The Virus May Be Riding Along: What a Philippine Study Found on ASF and Pig Transport Vehicles
When we talk about African Swine Fever (ASF) biosecurity, we usually think about farm gates, footbaths, protective clothing, and keeping infected pigs away from healthy herds.
But there’s another possible pathway we shouldn’t overlook:
The vehicle carrying the pigs. ๐
A 2025 Philippine study published in Veterinarni Medicina investigated environmental DNA (eDNA) contamination patterns of African swine fever virus (ASFV) in swine transport vehicles.
And the findings give us a good reason to rethink how we clean and disinfect livestock vehicles.
What Did the Researchers Do?
The researchers collected 450 environmental swabs from 30 swine transport vehicles operating in the Philippines.
They didn't just swab the cargo area.
They checked 15 different locations on the vehicles and hauling personnel—from the steering wheel and gear shift to the cargo floor, tires, hands, clothing, and footwear.
The samples were then tested using qPCR to detect ASFV DNA.
The big finding?
๐จ 5 out of 30 vehicles were ASFV eDNA-positive.
That's 16.67% of the vehicles tested.
In other words:
About 1 in every 6 vehicles sampled had detectable ASFV genetic material somewhere on the vehicle or associated personnel.
So… Where Was ASFV Found?
This is where things get interesting.
ASFV eDNA wasn't limited to the area where the pigs were kept.
The highest positivity rates were found on:
But ASFV eDNA was also detected on several other surfaces at 3.33% positivity, including:
Think about the sequence:
Pig → Cargo Floor → Boots → Cab → Steering Wheel → Another Location
A contaminated surface doesn't have to stay contaminated in just one place.
People can help move contamination around the vehicle.
Your Boots and Hands Matter More Than You Think
One particularly important finding was the detection of ASFV eDNA on haulers' hands and footwear.
"Did we disinfect the truck?"
We should also ask:
"Did we disinfect the PEOPLE interacting with the truck?"
Because biosecurity is a chain—and one contaminated boot can become a weak link.
Here's the Concerning Part
According to the study, 73.33% of the vehicles were reportedly cleaned and disinfected—but ASFV was still detected.
The authors noted that many haulers relied on regular detergent or dishwashing liquid for cleaning, while alcohol and chlorine were among the disinfectants used. They argued that the effectiveness of existing cleaning and disinfection practices needs improvement.
So simply saying:
"The truck was disinfected."
…may not be enough.
We need to ask:
Biosecurity isn't just about doing disinfection.
It's about doing disinfection correctly.
Even Wheel Baths Deserve a Second Look
The study also detected ASFV eDNA on tires/wheels.
This is notable because wheel baths are already used as a biosecurity measure at slaughterhouses.
The researchers suggested that their effectiveness should be reassessed and emphasized proper maintenance—including regularly replenishing disinfectant, preventing dilution by rainwater, removing mud and manure, and providing adequate soaking/contact time.
A dirty wheel bath isn't automatically a biosecurity barrier.
Sometimes, it may just be a dirty puddle with disinfectant in it.
Did the Study Find One Major Risk Factor?
Interestingly, no.
The researchers examined several factors, including:
- frequency of pig transportation
- frequency of vehicle cleaning
- cleaning materials
- disinfection practices
- number of pigs transported
- whether the hauler owned pigs
None showed a statistically significant association with ASFV eDNA-positive vehicles in this study (P > 0.05).
That doesn't mean these factors don't matter.
The study involved only 30 vehicles, and the authors themselves recommended larger studies to better identify possible relationships.
Important: Positive DNA ≠ Infectious Virus
This distinction is critical.
The researchers detected ASFV environmental DNA.
That tells us that viral genetic material was present on the sampled surface.
But it does NOT automatically prove that viable, infectious ASFV was present or that touching that surface would cause infection.
The authors specifically emphasized that eDNA detection does not confirm infectivity and recommended further studies to determine whether contaminated surfaces contain infectious virus and what infectious dose would be required.
So the correct message isn't:
❌ "16.67% of trucks were infectious."
It's:
✅ "ASFV genetic material was detected in 16.67% of the vehicles sampled, demonstrating environmental contamination and highlighting potential biosecurity gaps."
That's an important scientific distinction.
What Can Pig Farms and Haulers Learn From This?
ASF biosecurity needs to extend beyond the farm gate.
A stronger transport biosecurity program should consider:
4. Treat loading and unloading areas as potential contamination zones.
6. Audit the process—not just the presence of a footbath or wheel bath.
The study ultimately calls for more targeted cleaning and disinfection protocols, additional disinfection stations, stricter farm and slaughterhouse biosecurity, and better technologies for decontaminating vehicle cabins.
The Takeaway
ASF doesn't need to walk into a farm.
It can potentially hitch a ride.
This Philippine study reminds us that transport biosecurity is farm biosecurity.
And sometimes, the biggest biosecurity risks aren't the things we don't clean.
They're the things we thought we already cleaned properly.
