Ebola virus disease/ Ebola outbreak

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Ebola Virus Disease (EVD) Dr. Rizwan S A, M.D., Department of Community Medicine, VMCH&RI, Madurai, “Got no time for wild polemics, hung up on epidemics” – Anonymous

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A comprehensive yet crisp primer on Ebola virus and its public health relevance.

Transcript of Ebola virus disease/ Ebola outbreak

  • 1. Ebola Virus Disease (EVD)Dr. Rizwan S A, M.D.,Department of Community Medicine,VMCH&RI, Madurai,Got no time for wild polemics, hung up on epidemics Anonymous

2. Outline Why learn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threatRizwan SA, VMCHRI 2/35 3. Outline Why learn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threatRizwan SA, VMCHRI 4. Why learn about EVD? Limited scientific understanding Highly fatal disease Causes large outbreaks Difficult to contain No proven treatment or vaccine A pandemic threatRizwan SA, VMCHRI 4/35 5. Outline Why learn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threatRizwan SA, VMCHRI 6. A story 1/3Rizwan SA, VMCHRI 6/35 7. A story 2/3Rizwan SA, VMCHRI 7/35 8. A story 3/3Rizwan SA, VMCHRI 8/35 9. Outline Why learn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threatRizwan SA, VMCHRI 10. Epidemiological aspects Natural host - Fruit bats ofPteropodidae family Reservoir fruit bats Sources bush meat, NHP,Infected humans, fomites Incubation period 2 to 21 days Communicability high, virusisolated after 90 days of recovery Case fatality 50 to 90% Immunity long term notproven, deceased patients failedto produce immune response No. of outbreaks >30Rizwan SA, VMCHRI 10/35 11. Geographic distribution 1/2 First outbreak occurred inZaire (Congo) in 1976 Followed by severaloutbreaks, all in Africa(except one in Philippines,Italy, USA) Latest on-going outbreak inwest Africa started inMarch 2014 in GuineaRizwan SA, VMCHRI 11/35 12. Geographic distribution 2/2 13. Modes of transmission Direct contact (through broken skin or mucousmembranes) with a sick person's blood or body fluids (urine, saliva, faeces,vomit, semen) objects (such as needles) that have been contaminated withinfected body fluids infected animals High risk groups bush meat hunters, forest dwellers,health workers, relatives of patients, funeral attendees,corpse handlers, lab personnelRizwan SA, VMCHRI 13/35 14. Transmission cycleRizwan SA, VMCHRI 15/35 15. Outline Why learn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threatRizwan SA, VMCHRI 16. Virologicalaspects Family Filoviridae in the orderMononegavirales Five species Zaire, Sudan, Ta, Reston,Bundibugyo Enveloped, non-segmented,negative-strand RNA virus,filamentous Genes arranged linearlycoding for seven structuralproteins - NP, VP35, VP40, GP,VP30, VP24 and L with NP GP, transmembrane proteinand responsible for receptorbinding and membranefusionRizwan SA, VMCHRI 17. Clinical features Range from minor viral illnessto fatal haemorrhagic fever Ebola haemorrhagic fever(Ebola HF) is type of ViralHaemorrhagic Fevers Most common constellationof symptoms is togethercalled Ebola Virus Disease EVD duration 2 to 20 days,fever, nausea, vomiting, non-bloodydiarrhoea, abdominalpain, conjunctivitis,weakness, severe headacheand myalgia E. Hemorrhagic fever -hematemesis, epistaxis,increased postpartumbleeding, bleeding gums etc.,Rizwan SA, VMCHRI 18. Outline Why learn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threatRizwan SA, VMCHRI 19. Diagnosis CDC case definitions Person Under Investigation Probable case Confirmed case Non-case Exposure risk levels In early phase - Antigen-captureELISA, IgM ELISA,PCR, Virus isolation In later phase - IgM and IgGantibodies In deceased patients immunohistochemistry, PCR,virus isolation Strict precautions duringtransportation of samplesand all testing in BSL-4 lab Differentials Lassa fever,malaria, shigellosis, cholera,leptospirosis, plague,rickettsiosis, relapsing fever,other viral haemorrhagicfevers20/35 Rizwan SA, VMCHRI 20. Treatment Experimental treatments ZMapp a combo of 3 monoclonalantibodies TKM-Ebola targets RNA of thevirus MB-2003 - prevents infection inmice and non-human primateswhen administered as post-exposureprophylaxis within one totwo days BCX-4430 RNA polymerase inh Favipiravir, AVI 7288 Whole blood and convalescentserum transfusion from recoveredpatients No proven antiviral drug Symptomatic treatment only Providing intravenous fluidsand balancing electrolytes(body salts) Maintaining oxygen statusand blood pressure Treating other infections ifthey occur Barrier-nursing techniques Personal ProtectiveEquipment Infection control measures Isolation of Ebola patientsfrom contactRizwan SA, VMCHRI 21. Outline Why learn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threatRizwan SA, VMCHRI 22. Control measures 1/5 Public health measures - earlydetection and isolation, contacttracing and rigorous infectioncontrol measures Screening of travellers fromaffected countries in airports,seaports and land borders Quarantine and observation ofsuspected cases for 21 days fromexposure Awareness generation amongpeople, removing misconceptionsRizwan SA, VMCHRI 24/35 23. Control measures 2/5 All suspected or confirmed cases, singleclosed patient room Avoiding contact A log book containing details of personsentering Personal protective equipment forcaretakers Dedicated medical equipment Minimum use of sharps Disinfection of samples - heating to 60Cfor one hour, in 3% acetic acid Only BSL 4 lab should handle samples Hospital monitoring policy for staffIn this 2014 photo provided by the Samaritan's Purse aid organization, Dr. Kent Brantly, left, treats an Ebola patient at the Samaritan's Purse Ebola Case ManagementCenter in Monrovia, Liberia. On Saturday, July 26, 2014, the North Carolina-based aid organization said Brantly tested positive for the disease and was being treated at ahospital in Monrovia.View of an isolation center for people infected with Ebola at Donka Hospital in Conakry. Rizwan SA, VMCHRI 25/35 24. Control measures 3/5 Vaccines Virus like particles: ZEBOV (VP40, CG and NP) Non-replicating vectors: alpha virus, DNA vaccines, recombinant adenovirus basedvectors (rAD) Replication competent vectors: Recombinant Paramyxovirus-based vectors,Recombinant vesicular stomatitis virus-based vectors (rVSV), Recombinant rabiesvirus based (rRABV) The first vaccine platform that successfully protected NHPs from Ebola virus infectionwas a recombinant adenovirus serotype 5(rAd5) vector Latest - chimpanzee-derived replication-defective adenovirus (ChAd) vaccineRizwan SA, VMCHRI 26/35 25. Control measures 4/5 Social aspects Cultural practices burial rituals Illiteracy and lack of awareness Fear of modern medicine, equipment False rumours and misinformation Ethical issues of giving experimental treatmentRizwan SA, VMCHRI 27/35 26. Control measures 5/5 International cooperation CDC, WHO, European Mobile Laboratory (EMLab) Project, AfricanUnion Voluntary agencies - MSF, Samaritans Purse Staff, Outbreak response teams, lab experts, doctors, equipment,gloves, medicines, disinfectants Research for medicines and vaccinesRizwan SA, VMCHRI 28/35 27. Outline Why learn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threatRizwan SA, VMCHRI 28. Challenges to control Lack of effective treatment and vaccine Weak public health infrastructure, manpower, weak labs Poverty and Illiteracy Lack of political stability Delayed international response Failure to anticipate and incorporate social aspects Funding problemsRizwan SA, VMCHRI 30/35 29. Outline Why learn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threatRizwan SA, VMCHRI 30. Pandemic threat None of the past outbreaks have developed into a pandemicBut, 2014 outbreak As of August 31, 2014, 3707 cases and >1800people dead across 5 countries WHOs declared Public Health Emergency of International Concernin August 2014 Attack rate - 12.6 cases per 10,000 inhabitants, Ro is 2.7 No population level immunity BioterrorismRizwan SA, VMCHRI 32/35 31. Take home messages Ebola is an new and emerging infection Ability to cause large outbreaks with high casualty In the absence of proven treatments, prevention is themain weapon Social aspects are very important in control Simple and established PH measures are sufficient A potential pandemicRizwan SA, VMCHRI 33/35 32. Home work Group 1 - Learn the principles of outbreak investigation watch the movie Contagion and write a one pagesummary Group 2 - A one page summary on conditions needed todeclare a pandemic Group 3 - A one page summary of how India is planningto respond to this threat, the agencies involved and yourideas for preparedness in our hospitalRizwan SA, VMCHRI 34/35 33. Reference materials CDC website http://www.cdc.gov/vhf/ebola/about.html WHO website http://www.who.int/csr/disease/ebola/en/ The Lancet Ebola Resource Centrehttp://ebola.thelancet.com/ Journals - Bulletin of the WHO, NEJM and BMJ, August andSeptember 2014 issues Image courtesy bbc.co.uk, google images, CDC and WHORizwan SA, VMCHRI 34. Thank You