Homeland Security Watch

News and analysis of critical issues in homeland security

October 23, 2014

Ebola source sitrep 2

Filed under: Biosecurity,Preparedness and Response,Public Health & Medical Care — by Philip J. Palin on October 23, 2014

This is the second in an irregular update on efforts to slow and eventually stop the rate of Ebola virus transmission in west Africa.  The risk of transmission in the United States is a function of the rate of transmission at the source.

It is important to acknowledge issues with data quality.  Over the weekend a piece in Science magazine noted, “… it’s widely known that the real situation is much worse than the numbers show because many cases don’t make it into the official statistics. Underreporting occurs in every disease outbreak anywhere, but keeping track of Ebola in Guinea, Liberia, and Sierra Leone has been particularly difficult. And (as) the epidemic unfolds, underreporting appears to be getting worse.”

Still the data that is collected can help us understand some broad dynamics of transmission.

Yesterday afternoon — October 22 — the World Health Organization released a progress report on their response roadmap.  It provides details through the end of last week for all known cases of Ebola, but focuses primarily on the situation in Guinea, Sierra Leone, and Liberia.  Following is a timetable for transmission of the virus in Liberia and metropolitan Monrovia. Similar charts are available for Guinea and Sierra Leone in the online report.  The report also provides updates on treatment centers and other interventions underway.

WHO_liberiaClicking on the image will generate a larger version

CITYA.M., the City of London business publication, has produced a helpful visual analysis of the Ebola outbreak in Liberia, so far the hardest hit of the the three nations at the epicenter of the outbreak.  These maps communicate the crucial role that population density plays in transmission. They also suggest how the virus moved along human networks from the index case in southeastern Guinea into Lofa County and quickly to the economic/social/political center of metropolitan Monrovia.

Liberia density and number

Liberia per 100,000

MORE from CITYA.M.

While US media focus on early indications that transmission has been contained in the Dallas case, at least as important is the news that the Nigerian public health system has successfully contained an initial set of transmissions in densely urban Lagos.  Fundamental to this Nigerian success was a well-organized existing public health infrastructure and network of human expertise. An effective anti-polio process was essentially repurposed to rapidly contain a new infectious threat. Strategically it is important to recognize this was the adaptation of an existing capacity, not an ad-hoc insertion of a special or reserve capability.

According to the Associated Press, in Nigeria “Health workers tracked down nearly 100 percent of those who had contact with the infected, paying 18,500 visits to 894 people.”

The absence of such an existing capacity has been a principal cause of the outbreak in Liberia and its neighbors.  Sunday U.S. Army Maj. Gen. Gary J. Volesky, commanding general of the 101st Airbone Division and his thirty member command team arrived in Monrovia to assume leadership of DOD contributions to Operation United Assistance. The Army is sending approximately 700 Soldiers from the 101st, including members of the division headquarters staff, sustainment brigade, combat support hospital and a military police battalion. Another 700 troops will be deployed from multiple engineering units to build 17 100-bed medical treatment units and a 25-bed hospital. MORE.

New cases of transmission in Nigeria — the United States and elsewhere — are likely.  Until we can bend the exponential growth of transmission in Liberia, Sierra Leone, and Guinea, a networked and increasingly densely populated planet will be vulnerable.  (A few hours after the original version of this post appeared, a new case of Ebola was confirmed in New York City.)

The Foreign Affairs Council of the European Union met on Tuesday.  Despite some additional progress, the readiness and urgency of the European response will depend on the results of a summit of EU leaders that opens today in Brussels.

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3 Comments »

Comment by William R. Cumming

October 23, 2014 @ 10:22 am

Thanks Phil! Not sure what the following sentence in your post means: “The risk of transmission in the United States is a function of the rate of transmission at the source.”

Your are probably correct IMO but not sure!

Comment by Philip J. Palin

October 23, 2014 @ 12:10 pm

Bill: Good catch. I am making a claim which I am not qualified to competently defend. But back in grad school I learned a function is something like the defined relationship between a set of inputs and set of outputs. I am asserting — and assume someone has actually done the math — that given a certain transmission rate among a certain sized population with a defined set of connections with another population that the risk of transmission in the second population can be calculated. But… I have not done this calculation.

Pingback by Prepper News Watch for October 23, 2014 | The Preparedness Podcast

October 23, 2014 @ 1:02 pm

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