Two Australian teenagers died this week after becoming ill with suspected methanol poisoning in Laos, along with a dozen other tourists.
Six people have now died, and they are all believed to have consumed drinks laced with methanol.
The Australian government has updated its , telling residents to be alert to the potential risk of spirit-based drinks including cocktails.
But this is not the first instance of methanol poisoning. Experts say it is widespread but often goes undiagnosed, and describe it as a "forgotten crisis"
What is methanol poisoning?
Methanol is a chemical compound and is similar in structure to ethanol, which is the compound that makes drinks alcoholic.
It is poisonous to humans but is sometimes illegally used in place of ethanol in alcoholic drinks as a cheaper alternative.
When the human body attempts to break down methanol, the process creates toxic chemicals called formaldehyde and formic acid, which can cause severe damage.
Symptoms of methanol poisoning can include vomiting, seizures, dizziness and vision changes. It can lead to blindness, organ failure, coma and death.
How common is methanol poisoning?
Médecins Sans Frontières (MSF), also known as Doctors without Borders, monitors incidents of suspected methanol poisoning globally and is trying to improve awareness and treatment of the issue.
According to their research, there have been 58 suspected methanol poisoning incidents in the last 12 months. There were 1,200 affected people and 406 deaths.
And since 2019 when MSF started tracking suspected methanol poisonings, the charity believes there have 943 incidents leading to nearly 13,000 deaths.
Dr Chenery Ann Lim, project manager from the methanol poisoning initiative at Médecins Sans Frontières Hong Kong and family, said methanol poisoning is widespread in southeast Asia.
She said there have been cases in Indonesia, the Philippines, Cambodia and Thailand, along with the current situation in Laos, with many local cases going unreported in international media.
"I think this is really just the tip of the iceberg," she said.
"We don't really hear a lot of what is actually happening on the ground ... a lot of the (people) who are consuming (the drinks) are not tourists, but also the local population.
"This is what's really missing in all of this; there's so much highlighting of the international tourists and there's so much coverage, but we don't really know what is happening with local people."
Where is methanol poisoning most common?
The country with the most suspected methanol poisoning incidents in the last 12 months was Indonesia, with 24, according to MSF.
India had nine, including an incident in October that resulted in 65 deaths.
Bangladesh and Pakistan had four each, while Iran had three cases, including one in September that impacted 160 people and left 26 dead.
Methanol poisoning can be fatal. Source: Getty / Plateresca
The current situation in Laos is the only incident the country has had in the last 12 months, and Cambodia and Malawi have each had one.
'Lack of awareness' and a 'silent killer'
Lim said there is a lack of awareness about the issue of methanol poisoning.
"This is such a neglected disease and it's not something that we should judge the person that was victimised because for them it's not intentional; they don't know that they're being poisoned," she said.
"Even for the health professionals, there's lack of awareness on how to treat, how to diagnose, how to manage."
Dr Knut Erik Hovda is a senior consultant and professor at Oslo University Hospital and the University of Oslo, and a consultant for the National Poison Center in Norway.
He said methanol poisoning more often affects locals than tourists.
"It's affecting most commonly the poorest of the poor and the tension never gets to the media," he said.
"There are thousands and thousands being blinded, they're having brain damage and they're dying with never making it to the news at all."
Hovda said many victims of methanol poisoning do not get a proper diagnosis due to delayed symptoms, with people often not feeling ill until the day after they drink methanol.
"They have no idea what's going on, sometimes it's confused with food poisoning, and this is why methanol is called the 'big imitator'. It looks like anything else," he said.
"People are dying (and) never getting the diagnosis. This never gets to the attention of the public or the stakeholders, and that's why it's a silent killer and it's a forgotten crisis."
With additional reporting by the Australian Associated Press
