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The Epidemiology of Three Back-to-Back Filovirus Outbreaks in Central & Western Uganda, 2012. Joseph F. Wamala, MD, MPH Senior Epidemiologist, Uganda Ministry of Health The Fifth AFENET Conference, UN Convention Centre – Addis Ababa, Ethiopia 17 – 21 November 2013. Presentation outline.
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The Epidemiology of Three Back-to-Back Filovirus Outbreaks in Central & Western Uganda, 2012 Joseph F. Wamala, MD, MPH Senior 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 (Mbonye et al., 2013) • 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 StudyTeam. 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
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
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
FHF outbreaks in Uganda, 2012 Ebola - Central& western Uganda
Index Case Investigations, Ebola Kibaale, Western Uganda - 2012 16 yr; Female; Kikaara village, Buchuhya Parish, Bubango sub-county Subsequently admitted to hospital – not isolated Unsupervised Burial of Index case Death of Index Case in hospital Treatment at Local HC Discharged & stays with in-laws June 13-17 & 18-19th , 2012 June 12, 2012 June 19, 2012 June 21, 2012 Onset of illness
Index Case Investigations - Ebola Central Uganda, 2012 Subsequent care at Bombo GMH 30 yr; Male; Kakute village, Ssambwe Parish, Nyimbwa s-county Un supervised burial of Index case Death of Index Case at Bombo GMH Treatment at local HC Oct. 20-23, 2012 Oct. 13, 2012 Oct. 14-19, 2012 Oct. 23, 2012 Oct. 24, 2012 Onset of illness
All Ebola cases- Uganda, 2012 • 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 Cluster of cases among in-laws to index case DHO reports strange illness to MoH
Ebola case distribution by sex, 2012 • 80% of probable/ confirmed casesin Kibaale (Western Ug.) were females • Case distr. by sex was nearly even in Luwero (Central Ug)
Ebola case distribution by Age, 2012 • Majority [46-86%] of the cases were 20-39 years of age
Ebola Symptoms – Western Uganda, 2012 • 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 Caves with bats Index case
FHF outbreaks in Uganda, 2012 MARBUG in western Uganda
Marburg Index Case Investigations – Uganda, 2012 Kafunzo III village Ibanda: Cluster –[3 confirmed; 6probable/deaths] Burial of Kabale Index case Onset Index case for Kabale Death of Kabale index Case at Kabale RRH Treatment at Ibanda hospital /TBA Sept 3, 2012 July 20, 2012 Sep 20, 2012 Sep. 22, 2012 Late July-Early Aug. 2012 Onset of illness
All Marburg cases – Western Uganda, 2012 Overall, there were 14 cases each in each of the two districts in Western Uganda with CFR of 50-57%
Marburg cases by sex - Uganda, 2012 • The majority [60-69%] of the cases were females
Marburg cases by age – Uganda, 2012 • Majority [50%] of the cases were 20-39 years of age
Marburg case symptoms – Uganda, 2012 • Symptoms largely non-specific • Bleeding reported in 39%
Map Marburg cases - Uganda, 2012 DR CONGO Kampala DRCONGO Tanzania Kitaka Mines Lake Victoria Tanzania
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 AOR5.3 (1.9-14.8); p<0.001 • Participating in funeral AOR33.4 (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