Medical News Blog: Liberia

Showing posts with label Liberia. Show all posts

Snapdate: Ebola virus diseaseClick on image to enlarge.

case decline, Ebola virus, Guinea, Liberia, Sierra Leone, vaccine

This is one of the data visualizations from my Ebola virus disease (EVD) graphs and tallies page.[1]

A crude extrapolation from current publicly available Ebola virus disease (EVD) confirmed case numbers. To see how I made this please visit here.[2]
The P-value for this linear trend model is <0.0001.
The standard error = 6.13; R-squared = 0.20.
Click on graph to enlarge.

The first time I posted it I wondered if the end was in sight. That was 6th of May. Over three months later I'm wondering that again - but this time things are a bit different. There has been a steady decline in new cases, also in cases that cannot be tracked back to a known source and in cases found only after they have died of EVD. There have also been the first very promising results from one of the vaccine candidates in Guinea [4] - which has always been a difficult locale for the control of EVD case activity.

So it does look much more likely that the end to EVD in West Africa, or at least an end, is nigh.

By "an end" I mean that we may be close to seeing the cessation of new cases popping up in transmission chains each and every week. We may soon be seeing zero new cases for long periods of time. Those blissful stretches however, may be punctuated by a case arising from parts unknown. They may be tracked to a sexual transmission event, or their origin may never be fully understood. We saw this scenario in Liberia.[3] Virus characterisation indicated that the Ebola virus variant from the young Liberian man was most closely resembled other viruses that had been circulating in Liberia weeks before; the exact source of his infection though, remains unknown.

So we're not at all free and clear of this virus yet - but we are getting very close to shifting into another phase. It's still a long haul with many weeks of anxious waiting and heightened vigilance as well as the need to retain the capacity to cope with a new case or cases. But that said, we do seem to have taken one more step back from the precipice we once stared into as we imagined an Africa fending off a rolling EVD epidemic - and a world at risk as well - however unlikely that should have been.

References..

Ebola mysteriously returns to Liberia...[UPDATED]

case announcement, Ebola virus, EVD, Liberia

v2-1JULY2015 AEST
In a gut-wrenching, but not wholly unexpected event, a new case of Ebola virus disease (EVD) has popped up in a town called Nedowein (or Nedowian [8]), about 50km south west of Liberia's capital, Monrovia.

Liberia had been declared a country free of EVD on 9-May-2015 - 52 days ago, or 1 month, 21-days, or 1248 hours.

The 17 year old male (17M) died on Wednesday (about 6 days ago) and has already been buried by all accounts. Samples from his corpse tested positive at least twice.[3]

It's not an unexpected event because both Guinea and Sierra Leone, adjoining countries, continue to struggle with EVD and have been unable to stop the disease from spreading, even though in relatively small numbers compared to what was occurring in 2014.

What makes this new case in Liberia a little mysterious is that 17M died far from the border with either of these countries; approximately 150km from Sierra Leone's south-eastern border and about 200km from the nearest Guinean border. Sure, these are not insurmountable distances to travel while incubating an Ebola virus infection, but it would have been a simpler call that this was an imported case if it had occurred on or nearer to the border of one of the two countries with ongoing disease. However, it seems the young man did not travel outside Liberia.[8]

Hopefully the contact tracing and investigations that are going on now will find that 17M simply made contact with someone who had traveled from outside of Liberia, perhaps to Nedowein, which is described as the home town of 17M.[2,7] If this is not an imported case then one is left to wonder about various other scenarios including:

sexual or other less common transmission of Ebola virus from an as yet undiscovered convalescent EVD case
contact with an unknown case who had traveled across the border from a country with EVD
a new zoonotic acquisition of a different Ebola virus variant
there may still be clusters of EVD within Liberia that have been smouldering on without the knowledge of any authorities

Time and further hard work will no doubt tell.

UPDATE: A second case, associated with 17M ("Abraham") has been diagnosed.[9] Some discussion is evolving around the consumption of dog meat by 17M,[11] however, the same questions around how a dog would become infected (no record of the detection of active replication in a dog have been recorded to date, although antibodies have suggested the possibility in earlier outbreaks) will apply.

Further reading...

Version history..

New links added; town name variation added from Science report; hypothesis of contact with another imported case - #2; note on lack of travel outside of Liberia; announcmene tof a 2nd case

Liberia gave Ebola the boot...and a virus may soon be removed from the wild

bat, Ebola virus, endemic, enzootic, EVD, Liberia, WHO, zoonosis

The people of Liberia have earned our respect, some time for national celebrations and frankly any other rewards that may flow from denying the Makona variant of Ebola virus any hosts among their community.

The world considered this viral species to be one of the list-toppers when it came to ranking the causes of the most scary acute infectious diseases. Ebola virus has been the basis for all sorts of 'end-of 'the-world' mutating virus horror movies, books, and TV shows. It's not at all surprising that the public view of an Ebola virus infection had long been one of blood, fear and terror.

Figure 1. The decline of the Makona variant of
Ebola virus in Guinea, Sierra Leone and Liberia
(now free of EVD transmission).
Click on image to enlarge.

Behavioural change was a major factor in reducing virus transmission in Liberia. Alongside that was a broad range of aid given from within and beyond Africa's nations. By working together, a widespread outbreak that was not initially thought likely to happen at all, was routed.

For now.

Liberia is not immune to new cases of Ebola virus disease (EVD) crossing its borders or popping up due to a new animal-to-human jump (a zoonosis). That could happen any day - it might be happening now. But those who are still on watch will be searching out new cases while the remaining sites of transmission - Guinea and Liberia - do their best to deny Ebola virus a chance to replicate and spread. The people of Liberia will keep watch help because they have learned very tough lessons about viruses, epidemiology and communication. At least 10,604 suspect, probable and confirmed EVD cases, 4,769 deaths and way too many stories of sadness and families destroyed are a very strict teacher.

Figure 2. The number of confirmed EVD
cases (yellow) grinds to a standstill. Only
9 cases in the week to 10th May 2015.
Click on image to enlarge.

The crude prediction in Figure 1 suggests that zero cases across all three countries could happen at the end of May, but many stars must align for that to be a real event.

Human factors - the causal and sustaining variables of any outbreak of infectious disease in humans and sometimes animals - remain very much in play. But once that tri-country zero case value is attained, we have 42 days of watching and waiting - from the time the final case tests negative.

New cases may arise from sources as-yet-unknown. But even if they do keep popping up, it seems very unlikely that widespread transmission will amplify to earlier levels (see the steep slopes in Figure 2) unless a major lapse in attention occurs. Hence,the need for continued vigilance - and Liberia remains on alert for a further 90 days. That more recent figure comes about because we know that infectious Ebola virus can persist in some body sites for many weeks after signs of disease have passed. Whether that virus reservoir is present in every person and whether it actually does cause new Ebola virus infections remain unproven. When you consider what can happen when one person gets infected by an Ebola virus in a tiny remote village in a country that is ill prepared to cope with it and has traditions that lend themselves to its spread...even minor risks rightly come under more intense scrutiny.

What next for this particular virus though? The only place where the Makona variant of this member of the Zaire ebolavirus species will soon exist, is in the freezer of (hopefully) very biosecure laboratories in the US, UK, Africa, Russia, China and probably other laboratories in countries that hosted, evacuated or repatriated cases of EVD.

There is no sign at all - and this is because of the continued efforts and focus of many currently working throughout west Africa - of the fabled "endemic Ebola" becoming a reality. Unless you mean enzootic 'Ebola'- in which case , it already is, I suspect. It seems very, very likely that the forests of west Africa continue to shelter animal hosts with less mutated versions of this and other ebolaviruses (and filoviruses and who-knows-what else). The host species and route(s) of transmission to humans are yet to be confirmed but for now, we are not too far off eradicating one unwanted viral scourge from the wild. Impressive what we can do when we pull together.

Yes, there were signs that Ebola was in west Africa, perhaps as far back as 1973...

Ebola virus, Ebola virus disease, EVD, Liberia, long view

If a bat carries Ebola virus in the forest, people find signs of infection in humans, publish it and read about it, but no-one remembers, does it make a sound?

Apparently, it now does. The New York times [3] has found that there were studies reporting signs of Ebola virus antibodies in humans in Liberia in samples collected back in 1982.

I'll see your 1982 and raise you 1973! [1] That's when some other samples were collected that were found to contain antibodies to Ebola virus. This doesn't come up in the abstract for this article, but is buried in the Methods and Materials section.

"..antibodies specific for Marburg virus and Ebola virus antigens tested by immunoblotting (21% and 14%,respectively)"

We noted this paper in 2014 - in a piece for the Conversation [2] - and listed some other articles which found similar signs of prior human exposure to Ebola virus or something related. The NYT piece has also captured some of these papers by the looks of it.

In many (most?) cases, these scientific papers can only be reached after paying a fee, or being affiliated with an Institutions that has a good library. Many researchers, clinicians and public health professionals can be described as such.

For me, it seems clear that there were many people aware of the possibility the Ebola virus was pretty much "always" (in the context of our history with Ebola virus disease[EVD]) in the forests within the regions underneath the flyways of some likely filovirus-host bat species.

But seemingly no action was taken on these reports. Was that because...

the serology assays were perhaps too non-specific or otherwise unreliable (were they cross-reacting with as-yet unknown filoviruses perhaps (h/t Stephen Goldstein)
no-one thought much of EVD's capacity to cause a big outbreak?
we didn't care about smaller outbreaks because they had always been controlled previously?
we just didn't care because it was "over there" (in Africa)?
we just forgot about it as soon as it was published?

It really doesn't matter what the reason(s) was, because global political willingness to invest the mental and physical capital in a program that could think about, monitor and foresee the risks associated with anything found, and one with a very long view of protecting the public from possible infectious threats...just does not exist.

This is not a problem specific to EVD of course. Trying to stay ahead of infectious threats will take much more devotion than the world has shown it can muster to date. Even when we can see their potential for harm, there are only so many resources we will mobilize for an infectious threat that is not knocking on our specific door.

References...

Neppert J, G�hring S, Schneider W, Wernet P.
No evidence of LAV infection in the Republic of Liberia, West Africa, in the year 1973.
http://www.ncbi.nlm.nih.gov/pubmed/3015288
How Ebola started, spread and spiralled out of control
https://theconversation.com/how-ebola-started-spread-and-spiralled-out-of-control-32137
Yes, We Were Warned About Ebola
http://www.nytimes.com/2015/04/08/opinion/yes-we-were-warned-about-ebola.html

Hans Rosling, a micro-outbreak of Ebola in Liberia and trust issues in Guinea...

disease communication, Ebola virus, Ebola virus disease, EVD, Guinea, Hans Rosling, Liberia, science communication

As is always the case, Prof Rosling can be seen in front of an audience here, providing a beautifully articulated example of how trust in the Ebola virus disease (EVD) treatment centre/unit plays such a pivotal role in (a) the containment of EVD, even witting a family and its contacts, and (b), the likelihood of survival of EVD patients.

Frame taken from a BBC News video which was being hosted in
an African Geographic Magazine story here. Red dots are survivors,
black dots are deaths
Click on image to enlarge.

In this example, which you can listen to in its entirety here, as time went on, trust grew and this fewer transmission occurred and more f those infected, survived.

This would seem to be a great example of what is lacking in Guinea - trust - a lack of trust that others are be able to stop the spread of virus and to save the lives of those infected. Thus people are not presenting for help at all and still being managed in the community - possibly infecting others - or else they are not presenting early enough, before the disease has done too much damage to the person. Trust and communication is increasingly seen as being as important to the successful reduction of cases in Liberia and Sierra Leone as the building of treatment centres - the two must co-occur.

Trust comes from understanding, and that is heavily influenced by communication. Communication of accurate information, of clear and digestible information. Communication to the right people using the moist effective channels is also essential.

It still feels like communication, or at least accurate and successful communication accessing the key important and influential people, may be the weakest part of the response in Guinea. It seems to have been better implemented in Liberia and Sierra Leone - or maybe just better received. Is it a groundwork thing? Difference in the way science is presented in different countries? I know far too little to guess further.

There continue to be more security incidents and other types of refusal to cooperate in Guinea compared to the other two countries afflicted with the Makona variant of Ebola virus. These incidents are a marker of a community that does not believe or trust those claiming to be here to help. And that's a problem for stopping the constant rivulet of EVD cases in Guinea; a rivulet that never became the river of hundreds of EVD cases per week seen in Liberia or Sierra Leone, but was still a flow that seeded infection across the region and the world. A case anywhere is a threat everywhere, to paraphrase others.

Location of laboratories in Guinea,
Liberia, and Sierra Leone.
From WHO SitRep 01APR2015.

But there may be other issues to consider and question.

There are fewer treatment centres and laboratories in Guinea than in Liberia or Sierra Leone - strange given that Guinea is larger and that it still has a geographically widespread distribution of cases.

While it has lately been noted that new cases in Guinea could be adding to the tally more simply because of success in reaching more remote areas, this seems only to add support to the need for better communication and to provide more of a presence in these remote areas. Hopefully, now that this happening through the efforts of the US CDC and others, we will soon see the pay off as a reduction of EVD cases. But the rainy season is near and travel will be made into a muddy mess by that. Time has never been on the side of those trying to stop this epidemic.

Liberia enters the next phase of Ebola virus disease (EVD) eradication with a new case...

Ebola virus, Ebola virus disease, EVD, Liberia, semen

version 2

What a heartbreaking disappointment this is for the people of Liberia, with a reported new case of EVD in a 44-year old woman who showed signs of disease 15th March and tested positive for Ebola virus on Friday 20th in Monrovia, Liberia.[2,7,8] after more then 3-weeks (28 days or more[6]) with zero new cases and no ongoing, known, transmission of Ebola virus in any county in the country.[5] The previous final case in Liberia tested negative around the 3rd of March (about 17-days ago), when the 42-day clock was started.[5]

Now it has been stopped.

Starting it again will await this new case returning a negative test as well as all their contacts (who will be monitored for 21-days) being declared infection- (actually disease-, but I say infection intentionally) free.

And thus we enter the next phase � that of a different type of frustration and heartbreak as countries within the tri-nation hotzone come tantalisingly close to being declared free of known cases of Ebola virus disease (EVD; see how those seemingly pedantic words [1] have added meaning now?) or virus transmission, or in fact succeed only to have a random case pop up from somewhere unexpected or travel across a border causing disappointment for the people of the country, the aid workers and the family and friends of the new case.

A random case will also trigger all new contact tracing efforts to try and find the source and lock down further spread as quickly as possible.

There is noise on twitter (see Tweet below) and in the media quoting authorities [6] noting that the case may have been from a sexual contact with a previously infected male. Infectious virus has been found in semen in the past in which it can linger for more than a month [3,4], but this has not been a factor in the timing of release of convalescent males in the recent epidemic. If this is the route of acquisition, then the ensuing costs, scope of the response, risk to a country that had nearly cleared the virus and to the stamina of an Ebola-ravaged country may serve to justify additional testing the future.

#Liberia Min of Info says 'initial suspicions' are that country's 1st #Ebola victim in 28 days could have had sex w/ ebola survivor
� Katerina Vittozzi (@kvittozzi) March 20, 2015

The route of acquisition in this latest case remains totally unconfirmed at writing.[7] I'll update this post as I find more details.

My thoughts are with you Liberians � stay strong � it�s a setback to be sure, but you were very close this time and will get there.

References...

Ebola virus disease: obliterating a variant and stalled case decline...

Ebola virus, EBOV, EVD, Guinea, Liberia, Makona, phase, Sierra Leone, WHO

We've seen the words vigilant and vigilance used widely in recent weeks, ever since we entered a "new phase" of the Ebola virus disease (EVD) battle/fight/war.

The reason for vigilance in all things to do with this campaign has become obvious as the weeks have passed; the reduction in cases has stalled.

I've very crudely drawn in some trends below. Whether you agree with them or not, it is clear that since the fast fall in confirmed cases reported between November-January, it seems to have become very difficult to stamp out the last fires of EVD.

The phases.
(Very) rough trends in the number of EVD cases over time.
Date from World Health Organization situation reports (SitReps)
and situation summaries (SitSumms).
Click on image to enlarge.

Liberia has come the closest to completing this goal of obliterating the Makona variant of the Zaire ebolavirus (EBOV|Makona) with just 3-9 confirmed cases between World Health Organization (WHO) Situation Report (SitReps) during any of the past 7 weeks. It seems that recent cases can be traced to known transmission chains too and that means no surprise outbreaks.

However, the people of Guinea and Sierra Leone have not quite got the messages that those in Liberia seem to have embraced (without touching!) so admirably.

In the last WHO SitRep [1] it was noted that 39-45 unsafe burials (probably not all that occurred) occurred in a week and >40 EVD cases were identified post-mortem. This last observation means exposure of the community to virus, not getting help and treatment for ill people, and unnecessarily requiring contact tracers to play catch-up. Bad for the infected people their friends and families and the response to EVD. It doesn't have to be that way.

This paints a picture of problems with Ebola outreach and education, communication and cooperation. Those things will keep the latest EVD "phase" chugging along.

We do need to destroy this variant of Ebola virus by isolating it in the last human cases in each of Guinea, Liberia and Sierra Leone. Once those people recover, or regrettably die, EBOV|Makona will be gone, except for what's in lab freezers around the world and in sequence databases thanks to the efforts of a few expert research teams. Once gone from "the wild", the evolutionary clock resets back to the EBOV variants in the animals of the forest.

EBOV|Makona knows too much; it has seen too much; it has learned too much, to be allowed to "live". It has been passed through humans too many times and while there is a vanishingly small chance it will sprout wings, it is still a virus that spreads relatively easily under the right conditions and circumstances. Explosive loss of 8 litres of fluids a day provides many ways to pass along this blood/gastro virus. EBOV|Makona may also have adapted, and continues to adapt, in other ways that would mean its stay among humans becomes lengthy and its dissemination more widespread.

More bad news from an unsuccessful obliteration of EBOV|Makon-smouldering EVD in Sierra Leone and Guinea may release new case embers that drift across borders and set new fires in other countries. We don't need hundreds of cases a day for that to happen.[3] We know cases also fly with the aid of planes (not wings). And the cycle could renew. I don't think we'll see such big outbreaks of EBOV|Makona again, for reasons I laid out here, but chasing new fires is more work than stamping out the remnants of old ones. Vigilance and action.

I think vaccines still have an important role to play in the final phase of this epidemic, even if only 3 new healthcare worker cases were noted in the past SitRep week. Vaccine given to more than just healthcare workers could be useful here, if others will accept the needle.

Ebola outreach
Education
Communication
Cooperation

Oh, and vigilance.

References..

Cases of Ebola virus infection can be exported any old time...

Ebola virus, Ebola virus disease, EVD, exported case, Guinea, Liberia, Sierra Leone, transmission

I'm adding my two cents on the issues around remaining vigilant about Ebola virus disease (EVD) cases.

There are far fewer weekly EVD cases than there used to be but it remains absolutely essential to "kill off" this particular highly-passaged Zaire ebolavirus variant. In other words, push new cases down to zero per day in all three countries, keep it there for 42-days, and thus declare all three nations free of Ebola virus transmission.

Apart from the obvious desire to see these countries rid of this horrible and deadly pestilence, another, less likely thing to consider is that more spillovers to other countries can still happen at any time. And apart from the costs, the reaction from a certain country to its first imported case, just does not bear living through again.

Whether human cases were just kicking off, or after they began accruing at an exponential rate of hundreds per day, the hotspot countries have been the source of export of a case to another country.

That said, in my opinion we are in a much better global position today than we were six to twelve months ago. We can much more effectively engage and thwart the spread of infection from an EVD case that appears on our doorstep because we now know Ebola virus is out there and can hop on a plane, and many countries and regions within countries have done something to prepare for that rare arrival. Some countries were already in a better position than others, simply because they have (relatively) huge healthcare
processes in place and are now aware of how to help, and how quickly to respond, should a foreign neighbour acquire a case.

None of that is to say zero spread in other countries is a given in the near future; humans being humans, accidents and mistakes will always happen. But we are just very unlikely to see EVD spread in a new country to the extent that we saw last year. Hopefully I'm not being too naive on that call.

If we look at the images below, it's plain to see that EVD cases were exported from these countries both early on and late in the outbreaks and later epidemic. Guinea being slightly more of a culprit than the other two countries of intense and widespread transmission (Liberia and Sierra Leone).

Guinea's Ebola virus disease experience. The approximate time at which
another country receives a person infected by Ebola virus, most likely acquired
from within Liberia, are indicated by an arrow.
Click on graph to enlarge.

Sierra Leone's Ebola virus disease experience. The approximate time at which
another country receives a person infected by Ebola virus, most likely acquired
from within Liberia, are indicated by an arrow.
Click on graph to enlarge.

Liberia's Ebola virus disease experience. The approximate time at which
another country receives a person infected by Ebola virus, most likely acquired
from within Liberia, are indicated by an arrow.
Click on graph to enlarge.

The filovirus tree has been shooting wildly

Ebola virus, Ebola virus disease, EVD, Guinea, Liberia, Mali, next generation sequencing, Sierra Leone, United Kingdom, United States of America, West Africa

While there are not a lot of new branches, there are many, many new leaves on this growing tree. That is overwhelmingly due to the fantastic work of Dr Pardis Sabeti, and Stephen Gire at the Sabeti lab, Harvard University, and their many collaborators.

It sounds like even more sequences will be coming out in the future. This group is the face of the molecular epidemiology of history's largest Ebola virus disease epidemic in Sierra Leone. If a team of scientists could be said to embody an aspect of an epidemic, it has been these guys and their virus characterization. Hugely impressive stuff.

I only wish we could see more Guinean and Liberian sequences - they are both hugely under-represented in this tree of complete genomes downloaded from GenBank a week or so ago.

Click on tree to enlarge even further.
Coloured boxes surround those sequences generated during the
2014 EVD epidemic. Orange boxes point out the nearest neighbours
and the year from which the sample that was sequenced, originated.
The West African Ebola virus Makona variant has been
traced back to sharing an ancestor in common with a 2007
variant in 2004.

References

Genomic surveillance elucidates Ebola virus origin and transmission during the 2014 outbreak. Gire SK, Goba A, Andersen KG, Sealfon RS, Park DJ, Kanneh L, Jalloh S, Momoh M, Fullah M, Dudas G, Wohl S, Moses LM, Yozwiak NL, Winnicki S, Matranga CB, Malboeuf CM, Qu J, Gladden AD, Schaffner SF, Yang X, Jiang PP, Nekoui M, Colubri A, Coomber MR, Fonnie M, Moigboi A, Gbakie M, Kamara FK, Tucker V, Konuwa E, Saffa S, Sellu J, Jalloh AA, Kovoma A, Koninga J, Mustapha I, Kargbo K, Foday M, Yillah M, Kanneh F, Robert W, Massally JL, Chapman SB, Bochicchio J, Murphy C, Nusbaum C, Young S, Birren BW, Grant DS, Scheiffelin JS, Lander ES, Happi C, Gevao SM, Gnirke A, Rambaut A, Garry RF, Khan SH, Sabeti PC.
Science. 2014 Sep 12;345(6202):1369-72. doi: 10.1126/science.1259657. Epub 2014 Aug 28.

The United States of America is the 6th country to host a 2014 West African Ebola virus variant..

case announcement, Ebola virus, Ebola virus disease, EVD, import, Liberia, United States of America

v4 08102014 07:00am AEST

First thing...

CALM DOWN!

This (announced 30-Sept) is the first case of Ebola virus infection to arrive in the United States that was not deliberately flown in. Its not the first viral haemorrhagic fever case though (1 case of Marburg virus disease and at least 4 Lassa virus infections and the Reston ebolavirus outbreak among imported animals[3,5]), and none of the earlier infections resulted in secondary transmission among humans; no-one else got infected from by the case.[4]

Countries that have hosted people infected
with the Ebola virus variant causing the
& 2014 West African Ebola virus
disease epidemic.
Click on image to enlarge.

The male is in critical condition.
When he flew from Liberia to the United States (finally arriving in Dallas,Texas). The man was not showing signs of disease when leaving Liberia or on the plane or immediately after arriving.[6]

This means that the man was not infectious - he could not spread it to fellow travellers or airport workers - because it is well known that disease in another does not develop due to virus being shed before disease is obvious in the infected person.

Briefly[1,2]:

19th: Departed Liberia, checked and found to be symptom-free
20th: Arrived in Dallas, US (Brussels to Washington on United Airlines 951, then to Dallas Fort Worth on 822 [7])
24th: Started to develop symptoms
26th: Initially sought care for fever and abdominal pain (not vomiting). Sent home with antibiotics.[8]
28th: Admitted to Texas Health Presbyterian hospital in Dallas, Texas. Vomited as leaving home to get into ambulance.
30th: Texas public health laboratory found Ebola virus this morning of 30th Sept. CDC received samples, tested and confirmed as Ebola virus disease

CDC announced case

1st Oct: WHO announced case
Patient is ill and is under intensive care

US family and community contacts (a "handful") are known or being traced and will be under observation/monitoring for 21-days (~21-Oct) for fever. Will any become positive for Ebola virus? Perhaps. I look to Port Harcourt (Nigeria) for some comfort. There were around 60 "high risk" contacts of there and they did not all become ill.

The man identified his country of recent origin, Liberia-the country carrying more cases of Ebola virus disease than any other in history, to a triage nurse on the 26th when he first reported to the Texas Health Presbyterian Hospital. That the information was not passed along sufficiently.[7] While the signs and symptoms were non-specific-all sorts of infectious agents could cause fever and gut issues-the travel history should have been a very important red flag.

He was sent home with antibiotics. Many acute febrile illnesses are viral in nature, and antibiotics do not treat viral infections, just bacterial ones but do a great job at helping out antibiotic resistance. Sigh.

So now we have evidence that supports all those talking heads (me included) who noted that it was possible for sporadic cases of EVD to be imported into countries outside of those in West Africa (Guinea, Liberia, Sierra Leone, Nigeria, Senegal). It also, sadly, shows how human infectious disease are - literally by infecting us and using us to cough, vomit and bleed the bug onto to another person, but also figuratively in the roles we play in helping that spread to happen.

Soon, I very much believe, we will also have evidence that in richer countries with functioning healthcare systems, a good knowledge of what is needed to contain virus infections spread by all possible routes, stocks of the necessary personal protective equipment needed to protect healthcare workers from nosocomial infections and the training to use those stocks...that even when unexpected Ebola virus disease cases arrive or incubate and emerge, they will not result in outbreaks.

References...

https://www.youtube.com/watch?v=6Bxencye1cg&feature=youtu.be
http://www.nytimes.com/2014/10/01/health/airline-passenger-with-ebola-is-under-treatment-in-dallas.html?partner=rss&emc=rss&smid=tw-nytimes
http://scienceblogs.com/aetiology/2014/08/02/ebola-is-already-in-the-united-states/.
http://blogs.scientificamerican.com/molecules-to-medicine/2014/09/30/ebola-in-usno-need-to-panic/?WT.mc_id=SA_sharetool_Twitter
http://www.cdc.gov/media/releases/2014/s930-ebola-confirmed-case.html
http://news.sciencemag.org/health/2014/09/one-more-ebola-question-dr-frieden-answers-journalists-would-have-first-u-s-case?rss=1
http://www.usatoday.com/story/news/nation/2014/10/01/hospital-ebola-patient/16527143/
http://www.usatoday.com/story/news/nation/2014/10/01/texas-ebola-patient/16525649/

The control gap...

Control gap, Country totals, Ebola virus, Ebola virus disease, EVD, laboratory confirmation, Liberia

v2 300914

I have a theory.

This theory is meant only to apply to disease outbreak/epidemic/pandemic situations, and then only to those which include fatal cases.

This theory of mine has only emerged since I've been plotting Ebola virus cases numbers from the West African epidemic. I precede the explanation with the caveat that there is very probably already a well developed, well-known actual epidemiology term to describe this theory. But I'm not a trained epidemiologist and this is just a blog, so please forgive me my ignorance.

The theory goes that when a gap grows between the number of new cases being reported and the number of deaths or laboratory confirmations in that population, despite the outbreak having been going for a while, this represents an indication that control of the situation is slipping, or has been lost.

Mind the gap.

This "control gap" - my term, so don't expect to find it anywhere official or that knows of that which it speaks - can also appear when looking at suspected or probable cases of disease X, and the number of those that have been confirmed by a laboratory test.

Other explanations for the control gap may exist of course; testing may be scaled back deliberately, reporting of deaths may have been deliberately throttled for some political reason. So it may not reflect being "out of control" as much as someone else being "in control".

Probably still more variations that I have not thought of at all.

Ebola virus disease (EVD) in Liberia.

In the graphics below I've used the accumulation of World Health Organization data for Liberia, up to 23-Sept.

First up - the fold increase in total case numbers (suspect+probable+laboratory confirmed) compared to the fold-increase in the distance between that total and the total number of laboratory confirmed cases alone. This distance, or the "control gap|lab", has widened over time. It has widened because total cases have climbed more steeply than the number given a laboratory confirmed diagnosis of EVD.

For whatever reason(s), laboratory confirmations are not keeping pace with the total case numbers, and they seemed to start slipping at the end of July.

I suspect a principal reason - and I'm not on the ground of course, so this is all speculation and second-hand knowledge - is that laboratory capacity is overwhelmed.

Other reasons include that samples might not always be collected or that many recent clinically defined EVD cases are actually due to something clinically similar to EVD, but not an Ebola virus infection. If it were this last one though, the total numbers would be readjusted downwards as new diagnoses were made...if the laboratory has time to make those of course...so I doubt it as a major role.

The control gap|lab
A.) Ebola virus disease case graph for Liberia showing the accumulation of total (suspect+probable+laboratory confirmed) cases (pink line; left y-axis) and deaths (blue line; left y-axis), the laboratory confirmations (green line; left y-axis) and the proportion of fatal cases (right y-axis) at each reporting date (x-axis). The size of the gap between laboratory confirmed cases and total cases is indicated for a range of reporting dates, using a vertical green drop-line.

B.) The drop-lines have been copied and aligned and the amount they have grown has been measured using a scale bar so that the fold-increase can be compared to the first reporting date used, 8-July. The fold-increase value is written at the top of each drop-line. Along the bottom (enclosed within a grey box) are the case numbers at each reporting date examined and the fold-increase (in bold) compared to the 8-July baseline.

Next up -the fold increase in total case numbers (suspect+probable+laboratory confirmed) compared to the fold-increase in the distance between that total and the total number of deaths. The control gap|deaths comparison finds that the deaths and the total cases don't diverge as much as total cases and lab confirmations do.

The control gap|deaths
A.) Ebola virus disease case graph for Liberia showing the accumulation of total (suspect+probable+laboratory confirmed) cases (pink line; left y-axis) and deaths (blue line; left y-axis), the laboratory confirmations (green line; left y-axis) and the proportion of fatal cases (right y-axis) at each reporting date (x-axis). The size of the gap between laboratory confirmed cases and deaths is indicated for a range of reporting dates, using a vertical blue drop-line.

B.) The drop-lines have been copied and aligned and the amount they have grown has been measured using a scale bar so that the fold-increase can be compared to the first reporting date used, 8-July. The fold-increase value is written at the top of each drop-line. Along the bottom (enclosed within a grey box) are the number of deaths at each reporting date examined and the fold-increase (in bold) compared to the 8-July baseline.

So with that visualization under our belt, there is another, less laborious way to look at this, by graphing the numbers, rather than the gaps.

What we see when we plot the fold-change values against report date is that total cases lost control as we suspected, but deaths are less obviously out of control. From 9-Sept onwards the gap has widened a little more consistently. Before that though the deaths did not dramatically drift away from the rate at which new cases were being added.

I'll graph Sierra Leone, Guinea and Nigeria in the next day or two. Nigeria should serve as an example of how this looks for a country in which EVD is definitely in control.

Graphing the control gaps

The fifth I give you...[UPDATED]

Ebola virus, EVD, Guinea, Liberia, Nigeria, Senegal, Sierra Leone, West Africa, Zaire ebolavirus

Senegal.
According to it's Minister of Health, Awa Marie Coll Seck[1,2], a case of Ebola virus disease (EVD) has been imported from Guinea and it is confirmed by testing at the World Health Organization's collaboration Centre, the Pasteur Institute in Dakar.

Interesting that this occurred one week after Senegal closed its borders (again) with Guinea.[3,4] The infected 21-year old Guinean student travelled on 21-August to Dakar. On the 23rd he presented to a hospital but did not admit to being in contact with known EVD cases; Guinea issued an alert that a person with EVD contact has escaped surveillance 27-Aug; Senegal closed its borders around 22-August.[5,6,7,8].
[WHO Disease Outbreak News places his movements ahead of the closure of the border, arriving in Senegal 20-Aug [8]]

These borders are leaky and so the effect of "closure" essentially hinders aid, trade and economy (all very important to the region, especially right now) but ~~very clearly~~ ~~does~~ may not stop the spread of human hosts~~-as we have seen here~~.

Humans are the variable in outbreaks.

They behave differently each time.

They respond differently each time.

This is why no two outbreaks are identical.

It's why you're a mug to assume this outbreak will be like the last outbreak.

While it looks like this is now a case study in why closing a border is ineffective, I maintain a position that border closures can't contain infectious disease. And please, do not point me to "temperature measurement" as a way to ensure capture of infected individuals. You could easily be harbouring an infection that does not yet express the symptom of fever.

Click on image to enlarge.
Graphic lifted from a great CNN video narrated by
Dr Sanjay Gupta. The video describes an example of
contact tracing and its importance to the fight
to contain EVD.[2]

The contact tracing starts in Senegal now. A 42-day clock starts for the country and a signs and symptoms watch continues on all this case's contacts for 21-days.

References...

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