| Re: [stem-ebola] Ebola Rapid Antigen Tests re: Ira |
Thank you Ira for this very useful PDF.
Ebola 'screening' is something I have been thinking about quite a bit lately, as well as discussing with my spouse, who works as a P.A. in a clinical setting. She is skeptical of lab testing because her clinical experience has indicated often high rates of false negatives in certain viral tests... Interestingly, she mentioned seeing a surprising amount of false-negatives in HIV-1 patients subsets. (Perhaps the HIV-1 PCR primers are different, or the antibodies do not bind as well? The reason is unclear. The lab ended up doing both a Western Blot and PCR on the HIV patient, who was eventually diagnosed after some initial confusion.)
Anyway... I thought that really the world needs a way to reliably identify Ebola-infected patients at the time of symptom presentation (or before , if that's even possible at all)... Perhaps this can be achieved by slightly modifying existing innovative technologies.
New Ebola screening technologies could check for infection using a 'rapid test' , perhaps something robust enough for both clinical use and field use. I published a post on the Operon Labs site suggesting the use of antibody technology somewhat like the OraQuick home HIV-1 test, which produces decent results within 20 minutes. In the article you posted Ira, they discuss the Lassa field test, which operates much in the same way as the home HIV OraQuick test. http://www.operonlabs.com/?q=node/13
The only real limitation I see in Ebola testing is this statement -- per CDC (and I see no evidence to the contrary) -- is CDC writes that even highly sensitive tests like RT-PCR will sometimes be Ebola false-negative until 1-3 days after the onset of Ebola-symptoms. This problem makes the use of testing for 'early detection' of Ebola difficult and pointless, unless innovations are made in how the tests work.
Digression: In existing Ebola 'confirmatory' tests at state labs and CDC, I've got to wonder what procedures are being used ... I'm not familiar with the exact procedures... For RT-PCR, what primers are being used, and what regions are they targeting? What are the primer sequences? Have the Ebola RT-PCR primers been adapted for the 2014 outbreak (if necessary)? I'd love to know the answers, but I don't at the moment.
What the world really needs is a portable Ebola test that is very sensitive and accurate, and can be donated in large quantities. One way to do this is to start with a test (like the experimental Lassa field test) which uses 'blood drop' and 'on-the-spot' ELISA-type testing with a 'wick' so to speak.
But even this would still suffer from the CDC's 1 to 3 day lag time in detection, relegating such testing to a mere 'rapid confirmatory' role rather than any disease surveillance role . This would help at the field hospitals, but it would not help with disease detection on transnational flights or large-scale clinical surveillance.
One workaround to increase the surveillance capabilities of Ebola testing might be new ideas... Here is one of my ideas...Run an Ebola Blood 'rapid-antigen' test *after* blood fractionation using only the buffy coat from a vein draw (not a 'whole blood' drop). By testing the buffy coat (leukocytes) only after blood centrifuging, one might be able to develop a test with a far more accurate result, since PBMCs (minus the lymphocytes) are the early targets in Ebola infection.
Additionally, another enhancements to an Ebola test that occurred to me (depending on whether ELISA/Antibody or PCR based) could use the following method...
1. Prior to the test, homogenize the 'buffy coat' leukocyte membranes to release and liberate the intracellular contents ... either ...
2A. Liberate / Extract Antigenic viral proteins from Monocytes/Macrophages (for ELISA type tests), or
2B. Liberate / Extract Targeted viral RNAs from Monocytes/Macrophages (for PCR).
You could use a variety of disruption techniques like cell lysis buffers , and/or bead disruption, etc, depending on the needs of the application, and whether the tests need the proteins or the vRNA intact. The key would be to target only leukocytes... More preferably , only target Monocytes and Macrophages for testing.
This latter suggested method (disruption / homogenization of leukocytes in the buffy coat) might increase the specificity and sensitivity of these 'rapid' Ebola tests, since the homogenization of leukocytes would 'de-cloak' the Ebola virus from it's early hiding spot in the Monocytes and Macrophages, exposing the infected cell contents to the test.
Perhaps the false negative rates would go down, and the disease could potentially be detected earlier than is possible now.
With some luck (if possible with such technology), we might be able to detect Ebola prior to manifestation of symptoms by looking specifically in isolated and homogenized Monocytes and Macrophages.
In any case... I'm looking forward to your call next week Ira. I'm sure it will be a great discussion.
Thanks,
Alex
On 2014-10-15 10:51, Ira Schwartz wrote:
See attached._______________________________________________
Ira
On Wed, Oct 15, 2014 at 1:02 AM, <alex@xxxxxxxxxxxxxx> wrote:
EBOLA VIRUS DISEASE - ex AFRICA (14): UN DOCTOR DIES, USA,*********************************************************************
PREVENTION
A ProMED-mail post<http://www.nbcnews.com/storyline/ebola-virus-outbreak/ebola-kills-united-nations-medic-hospital-leipzig-germany-n225151
<http://www.promedmail.org [1]>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org [2]>
In this update:
[1] UN doctor dies in Germany
[2] USA: Texas contact quarantined
[3] Prevention & false alarms
******
[1] UN doctor dies in Germany
Date: Tue 14 Oct 2014
Source: NBC News [edited]
[3]><http://www.star-telegram.com/2014/10/14/6199347/facebook-founder-donates-25-million.html?rh=1
A United Nations medical worker [originally from Sudan] who was
infected with Ebola in Liberia has died despite "intensive medical
procedures," authorities said Tue [14 Oct 2014]. The St. Georg
hospital in Leipzig said the 56-year-old man, whose name has not
been
released, died overnight of the infection. It released no further
details. The man tested positive for Ebola on 6 Oct 2014, prompting
Liberia's UN peacekeeping mission to place 41 staff members who had
possibly been in contact with him under "close medical
observation."
He arrived in Leipzig for treatment on 9 Oct 2014, where he was put
into a special isolation unit...
--
Communicated by:
Ryan McGinnis
<ryan@xxxxxxxxxxxxxxxxxxx>
******
[2] USA: Texas contact quarantined
Date: Tue 14 Oct 2014
Source: Star Telegram [excerpted, edited]
[4]><http://www.nbcnews.com/storyline/ebola-virus-outbreak/no-ebola-checks-brussels-airport-after-flights-liberia-n223581
"The lone person believed to have had direct contact with the Ebola
[nurse] works at Fort Worth-based Alcon and was admitted to Texas
Health Presbyterian Hospital with no symptoms," a company
spokeswoman
said...
Alcon is a medical company that specializes in eye care products.
The
Alcon employee is being hospitalized as a precaution, the statement
said, adding: "The Alcon associate has not shown any signs or
symptoms
of the Ebola virus. After consultation with the Texas Department of
Health, we are confident that there is no risk for Alcon
associates.
We are working closely with the Centers for Disease Control and
Prevention and the Texas Department of Health to ensure we are
following proper public health measures." ...
[Byline: Gordon Dickson]
--
Communicated by:
Jonathan Ezekiel <jezekiel@xxxxxxx>
******
[3] Prevention & false alarms
Belgium: No Ebola checks at Brussels Airport after flights from
Liberia
-----------------------------------------------
Mon 13 Oct 2014: (NBC News) It's the classic airport scene: a man
hugs
his wife and 2 daughters at arrivals. But in this case, the
traveler
had just stepped off a plane from the Ebola-stricken Liberian
capital
of Monrovia, meaning that some might shy away from such embraces.
"I've been screened before getting on the plane," he pointed out
before heading for the exit. The twice-weekly flight from Monrovia
to
Brussels is now the only air link from that city to the European
continent and is the route most Americans would likely travel on
their
way home. Thomas Eric Duncan, who died in a Dallas hospital last
week,
traveled to the U.S. from Liberia via Brussels...
[5]><http://online.wsj.com/articles/in-brazil-man-suspected-of-carrying-ebola-tested-negative-again-1413231294
[Byline: Carlo Angerer & Becky Bratu]
[The link shows Ebola advice posters at Monrovia airport. - Mod.JW]
--
Brazil: Man suspected of carrying Ebola tested negative again.
-----------------------------------------------
Mon 13 Oct 2014: (WSJ) A man suspected of carrying the ebolavirus
was
tested negative for the 2nd time, Brazil's Health Ministry said Mon
[13 Oct 2014]. The test eliminates the possibility of Ebola, Health
Minister Arthur Chioro told reporters. The man, identified by
authorities as a 47-year-old from Guinea, one of the 3 countries
hardest hit by the Ebola outbreak, was isolated at a Rio de Janeiro
hospital... Doctors were still monitoring for other possible
diseases,
even after Ebola had been ruled out... Two blood tests were made,
following standard protocol to deal with the deadly virus. Dozens
of
people who had contact with the man were monitored, but now they
are
no longer under watch, he said. The minister said the case showed
Brazil is ready to deal with the epidemic. He also said that the
risk
of contagion in the country is low.
[6]><http://haraethiopiadotcom.wordpress.com/2014/10/13/ebola-outbreak-spreads-in-ethiopia-kenya-and-south-sudan-as-passenger-dies-at-kenyas-jomo-kenyatta-international-airport
[Byline: Paulo Trevisani]
--
Kenya ex South Sudan: passenger dies, Ebola negative
----------------------------------------------------------------
Mon 13 Oct 2014: (Hara Ethiopia) Anxiety has gripped Kenya after a
female passenger from South Sudan died on Saturday night [11 Oct
2014]
from Ebola-like symptoms after arriving in the country. Health
officials at Kenya's Jomo Kenyatta International Airport (JKIA)
told
Xinhua on Sun [12 Oct 2014] that the female passenger on board the
Kenya Airways flight alighted at 6:45 p.m. with high fever and
bleeding from the openings of her body. "We have not established
what
exactly caused the death, but medical officials including the
director
of medical services are carrying out tests to establish the cause,"
an
official who sought anonymity told Xinhua by telephone.
The official said the female passenger who had arrived from Juba
was
later rushed to the hospital but died in the evening... The
incident
caused panic at the busy airport, which was immediately deserted
for
hours after the death of the passenger... Kenya is vulnerable
because
it is a major transport hub, with many flights from West Africa, a
WHO
official said...
[7]><http://www.standardmedia.co.ke/health/article/2000137966/suspected-ebola-case-at-jkia-tests-negative
[The passenger tested negative for Ebola virus disease:
[8]>.------------------------------------------------------------------------------------------------------------
The Ethiopian and Kenyan governments said that they would not ban
flights from the 4 countries hit by Ebola. Ethiopia's and Kenya's
national carriers are major airlines connecting countries across
Africa and have on their part been pursuing the usual flights into
West Africa. Bole international airport [Addis Ababa] and Jomo
Kenyatta International Airport (JKIA) [Nairobi] so far haven't any
infrared thermometers or non-contact thermometers to measure body
temperature of in-bound and out-bound passengers for possible Ebola
symptoms. - Mod.JW]
--
Nigeria: 850 solders returning from peacekeeping in Liberia [in
March
2015] to be quarantined.
Mon 13 Oct 2014: (BellaNaija) Ever since the World Health<http://www.bellanaija.com/2014/10/13/ebola-850-nigerian-soldiers-returning-from-liberia-to-be-quarantined/
Organization
(WHO) declared Nigeria Ebola-free, the government has been doing
everything within its power to ensure that status is maintained. As
a
result, precautionary measures are being taken as 850 Nigerian
soldiers who are on a peace-keeping mission in Liberia, where the
Ebola epidemic is rampant, return to Nigeria in March 2015.
Arrangements are already being made to quarantine the soldiers in
Gwagwalada, Abuja for 28 days before they rejoin their respective
platoons, The Stream reports.
[9]>----------------------------------------------------------------------------------
--
Sierra Leone: peacekeepers bound for Somalia quarantined over Ebola
Tue 14 Oct 2014 (Reuters) A battalion of 800 Sierra Leone soldiers<http://www.reuters.com/article/2014/10/14/us-health-ebola-idUSKCN0I311420141014
awaiting deployment as peacekeepers in Somalia has been placed in
quarantine after one of its members tested positive for the deadly
ebolavirus, military officials said on Tue [14 Oct 2014]. The
soldiers
were due to relieve the West African nation's contingent already
deployed with Somalia's African Union peacekeeping mission, known
as
AMISOM. However, they will now be subject to a 21-day isolation
period, a senior officer in Sierra Leone's army told Reuters,
asking
not to be named. Colonel Michael Samoura, spokesman of the Republic
of
Sierra Leone Armed Forces, confirmed that a member of the battalion
had tested positive for the disease. He said the soldier was
infected
after leaving the military camp where the force is based without
permission...
[10]><http://abcnews.go.com/US/wireStory/dallas-officials-vow-care-ebola-patients-dog-26166242
[Byline: Umaru Fofana]
--
USA: Texas nurse's dog quarantined
------------------------------------------
Mon 13 Oct 2014: (ABC News) Officials say a one-year-old King
Charles
Spaniel has been taken from the Dallas apartment of an
Ebola-infected
nurse and will be cared for at an undisclosed location. [The
nurse's]
apartment is being thoroughly cleaned after tests over the weekend
confirmed she is infected. Dallas County Judge Clay Jenkins said
Monday evening [13 Oct 2014] that the dog would be cared for in an
"undisclosed location in a humane, caring way." City spokeswoman
Sana
Syed says the dog named Bentley will be comfortable and have toys
to
play with while he is monitored away from people.
[11]>
--
Communicated by:
ProMED-mail
<promed@xxxxxxxxxxxxxx>
[A HealthMap/ProMED-mail map can be accessed at:
<http://healthmap.org/promed/p/106 [12]>.]
[See Also:
Ebola virus disease - ex Africa (13): Ethiopia susp., USA (TX)
prevention 20141013.2859164
Ebola virus disease - ex Africa (12): USA new case, Spain, more
quarantined 20141012.2856660
Ebola virus disease - ex Africa (11): Europe, threat to N. America,
recurrence 20141011.2854247
Ebola virus disease - ex Africa (10): WHO, UN, Liberia, medevac, S.
Leone, USA 20141010.2851248
Ebola virus disease - ex Africa (09): WHO, Spain, Australia,
Canada,
USA 20141009.2848352
Ebola virus disease - ex Africa (08): US death, concern re. spread,
travel ban 20141008.2843902
Ebola virus disease - ex Africa (07): Europe cases, USA quarantine
stations 20141007.2840925
Ebola virus disease - ex Africa (06): Spain case, USA case, US case
medevaced 20141006.2837374
Ebola virus disease - ex Africa (05): USA ex Liberia, prevention
20141005.2834301
Ebola virus disease - ex Africa (04): USA ex Liberia, prevention
20141004.2832236
Ebola virus disease - ex Africa (03): USA ex Liberia, Germany case
ex
S. Leone 20141003.2830392
Ebola virus disease - ex Africa (02): USA ex Liberia, prevention,
false alarms 20141002.2827166
Ebola virus disease - ex Africa: USA ex Liberia, WHO
20141001.2823539
Ebola virus disease - West Africa (184): USA (TX) first case ex
Liberia 20140930.2819341]
.................................................sb/jw/msp/ml
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--
Dr. Ira B. Schwartz
Head, Nonlinear Dynamical Systems Section
Code 6792
Naval Research Laboratory
Washington, DC 20375
ira.schwartz@xxxxxxxxxxxx
ira.schwartz@xxxxxxxxx
Links:
------
[1] http://www.promedmail.org
[2] http://www.isid.org
[3]
http://www.nbcnews.com/storyline/ebola-virus-outbreak/ebola-kills-united-nations-medic-hospital-leipzig-germany-n225151
[4]
http://www.star-telegram.com/2014/10/14/6199347/facebook-founder-donates-25-million.html?rh=1
[5]
http://www.nbcnews.com/storyline/ebola-virus-outbreak/no-ebola-checks-brussels-airport-after-flights-liberia-n223581
[6]
http://online.wsj.com/articles/in-brazil-man-suspected-of-carrying-ebola-tested-negative-again-1413231294
[7]
http://haraethiopiadotcom.wordpress.com/2014/10/13/ebola-outbreak-spreads-in-ethiopia-kenya-and-south-sudan-as-passenger-dies-at-kenyas-jomo-kenyatta-international-airport
[8]
http://www.standardmedia.co.ke/health/article/2000137966/suspected-ebola-case-at-jkia-tests-negative
[9]
http://www.bellanaija.com/2014/10/13/ebola-850-nigerian-soldiers-returning-from-liberia-to-be-quarantined/
[10]
http://www.reuters.com/article/2014/10/14/us-health-ebola-idUSKCN0I311420141014
[11]
http://abcnews.go.com/US/wireStory/dallas-officials-vow-care-ebola-patients-dog-26166242
[12] http://healthmap.org/promed/p/106
[13] http://www.isid.org/donate/
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