What’s New in Malaria Epidemiology?

为了减轻全球范围内的疟疾负担,全球一致的努力将需要增强对地方性传播和进口疟疾病例的监视,蚊子矢量种群,气候变化和人类流动性,再加上创新的预防和控制策略。

疟疾是一种通过咬伤传播的传染病Anopheles蚊子。单细胞的寄生虫疟原虫属是这种疾病的原因,并进一步分为一百多种(其中五种)(恶性疟原虫,P. vivax,P. malariae,P. ovale,P. knowlesi)primarily infect humans resulting in flu-like symptoms (including fever, headache, and nausea). The average incubation period is 2 weeks but can be many months for some species.恶性疟原虫如果未给予及时治疗,则会导致最严重和可能致命的疟疾形式。但是,在过去几年中,疾病流行病学发生了一些变化。

发病率和死亡率

Malaria is endemic throughout the tropics and sub-tropics including in areas of Sub-Saharan Africa, Asia, the Caribbean, Oceania, and South America. The World Health Organization (WHO) reported 228 million malaria cases in 2018 with23 million fewer cases from 2010. The WHO Africa Region contributes most malaria cases (93%) followed by South-East Asia (3.4%). Globally, the incidence rate declined between 2010 and 2018 from 71 to 51 cases per 1000 persons at risk.

In the past 2 years, four countries – Uzbekistan, Paraguay, Argentina Algeria were declared malaria free.

恶性疟原虫accounted for 99.7% and 50% of cases in Africa and South-East Asia, respectively, whereasP. vivax是美洲的主要物种(75%)。2018年有405,000例疟疾相关的死亡,比2010年的585,000人减少了。5岁以下的儿童仍然是最脆弱的人群,并继续说明与疟疾相关的每三个相关死亡中的两名。非洲和东南亚已经注意到,从2010年到2018年,死亡率最近降低(非洲的下降最大),在过去的两年中,四个国家 - 乌兹别克斯坦,巴拉圭,阿根廷阿尔及利亚were declared malaria free.

尽管加勒比海的疟疾风险仍然很低,但2017年至2018年,多米尼加共和国的疟疾增加了20%(360至438例),几乎所有疟疾都在恶性疟原虫. Canada has about500 cases of malaria annuallyimported by returning travelers and new migrants. According to the Public Health Agency of Canada, severe malaria cases requiring more intensive medical management are uncommon in Canada with about 14 cases per year and over the past decade, the national rate of malaria has gradually increased (from 1.1 cases per 100,000 people in 2005 to 1.7 cases per 100,000 people in 2016).

Transmission of Malaria in Non-endemic Areas

近年来,有一些关于非流行国家局部传播疟疾的报道。从2017年8月至9月在法国,有2例本地收购的案件恶性疟原虫报道了。两个受影响的人都参加了同一场婚礼,最近没有去过一个疟疾流行的国家。经过调查,发现恶性疟原虫婚礼前两周被诊断出在婚礼举行的同一地区。这意味着居民进行了当地的矢量传播传播Anopheles蚊子或机场疟疾,其中一个被特有国家的被感染的蚊子乘飞机或行李前往法国。

2018年8月,was also a report of delayed diagnosis of恶性疟原虫in a Moroccan man living in Tuscany, Italy. He was not suspected of having malaria initially as he did not have recent travel to an endemic country. During the summer, he had worked outdoors on the beach with sub-Saharan Africa travelers and reported having many mosquito bites. Although how he caught malaira was uncertain, the delayed diagnosis led to severe anemia, requiring treatment with artesunate and blood transfusion.

The distribution of malaria could change with climate change

Climate Change

气候变化can affect the survival of the malaria mosquito vector,按蚊,和also influences the development of the疟原虫蚊子中的寄生虫。Anopheles在温暖和潮湿的条件下填充恶性疟原虫寄生虫需要温度超过20oC完成其生命周期,这就是为什么热带和亚热带地区的疟疾负担最高的原因。

但是,疟疾的分布可能会随气候变化而变化。在气候变化导致降雨减少的地区,可能会减少疟疾。然而,可能导致干旱情况的严重气候事件发生了极端降水和洪水,这将导致蚊子的扩散和疟疾传播增加。全球变暖,世界上较凉爽的地方,疟疾目前不是地方性的,而是热情好客Anophelesmosquitoes could also see an increase in mosquito population and higher probability of the parasite completing its life cycle leading to local transmission and epidemics.

Concerted global efforts around enhanced surveillance of endemic transmission and imported malaria cases, mosquito vector populations, climate change, and human mobility, coupled with innovative prevention and control strategies are critical to reduce malaria burden on a global scale.

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