The Epidemiology of Three Back-to-Back Filovirus Outbreaks in

Central & Western Uganda, 2012

Joseph F. Wamala, MD, MPHSenior Epidemiologist,

Uganda Ministry of Health

The Fifth AFENET Conference, UN Convention Centre – Addis Ababa, Ethiopia

17 – 21 November 2013

Presentation outline

• Background

• Objectives and rationale

• Investigation methods

• Description of the 2012 FHF outbreaks in Uganda

• Conclusions & recommendations

• Acknowledgements

Background• International public health security is essential for the

globalised world (WHO, 2008)

• Global threat of emerging & re-emerging infectious diseases like Filovirus hemorrhagic fevers [FHF] of Ebola and Marburg is escalating (Jones et al., 2008)

• Uganda located in the Congo basin - a major hotspot for emerging & reemerging disease like FHF (Jones et al., 2008)

World Health Organization. (2008). International Health Regulations (2005) (2nd ed). Switzerland, Geneva: WHO Press.

Jones, K. E., et al (2008). Global trends in emerging infectious diseases. Nature, 451(7181), 990-993. doi:http://dx.doi.org/10.1038/nature06536

Background...• Uganda has experienced escalating Filovirus

outbreaks in recent years • 8 FHF outbreaks in the last 12 years– Ebola: 2000, 2007, 2011, 2012a, 2012b– Marburg: 2007, 2008, 2012

• FHF outbreaks increasing in frequency– 3 FHF outbreaks in five districts in 2012 alone

Mbonye, A., et al (2013). Repeated outbreaks of Viral hemorrhagic fevers in Uganda. African Health Sciences, 12(4): 579-583. http://dx.doi.org/10.4314/ahs.v12i4.31

Filovirus hemorrhagic fevers [FHF]• Family: Filoviridae• Reservoir: – Ebola virus: forest-dwelling fruit eating bats– Marburg virus: cave-dwelling fruit eating bats

• Transmission: person-to-person spread• Incubation period: 3-21 days• Clinically: initially non-specific; ~45% bleeding , high

CFR [53-90%]• Treatment: supportive• Control: infection control, follow contacts

Ebola hemorrhagic fever in Sudan, 1976. Report of a WHO/International Study Team. Bull World Health Organ. 1978;56:247–70.

Ebola hemorrhagic fever in Zaire, 1976. Bull World Health Organ. 1978;56:271–93

FHF 2012 - Investigation objective

• Describe the epidemiology of the 2012 Filovirus outbreaks in Uganda to inform interventions for disease prevention and control within the context of the Integrated Disease Surveillance strategy and the International Health Regulations of 2005 [IHR (2005)]

Methods

• Rapid response teams deployed to investigate and initiate response interventions

• Standard & working case definitions were used to identify FHF cases

• Standardised FHF case investigation forms used to obtain epidemiological information

• Blood & skin snips obtained for testing at the Uganda Virus Research Institute [UVRI] using standardised WHO/CDC FHF laboratory protocols

7

Methods....

• Suspect FHF cases were actively sought among contacts

• All new suspect FHF cases were promptly isolated and started on supportive therapy

• All FHF case & contact data were entered into a centrally managed database

• Regular epidemiological analyses were disseminated to guide national response

8

Enhancing Local Response Capacities

• Trainings were conducted to

– Enhance local coordination & response

– Enhance infection control in health facilities & at community level

– Enhance local capacities for case management & barrier nursing

EBOLA - KIBAALE & LUWERO

FHF outbreaks in Uganda, 2012

Index Case Investigations, Ebola Kibaale, 2012

June 12, 2012

Onset of illness

16 yr; Female; Kikaara village, Buchuhya Parish, Bubango sub-county

Treatment at Local HC

June 13-17 & 18-19th , 2012

Subsequently admitted to hospital – not isolated

Death of Index Case in hospital

June 19, 2012

Unsupervised Burial of Index case

June 21, 2012

Discharged & stays with in-laws

Index Case Investigations - Ebola Central Uganda, 2012

Oct. 13, 2012

Onset of illness

30 yr; Male; Kakute village, Ssambwe Parish, Nyimbwa s-county

Treatment at local HC

Oct. 20-23, 2012

Subsequent care at Bombo GMH

Death of Index Case at Bombo GMH

Oct. 23, 2012

Un supervised burial of Index case

Oct. 24, 2012Oct. 14-19, 2012

All Ebola cases- Uganda, 2012

Cases DeathsCase Status Central Western Central Western

Confirmed 6 11 3 (50%)

4 (36.4%)

Probable 1 13 1 (100%)

13 (100%)

Total 7 24 4 (57.1%)

17 (70.8%)

• Overall, there were 24 cases in Western Ug. & 7 cases in Central Ug. with • CFR of 57% in Central Ug. & 71% in Western Ug.

Ebola Epidemic Curve –Western Uganda, 2012

07/06/2012

10/06/2012

13/06/2012

16/06/2012

19/06/2012

22/06/2012

25/06/2012

28/06/2012

01/07/2012

04/07/2012

07/07/2012

10/07/2012

13/07/2012

16/07/2012

19/07/2012

22/07/2012

25/07/2012

28/07/2012

31/07/2012

03/08/2012

06/08/20120

1

2

3

4

5

6

12

5

1 1 1 1 11 1 1 1 12

1 1 1

(blank)

Probable

Confirmed

Date of Onset

Case

s [N

o.]

Index case ill-ness starts

Index case stays with in-laws

National Rapid Response Team Deployed

Cluster of cases among in-laws to index case

DHO reports strange illness to MoH

Ebola Epidemic Curve –Central Uganda, 2012

23 24 25 26 27 28 29 30 31 320

1

2

3

4

5

6

7

8

9

10

1

8

2

2

1 12

1

4

1

(blank)

Probable

Confirmed

Date of Onset by epidemiological week

Case

s [N

o.]

Ebola case distribution by sex, 2012

80% of probable/ confirmed cases in Kibaale (Western Ug.) were femalesCase distr. by sex was nearly even in Luwero (Central Ug)

Kibaale Luwero -

20

40

60

80

100

120

21 57

79 43

FemaleMale

District

Case

s [%

]

Ebola case distribution by Age, 2012

Majority [46-86%] of the cases were 20-39 years of age

0-9yrs 10-19yrs 20-29yrs 30-39yrs 40-49yrs 50+yrs -

10

20

30

40

50

60

17 17 21 25

13 8 - 14

57

29

- -

KibaaleLuwero

Age in Years

Case

s [%

]

Ebola Symptoms – Western Uganda, 2012

Symptom Present

Fever 23 (95.8%)

Vomiting 21 (87.5%)

Diarrhea 19 (79.2%)

Abdominal Pain 13 (54.2%)

Any Bleeding 13 (54.2%)

• Ebola case symptoms were largely non-specific• Unexplained bleeding reported in 54% cases & was

often late & not overt

Map Ebola cases in Western Uganda, 2012

Epicentre with majority being contacts (also in laws) to the index case

Index case

Caves with bats

MARBUG IN WESTERN UGANDA

FHF outbreaks in Uganda, 2012

Marburg Index Case Investigations – Uganda, 2012

July 20, 2012

Onset of illness

Kafunzo III village Ibanda: Cluster –[3 confirmed; 6probable/deaths]

Treatment at Ibanda hospital /TBA

Sept 3, 2012

Onset Index case for Kabale

Death of Kabale index Case at Kabale RRH

Sep 20, 2012

Burial of Kabale Index case

Sep. 22, 2012Late July-Early Aug. 2012

All Marburg cases – Western Uganda, 2012

Cases DeathsCase Status/district Kabale Ibanda Kabale Ibanda

Confirmed 9 6 2(22%)

2(33.3%)

Probable 5 8 5 (100%)

6(75%)

Total 14 14 7(50%)

8(57%)

Overall, there were 14 cases each in each of the two districts in Western Uganda with CFR of 50-57%

Marburg Epidemic Curve- Uganda, 2012

16/07/2012

21/07/2012

26/07/2012

31/07/2012

05/08/2012

10/08/2012

15/08/2012

20/08/2012

25/08/2012

30/08/2012

04/09/2012

09/09/2012

14/09/2012

19/09/2012

24/09/2012

29/09/2012

04/10/2012

09/10/2012

14/10/2012

19/10/2012

24/10/2012

29/10/20120

1

2

3

4

Confirmed Probable (blank)

Date of Onset

Case

s [N

o.]

Onset of in-dex case in Ibanda

Onset of ill-ness for initial Kabale case

DHO Kabale reports strange illness to MoH

Rapid response team dispatched

Marburg Epidemic Curve- Uganda, 2012

29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 440

1

2

3

4

Confirmed Probable (blank)

Date of Onset

Case

s [N

o.] Onset of in-

dex case in Ibanda

Onset of ill-ness for initial Kabale case

DHO Kabale reports strange illness to MoH

Rapid response team dispatched

Marburg cases by sex - Uganda, 2012

The majority [60-69%] of the cases were females

Female Male0

20

40

60

80

100

120

140

6040

69.2

30.8

Probable Confriemed

Case

s[%

]

Marburg cases by age – Uganda, 2012

Majority [50%] of the cases were 20-39 years of age

0-9yrs 10-19yrs 20-29yrs 30-39yrs 40-49yrs 50-59yrs 60+yrs -

5

10

15

20

25

30

35

21

7

32

18

7 7 7

Case

s[%

]

Marburg case symptoms – Uganda, 2012

Symptom FrequencyFever 25 (89.3%)Loss of Appetite 21 (75.0%)Vomiting 20 (71.4%)Headache 19 (67.9%)Fatigue 19 (67.9%)Abdominal Pain 15 (53.6%)Diarrhea 11 (39.3%)Any Bleeding 11 (39.3%)Muscle/Joint Pain 10 (35.7%)• Symptoms largely non-specific • Bleeding reported in 39%

Map Marburg cases - Uganda, 2012

Tanzania

DRCONGO

Tanzania

DR

CONGO Lake Victoria

Kampala

Kitaka Mines

Marburg Risk Factors – Uganda, 2012

• Exposures assessed– Travel to affected areas, contact with case,

participating in funeral, nursing a case, visiting spiritual/native healers, contact with wild animal

• Significant risk factors included – Contact with a case AOR 5.3 (1.9-14.8); p<0.001– Participating in funeral AOR 33.4 (4.3-256.7);

p<0.0001

Conclusions

• Uganda experienced three (3) FHF outbreaks in 2012

– Ebola: Kibaale & Luwero

– Marburg: Ibanda, Kabale, Kamwenge

– Cases were more likely to have been exposed to another

case or to have participated in a funeral

• Uganda remains prone to the two FHF outbreaks

– Source of the Ebola outbreaks not identified

– Marburg outbreak linked to mining activity in Kitaka

Recommendations

• Surveillance for FHF should be enhanced

– Strengthen Clinical & lab diagnostic capacities &

specimen referral at all levels

– Surveillance for clusters of strange illnesses/deaths at

community level

• Research into FHF ecology & risk factors for introduction

of FHFs into human populations

• Regulation of mining activities in Western Uganda

Acknowledgements

• Ministry of Health • The District Local Governments• World Health Organization • Centres for Disease Control and prevention • African Field Epidemiology Network• Medecins Sans Frontiers• USAID• Uganda Red Cross Society• All other partners

Thank You