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氣候變化會使一半以上的傳染病惡化

氣候變化會使一半以上的傳染病惡化

資料來源:醫學博士朱迪·斯通 / 2022 年 8 月 8 日 / Medscape / 葉財團法人台灣紅絲帶基金會編譯

 

一項廣泛的新研究顯示,氣候變化可以加重超過一半以上已知的人類致病性疾病。這項對文獻的全面系統回顧縮小了 3,213 例病例的範圍,將 286 種傳染病與特定的氣候變化危害聯繫起來。其中,58% 的情況是惡化,只有 9 種情況顯示出與環境變化相關的任何益處。

該研究今天在線上發表於《自然氣候變化》上。可以詳細探索完整的案例列表、傳播途徑和相關論文——一種非凡的交互式數據之可視化。

為了彙編數據,研究人員在 GIDEON(Global Infectious Disease and Epidemiology Network,全球傳染病和流行病學網絡)和 CDC(疾病控制和預防中心)數據庫中搜索了 10 個關鍵詞。然後,他們透過檢查疾病、病原體和危害的替代名稱來填補空白。

  

特里斯坦·麥肯齊博士 ( Dr Tristan McKenzie )

共同作者、瑞典哥德堡大學博士後研究員 Tristan McKenzie 博士告訴 Medscape 醫學新聞:「如果有人對某條途徑感興趣,這是一個很好的起點」。或者,如果有人想要「進行建模研究並且他們想要專注於特定領域,那麼文獻中的特定示例已經存在」在廣泛的數據庫中。

一個早期的關鍵發現是,變暖和降雨增加透過擴大其棲息地擴增了許多病原體的範圍。這種轉變使許多病原體更接近人類。我們已經看到蚊子、蜱、跳蚤、鳥類和幾種哺乳動物等媒介在更廣泛的範圍內傳播感染。例如病毒(登革熱、屈公熱)、細菌(萊姆病)、原生動物(錐蟲)等。變暖已經影響到水生系統(例如弧菌)和更高的海拔和緯度(瘧疾、登革熱)。

致病性危害不僅僅是靠近人們。人們也越來越接近病原體危害,例如,熱浪導致人們透過水上活動尋求庇護。這增加了他們接觸病原體的機會,例如弧菌、肝炎和水傳播腸胃炎。

一些危害,例如變暖,甚至可以使病原體更具毒性。熱量可以上調弧菌對影響傳播、粘附、穿透和宿主損傷的蛋白質之基因表達。

高溫和降雨會增加積水,增加蚊子的繁殖和生長地,使它們能夠傳播更多的感染。

人們應對氣候災害的能力也會受到損害。例如,在高二氧化碳水平下,作物中的養分濃度會降低,這可能導致營養不良。作物產量下降會進一步加劇麻疹、霍亂或隱孢子蟲的爆發。乾旱也可能迫使人們飲用受污染的水。

在所有這些壞消息中,作者發現了少數氣候危害降低感染風險的案例。例如,乾旱減少了蚊子的滋生地,降低了瘧疾和屈公熱的流行。但在其他情況下,一些水池中蚊子的密度增加,導致當地感染風險增加。

Naomi Hauser 醫學博士、公共衛生碩士、加州大學戴維斯分校臨床助理教授告訴 Medscape Medical News,她對數據可視化印象特別深刻。 「它確實強調了我們正在處理的事情的大小範圍。它讓你感受到他們試圖代表的東西的重量」,她說。

另一方面,豪瑟說,她希望「更多地強調氣候危害是如何彼此相互作用的。這聽起來像是每一種氣候危害都處於一個空間的狀態——比如發生洪水時,這就是問題所在。 但是還有很多其他的事情……比如當我們變暖和地表水溫發生變化時,它也會改變水的 pH 值和水的鹽度,這些也會影響我們在水中看到的病原體」。

McKenzie 解釋了一個限制:該研究只查看了 10 個關鍵字。因此,這種方法無法識別非洲沙塵暴導緻美國弧菌增加的例子。 「這也可以追溯到問題的規模,因為在撒哈拉沙漠發生了一些影響美國東海岸的事情」,他說。 「而且發現這種關聯並不一定很明顯——或者至少不像[如果]有一場颶風和一群人因水傳播疾病而生病那麼明顯。所以我認為這確實突顯出了這個規模的問題」。

該研究不僅只關注一個個體或一組病原體,而是對一系列氣候危害引起的感染進行了更廣泛的審查。正如 McKenzie 所說,「以前沒有人真正做過這項工作,只是真正為了嘗試全面地了解我們可能要處理的事情;而這就是我們的目標」。對氣候變化導致疾病惡化的 58% 估計是保守的,他說,「可以說,這是一個比我們目前所呈現的更大的問題」。

McKenzie 總結道:「如果我們正在研究一些更嚴重或罕見疾病在某些地區的傳播,那麼對我來說,答案是……我們需要積極減少溫室氣體排放。讓我們從源頭開始」。

 

McKenzie 和 Hauser 報告沒有任何相關財務上的關係。

《自然氣候變化》期刊。 2022年8月8日線上發布。

醫學博士朱迪·斯通 (Judy Stone) 是傳染病專家,著有《復原力:一個家庭的希望和戰勝邪惡的故事》和《進行臨床研究》。 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Climate Change Can Worsen More Than Half of Infectious Diseases

Judy Stone, MD / August 08, 2022 / Medscape

An extensive new study shows that climate change can aggravate over half of known human pathogenic diseases. This comprehensive systematic review of the literature narrowed down 3213 cases, linking 286 infectious diseases to specific climate change hazards. Of these, 58% were worsened, and only 9 conditions showed any benefit associated with environmental change.

The study was published online today in Nature Climate Change. The complete list of cases, transmission pathways, and associated papers can be explored in detail — a remarkable, interactive data visualization.

To compile the data, investigators searched 10 keywords on GIDEON (Global Infectious Disease and Epidemiology Network) and CDC (Center for Disease Control and Prevention) databases. They then filled gaps by examining alternative names of the diseases, pathogens, and hazards.

 

Dr Tristan McKenzie

Co-author Tristan McKenzie, PhD, a postdoctoral researcher at the University of Gothenburg, Gothenburg, Sweden, told Medscape Medical News: “If someone is interested in a certain pathway, it’s a beautiful starting point.” Or if someone wants to “do a modeling study and they want to focus on a specific area, the specific examples in the literature are already there” in the extensive database.

An early key finding is that warming and increased precipitation broadened the range of many pathogens through expansion of their habitat. This shift brings many pathogens closer to people. We have already seen vectors such as mosquitoes, ticks, fleas, birds, and several mammals spreading infections over a broader range. Examples are viruses (dengue, Chikungunya), bacteria (Lyme), protozoans (trypanosomes), and more. Warming has affected aquatic systems (eg, Vibrio) and higher altitudes and latitudes (malaria, dengue).

Pathogenic hazards are not just moving closer to people. People are also moving closer to the pathogenic hazards, with heat waves causing people to seek refuge with water activities, for example. This increases their exposure to pathogens, such as Vibrio, hepatitis, and water-borne gastroenteritis.

Some hazards, such as warming, can even make pathogens more virulent. Heat can upregulate Vibrio’s gene expression of proteins affecting transmission, adhesion, penetration, and host injury.

Heat and rainfall can increase stagnant water, enhancing mosquitoes’ breeding and growing grounds and enabling them to transmit many more infections.

People’s capacity to respond to climate hazards can also be impaired. For example, there is a reduced concentration of nutrients in crops under high CO2 levels, which can result in malnutrition. Lower crop yields can further fuel outbreaks of measles, cholera, or Cryptosporidium. Drought also likely forces people to drink contaminated water.

Among all this bad news, the authors found a small number of cases where climate hazards reduced the risk of infection. For example, droughts reduced the breeding grounds of mosquitoes, reducing the prevalence of malaria and chikungunya. But in other cases, the density of mosquitoes increased in some pools, causing an increased local risk of infection.

Naomi Hauser, MD, MPH, assistant clinical professor at UC Davis in Sacramento, California, told Medscape Medical News she was particularly impressed with the data visualization. “It really emphasizes the magnitude of what we’re dealing with. It makes you feel the weight of what they’re trying to represent,” she said.

On the other hand, Hauser said she would have liked “more emphasis on how the climate hazards interact with each other. It sort of made it sound like each of these climate hazards is in a vacuum — like when there’s floods, and that’s the problem. But there are a lot of other things…like when we have warming and surface water temperature changes, it can also change the pH of the water and the salinity of the water, and those can also impact what we see with pathogens in the water.”

McKenzie explained one limitation: the study looked only at 10 keywords. So an example of a dust storm in Africa causing an increase in Vibrio in the US could not be identified by this approach. “This also goes back to the scale of the problem, because we have something going on in the Sahara that’s impacting the East Coast of the US,” he said. “And finding that link is not necessarily obvious — or at least not as obvious as [if] there was a hurricane and a bunch of people got sick from waterborne disease. So I think that really highlights the scale of this problem.”

Instead of looking at only one individual or group of pathogens, the study provided a much broader review of infections caused by an array of climate hazards. As McKenzie said, “No one’s actually done the work previously to really just try and get a comprehensive picture of what we might be dealing with. And so that was the goal for us.” The 58% estimate of diseases worsened by climate change is conservative, and, he says, “Arguably, this is an even bigger problem than what we present.”

McKenzie concluded: “If we’re looking at the spread of some more serious or rare diseases in areas, to me then the answer is…we need to be aggressively mitigating greenhouse gas emissions. Let’s start with the source.”

McKenzie and Hauser report no relevant financial relationships.

Nature Climate Change. Published online August 8, 2022.  

Judy Stone, MD, is an infectious disease specialist and author of Resilience: One Family’s Story of Hope and Triumph Over Evil and of Conducting Clinical Research .

 

 

 

 

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