Is ‘tomato flu’ dangerous or all hype? Reporting new viruses in a post-COVID world

A virus in India is providing insight into the messy science of uncovering emerging diseases as they happen – particularly in a hypervigilant post-COVID world.

The disease of the moment is called ‘tomato flu.’  It’s a virus observed in the south western state of Kerala in India. It causes fevers, rashes, and intense pain in the joints of children it infects. The rash is raised and red, with some pustules getting as large as a cherry tomato – hence the name.

A paper published in The Lancet last week broke the news of this tomato flu, providing the first scientific evidence of the virus in Kerala, reporting 82 children under five with the disease.

“These blisters sort of resemble monkey pox, and sort of resembles hand foot and mouth – it’s a bit of a mixture,” says Australia’s Victoria University immunologist Professor Vasso Apostolopoulos, who was one of the researchers on The Lancet paper.

“What’s fortunate is it’s hitting kids under the age of about eight … but the kids get over it quite effectively. After about 7-10 days they’re back to normal.”

The researchers have also suggested it could be an after-effect of vector borne diseases like chikungunya or dengue fever, which are common to the region.

All of this is speculation.  

Apostolopoulos worries about what could happen if it gets into an older or immune compromised population, however, as of yet, that hasn’t occurred.

With the world on high alert post-COVID-19, there’s increased worry about any new virus becoming the next pandemic. From 35 cases of Langya virus in China last month to tomato flu in India this month, these traditionally uncovered stories have the research community, media and lay public on the edge of their seats.

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Read more: What do we know about the mysterious new hepatitis cases in children?

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Experts are divided on whether identifying and researching every new “claimed” outbreak of a virus is a good thing.

“With every viral outbreak we’re now going ‘oh god, is this the next COVID?’, with folks trying hard to be the first to reveal a new threat. Perhaps we are now a little hyper vigilant and risk alarming the public over issues that may not be particularly new or particularly concerning,” says Professor Andreas Suhrbier, a virologist at QIMR Berghofer, in Australia.

“The media also seems particularly keen to carry these stories, and in some ways may end up feeding a frenzy.  In the pre-COVID era, a small outbreak of a non-lethal disease in India would likely not have seen such international media attention.

“As a virologist, I take some, perhaps perverse, delight in this overabundance of attention to viral diseases. At least we are now pay a bit more attention to infectious diseases, they are still with us, despite our many advances in medicine.”

However, he cautions that we can only ‘cry wolf’ about these new diseases a certain number of times.

A paper published in The Pediatric Infectious Disease Journallast week has suggested that in the case of tomato flu at least, we might have jumped the gun. The researchers looked at two cases of ‘tomato flu’ in children in England who had just returned from a holiday to Kerala. The rash looked similar to other cases from the area, with large tomato-like pustules.

The UK team did a PCR test for enteroviruses, and the results returned positive – meaning that the mysterious virus could just be hand-foot-and-mouth disease. Further sequencing was done, providing a result of Coxsackie A16.  Hand-Foot-And-Mouth disease – or coxsackievirus – is a common virus that creates regular outbreaks around the world. It has similar symptoms like fever, nausea, vomiting, and a signature flat rash.

“Initial work by a group in the UK would appear to indicate that tomato flu is nothing other than hand foot and mouth disease caused by the well-known, ever so common and not so concerning coxsackie virus A16.  Hopefully this can soon be confirmed by the Indian authorities,” says Suhrbier.

“It is perhaps a little odd that a journal with the sort of reputation of The Lancet would have jumped the gun quite so quickly without at least some diagnostic investigations to exclude the ‘common as muck’ viruses.”

Ashley Quigley, the Epidemiology Team Leader of Global Biosecurity at the Kirby Institute, thinks that being more aware of these diseases – even if that does come with some potential scare mongering – is overall better.

“If we had the level of hyper vigilance before COVID maybe things would be bit different,” she says.

With monkey pox, “we certainly were a lot more on top of it and were better able to coordinate what needed to happen before it spread through so many countries.”

“I think the more aware [the public] are, the better it is.”

Even if the tomato flu does end being coxsackie there are still plenty more questions to be answered.

“Hand foot and mouth disease in kids doesn’t particularly look like [the cherry tomato shaped lesions] at its max infection,” says Quigley.

“In saying that, we have not seen what all of these diseases look like if someone has a weakened immune system from COVID.”

Suhrbier also suggests that we are regularly not aware of what diseases look like on skin that is not white, so this could also be a factor in the case.

This is all speculation at this point, and Quigley suggests either way more testing is required, particularly to confirm if tomato flu is a new presentation or variant of hand-foot-and-mouth.

“We’re not sure if these outbreaks are caused by a single virus or more than one virus at the moment. Urgent laboratory testing and genotyping of all samples really need to happen at a rapid pace to confirm whether this is of a viral origin,” says Quigley.

“That changes the landscape of things, whether it is a new virus, or if it’s just a presentation of an earlier disease.”

But even the name has a confusing history. According to Quigley, the name “tomato flu” had been picked up in the Kirby ‘EPIWATCH’ program, which is an AI system which monitors news for outbreaks worldwide – particularly those with unknown origins.

“’Tomato flu’ is actually a colloquial term that has long been used in India to describe fever and rash in children,” she says.

“We’ve been monitoring tomato flu as a term for unknown rash and illness in children for quite a while. So, we started picking this up in around May as potentially an early epidemics signal, but that’s not to say that we know what it is.”

With the emergence of a new COVID-19-style virus at the forefront of both researchers’ and media’s minds, EPIWATCH – and programs like it – are providing more information about these new, unknown outbreaks. However, even with extra information available, it seems the line isn’t drawn for when to remain calm and when to panic.