With theCOVID-19 pandemicraging across the globe, it’s easy to forget about the many other infectious diseases, some of them transmitted by insect vectors, which arestill around infecting people. While we fight the pandemic, and try everything to keep our societies going until we can get this disease under control, we keep emitting CO2 and other greenhouse gases, which continue warming our atmosphere and changing our climate. The impact of climate change on infectious diseases, including vector-borne diseases, has long beendemonstrated但是，在这些复杂的关系中，我们仍在尝试理解许多方面。像往常一样，没有简单的答案，每个系统对气候变化的反应都不同，这只是影响它们的许多因素之一。
昏睡病
A recentpaperby Elisha Are and John Hargrove noted that tsetse flies (Glossinaspp）不能忍受极端的冷或极端的温度，突出了气候变化的可能益处，因为较高的温度可能会降低该载体和其他向量的范围。Dr. Hargrovehas spent a lifetime studying and modeling the life cycle of tsetse flies and how best to control them.Glossina采采蝇是，除其他事项外Trypanosomaparasites that causesleeping sicknessin humans and the similar disease “nagana” in livestock. Tsetse flies and the disease they cause are difficult to control, and havedevastating human health and economic consequences. Fortunately, it looks like tsetse flies have a fairly limited range of optimal temperatures, outside which they rapidly go extinct. In recent decades, both tsetse flies and sleeping sickness have been significantlyreduced in the Zambezi Valley of Zimbabwe,建立相关的显著提高ures. Phelps and others in the 1960s and 70s have conducted开创性实验that showed how life history parameters such as daily adult mortality, pupal mortality, pupal duration and inter-larval period varied with temperature in the lab forGlossina m. morsitans.
In the above mentioned paper, Are and Hargrove incorporated the results of those laboratory experiments to determine how the expected number of surviving female offspring per adult female, the expected growth in the number of adult females per generation, and the daily growth rate of a population changes with different constant temperatures.
使用这些措施，他们还确定了灭绝的概率和预期的世代数量在初始人群中与不同数量的女性灭绝。他们发现，每位雌性的幸存女性后代数量最多，在约19°C下产生，而少于1个幸存的女性后代则在16°C以下或31°C以上产生，表明人口是不可持续的。预计采采群体将在任何温度下或高于20°C的温度下成倍增长，但随着温度升高，速度较慢，速度较慢。在25°C时的每日生长速率最高，在极度冷（15°C）和极度热（31°C）条件下均大幅下降。同时，当初始种群大小较低时，灭绝都肯定是15°C低于15°C和高于31°C，并且在中等温度（约17°C）处最长。
The study certainly highlighted the extreme temperature sensitivity ofGlossina m. morsitans, and suggests that the increasing frequency of extreme temperatures due to climate change has the potential to limit the range of these flies and their parasites. While this is welcome news, it also means that some areas of Africa, that were hitherto unsuitable for tsetse flies due to extreme cold temperatures, might become suitable to sustain their populations, as has happened withAnopheles mosquitoes and malaria in the Kenyan highlands. The authors also warn that their study does not incorporate fluctuating temperature conditions, or the impact of other anthropogenic and environmental factors on tsetse fly survival and parasite transmission.
Zikavirus
虽然气候变化可能会限制采采蝇的分布并帮助我们控制睡眠病，但它可能对温度区域的寨卡病毒传播产生相反的影响paper.Zikavirusis a flavivirus transmitted by mainly Aedes mosquitoes between people, and can (among other things) causecongenital Zika virus syndrome, including microcephaly, in the developing fetus. The largeZikavirus epidemicin 2016 was mainly concentrated in tropical regions of Asia and the Americas, but many competent mosquitoes, such asAedes albopictus, have spread across both eastern North America and Europe.
最近，英国学术机构和政府机构的一群研究人员已经评估了温带地区各种物种传播寨卡病毒的潜力from Brazil at a range of temperatures in the laboratory. They collected and reared bothOchlerotatus detritus,Culex pipiens pipiensandCuliseta Annulatamosquitoes from the UK, as well as recently colonizedAedes albopictus来自罗马。他们为所有含有寨卡病毒的雌性蚊子喂食，并在感染后28天内评估了其在17°C和31°C之间的六个不同温度下的死亡率和能力，包括在其唾液和身体中。他们还使用细胞病理测定法来测试蚊子样品中是否检测到的ZIKV是传染性的。然后，他们将这些结果用于估计EIP10，当时测量的外部孵育周期直到10％的感染蚊子在给定的温度中变得具有感染性，然后将其掺入ZIKV的标准化基本繁殖数中。最后，他们使用1980 - 2010年平均值以及不同场景下的未来预测的气候数据绘制了全球标准化的基本繁殖数量，并估计了每个位置和场景的传输季节的长度。
他们的发现很有趣。首先，他们观察到，而Culex pipiens pipiensandCuliseta Annulatawere not competent vectors, bothAedes albopictusandOchlerotatus detrituswere positive for Zika virus at all temperatures 19-31 °C, but not at 17 °C. The earliest time point of detection decreased with increasing temperatures, such thatAedes albopictuswas already positive 7 days after post-infection. EIP10 decreased with increasing temperature for both species, suggesting faster viral replication in warmer conditions, but in general it was shorter forAedes albopictuscompared toOchlerotatus detritus. ZIKV titer was 3.8 times higher in the saliva ofAedes albopictusthan in the saliva ofOc. detritus, suggesting that it is a more competent vector. Cytopathic assays showed thatAedes albopictus在19°C饲养的蚊子含有传染病。他们发现，标准化的基本繁殖数在29.2°C左右最高。
The map of annual mean standardized basic reproduction numbers based on observed rainfall and temperature data was in good agreement with the known distribution of Zika virus transmission, suggesting a low probability of a large Zika outbreak e.g. over southern Europe, despite the presence of the vector. However, future projections of climate change indicate increasing annual mean standardized basic reproductive number in many locations across the globe, increasing with the severity of emission scenario and with time, with the largest changes under the RCP8.5 scenario in the 2080s. In particular, large increases are predicted in the Mediterranean and southern and eastern Europe, with ZIKV transmission season increasing to six to seven months. In the UK, while no ZIKV transmission was projected under current conditions, a short seasonal transmission was possible over the southern part of the country in the 2080s under the RCP8.5 scenario. ZIKV transmission was also projected to extend north in the US, as well as in Asia. In tropical regions,Aedes albopictusis not the main competent vector, and therefore its impact is limited, but increased temperatures could lead to increased ZIKV transmissions in high altitude regions, and decreased transmission in areas experiencing extreme high temperatures.
Conclusion
上面突出显示的两项研究提供了两个例子，说明气候变化如何在不同的地理量表下不同模型系统中在不同模型系统中如何产生非常不同的影响（TSETSE FLY的收缩分布，而扩大了Zika病毒的分布）。他们提醒我们，诸如“气候变化将增加一般的传染病风险”之类的毯子陈述令人怀疑，我们需要投资于这些作者所做的漫长而艰苦的工作，以真正了解气候变化对气候变化的影响每种传染病一一一个，否则我们将做出错误的假设。这些研究还证明了如何使用数学和统计模型来合成在实验室中收集的信息以产生有意义和可靠的预测，但是如果没有这些实验中生成的巨大工作和数据，这种模型将无用。我们已经在经历气候变化，这对传染病的影响。我们很快就花费了时间来进行巨大的工作，以一一调查每个疾病系统，我们比以往任何时候都更需要实验性和定量科学家之间的这些合作。最后，尽管上面的两篇论文侧重于温度对这些媒介传播疾病的影响，但我们不应该忘记，还有许多其他影响这些疾病系统的因素，这是我们自身最重要的anthropogenic impacts.
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