That message you saw yesterday? It was written in Malaysia, and travelled via Australia.

The first I heard of it was just after 8.15am yesterday, when a friend sent a concerned message wondering, “have you heard anything?” Through the morning four other friends sent it to me. It landed over and over again in the inboxes at The Spinoff. The word was that New Zealand was about to go into lockdown. According to the list of measures, purportedly provided by someone in the New Zealand parliament, within hours everything but “essential services” would close.

When I wandered from my makeshift home workplace up to the local supermarket just before noon, two unconnected people were discussing the imminent lockdown in the line for the checkout. One had heard that the police were mobilising.

In one particularly fruity version of the rumour, it had filtered out via a text to the head of a fashion label from the prime minister’s partner Clarke Gayford. Which is fitting enough, given that the last time such a rumour propagated so rapidly it involved a trailer load of bullshit that falsely implicated Gayford to the extent that the police commissioner issued a statement saying he “is not and has not been the subject of any police inquiry”.

That, however, was disinformation: false claims designed to damage Gayford and his partner, propelled by a bunch of frog-faced trolls. This time, I think it’s better described as misinformation – that is, false information disseminated (for the most part) by people who think there’s truth in it.

Ardern addressed the rumours at her stand-up in Rotorua just before 1pm yesterday.

“I am present on social media, I see it myself. I cannot go around and individually dismiss every single rumour I see on social media, as tempted as I might be. So instead I want to send a clear message to the New Zealand public: We will share with you the most up-to-date information daily. You can trust us as a source of information.”

Of the specific rumour, she said: “That’s the kind of thing that adds to the anxiety people feel … Do not panic – prepare. When you see those messages, remember that unless you hear it from us it is not the truth.”

The place to look for official information, she said, was covid19.govt.nz.

A few minutes later, the director general of health, Ashley Bloomfield, was asked at his daily briefing whether he was aware of the rumours. “Someone mentioned that to me as I was on my way in here,” he said, bemused, “and that’s not something that I’ve heard discussed by anybody.”

Was lockdown an option, he was asked. “We’ve seen other countries do that. When they have tended to do that is when they have a very high proportion of cases with community spread.”

New Zealand currently has no evidence of community spread.

With the exception of one mainstream journalist who tweeted (and soon deleted), “I’m told the total lockdown is being announced shortly”, the New Zealand media, as far as I could see, held the line, reporting the story only in the context of debunking it. It’s a tricky decision with rumours such as those – to report even in the context of controverting can, perversely, just add fuel to the rumour. But this was so widespread it had become properly dangerous. It absolutely sparked panic buying.

Last night, as part of a lengthy Facebook update, Jacinda Ardern addressed the rumour again.

“Today, a worrying piece of misinformation regarding Covid-19 was brought to my attention that I want to address. A social media post, claiming to have insider information regarding our government’s planned response to the virus, was being widely shared among New Zealanders, causing real anxiety. I want to reassure you that if you saw this, it is not true.”

Ardern’s words were strikingly similar to something Scott Morrison said a day earlier. “There’s a lot of misinformation out there,” said the Australian prime minister after announcing a limit on social gatherings to 100 people.

“There’s a lot of ridiculous stuff that’s circulating on text messages and internets about lockdowns, and sadly even cases of wilful fraud and fraudulent preparation of documents – even recordings alleging to represent cabinet meeting and things of this nature. Don’t believe it – it’s rubbish. Avoid that nonsense that you’re seeing on social media,” he said, before directing people to official government sites.

The reason his words were so similar to Ardern’s is he was responding to precisely the same contagion. In both cases the text circulating was – as spotted by Australian journalist Osman Faruqi – a version of measures issued in Malaysia. On Monday, the Malaysian prime minister declared a “Movement Control Order”, the text of which was cut and pasted and repurposed in both Australia and New Zealand.

There’s a viral hoax message doing the rounds claiming the PM is about to shutdown the country. It’s a direct copy of Malaysia’s announcement. It isn’t true, please let people know if you see it pic.twitter.com/crgEETQ6Bk — Osman Faruqi (@oz_f) March 17, 2020

As if there were any doubt about that, the first point in the list of measures that came, according to the messages I received yesterday morning, from a New Zealand “cabinet briefing”, specified a “restriction on mosques and Islamic events subject to Musakarah meeting”.

The Muzakarah (meaning “discussion”) is a committee of the Malaysian National Council for Islamic Religious Affairs.

One of the reasons the rumour spread like wildfire is because it’s not out of the question that at some point in the future the New Zealand government might order a lockdown. To varying degrees, a number of countries – Malaysia among them – have done so already. What’s more, there is some ambiguity in the language. As of this morning New Zealand’s border could be described as locked down – indeed Ardern herself used the word lockdown in her speech last night.

But as the unflappable Ashley Bloomfield laid out yesterday, a lockdown proper is unlikely unless we have evidence of widespread community transmission. In any case, I’m going to look to him, or government ministers, to tell me if it’s a thing, rather than anonymous, anxiety-fuelled messages that spread through friend groups and across continents.

The virality metaphor is so thuddingly obvious it becomes trite, and yet, there it is. As we all learn a lot more about pandemics and viral outbreaks it wouldn’t hurt to apply some of the same measures: isolate yourself from (from anything unverified) and practise social media distance – that is, if in doubt, just don’t pass it on.