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Ebola virus disease/ Ebola outbreak
This document discusses Ebola Virus Disease (EVD) and provides an overview of its history, epidemiology, virology, clinical manifestations, diagnosis, treatment, control measures, challenges, and pandemic threat. It outlines the key topics in a point form and includes sections on the natural history of the virus, modes of transmission, outbreak investigation principles, and India's response planning. The goal is to educate about Ebola as it is a new and emerging infection that can cause major outbreaks without proven treatments or immunity.
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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 Whylearn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threat Rizwan SA, VMCHRI 2/35
- 3. Outline Whylearn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threat Rizwan SA, VMCHRI
- 4. Why learn aboutEVD? Limited scientific understanding Highly fatal disease Causes large outbreaks Difficult to contain No proven treatment or vaccine A pandemic threat Rizwan SA, VMCHRI 4/35
- 5. Outline Whylearn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threat Rizwan SA, VMCHRI
- 6. A story –1/3 Rizwan SA, VMCHRI 6/35
- 7. A story –2/3 Rizwan SA, VMCHRI 7/35
- 8. A story –3/3 Rizwan SA, VMCHRI 8/35
- 9. Outline Whylearn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threat Rizwan SA, VMCHRI
- 10. Epidemiological aspects Natural host - Fruit bats of Pteropodidae family Reservoir – fruit bats Sources – bush meat, NHP, Infected humans, fomites Incubation period – 2 to 21 days Communicability – high, virus isolated after 90 days of recovery Case fatality – 50 to 90% Immunity – long term not proven, deceased patients failed to produce immune response No. of outbreaks – >30 Rizwan SA, VMCHRI 10/35
- 11. Geographic distribution –1/2 First outbreak occurred in Zaire (Congo) in 1976 Followed by several outbreaks, all in Africa (except one in Philippines, Italy, USA) Latest on-going outbreak in west Africa started in March 2014 in Guinea Rizwan SA, VMCHRI 11/35
- 12.
- 13. Modes of transmission Direct contact (through broken skin or mucous membranes) with a sick person's blood or body fluids (urine, saliva, faeces, vomit, semen) objects (such as needles) that have been contaminated with infected body fluids infected animals High risk groups – bush meat hunters, forest dwellers, health workers, relatives of patients, funeral attendees, corpse handlers, lab personnel Rizwan SA, VMCHRI 13/35
- 14. Transmission cycle RizwanSA, VMCHRI 15/35
- 15. Outline Whylearn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threat Rizwan SA, VMCHRI
- 16. Virological aspects •Family Filoviridae in the order Mononegavirales • Five species • Zaire, Sudan, Taï, Reston, Bundibugyo • Enveloped, non-segmented, negative-strand RNA virus, filamentous • Genes arranged linearly coding for seven structural proteins - NP, VP35, VP40, GP, VP30, VP24 and L with NP • GP, transmembrane protein and responsible for receptor binding and membrane fusion Rizwan SA, VMCHRI
- 17. Clinical features •Range from minor viral illness to fatal haemorrhagic fever • Ebola haemorrhagic fever (Ebola HF) is type of Viral Haemorrhagic Fevers • Most common constellation of symptoms is together called Ebola Virus Disease • EVD – duration 2 to 20 days, fever, nausea, vomiting, non-bloody diarrhoea, abdominal pain, conjunctivitis, weakness, severe headache and myalgia • E. Hemorrhagic fever - hematemesis, epistaxis, increased postpartum bleeding, bleeding gums etc., Rizwan SA, VMCHRI
- 18. Outline Whylearn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threat Rizwan SA, VMCHRI
- 19. Diagnosis CDCcase definitions Person Under Investigation Probable case Confirmed case Non-case Exposure risk levels • In early phase - Antigen-capture ELISA, IgM ELISA, PCR, Virus isolation • In later phase - IgM and IgG antibodies • In deceased patients – immunohistochemistry, PCR, virus isolation • Strict precautions during transportation of samples and all testing in BSL-4 lab • Differentials – Lassa fever, malaria, shigellosis, cholera, leptospirosis, plague, rickettsiosis, relapsing fever, other viral haemorrhagic fevers 20/35 Rizwan SA, VMCHRI
- 20. Treatment Experimentaltreatments ZMapp – a combo of 3 monoclonal antibodies TKM-Ebola – targets RNA of the virus MB-2003 - prevents infection in mice and non-human primates when administered as post-exposure prophylaxis within one to two days BCX-4430 – RNA polymerase inh Favipiravir, AVI 7288 Whole blood and convalescent serum transfusion from recovered patients • No proven antiviral drug • Symptomatic treatment only • Providing intravenous fluids and balancing electrolytes (body salts) • Maintaining oxygen status and blood pressure • Treating other infections if they occur • Barrier-nursing techniques • Personal Protective Equipment • Infection control measures • Isolation of Ebola patients from contact Rizwan SA, VMCHRI
- 21. Outline Whylearn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threat Rizwan SA, VMCHRI
- 22. Control measures –1/5 Public health measures - early detection and isolation, contact tracing and rigorous infection control measures Screening of travellers from affected countries in airports, seaports and land borders Quarantine and observation of suspected cases for 21 days from exposure Awareness generation among people, removing misconceptions Rizwan SA, VMCHRI 24/35
- 23. Control measures –2/5 All suspected or confirmed cases, single closed patient room Avoiding contact A log book containing details of persons entering Personal protective equipment for caretakers Dedicated medical equipment Minimum use of sharps Disinfection of samples - heating to 60°C for one hour, in 3% acetic acid Only BSL 4 lab should handle samples Hospital monitoring policy for staff In 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 Management Center 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 a hospital 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 based vectors (rAD) Replication competent vectors: Recombinant Paramyxovirus-based vectors, Recombinant vesicular stomatitis virus-based vectors (rVSV), Recombinant rabies virus based (rRABV) The first vaccine platform that successfully protected NHPs from Ebola virus infection was a recombinant adenovirus serotype 5(rAd5) vector Latest - chimpanzee-derived replication-defective adenovirus (ChAd) vaccine Rizwan 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 treatment Rizwan SA, VMCHRI 27/35
- 26. Control measures –5/5 International cooperation CDC, WHO, European Mobile Laboratory (EMLab) Project, African Union Voluntary agencies - MSF, Samaritan’s Purse Staff, Outbreak response teams, lab experts, doctors, equipment, gloves, medicines, disinfectants Research for medicines and vaccines Rizwan SA, VMCHRI 28/35
- 27. Outline Whylearn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threat Rizwan 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 problems Rizwan SA, VMCHRI 30/35
- 29. Outline Whylearn about EVD? History Epidemiology Virological and clinical aspects Management Control measures Challenges Pandemic threat Rizwan SA, VMCHRI
- 30. Pandemic threat None of the past outbreaks have developed into a pandemic But, 2014 outbreak – As of August 31, 2014, 3707 cases and >1800 people dead across 5 countries WHO’s declared ‘Public Health Emergency of International Concern’ in August 2014 Attack rate - 12.6 cases per 10,000 inhabitants, Ro is 2.7 No population level immunity Bioterrorism Rizwan 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 the main weapon Social aspects are very important in control Simple and established PH measures are sufficient A potential pandemic Rizwan SA, VMCHRI 33/35
- 32. Home work Group 1 - Learn the principles of outbreak investigation – watch the movie ‘Contagion’ and write a one page summary Group 2 - A one page summary on conditions needed to declare a pandemic Group 3 - A one page summary of how India is planning to respond to this threat, the agencies involved and your ideas for preparedness in our hospital Rizwan 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 Centre http://ebola.thelancet.com/ Journals - Bulletin of the WHO, NEJM and BMJ, August and September 2014 issues Image courtesy – bbc.co.uk, google images, CDC and WHO Rizwan SA, VMCHRI
- 34.
Editor's Notes
- #7 Yambuku village in Zaire, Belgian missionary, A Belgian nun taken ill, a Belgian doctor sent her blood sample to a Antwerp Belgium in a commercial flight in a passenger baggage. In the lab it was received by Dr. Peter Piot a clinical microbiologist,
- #8 who under electron microscope saw this spagetti shaped virions, he did not know what they were, they looked like marburg virus, so he sent the foto to other experts in the world. They confirmed that it was not marburg virus. That was the moment of discovery for Piot. The nun died and several villagers were affected by similar illness and were dying. Piot travelled to Yambuku and
- #9 Investigated the epidemic through detailed history taking and maps to make connections. In three months time they carried out extensive isolation of cases and contacts. They thought of naming the virus after the Yambuku village but thought that it would stigmatise the village, so they name the virus after the nearest river, the Ebola River.
- #15 NHP Gorillas, chimps are considered carriers, Human carrier not established
- #16 Transmission between natural reservoirs and humans is rare, and outbreaks are often traceable to a single case where an individual has handled the carcass of a gorilla, chimpanzee, or duiker.[5] The virus then spreads person-to-person, especially within families, hospitals, and during some mortuary rituals where contact among individuals becomes more likely
- #18 It is an enveloped, non-segmented, negative-strand RNA virus. (1) It is filamentous in appearance, but it might have various shapes as branched, circular, U, 6, or long and straight. (5) The virus particles of Ebola contains genes arranged linearly coding for seven structural proteins - NP, VP35, VP40, GP, VP30, VP24 and L with NP as 3’ end (leader) and L as 5’ end (trailer). (6,7,8) (13) Among the seven, GP is the only transmembrane protein of Ebola virus and is responsible for receptor binding and membrane fusion.
- #31 People should be made aware that this disease can be prevented from spreading by following certain hygiene practices but it is very difficult to treat and cure already affected patients. A misinformed community can severely hamper surveillance systems as people avoid giving contact histories for tracing exposed individuals, travel histories for fear of being subjected to quarantine, concealing affected family members from surveillance staff, and unauthorised removal of dead bodies from hospitals to fulfil native burial rituals. duration of precautions for Ebola should be determined on a case-to-case basis, in coordination with local, state, national and international health authorities.