大流行限制提供了有关人类运动如何影响媒介传播疾病的见解

大流行期间,不同国家采取的公共卫生措施为研究人员提供了了解运动限制对媒介传播疾病的影响的机会。

我们中的许多人都记得“呆在家里”,“保持6英尺相距”的第一批信息开始流传。在整个Covid-19-19大流行中,各国通过锁定,宵禁和旅行禁令来规范人口流动,以限制病毒的传播。但是这些限制也影响了其他感染的传播,媒介传播疾病(VBD)也不例外。大流行期间,不同国家采取的公共卫生措施为研究人员提供了理解运动限制对这些疾病的影响的机会。

登革热:预期与观察案件

Although ~80% of dengue infections are estimated to be asymptomatic or mild, people suffering severe dengue still face many complications, and it remains an important cause of serious illness and death in many countries. The virus is transmitted by艾德斯蚊子,在瓶子,轮胎和垃圾等任何水上容器中都很容易繁殖的白细胞,这解释了它们在城市和郊区的普遍分布。在2019年,世界经历了历史上最大的登革热爆发with 5.2 million cases recorded, mainly in the Americas and southeast Asia. But cases appeared to decrease in 2020, after the pandemic started and public health measures were put in place.

一个与登革热生病的孩子的照片,手臂上有静脉注射,一个女人轻轻地将手放在额头上
巴西的登革热病人。照片来源:赛诺菲/ cc by-nc-nd 2.0

发表在柳叶刀传染病sought to understand the effects of movement restrictions on the transmission of dengue. Chen and colleagues looked at data from 23 countries, which included WHO dengue case reports (2014-2020), climate and population variables, as well as public health and social measures. The latter came from the牛津冠状病毒政府反应示踪项目,其中收集有关不同国家在解决大流行期间使用的政策措施的信息;其中包括关闭学校和工作场所,公共交通的局限性以及公共聚会的限制。通过Google移动性报告,他们还获得了社会地理信息 - 无论人们呆在家里,上班还是去杂货店。

基于之前的报道s years, they created a historical model to calculate the difference between observed and expected dengue cases for 2020. With these, the authors focused on two aspects: 1) announced containment policies and 2) recorded changes in people’s behaviour. Through their analyses, researchers estimated that 2020 saw 720,000 fewer dengue cases due to pandemic-related disruptions. Nineteen out of the 23 countries experienced a decline in dengue cases (except for Bolivia, Brazil, Peru, and Singapore), coinciding with the establishment of public health and social measures that increased the time people spent at home. Interestingly, the study showed that ‘school closures’ and ‘reductions in non-residential movements’ had the strongest association with reduced dengue risk; this provided an insight into where transmission of dengue is taking place and where control should be targeted.

The study is not without its limitations, and the authors caution that the effects of pandemic restrictions “are likely to be complex, country-specific, and delayed”. Further analyses as public health and social measures are lifted will increase our understanding of these dynamics, especially once we have the opportunity to look at different time and spatial scales.

Effects on other vector-borne diseases

登革热研究期间审查的一篇论文也研究了中国大流行遏制措施on four other VBDs. The researchers noticed that the average yearly incidence of malaria, leishmaniasis, and epidemic encephalitis B had decreased in 2020 as compared to the previous five years; this was attributed in part to international travel restrictions (which decreased imported cases) and the continuity of some vector control in the region.

根据世卫组织2021World Malaria Report,,,,malaria cases in Latin America went down in 2020 after the pandemic started. This was especially evident in Venezuela and was attributed to both movement restrictions as well as a fuel shortage that affected the illegal mining industry (the main driver of malaria in the region). In other places like卢旺达东部,,,,lockdowns presented a challenge to nurses and health staff who were unable to travel to work and provide malaria diagnosis and treatment. This also affected the patients who, in trying to find a way to healthcare centres, sometimes delayed their malaria diagnosis until their condition was quite severe; despite these access limitations, case reports did not decrease during pandemic restrictions.

However, restrictions did not affect all VBDs equally during the pandemic. In Queensland (Australia),研究人员发现蚊子出生的情况罗斯河病毒在实施Covid-19运动限制期间,大大增加了;似乎人们在家里附近的户外活动中花费更多的时间,冒着接触蚊子叮咬的风险。观察到类似的效果in Germanytick传播脑炎。澳大利亚的旅行限制也减少了进口登革热和疟疾的病例(并有可能限制侵入性蚊子物种的流入)。

森林的照片显示一个读物的标志:警告tick式栖息地
In some places, increased outdoor activities closer to home resulted in higher exposure to mosquito or tick bites. Photo credit:波莉·哈钦森/CC BY-NC-SA 2.0

大流行可以以不同的方式影响媒介传播疾病的传播。一方面,可能会有较少的情况,因为监禁减少了对媒介的接触,并且在人们用作储层的地方,病原体可能会较少。另一方面,限制限制了我们获得医疗保健的机会,可能导致不足的报道,并中断vector control programmes在全球范围内。此外,在过去的两年中,人类对健康的行为也发生了变化。要充分了解大流行对这些疾病的长期影响将需要一些时间。

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