life in mokievision

The Black Death wasn't spread by rat fleas, says a researcher...

...promoting a TV special.

...based on 25 bodies in one British plague pit and a modern account of pneumonic plague.

...ignoring contemporary reports of the Black Death's spread and symptoms, which acknowledge that respiratory infections (pneumonic plague) occurred, but that they were less common than the regular infection presumed to be spread by fleas, whose symptoms (buboes, or swollen lymph nodes) gave the Plague its other common name.

...based in part on genetic analysis of the Yersinia pestis bacteria from those bodies, which he found to be almost identical to modern bacteria in modern outbreaks and which he thus concludes couldn't have spread as fast in its bubonic form as the Black Death's scale would have required, which ignores that (a) modern folks are by and large less cozy with fleas than medieval Europe was, (b) medieval Europe had seen a series of massive famines in the years leading up to the Black Death, and malnutrition leaves populations vulnerable to disease and infection, and (c) European researchers have found previously unknown (and hopefully extinct) strains of the plague bacteria which could easily have been nastier than the modern version.

...apparently jumping into the "It wasn't rats!" debate without actually addressing any of the rat-related evidence.

I love the hemorrhagic plague theory - the idea that Europe was struck not by the rat-spread Yersinia pestis bacteria, but by an Ebola-like virus. Or better, both, sweeping through a weakened population at the same time! And according to some researchers, there are a few assumptive leaps when it comes to rats spreading the plague in Europe, because of where specific rat species lived or had been recorded during the period.

But at the same time, we know Yersinia pestis hit Europe because the DNA is there, and we've known rats and their fleas spread the plague for years, because regular outbreaks in outbreak-prone areas in Asia were preceded by massive rat die-offs. That's what led researchers to specifically study transmission via rats and fleas. We know how that mechanism works. Getting rats and fleas off the hook requires more than proving that 25 bodies in a single British plague pit died of pneumonic plague rather than bubonic, because for all we know that pit was reserved specifically for victims of the pneumonic plague, since it was so very contagious and deadly.

Of course, you could argue that the real problem is that I don't know for sure that this is what the researcher is saying: I'm responding to a flurry of articles proclaiming that the flea and rat are innocent of all charges, and for all I know, it's just a bunch of writers misinterpreting one researcher's findings, just like the regular articles proclaiming that a cure for AIDS has been found because one researcher or another has found a promising technique that still needs years and years and years of testing.

I recently discovered I might not be allergic to coconut after all.

When is an allergy not an allergy? When it's Oral Allergy Syndrome, also called Pollen-Food Allergy Syndrome (along with several other names, because everybody wants to be the one whose name gets used on House M.D.), in which regular nose-based allergies masquerade as food allergies, due to certain fruit and veggie proteins vaguely resembling problematic pollen proteins.

Basically, it's like your body mistaking a dust-bunny for a spider and wigging out inappropriately.

Outside of allergy season the problem food isn't a problem, because your body hasn't been primed by pollen and pushed into kill it with sneezing! mode. The heat involved in cooking and canning can also denature the troublesome proteins, which is how some folks can be allergic to a raw fruit or veggie but able to eat the same item cooked--because they're not allergic to the food itself, even though they are having an allergic reaction to it. Either of these could explain why I've been able to eat coconut just fine until recently, mostly baked in cookies or simmered in soups, but also just noshing on raw flakes without any ill effect. I just happened to do it at the wrong time of year this time.

The upside of this, apart from that OAS usually doesn't cause anaphylactic shock, is that it would also explain why my late winter/early spring allergies have been so bad since moving to this neighborhood: birch.

I used to live next to Tower Grove Park and the Missouri Botanical Garden, two big green spaces dedicated to growing a large variety of greenery, pretty much all of which I tested allergic to back in middle school. Apart from swollen hands when walking past a bushy area on Magnolia Avenue, though, my allergies just translated to a runny nose and some occasional sneeziness--and good luck narrowing down which bit of all that greenery was responsible for which sneeze. (Especially since the allergy scratch test throws a lot of false positives, as dracunculus pointed out.)

What the old neighborhood didn't have, and this neighborhood does, was a lot of birch trees. Specifically, a cluster of them half a block down from my current apartment.

In springtime, two of the biggest cross-reaction offenders are birch and alder trees. Depending on where you live, anywhere from 20 to 70 per cent of people who are allergic to birch and alder pollens will also have oral allergy syndrome. (Janet French, "Oral Allergy Syndrome: Why do Pollens and Foods Cross-React?" Allergic Living 2 July 2010)

The doctor interviewed in that article pointed out that OAS is more common than the legitimately scary food allergies like peanut, which might explain why so very many people believe they have food allergies even after a smug host points out that they just ate something they're supposed to be allergic to. (And fuck you if you do that to people. Seriously.) The article also mentions a point I regularly make, that chamomile and echinacea cause cross-reactions to ragweed because they're in the same family, which makes it really annoying when every suggested cure for your allergy woes is a nice cup of chamomile and echinacea tea.

The author does lose points for bad editing when she inadvertently (I hope) suggests that honey is somehow a plant related to ragweed, rather than that honey could contain ragweed (or related) pollen. That in itself sidesteps the point that many allergy sufferers intentionally eat honey hoping there's allergy-causing pollen in it, due to the old wives' tale that this will desensitize them. It doesn't work, though, because most of the honey on store shelves is (a) filtered, microfiltered, and then filtered some more to remove all possible pollen; (b) heated and treated till it's thoroughly dead so that it won't crystallize on store shelves; and (c) from China, and thus unlikely to contain any pollens you're familiar with. You could try raw local honey, but as someone who gave it a go, just go take a Claritin and save yourself the disappointment. (And the awfulness that is clover honey. Ugh.)

Back to the point! How vile is birch?

Here is the Wikipedia checklist of foods that are cross-reactive with birch: almonds, apples, apricots, avocados, bananas, carrots, celery, cherries, chicory, coriander, fennel, figs, hazelnuts, kiwis, nectarines, parsley, parsnips, peaches, pears, peppers, plums, potatoes, prunes, soy, strawberries, walnuts and wheat. That's not even a definitive list--other lists add all the tree nuts, and coconuts, and peanuts, and tomatoes, and turnips...

If you Google "oral allergy syndrome" and a food, Google will say, "Birch. It's the fucking birch, man."

Birch will take from you everything that you love.

Apart from a visit to an allergist, the only way to know for certain if my coconut allergy is a real allergy or a birch cross-reaction is to wait till the birch stops its arboreal spooging around June or July, and then nibble a little raw coconut while someone stands by with a heavy dose of Benedryl. A preemptive strike on the trees is out, as they wisely chose to be planted in front of a cop's house.

Sneaky, bastardly birch.

Update: TESTED AND CONFIRMED. The same coconut that made me miserable in April and May caused no reaction at all in June. Of course, now my grass allergies are in full effect, so I couldn't taste the coconut, but still...