早期感染似乎不能預防過敏——但在大自然中變臟或許可以

早期感染似乎不能預防過敏——但在大自然中變臟或許可以

Over the past few decades, allergies and asthma have become common childhood diseases, especially in developed countries. Almost 20 percent of Australians experience some kind of allergy, whether it's to food, pollen, dust, housemites, mould or animals.

在過去的幾十年里，過敏和哮喘已經(jīng)成為常見的兒童疾病，尤其是在發(fā)達國家。近20%的澳大利亞人對某些食物、花粉、灰塵、室友、霉菌或動物過敏。

When people suffer from food allergies, hay fever or asthma, their immune system incorrectly believes the trigger substances are harmful and mounts a defence.

當人們遭受食物過敏、花粉熱或哮喘時，他們的免疫系統(tǒng)錯誤地認為觸發(fā)物質是有害的，并進行防御。

The response can range from mild symptoms, such as sneezing and a blocked nose (in the case of hay fever), to anaphylaxis (from severe food allergies or bee stings) and asthma attacks.

過敏反應的范圍從輕微的癥狀，如打噴嚏和鼻塞(花粉熱)，到過敏反應(嚴重的食物過敏或蜜蜂叮咬)和哮喘發(fā)作。

We used to think the rise in allergic conditions was because we weren't exposed to as many early infections as previous generations. But the science suggests that's not the case.

我們過去認為過敏癥狀的增加是因為我們沒有像前幾代人那樣暴露在那么多的早期感染中。但科學表明事實并非如此。

However it seems being out in nature, and exposed to diverse (but not disease-causing) bacteria, fungi and other microorganisms may help protect against asthma and allergies.

然而，它似乎是在大自然中，并暴露在各種(但不是致病的)細菌、真菌和其他微生物可能有助于防止哮喘和過敏。

Remind me, what's the hygiene hypothesis?

提醒一下，什么是衛(wèi)生假說?

In 1989, researcher David Strachan examined allergy patterns in more than 17,000 children in England. He noticed young siblings in large families were less likely to have hay fever than older siblings or children from small families.

1989年，研究人員David Strachan對英國17000多名兒童的過敏模式進行了研究。他注意到大家庭中的年輕兄弟姐妹比年長的兄弟姐妹或小家庭的孩子患花粉病的可能性更小。

He proposed that these younger siblings were exposed to more childhood illness at a younger age, as more bugs were circulating in these large families and the younger children were less likely to wash their hands and practise good hygiene.

他提出，這些年幼的兄弟姐妹在更小的時候接觸到更多的兒童疾病，因為更多的病菌在這些大家庭中傳播，而年幼的孩子不太可能洗手并養(yǎng)成良好的衛(wèi)生習慣。

Greater exposure to these childhood infections helped "train" their immune systems not to overreact to harmless things like pollen.

更多地接觸這些兒童感染，有助于“訓練”他們的免疫系統(tǒng)不要對無害的東西如花粉過度反應。

Strachan coined the term "hygiene hypothesis" to explain this phenomenon, and the idea has been appealing to our dirty side ever since.

斯特拉坎創(chuàng)造了“衛(wèi)生假說”這個術語來解釋這一現(xiàn)象，從那以后，這個觀點就一直吸引著我們骯臟的一面。

Strachan wasn't the first to notice exposure to "dirty environments" seemed to prevent allergic disease. A century earlier, in 1873, Charles Blackley noted hay fever was a disease of the "educated class", and rarely occurred in farmers or people living in less sanitary conditions.

斯特拉坎并不是第一個注意到“骯臟的環(huán)境”似乎可以預防過敏性疾病的人。一個世紀以前，也就是1873年，查爾斯·布萊克利指出，花粉熱是“受過教育的階層”的一種疾病，很少發(fā)生在農(nóng)民或生活在衛(wèi)生條件較差的人身上。

Ditching the hygiene hypothesis

拋棄衛(wèi)生假設

However, Blackley and Strachan were wrong about one important thing: the association between sanitation and allergies is not due to reduced exposure to early childhood infections (or "pathogens").

然而，布萊克利和斯特拉坎在一件重要的事情上是錯誤的:環(huán)境衛(wèi)生和過敏之間的聯(lián)系并不是因為兒童早期感染(或“病原體”)的減少。

Large studies from Denmark, Finland, and the United Kingdom have found no association between the number of viral infections during childhood and allergic disease. In other words, exposure to disease-causing pathogens doesn't appear to prevent allergies.

來自丹麥、芬蘭和英國的大型研究發(fā)現(xiàn)，兒童時期的病毒感染數(shù)量與過敏性疾病之間沒有聯(lián)系。換句話說，接觸致病的病原體似乎并不能預防過敏。

In fact, exposure to childhood viral infections, in addition to making a child sick, may contribute to the development of asthma in predisposed children.

事實上，接觸兒童病毒感染，除了使兒童生病外，可能有助于易感兒童哮喘的發(fā)展。

Many researchers now argue the term "hygiene hypothesis" is not only inaccurate but potentially dangerous, because it suggests avoiding infection is a bad thing. It's not.

許多研究人員現(xiàn)在認為，“衛(wèi)生假說”這個術語不僅不準確，而且有潛在的危險，因為它表明避免感染是一件壞事。它不是。

Good hygiene practices, such as hand washing, are critical for reducing the spread of infectious and potentially deadly diseases such as influenza and the Wuhan coronavirus.

良好的衛(wèi)生習慣，如洗手，對減少傳染性和潛在致命疾病的傳播至關重要，如流感和武漢冠狀病毒。

What about 'good' exposure to bacteria?

“有益”的細菌接觸會怎樣呢?

For healthy immune function, we need exposure to a diverse range of bacteria, fungi and other bugs – known as microbes – in the environment that don't make us sick.

為了保持健康的免疫功能，我們需要接觸環(huán)境中各種各樣的細菌、真菌和其他微生物，這些微生物不會讓我們生病。

Within urban environments, recent research shows people who live closer to green, biodiverse ecosystems tend to be healthier, with less high blood pressure and lower rates of diabetes and premature death, among other things.

最近的研究顯示，在城市環(huán)境中，生活在更接近綠色、生物多樣性更豐富的生態(tài)系統(tǒng)中的人往往更健康，高血壓發(fā)病率更低，糖尿病和過早死亡的幾率也更低。

More specifically, research has found growing up on a farm or near forests, with exposure to more biodiverse ecosystems, reduces the likelihood of developing asthma and other allergies.

更具體地說，研究發(fā)現(xiàn)，在農(nóng)場或森林附近長大，接觸更多生物多樣性的生態(tài)系統(tǒng)，可以降低患哮喘和其他過敏癥的可能性。

This is potentially because exposure to a diversity of organisms, with a lower proportion of human pathogens, has "trained" the immune system not to overreact to harmless proteins in pollen, peanuts and other allergy triggers.

這可能是因為，接觸到多樣性的有機體，以及比例較低的人類病原體，“訓練”了免疫系統(tǒng)，使其不會對花粉、花生和其他引發(fā)過敏的無害蛋白質產(chǎn)生過度反應。

How can we get more 'good' exposure?

我們怎樣才能獲得更多的“好”曝光率?

We can try to expose children to environments more like the ones in which humans, and our immune systems, evolved.我們可以讓孩子們接觸到更像是人類和我們的免疫系統(tǒng)進化的環(huán)境。

Most obviously, children need to have exposure to green space. Playing outdoors, having a garden, or living near green space (especially near a diverse range of native flowering plants) is likely to expose them to more diverse microbes and provide greater protection from allergic diseases.

最明顯的是，孩子們需要接觸綠色空間。在戶外玩耍，擁有一個花園，或者住在綠地附近(尤其是在多種多樣的本地開花植物附近)，都有可能使他們接觸到更多的微生物，從而更好地保護他們免受過敏性疾病的侵害。

Infants who are breastfed tend to have more diverse gut microbiomes (a larger variety of bacteria, fungi and other microscopic organisms that live in the gut), which makes them less likely to develop allergic diseases in childhood.

母乳喂養(yǎng)的嬰兒腸道微生物群更多樣化(腸道內(nèi)的細菌、真菌和其他微生物種類更多)，這使得他們在童年時期更不容易患上過敏性疾病。

Having a varied diet that includes fresh and fermented foods can help cultivate a healthy gut microbiome and reduce allergic disease. As can using antibiotics only when necessary, as they kill off good bacteria as well as the bad.

飲食多樣化，包括新鮮和發(fā)酵食品，可以幫助培養(yǎng)健康的腸道微生物群，減少過敏疾病。只有在必要的時候才可以使用抗生素，因為它們會殺死有益菌和有害菌。

So keep washing your hands, especially in cities and airports, but don't be afraid of getting a little dirty in biodiverse environments.

所以要勤洗手，尤其是在城市和機場，但不要害怕在生物多樣性的環(huán)境中會變得有點臟。