infection.
Equally important, she added, is access to information that explains the reasoning behind each biosecurity measure, no matter how small. This helps both farmers and farm workers understand the importance of consistently maintaining these protocols.
“It helps to sit down with your veterinarian or another animal health expert to identify the biosecurity risks to your livestock farm and rank them in order of importance. The biggest risks are usually external, such as animals, people and vehicles that could bring the virus onto the farm. These should be addressed first.
“Once those are managed, attention should turn to the remaining risk factors, from the largest to the smallest. It should be a methodical and efficient process.”
Avoid contact
Biosecurity involves minimising any contact between animals and anything that could carry or transmit the FMD virus or other infectious pathogens.
Ideally, this means creating clearly demarcated “dirty” and “clean” zones on the farm. A perfect system would enforce strict protocols to ensure that nothing from a dirty area ever enters a clean one. In practice, however, such permanent separation is rarely feasible on a working farm.
The next best option is to sterilise anything moving from a dirty to a clean area as thoroughly as possible. This includes setting up proper washing and disinfection stations at all farm entrances and exits.
Biosecurity protocols should require that farm workers, vehicles, consultants, veterinarians, the farmer and their family – in short, anyone and anything entering a clean area – are as free as possible from the FMD virus and other infectious agents.
Detailed records should be kept of all movements between dirty and clean areas. Washing and disinfection procedures must be strictly followed and monitored. These records are crucial for tracing the source of any contamination on or off the farm, and for identifying gaps in the farm’s biosecurity strategy.
To support the separation between clean and dirty areas, farms should have proper fencing that is regularly inspected for gaps or weaknesses. Any holes should be repaired immediately. Everything outside the farm’s boundaries should be treated as contaminated.
“Did you know that a fox, dog or other animal dragging a single afterbirth from a cow infected with brucellosis onto your farm can infect up to 500 animals?” Dr Shepherd asked. “Your farm should be managed as a self-imposed quarantine zone.”
She noted that both people and animals can spread the virus simply by coming into contact with a boundary fence. While the ideal solution is to erect two parallel fences to create a buffer zone between the farm and the outside, this is often prohibitively expensive.
An alternative is to plant dense, preferably thorny, vegetation on one or both sides of the boundary fence, or to create non-livestock buffer zones, such as macadamia orchards.
“Cattle are very curious animals; they like to sniff and lick things. This is a major reason they are so vulnerable to contracting or spreading the foot-and-mouth disease virus.”
There are also many on-farm activities that can spread FMD and other infectious pathogens between animals – chief of which is the introduction of new animals.
For this reason, animal health authorities require that newly bought animals be quarantined for at least 28 days in a separate area of the farm, as far as possible from other livestock. While this period is generally considered sufficient, it does not guarantee that infected animals will show symptoms before mixing with the rest of the herd.
Different groups, different risks
“The quarantine area for new animals, the hospital camp for sick animals already on the farm, and the rest of the herd should all be separated and managed independently,” Dr Shepherd said. “Ideally, staff should be assigned to only one of these areas to prevent potential cross-contamination.”
She acknowledged that this wasn’t always practical or financially feasible. “The next best option is to have designated work clothes and equipment for each area. Staff should remove their work gear from one section, disinfect themselves thoroughly, and put on clean gear before entering another. All clothing and equipment should also be cleaned and disinfected regularly.”
In such a setup, the best workflow is to begin the day in the cleanest area, among the healthy animals, then proceed to the hospital camp, and finally attend to the animals in quarantine.
Even seemingly harmless objects or actions on a livestock farm can lead to devastating outbreaks of FMD and other infectious illnesses. For example, a delivery of bought feed may carry viable pathogens. Even feed produced and stored on the farm can become contaminated if it is transported through or kept near a quarantine area or hospital camp.
Dr Shaun Morris, a consultant veterinarian and FMD expert, highlighted a little-known but critical transmission risk. “People who come into contact with an animal shedding the virus are likely to inhale it. While it doesn’t harm the person, the virus can remain viable in the human respiratory tract for up to five days. During that time, every breath exhaled can release the virus into the air. If susceptible animals are nearby, they may inhale the virus and become infected.
“I’m here today to scare you,” Dr Morris said. “Foot-and-mouth disease is highly contagious and extremely serious. If you’ve been near an infected animal, go straight home. Stay away from other livestock, equipment and feed, and don’t leave your house for the next five days.”
Cross-contamination can be catastrophic
Another major and unacceptable practice is using the same syringes, needles and dosing equipment for different groups of animals on a farm, Dr Shepherd said. This should only be done if the equipment has first been thoroughly washed and disinfected.
She even recommended assigning specific sets of syringes and needles to a single type of vaccine or injectable medication. Using the same equipment for different vaccines or animals without proper cleaning poses a serious risk of spreading disease.
Similarly, carcasses of animals that have died from disease must be disposed of with extreme care. Based on her extensive experience, Dr Shepherd noted that the same tractor, trailer or multi-purpose loader used to transport animal feed is too often repurposed to move carcasses to landfills. This is only acceptable if the equipment is properly cleaned and disinfected between tasks.
Farmers should also avoid transporting carcasses through areas where different groups of animals are kept or where livestock frequently congregate. Bodily fluids from dead animals may contain high concentrations of the FMD virus. If any fluid drips onto the ground during transport, healthy animals that come into contact with it could become infected.
“Start educating yourself and your workers now on the importance of establishing and following strict biosecurity protocols,” Dr Shepherd urged. “Everyone on the farm should understand the potentially devastating consequences of inadequate biosecurity. These protocols must become routine; they must become second nature.
“Remember, a virus like foot-and-mouth disease is microscopic. There are countless places it can hide and many ways it can reach your animals. Nothing is too small, too excessive or too silly when it comes to biosecurity.
“It’s your livestock, your farm, your workers’ jobs and ultimately your livelihood that are at stake.”
Queries: Dr Ariena Shepherd, email: ajvrensburg@telkomsa.net
