Official guidance first. This protocol provides general best-practice guidance. During active FMD outbreaks or in declared controlled areas, your State Veterinarian's specific disinfectant requirements and procedures take precedence. Disinfectant concentrations and product approvals may differ from those listed here.
Why Vehicle Disinfection Matters
FMD is a contact disease. Vehicles that have moved between farms, livestock markets, abattoirs, or feed depots are a primary mechanical vector — the virus hitchhikes on mud, organic matter, and moisture trapped in tyre treads, wheel arches, and undercarriage surfaces.
A single feed delivery truck or casual visitor vehicle that has come from an area with active FMD can introduce the virus to a previously clean property. No amount of animal-level biosecurity compensates for allowing uncontrolled vehicle access.
Step 1 — Pre-Entry Inspection
Before any disinfectant is applied, assess the vehicle's contamination level:
- Check tyres and wheel arches for visible mud, manure, or plant material
- Check the undercarriage for heavy organic accumulation
- Check cab steps and door sills if the driver has had livestock contact
If heavy contamination is present: organic material must be removed before disinfectant is applied. Disinfectants cannot penetrate mud or manure — they are neutralised by organic matter. Have the driver remove gross contamination with a brush or high-pressure water before proceeding to disinfection.
Step 2 — Disinfectant Selection
Not all disinfectants are effective against FMD virus. Suitable options include:
- Citric acid (2% solution): Effective against FMD, relatively stable at ambient temperature, lower corrosivity. Suitable for general vehicle use including tyres, wheel arches, and cab steps.
- Sodium hypochlorite (pool chlorine) at 0.2–0.5%: Highly effective, fast-acting. More corrosive — best for hard surfaces, concrete, and equipment; avoid prolonged contact with painted metal.
- Glutaraldehyde-based products: Broad-spectrum, effective at lower concentrations. Follow label instructions for dilution and contact time. Consult your State Veterinarian or agricultural chemical supplier for current product recommendations.
Do not mix disinfectant types. Combining products can result in chemical reactions that neutralise both — always use one product at the correct dilution.
Prepare disinfectant fresh daily when possible. Solutions stored in sunlight or heat degrade faster. Label containers with the preparation date and concentration.
Step 3 — Apply Disinfectant to the Vehicle
- Spray all four tyres and wheel arches thoroughly — cover the full tyre surface, not just the visible sidewall
- Spray the undercarriage with a long-nozzle or undercarriage sprayer if available
- Spray the cab step, running boards, and door sill if the driver has entered a livestock area
- For vehicles carrying livestock or animal products: spray the exterior of the load compartment before entry and after unloading
- Allow a minimum dwell time of 2 minutes before the vehicle proceeds — this is the minimum contact time for most approved disinfectants to act on the FMD virus
Step 4 — Footwear Disinfection for the Driver
The driver or any person exiting the vehicle must also be treated as a potential vector if they have recently been in contact with livestock or livestock environments.
- All persons must step through the farm footbath or have footwear sprayed with disinfectant
- Footbath solution must be visually clear — replace if cloudy
- Footwear with heavy organic contamination must be cleaned before the footbath is effective
- Provide disposable boot covers as an alternative if the visitor's footwear cannot be adequately disinfected
Step 5 — Equipment and Portable Tools
Equipment and tools brought onto the property from another farm carry the same risk as vehicles:
- Log all equipment entering the property (type, owner, origin)
- Equipment that has been in direct contact with livestock on another property should be disinfected before use on your farm
- Where possible, use on-farm equipment rather than shared or contractor equipment for any task involving livestock contact
- Shared equipment (scales, crushes, squeeze chutes) should be disinfected between farm uses
Step 6 — Record Keeping
Every vehicle entry and disinfection event should be recorded. Minimum record requirements:
- Date and time of arrival
- Vehicle registration number
- Driver name
- Origin (where the vehicle came from last)
- Disinfectant applied (Y/N) — and any exceptions noted
- Gate operator's initials
Keep records for a minimum of 6 months. During disease investigations, these records may be requested by your State Veterinarian or DALRRD inspector.
Common Mistakes That Reduce Effectiveness
- Applying disinfectant to muddy surfaces: Organic matter neutralises the active ingredient before it can kill the virus. Clean first, then disinfect.
- Insufficient dwell time: Moving the vehicle forward immediately after spraying does not allow contact time. Enforce the 2-minute minimum.
- Exhausted footbath solution: A discoloured footbath provides psychological comfort, not biosecurity. Replace it.
- Inconsistent enforcement: "Trusted" regular visitors who bypass the procedure are the most common failure point. The procedure applies to everyone, every time.
- Wrong dilution: Too dilute is ineffective; some products can be harmful to equipment or animals at high concentrations. Follow product label instructions.
Also see: Farm Gate Biosecurity Checklist | Visitor & Contractor Control | FMD Biosecurity in South Africa
