Monday, June 08, 2015

The Never Ending Battle

# 10,165

A little over a year ago, in Dealing With A Lighter Shade Of MERS, we looked at the scenario where this emerging coronavirus needn’t acquire enhanced transmissibility or start to sweep madly across the landscape to become a serious public health issue.

Instead of sparking a pandemic, it could simply start brush fires - much like the one we are seeing in South Korea - that could instill fear in the populace, damage local economies, and seriously impact public health resources. 

And while the focus today is on MERS, the simple truth is we could easily replay what is happening in Korea with H5N1, or H7N9, Ebola, or any other highly pathogenic virus.

A single introduction by an infected traveler - combined with a little bad luck - could easily lead to an outbreak anywhere on the earth.  

While not necessarily a pandemic threat, you nonetheless end up with a local public health crisis which can exact a heavy toll in both lives and money.

We know this, because it has happened before.  A couple of recent examples . . . 

In late 2013 Chikungunya arrived on the Caribbean Island of St. Martins - likely carried in by an unidentified viremic tourist - and in short order it spread to neighboring islands.  Within a few months it had extended its reach into South and Central America, and has now infected roughly 1.5 million people in the Americas.

PAHO - 2015 autochthonous Chikungunya  

Essentially the same thing happened in 1999 when West Nile Virus arrived in New York City, and within a few years had spread across the lower 48 states of the United States, infecting thousands and killing scores every year.  Both Chikungunya and WNV are helped considerably by having a competent vector (Aedes mosquitoes) to maintain endemicity.

But even flash-in-the-pan outbreaks, which can be quickly contained, are costly. 

Last year's importations of Ebola and MERS into the United States illustrate how expensive and disruptive they can be; hundreds of people potentially exposed, scores of healthcare workers furloughed to home isolation, extensive contact tracing & testing programs initiated, and scores of lives and jobs interrupted.

Luckily, no community spread of either virus occurred.  But the next time we might not be so lucky. 

Even if community transmission is considered a long shot, it must be taken seriously by public health agencies. Every time an infected traveler is detected – even if we are talking a relatively small number – it sets into motion a very resource intensive public health response.

And this impact extends beyond the few infected arrivals that may show up at the gate – as anyone symptomatic and with a travel history to an area where there are major outbreaks of MERS, or Ebola, or Avian flu must be isolated, tested, and their infection ruled out

If that doesn’t sound like a big deal, consider these opening lines from a Clinical Infectious Diseases study - Unmasking Masks in Makkah: Preventing Influenza at Hajj – from 2012.

Each year more than 2 million people from all over the world attend the Hajj pilgrimage to Saudi Arabia. At least 60% of them develop respiratory symptoms there or during outward or homebound transit [1, 2

While the vast majority of these respiratory infections will no doubt be due to rhinoviruses or influenza, figuring out which ones might be due to the MERS coronavirus will be a pretty tall order. And a challenge that must be faced by scores of countries - some far less equipped to do so than others – with returning pilgrims from all around the globe.

While pandemics are far more dramatic and costly, the stakes in this never-ending battle against imported infectious diseases rises every year, even as many public health agencies see cuts in their operating budgets.  

A risky strategy, since when it comes to protecting public's health, officials needs to get it right pretty much 100% of the time, while an emerging virus only needs to only succeed once.

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