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Notes from The Field: Ebola Virus Disease Cluster - Northern Sierra Leone, January 2016 (vol 65, pg 681, 2016)

Authors:
  • Ministry of Technical and Higher Education/Ministry of Health and Sanitation
Morbidity and Mortality Weekly Report
MMWR / July 8, 2016 / Vol. 65 / No. 26 681
US Department of Health and Human Services/Centers for Disease Control and Prevention
Ebola Virus Disease Cluster — Northern Sierra
Leone, January 2016
Charles Alpren, MBChB1; Michelle Sloan, MA2; Karen A. Boegler,
MSPH3, Daniel W. Martin, MSPH2; Elizabeth Ervin, MPH4; Faith
Washburn, MPH2; Regan Rickert, MPH2; Tushar Singh, MD, PhD5;
John T. Redd, MD2; Interagency Investigation Team
On January 14, 2016, the Sierra Leone Ministry of Health
and Sanitation was notified that a buccal swab collected on
January 12 from a deceased female aged 22 years (patient A) in
Tonkolili District had tested positive for Ebola virus by reverse
transcription–polymerase chain reaction (RT-PCR). The most
recent case of Ebola virus disease (Ebola) in Sierra Leone had
been reported 4 months earlier on September 13, 2015 (1),
and the World Health Organization had declared the end of
Ebola virus transmission in Sierra Leone on November 7, 2015
(2). The Government of Sierra Leone launched a response to
prevent further transmission of Ebola virus by identifying con-
tacts of the decedent and monitoring them for Ebola signs and
symptoms, ensuring timely treatment for anyone with Ebola,
and conducting an epidemiologic investigation to identify the
source of infection.
Patient A lived in Port Loko District and traveled to Kambia
District on December 28, 2015, where she stayed with fam-
ily and became ill on January 3, 2016 (Figure). Her initial
complaints were severe weakness, constipation, and an episode
of self-induced vomiting. On January 7 she left Kambia by car,
stopping briefly in Bombali District to change to a motorbike
before proceeding to Tonkolili, where she was cared for by rela-
tives and saw a traditional healer. She was seen as an outpatient
at a government hospital on January 9, but was not tested for
Ebola virus. After this visit, she continued to Bombali to see
another traditional healer and spent the night there, returning
to Tonkolili on January 10. On January 11, she sought care
from the traditional healer in Tonkolili a second time. She
died in Tonkolili on January 12. As per national policy for all
deaths at that time, a routine postmortem buccal swab was
collected for Ebola virus RT-PCR by a person trained in swab
collection. Her family and community members performed
a traditional burial during which they washed the decedent’s
body and her clothes, prior to RT-PCR results being available.
Investigations identified 131 contacts across four districts,
with the majority in Tonkolili (46 persons [35%]) and Kambia
(45 [34%]). Where possible, contacts were monitored for
21 days after their last possible exposure to patient A; however,
12 contacts potentially at high risk and 36 persons of interest
from Kambia were not located. Because some contacts were
not located, Kambia implemented enhanced community
surveillance for 2 months after the end of contact monitoring.
Notes from The Field
FIGURE. Timeline of events for patients A and B in the Tonkolili cluster of Ebola virus disease (Ebola) — Sierra Leone, December 2015–
February 2016
27 28 29 30 31 12345678910 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 12345
December
2015
January
2016
February
2016
Patient A
visited
traditional
healer in
Tonkolili
Patient A
traveled
from Port
Loko to
Kambia
Onset of
illness in
patient A
in Kambia
Patient A traveled
from Kambia to
Bombali by car,
then from Bomb ali
to Tonkolili by
motorbike; visited a
traditional healer
in Tonkolili
Patient A
examined as
hospital
outpatient
then
traveled
from
Tonkolili to
Bombali
Patient A
traveled
from
Bombali
back to
Tonkolili
Patient A died in
Tonkolili; buccal
swab collec ted
and traditional
burial performed
Patient B
onset of
illness in
Tonkolili
Patient B
discharged
from Ebola
Treatment
Unit
30 31
Please note: Errata have been published for this issue. To view the errata, please click here and here.
Morbidity and Mortality Weekly Report
682 MMWR / July 8, 2016 / Vol. 65 / No. 26 US Department of Health and Human Services/Centers for Disease Control and Prevention
Interviews with contacts of patient A failed to identify a
source of infection. The viral genome obtained from her buc-
cal swab (1601_C12_KT014149b, GenBank KX121193)
indicated a high similarity (one and two nucleotide differ-
ences) to two viral genomes from Western Area, Sierra Leone,
from November 2014 (KP759709, KP759704). The minimal
genetic change in the viral genome during the interval from
November 2014 until patient A’s illness onset suggests viral
persistence in a survivor as the source of infection (3), although
no survivors were identified who could conclusively be linked
to patient A.
On the night of January 19, a high-risk female contact of
patient A who was in quarantine (patient B) complained of
weakness, chest pain, nausea, and a single episode of self-
induced vomiting. Patient B was isolated on the morning
of January 20, and her blood tested positive for Ebola virus
by RT-PCR that day. Patient B’s viral genome (2001_C11_
KTO14515b, GenBank KX121194) was identical to that of
patient A. Patient B was transferred to an Ebola Treatment
Unit in Freetown, Sierra Leone, where she was successfully
treated; she was discharged on February 5.
After the declaration of the end of Ebola virus transmission
in Sierra Leone, the nations policy of performing buccal swabs
for Ebola virus RNA on all decedents continued. Without this
policy, patient As infection would not have been detected.
The success of this response, the first led by the Sierra Leone
Ministry of Health and Sanitation after transition from the
National and District Ebola Response Centers on January 1,
2016, can be measured by the case’s detection from a routine
swab, genetic sequencing performed by locally trained scien-
tists, and the limitation of transmission of Ebola virus from
the index case to a single, identified high-risk contact.
1CDC-Sierra Leone Country Office; 2Division of Global Health Protection,
Center for Global Health, CDC; 3 Division of Vector-Borne Diseases, National
Center for Emerging and Zoonotic Infectious Diseases, CDC; 4Viral Special
Pathogens Branch, Division of High-Consequence Pathogens and Pathology,
National Center for Emerging and Zoonotic Infectious Diseases, CDC;
5Epidemic Intelligence Service, CDC.
Corresponding author: Daniel W. Martin, DMartin4@cdc.gov, 404-639-0476.
Interagency Investigation Team
Andrew Bangalie, eHealth Africa; Micah Bass, MPH, CDC;
Sarah D. Bennett, MD, CDC; Isaac Akuamoah Boateng, MD,
World Health Organization; Deanna Campbell, MPH, CDC;
Cynthia Cassell, PhD, CDC; Matt Cotton, PhD, Wellcome Trust
Sanger Institute, United Kingdom; Nadezhda Duffy, MD, CDC;
Ian Goodfellow, PhD, University of Cambridge, United Kingdom;
Sara Hersey, MPH, CDC; Eddie L. Jackson, CDC; Umaru Jah,
School of Public Health, University of Makeni, Sierra Leone;
Augustine S. Jimissa, MBChB, Ministry of Health & Sanitation,
Sierra Leone; Ansumana S. Kamara, MSc, CDC; Fatmata Kamara,
MSc, CDC; Paul Kellam, PhD, Wellcome Trust Sanger Institute,
United Kingdom; Rebecca Levine, PhD, CDC; Luke Meredith, PhD,
University of Cambridge, United Kingdom; Leigh Ann Miller, PhD,
CDC; Stephanie Moody-Geissler, MPH, CDC; Robert Musoke,
MSc, World Health Organization; Dhamari Naidoo, MSc, World
Health Organization; John Ndyahikayo, MBChB, World Health
Organization; Gibril Njie, MPH, CDC; My Phan, DPhil, Wellcome
Trust Sanger Institute, United Kingdom; Andrew Rambaut, DPhil,
University of Edinburgh, United Kingdom; Foday Sesay, MBChB,
Ministry of Health and Sanitation, Sierra Leone (all these individuals
meet authorship criteria).
Reference
1. World Health Organization. Ebola situation report. Geneva, Switzerland:
World Health Organization; 2015. http://apps.who.int/iris/
bitstream/10665/184623/1/ebolasitrep_16Sept2015_eng.pdf?ua=1
2. World Health Organization. Sierra Leone stops transmission of Ebola virus.
Geneva, Switzerland: World Health Organization; 2015. http://www.who.
int/mediacentre/news/releases/2015/sierra-leone-stops-ebola/en/
3. Blackley DJ, Wiley MR, Ladner JT, et al. Reduced evolutionary rate in
reemerged Ebola virus transmission chains. Sci Adv 2016;2:e1600378.
http://dx.doi.org/10.1126/sciadv.1600378
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