Darryl Gracie was pig-hunting in Litchfield Park along the Finniss River when he was bitten by a mite. Two weeks later when he was diagnosed with scrub typhus, he was on the brink of organ failure.

Key points: Spread by the often painless bite of a small mite carrying the disease

Spread by the often painless bite of a small mite carrying the disease Symptoms usually occur within 2 weeks of being bitten and may include fever, chills, sweating, headache, cough, swollen glands and/or a dull red skin rash. The bite site often becomes red with a central black scab.

Symptoms usually occur within 2 weeks of being bitten and may include fever, chills, sweating, headache, cough, swollen glands and/or a dull red skin rash. The bite site often becomes red with a central black scab. Can be treated with antibiotics

"I thought I had the flu, the headaches, feeling bad, the symptoms got worse and worse and I presented myself up to the Royal Darwin Hospital in a very bad way," he said.

"They couldn't find out exactly what was wrong ... I was going downhill extremely fast."

Professor Bart Currie identified that he had been bitten by the mite, and within two days, Mr Gracie had gone from death's doorstep to a rapid turnaround on antibiotics.

"My liver was trashed," he said.

"That was 12 years ago and now I've got a medical plan where my doctor checks my kidney and liver function regularly and has got me on tablets. I'll be on medications to balance those two out for the rest of my life."

What is scrub typhus?

Scrub typhus is a bacterial infection transmitted by mites that normally live on native animals. They most often crawl into warm and moist parts of the body, such as the armpit or groin, and their bite can leave a tell-tale black oval scab up to one centimetre long.

"It's one slimy little bug that can bite you, mainly around the crotch or armpit-type areas, but no matter how big and strong you think you are, that's going to knock you down," Mr Gracie said.

Scrub typhus causes a generalised illness in affected people up to two weeks after they are bitten, and although easily treated with antibiotics, some people can become seriously ill, or even die, as in the case of one man in the NT in the 1990s. The disease cannot be spread from one person to another.

Darryl Gracie almost died after he contracted scrub typhus, and suffers lasting effects. ( Supplied: Darryl Gracie )

"It can often start out as a mild non-specific illness where people might have a fever and headache and feel unwell, sweating a lot, and then over a couple of days can progress because the bacteria can then spread to other organs within the body from the site at which the mite has injected into the person," Professor Currie said.

"Because it's a non-specific type of illness initially, unless you're asking questions about travel and where they've been, you might not be thinking about this as one of the infections, and so the medical staff do need to be aware of this so they can do appropriate tests."

Bushwalkers can protect themselves by wearing long pants, using insect repellent, and not sitting on patches of bare dirt or scrub.

Litchfield National Park was only opened to the public as a park in 1986, and the first scrub typhus case was detected in 1990, even though it is well-known to be established in far-north Queensland, as well as being prevalent across the Asia-Pacific region.

"During the Second World War it actually caused more deaths in Australian soldiers than malaria did in Papua New Guinea," Professor Currie said.

Parts of Litchfield considered 'sickness country'

Professor Currie said an Aboriginal elder had reported that there were relic rainforest parts of the popular park considered to be "sickness country" by local Aboriginal people.

The translation of its name "was like 'nit dreaming', which we could say is potentially the same as saying 'mite dreaming', which would mean that those Indigenous people historically in their traditional living had identified a place where if people went there would get a sickness related to this little mite," he said.

"It's a wonderful story about traditional knowledge, there were parts of Litchfield that were basically no-go areas for Aboriginal people in their moving around.

"So potentially some of the traditional healers recognised this scrub typhus story, and we only figured it out in 1990."

However, since an initial spate of NT cases, half of which were contracted in the park, the number of diagnoses from Litchfield has dropped off since 2010, which Professor Currie attributes in part to rangers keeping tracks and pathways clear.

"Where the vast majority of people are going, people aren't much exposed to the grassy areas where the mites and rodents are still present," he said.

Travellers to NT and those returning from Asia to be alert

Scrub typhus is just one of many tropical diseases in the NT that are not so well known down south, and Professor Currie pointed out that melioidosis was a far greater concern.

"It's way less important than melioidosis," he said.

Professor Bart Currie says there's a need for speed in diagnosing melioidosis. ( Supplied: Menzies School of Health Research )

He said perspective is important: there has only been one known scrub typhus death in the NT, compared to close to 120 caused by melioidosis, and for the 17 known cases of scrub typhus in the NT since 1990, there have been 1,000 reported cases of melioidosis.

"Education needs to be ongoing ... We need to have it out there for people who are visiting that there are these things up here which are not seen in the southern parts of Australia," Professor Currie said.

"There's people coming and going all the time, and new people and new doctors may not have heard of any of this stuff."

Because it can take up to two weeks for symptoms to appear, people may have moved on from the region of infection, and may be misdiagnosed, or there may be a delay in diagnosing them elsewhere, he said.

Travellers coming to the NT from northern Queensland and from Asia should also be aware they may have contracted the disease.

"We've had several people come back as returned tourists from many parts of the world but [particularly] South Africa, Timor-Leste, and Thailand, it's a big issue in Thailand," he said.