疾病hotspots flourish when the city meets the country

By: Gareth Willmer

With global cities grinding to a halt in the COVID-19 pandemic, the ability of urban centres to cope with sudden infectious disease outbreaks has been brought under the microscope.

Megacities will struggle to cope with sudden infectious disease outbreaks unless they embrace sustainable growth and the urban poor, as metropolitan populations are set to surge.

This population explosion is a major concern for urban planners and epidemiologists, in light of changing landscapes in cities and expectations that they will draw another2.5 billion people by 2050。这种增长将使城市居民的数量从全球55％的人口增加到三分之二以上，而亚洲和非洲预计的城市增长占90％。

Such trends lead to big questions, say the authors of apaper inUrban Studies。他们说：“在过去的几十年中，全球城市人口的大量增加主要集中在前城区，这对控制传染病的控制提出了新的挑战。”前城市地区被归类为比郊区低密度住宅人口的地区，并且可以在城市范围内进一步找到。

City-nature conflict

“Rural-to-urban migrants tend to land on the edges of cities, where there isn’t necessarily as much infrastructure and governance regimes to make those areas less at risk to infectious disease outbreaks,” says lead author Creighton Connolly, a senior lecturer in development studies and the global South at the University of Lincoln.

“问题本身不是密度，而是密度管理的方式 - 那时，当它变得不良管理并且密度变得拥挤，不合格的住房和不良的基础设施时。”

Sameh Wahba, World Bank

康诺利（Connolly）和加拿大约克大学（Canada York University）的同事认为，“新的生态壁ches”正在出现疾病传播，这表明城市侵占野生动植物栖息地，增加了对人畜共患病的暴露 - 从动物跳到人类的疾病。

世界卫生组织指出，在2014年西非的埃博拉疫情爆发期间spilled over into citiesafter almost 40 years of outbreaks in central Africa that were largely confined to remote rural areas.

Connolly’s team point out that 12 million people already live in the Democratic Republic of Congo’s capital Kinshasa — triple the joint population of cities affected by the 2014 outbreak. The DRC recently declared the end to its tenth Ebola outbreak in the east of the country, as agenetically unrelated strainof the disease emerged in the northwest.

Eric Fèvre, professor of veterinary infectious diseases at the University of Liverpool and jointly appointed at the International Livestock Research Institute in Nairobi, Kenya, says food systems supplying urban areas are an interface “bringing elements of the farm deep into the city”.

“Clearly, thinking about how we design our built environments will make a difference to the scale of risks,” he says.

拥挤与密度

但是，世界银行的城市灾害管理，韧性和土地全球实践的全球总监Sameh Wahba强调，城市的增长本身并不是问题。

“The issue is not densityper se, but rather the way the density is managed — [that is] when it becomes poorly managed and density becomes crowdedness, with substandard housing and poor infrastructure,” he says.

Even in poorer cities with limited governance capacity, Wahba says, a “liveable density” is possible. It just means that city leaders and governments need to carefully plan ahead for anticipated urban growth — with retrospective interventions in crowded slums potentially costing four to seven times more.

他说，实际上，密度需要通过一或两层楼的棚屋的某些地区通过更高的建筑物增加，因为如果城市继续外围扩张，城市将是难以管理的。

对于疾病管理，拥挤可能意味着灾难。

映射疾病

开放式映射工具有助于揭示疾病风险热点。

Wahba points to a World Bank-developed方法that combines data from high-resolution satellite imagery with population and mapping datasets from WorldPop, Facebook and OpenStreetMap.

During COVID-19, Wahba and colleagues have used this methodology to map Mumbai, Kinshasa and Cairo, which indicated the location of high-risk hotspots due to overcrowding, or overloaded public facilities because of a lack of domestic water and sanitation facilities.

发现金沙萨的80％以上的人口在孟买和开罗的疾病风险高达25％，其方法表明需要短期紧急关注和长期贫民窟升级的地区未来的疾病弹性。

孟加拉国达卡国际气候变化与发展中心（ICCCAD）的主任Saleemul Huq说，发展中国家城市的现有紧急系统也可以重新使用以管理流行病学。

同时，ICCCAD一直在推动方案精确20 smaller townsthat could permanently resettle up to one million people each, to spread the expected sizeable burden of people displaced by flooding over the next two decades.

Exclusion issues

But, says Huq, one of the biggest problems is that people living in burgeoning slums and informal settlements are regularly omitted from decisions — partly because their identity is frequently unknown — and their vulnerability will only increase without effective schemes to include them in city and national strategies as populations swell.

“The urban [poor] have been forgotten — they leave their villages, they come to the city, they live in a slum, and then that’s it,” he says.

“I think the [COVID-19] crisis has just shown us how big this issue was. It’s been under the radar for a long time … It’s bursting out and making itself visible.”

Sheela Patel is founder and director of the India-based Society for the Promotion of Area Resource Centers (SPARC), which supports the urban poor in developing countries. She believes urban communities need to be involved from the outset in programmes aimed at improving city facilities or solving problems with technology. She thinks these have all-too-often been top-down, non-scalable and fail to reach the people they are intended for.

帕特尔说：“您需要可以成为支持和援助的代理人的本地举措，”帕特尔说，这不是宣布新技术或治疗策略的“魔术棒”。

Meanwhile, a whole host of data on urban conditions has been collected by slum dwellers via the知道你的城市initiative of organisation Slum Dwellers International, which Patel chairs.

但是在全球范围内，她担心一旦发现了Covid-19的疫苗，但她说，尽管她说的道路已经在那里解决了城市贫困人口和整个城市所面临的问题，但事情会像往常一样恢复“往常”。她说：“世界上不乏资源来实现这一目标。”

Sustainable growth

城市为人们提供许多健康和其他公共服务的福利，这正是由于人们的接近性而提供的，但是Covid-19危机强调了需要更具联系，韧性的城市。

Sustainable urban growth is possible if cities are fully inclusive, says Aniruddha Dasgupta, global director of the Ross Center for Sustainable Cities at the World Resources Institute.

数据can make vulnerable people visible and encourage decision-makers to allocate resources, he says.

他说：“我真的希望我们现在目睹的目的实际上可以睁开人们对未来危机的样子的眼睛。”

尽管199年的大流行是一场非常城市的灾难，不仅强调了城市卫生系统的脆弱性，而且还在人们处于这种规模上的疾病风险时，国家康复计划经常缺乏以城市为中心的观点。达斯古普塔。

He says this is reflected in the climate emergency, where a recent report estimated that五个国家 /地区不到两个有明确的城市国家战略。

With climate intrinsically linked to urban health, COVID-19 has highlighted the urgency of sustainable growth, says Dasgupta.

“Where there are politicians that are progressive, they will use this moment to bring in changes that were much-needed,” he says.