Morbidity and Mortality Weekly Report
Notes from the Field
Crimean-Congo Hemorrhagic Fever Outbreak —
Central Uganda, August–September 2017
Susan Kizito, MSc1; Paul E. Okello, MSc1; Benon Kwesiga, MPH1;
Luke Nyakarahuka, PhD2; Stephen Balinandi, MSc2; Sophia
Mulei2; Jackson Kyondo2; Alex Tumusiime2; Julius Lutwama, PhD2;
Alex R. Ario PhD1,3; Joseph Ojwang MD4; Bao-Ping Zhu, MD4,5
On August 20, 2017, physicians in two noncontiguous
districts in central Uganda (Kyankwanzi and Nakaseke)
reported two unrelated cases of Crimean-Congo hemorrhagic
fever (CCHF). CCHF is the most widespread tickborne viral
hemorrhagic fever in the world and represents a global health
security threat (1–3); a single case of CCHF constitutes an
outbreak. Humans are infected through tick bites or contact
with the blood or body fluids of infected persons or animals.
Treatment of infected patients is supportive, and the casefatality rate ranges from 3%–40% (2,3). No licensed vaccine
is available (2). Although CCHF cases were first reported in
Uganda between 1958 and 1977, no subsequent cases were
reported until 2013, when enhanced viral hemorrhagic fever
surveillance capacity began to identify CCHF outbreaks (3–5).
The two cases were confirmed by serology and reverse-transcription–polymerase chain reaction (RT-PCR) testing at the
Uganda Virus Research Institute (UVRI), a specimen referral
system established in 2013 with assistance from CDC/Uganda
in an effort to advance the global health security agenda (5).
Upon confirmation of the two cases, the Uganda Ministry of
Health deployed a team to investigate on August 22, 2017. A
suspected case was defined as sudden onset of fever >100.4°F
(38°C) for ≥3 days during July 1–September 30, 2017, plus
either spontaneous bleeding or bruising, or laboratory evidence
of unexplained leukopenia or thrombocytopenia in a resident
of either of the two affected districts. A confirmed case was
one that tested positive for CCHF by both RT-PCR and
immunoglobulin M serology (4).
To identify cases, medical records of patients seen at area
referral hospitals with fever and bleeding symptoms were
reviewed. An active case search was also conducted in the
affected communities. In addition to the two initial patients
with confirmed cases, both of whom survived, among 23 medical records reviewed, five additional patients met the suspected
case definition, two of whom died. Symptom onset occurred
during July 9–September 17, 2017. Specimens were unavailable for confirmatory CCHF testing from the five patients with
suspected cases. All cases occurred in men aged 19–87 years; no
secondary cases were found.
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A case-control study was conducted to compare potential
exposures of case-patients and controls. Controls (four per
case) were selected from among case-patients’ asymptomatic
neighbors, matched by sex and age. Data on potential exposures, including tick bites or barehanded crushing of ticks,
milking or butchering livestock, butchering wildlife, and
caring for sick persons, were collected using a standardized
questionnaire. Because infected animals might develop high
viral load titers yet remain asymptomatic (6), blood samples
were collected from cattle and goats from two farms where
patients with confirmed cases worked and were tested using
an enzyme-linked immunosorbent serologic assay.
Tick exposure was reported by four of seven suspected
and confirmed case-patients and three of 28 (11%) controls
(Mantel-Haenszel odds ratio = 11.0; Fisher exact 95% confidence interval [CI] = 1.1–112.0). At farms where patients with
confirmed cases worked, 37 (60%) of 62 cattle and 5 (24%)
of 21 goats were found to be seropositive for CCHF. Animals
from these farms were quarantined for 1 month, during which
time farm owners and workers were advised to use adequate
protection when handling them.
A district rapid response team in each of the two affected
districts was activated on August 23, 2017, including establishment of an emergency hotline for case reporting. Area
hospitals designated isolation units for screening and isolating
patients with suspected cases and collecting blood samples for
testing at UVRI. Health care workers were trained in patient
management and infection control; and district veterinary
officers reached out to farmers, especially those whose farms
had seropositive animals, regarding tick control (e.g., dipping
livestock in acaricide concentrates). Community outreach
concerning the signs, symptoms, and complications of CCHF
and preventive measures was conducted via radio during
August 24–September 30, 2017. Area residents were advised
to avoid handling ticks with bare hands and to wear protective gear such as gloves, boots, and clothes to minimize their
exposure risk while grazing livestock. No subsequent cases were
reported after these measures were implemented. The rapid
and coordinated response to this outbreak demonstrated the
significant progress made to enhance global health security
in Uganda.
US Department of Health and Human Services/Centers for Disease Control and Prevention
Morbidity and Mortality Weekly Report
Acknowledgments
References
Ministry of Health of Uganda; CDC; World Health Organization;
Uganda Virus Research Institute; Ministry of Agriculture, Animal
Industry and Fisheries of Uganda; District Local Governments of
Kiboga, Kyankwanzi, and Nakaseke.
1. Dreshaj S, Ahmeti S, Ramadani N, Dreshaj G, Humolli I, Dedushaj I.
Current situation of Crimean-Congo hemorrhagic fever in Southeastern
Europe and neighboring countries: a public health risk for the European
Union? Travel Med Infect Dis 2016;14:81–91. https://doi.org/10.1016/j.
tmaid.2016.03.012
2. Leblebicioglu H, Ozaras R, Erciyas-Yavuz K. Emergence of CrimeanCongo hemorrhagic fever. Trans R Soc Trop Med Hyg 2015;109:676–8.
https://doi.org/10.1093/trstmh/trv083
3. Bente DA, Forrester NL, Watts DM, McAuley AJ, Whitehouse CA,
Bray M. Crimean-Congo hemorrhagic fever: history, epidemiology,
pathogenesis, clinical syndrome and genetic diversity. Antiviral Res
2013;100:159–89. https://doi.org/10.1016/j.antiviral.2013.07.006
4. CDC. Crimean-Congo hemorrhagic fever (CCHF). Diagnosis. Atlanta,
GA: US Department of Health and Human Services, CDC; 2018. https://
www.cdc.gov/vhf/crimean-congo/diagnosis/index.html
5. Borchert JN, Tappero JW, Downing R, et al. Rapidly building global
health security capacity—Uganda demonstration project, 2013. MMWR
Morb Mortal Wkly Rep 2014;63:73–6.
6. Heymann DL. Control of communicable diseases manual. 20th ed.
Washington, DC: APHA Press; 2015.
Conflict of Interest
No conflicts of interest were reported.
1Uganda Public Health Fellowship Program, Kampala, Uganda; 2Uganda Virus
Research Institute, Entebbe, Uganda; 3Ministry of Health Kampala, Uganda;
4CDC, Uganda; 5Division of Global Health Protection, Center for Global
Health, CDC.
Corresponding author: Susan Kizito, kizitosusan@musph.ac.ug,
256-776-222722.
US Department of Health and Human Services/Centers for Disease Control and Prevention
MMWR / June 8, 2018 / Vol. 67 / No. 22
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