How does TB spread?

TB is spread through contact with respiratory fluids. It can be contracted by inhalation following close contact with an infected animal, or scavenging the carcass, head or offal of an infected animal. TB bacteria can be found in various sites in infected animals. If TB bacteria is present in the lungs, then an animal’s breath can be infectious. This is how TB is spread through social groups of both domestic and wild animals.

Cattle and deer are naturally curious and will sniff possums which stray into fenced farmland. Scavengers such as possums, ferrets, stoats or pigs feeding on an infected carcass or offal may contract TB. A grossly infected animal may have externally exposed weeping lesions which can be infectious. In wild pigs TB is found 95% of the time in lymph nodes just below the jaw. This is why dumping pig heads where scavenging animals may have access is a major issue for OSPRI’s TBfree programme.

Graphic showing how TB spreads among animals

Key information for hunters

Notify OSPRI if you suspect you have found TB in wild deer or pigs.

  • In pigs, TB infection is mostly found in the lymph nodes (glands) found just under the jaw, and alongside the intestines.
  • In deer, the lymph nodes behind the throat and at the join between the windpipe and the lungs are the most common site.

The infection will usually be in the form of pus-filled abscesses or lesions that look like whitish lumps.

Always dispose of wild carcasses carefully. Hunters may accidentally spread TB by taking infected pig or deer carcasses from TB-risk areas to TB-free areas.

If heads or unwanted body parts are dumped, they can be scavenged by ferrets or possums. This can establish or re-establish infection in ferrets and possum populations and can lead to disease being passed on to nearby cattle and deer herds.

Help reduce the risk of spreading TB

Find out if the area you want to hunt in is a Vector Risk Area (VRA) where TB infection is present. If you're hunting in a TB-infected area, assume all wild animals are infected — even if no TB lesions are visible. Remove the head or any unwanted parts and leave these behind where the animal was killed. The head and upper neck is the most likely site of any infection. The rest of the carcass will then be safer to transport. If taking the head or whole carcass out, dispose of it properly, either at an official offal facility or by negotiating to use a farmer’s offal pit.

Do not transport or release wild animals to new areas

Hunters may spread TB by taking pigs or deer from TB risk areas and releasing them in TB-free areas. This is an illegal practice. It could also undermine regional TB control efforts. To help reduce this risk, please do not move live wild animals.

Keeping safe

While the risk is small, hunters could get TB when cutting up infected wild pigs or deer.

To reduce the risk:

  • use disposable thin rubber gloves when cutting up animals.
  • wash your hands well (ideally with a disinfectant) before smoking or eating.
  • wash your bloodstained hunting clothes and gear separately from other clothes.
  • clean your knife often, especially when moving from skinning and gutting the animal to butchering it.

Dogs can also become infected with TB. Feeding raw pig heads and other offal to your dogs is not recommended.