The deaths of three Victorians after a Saturday lunch in the small town of Leongatha sent shock waves through the community, but also shone the spotlight on one of the most poisonous organisms on earth.
Police say the three people dead, and the person in a critical condition in hospital, showed symptoms consistent with having consumed death cap mushrooms, although the official cause of death is yet to be determined.
The death cap mushroom – or Amanita phalloides – is responsible for nine out of every 10 poisoning deaths, and kills somewhere between 10 and 30 per cent of those who ingest it.
While just one mushroom can kill an adult, death caps are said to taste pleasant and look similar to edible mushrooms used in cooking.
The innocuous look, feel and taste of a death cap mushroom means it can be hard for someone who has eaten one to even know they’ve been poisoned.
The timeline of death cap mushroom poisoning
Illness from death cap poisoning generally takes place in stages, with symptoms arising anywhere from six to 24 hours after eating the mushroom.
After the initial period of no symptoms, someone who has consumed the mushroom will experience nausea, vomiting, cramps and diarrhoea – symptoms which could be mistaken for another illness such as gastroenteritis.
The next stage of illness is marked by an improvement of physical symptoms, as the ill person begins to feel better for the next day or two.
However, serious damage is still occurring to the internal organs.
Independent Forensic Consulting director Michael Robertson has been working as a forensic toxicologist for decades, and says the internal damage caused by toxins such as mushrooms is a silent killer.
“It’s a little bit like paracetamol in that sense. You can take an overdose of paracetamol and you might get a little bit sick for a day, and then you recover,” Dr Robertson says.
“But what’s happening in the body is you’re getting liver toxicity, and that’s when people die.”
Eventually, the damage done to the liver and kidneys become apparent, leading to potentially irreversible damage and failure.
At this point, a person may begin to experience jaundice, seizures and could fall into a coma as the liver and kidneys begin to shut down.
Death can ensue seven to 10 days after mushroom ingestion.
What do death cap mushrooms do to our bodies?
Despite their deadliness, the exact mechanisms of how the mushrooms poison humans are still not well understood.
The mushrooms contain a toxin known as α-amanitin, found in the highest concentrations in the ring, gills and cap.
Washing, cooking or preparing the mushroom does not remove the toxin. A fatal case was reported occurring even after mushrooms had been dried and then frozen for more than seven months.
Researchers recognise that this toxin inhibits a crucial protein in the liver known as RNA polymerase II, which helps transcribe our DNA. Without this essential protein, the liver can’t repair the damage it sustains, and necrosis – or cell death – begins.
Treatments mainly target the symptoms with decontamination and rehydration of the body. Drugs and ultimately transplants of the liver and/or kidneys are necessary if the damage has progressed past a certain point.
There is no known antidote for death cap mushroom poisoning, although researchers have had recent success in using a green dye to combat the toxin.
How are poisonings identified?
Police have not been able to definitively conclude that death cap mushrooms were involved in the recent deaths in Victoria’s east.
In cases of suspected poisonings, samples taken from victims are analysed by forensic toxicologists to assess whether toxins are present.
While samples are taken in hospital and during autopsies in the days following a suspected poisoning death, identifying toxins is not always straightforward.
Dr Robertson says the actual testing for toxins could take a number of weeks depending on how equipped the laboratory is.
“They may have to purchase some additional standards or compounds that are known toxins so that then the laboratory can compare what they find in the urine, to what is known to be the toxin … and that process might take a couple of weeks,” he says.
He says the relative rarity of mushroom toxins means a standard might have to be procured from interstate or overseas, potentially delaying the process.
“If it were cocaine and this was a high profile case, you could get the results in 24 hours, or 48 hours,” he says.
“When you get these unusual cases, it can take a little bit longer to do.”
Dr Robertson says once a “standard” of the mushroom toxin has been obtained, toxicologists will be able to tell with “scientific certainty” whether someone had those toxins in their body at the time of their death.
Toxicologists from the Victorian Institute of Forensic Medicine declined to speak to the ABC given their proximity to the suspected poisonings in Leongatha.
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