The fever and rash appeared the day before we were scheduled to get on a 747 from London to New York. Twin 1’s face was a streaky, sickly red except for death-pale stripes around her mouth. I knew what I was looking at, because Twin 2 had just finished the last of her 10-day course of liquid antibiotics. We had our second case of scarlet fever.
“I wouldn’t recommend flying,” the GP told me, modelling characteristic British understatement. “Airline policy is that if you board a plane with a condition you were previously aware of, and then your illness requires an emergency landing, insurance won’t cover you. You’ll be on the hook for the cost of the unscheduled landing.” She doubled down on the understatement. “It could get expensive.”
It took me a moment to digest the unspoken reality behind the advice. “Sorry… “ I said incredulously, “but that means it’s legal to get on an airplane carrying a Victorian disease?”
It is. According to official guidance, within 24 hours of the first dose of antibiotics, scarlet fever is no longer contagious. The rest of the 10-day course is meant to ensure you’ve killed off any stragglers. Still, what if I had taken my tiny Typhoid Mary on the plane today instead of tomorrow? Or yesterday? During its contagious period, scarlet fever is incredibly contagious, passed in airborne droplets from coughing and sneezing, skin contact, and touching shared surfaces. Cozied up to my diseased progeny, the 400-plus passengers trapped with us for 8 hours in that unventilated tin can would have enjoyed a 35 percent chance of infection.
Global travel may be one factor in the massive scarlet fever outbreak that’s been hitting England the past couple of years, and which has now become the biggest in half a century. Outbreaks began a couple of years earlier in Hong Kong, South Korea and other east Asian regions, and then hit the UK. Now the US is nervously waiting for the shoe to drop. No one knows where it will show up next because no one can explain why the disease has come roaring back in the first place.
Twin 1’s clinic visit was déjà vu all over again. Ten days earlier, I had taken Twin 2 to a different practitioner with a similar laundry list of symptoms: vomiting, high fever, sore throat, red rash. “This is almost certainly scarlet fever,” he said. My reaction the first time was a whole lot less blasé.
“Isn’t this a little bit Dickensian?” I asked him. I meant that quite literally. Charles Dickens cast scarlet fever in several of his novels (two of his children died of it). Louisa May Alcott’s sister died of it when she was a child, and so, later, did Alcott’s character Beth March in Little Women.
Part of the horror of the disease is in its predilection for children under 10. Scarlet fever peaked in the 1800s and 1900s, with raging epidemics whose mortality rates in some areas reached 25 percent. Even if these children survived, they would often be left with devastating heart damage and lifelong kidney and joint diseases.
The discovery of penicillin put an end to these cruel deaths and complications – it’s just the same bacteria that causes step throat, after all, easily vanquished by a course of antibiotics. These were so successful a vaccine was deemed unnecessary. Soon, a diagnosis became less terrifying and more an exercise in box-ticking: high fever; vomiting; scaly, sandpapery rash all over the body that peels over the course of antibiotic treatment like a sunburn. Some kids get a “strawberry tongue”, in which the tongue looks exactly like a strawberry – raw, bright red and dappled with swollen papilla that look like seeds. By the mid-20th century, new diagnoses had dropped so steeply that a doctor would need to go through this checklist to make sure you were really infected with scarlet fever.
“Is it weird that scarlet fever is coming back?” I asked the GP, panic rising as I pictured the prologue of every zombie apocalypse movie.
“Oh no,” he said blithely. “There’s an outbreak pretty much every year.”
An older, more experienced doctor might have had a different perspective. After 1970, it was unheard of to have more than 10,000 cases a year in the UK. After 1980, that number dropped under 5000. In 2010, it was around 1500.
Then the numbers started edging up again. By 2015 there were 17,586 cases. By 2016, nearly 20,000 in England and Wales – the highest number of cases in 50 years, British scientists reported last November. But why?
Antibiotic resistance is almost certainly involved, though there’s been no strain of antibiotic resistant super scarlet fever to provide a smoking gun.
Climate change may also play a role. It has aided the spread of other previously localised diseases including zika and chikungunya.
But zika and chikungungya are spread by mosquitoes (that’s why climate change is aiding their spread – their vector is finding many more parts of the world quite hospitable in a warmer world). Scarlet fever isn’t spread by mosquitoes though, so it’s harder to make the connection.
What about globalisation – unwitting parents like me taking their infected kids on international travel? The science doesn’t quite bear out there either. The UK cases come from at least three known strains, but only one of those strains was also found in Hong Kong, and not even in all of the city’s cases.
But there is one factor that seems to be associated with the outbreaks: pollution.
The connection wad first made in an intriguing 2016 paper out of Beijing, where the authorities are keenly interested to understand the rise of scarlet fever and thereby curb it.
Xiuhua Guo and colleagues did a retrospective ecological study to track the epidemic characteristics of scarlet fever incidence in several Beijing districts from January 2013 to November 2014, comparing them against various highly localised environmental variables ranging from average wind speed to pollution.
Specifically they compared scarlet fever reports against 24-hour real-time air pollutant data, and found association with several of these, including two especially nasty characters called pm2.5 and nitrogen dioxide (NO2).
So what does NO2 have to do with scarlet fever? Short-term exposure has been shown to create respiratory problems, including airway inflammation in otherwise healthy people. Scarlet fever affects the upper respiratory tracts, which accounts for the sore throat. “Therefore, high NO2 exposure is more likely to increase scarlet fever, as well,” the authors wrote.
In other words, NO2 may inflame or damage the throat just enough to allow the bacterium get a foothold where they otherwise might not have.
The results also suggested that the particulate air pollution called PM2.5 was positively associated with scarlet fever – though these, the authors were quick to add, didn’t meet criteria for significance and so need to be studied in more individual detail.
It’s a retrospective ecological study and this kind of study design is prone to bias. However, there is other evidence to support their conclusion. Last year a study out of Italy found that higher levels of particulates in the air correlated with a lower diversity of bacteria in the respiratory tract. This decreased diversity might reduce protection against invaders.
Beijing, Hong Kong and London are all battling alarming levels of air pollution – and rising outbreaks of scarlet fever. We already know pollution leads to thousands of premature deaths. The mechanism is indirect, but maybe we’re seeing the start of a new one.
The good news is that unlike antibiotic resistance and climate change, pollution is something a government can tackle locally. If there turns out to be a link between pollution and scarlet fever, well, that’s another one for the pollution lawsuits I suppose.
The antibiotics restored Twin 1 and Twin 2 to good health. I got strep throat and am still battling the airline for a refund on those cancelled plane tickets. I’m still not wholly convinced we’re not living in the prologue of the zombie apocalypse, though.
Photo Credit: Paul Griggs, Red Laser