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Ebola Virus Disease. Dr. Oluwafemi Akinyele Popoola Lecturer and Consultant Community Physician. Session Objectives. Describe the epidemiology of Ebola virus Highlight past outbreaks State main symptoms
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Ebola Virus Disease Dr. Oluwafemi Akinyele Popoola Lecturer and Consultant Community Physician Lecture delivered at Bodija-Ashi Baptist Church 14thSeptember, 2014.
Session Objectives • Describe the epidemiology of Ebola virus • Highlight past outbreaks • State main symptoms • Describe how knowledge of the epidemiology and transmission dynamics of Ebola Virus informs its control strategies
What is Ebola Virus Disease • Ebola Virus Disease: is one of the numerous viral Hemorrhagic Fevers. It is a severe, often fatal disease in humans and nonhuman primates – CDC • Incubation period 2-21days (usual 8 – 10 days) • Causation: infection with a virus • Family Filoviridae and genus Ebolavirus • Five subspecies of Ebolavirus • Zaire ebolavirus; Sudan ebolavirus; Tai Forest ebolavirus; and Bundibugyo ebolavirus • Reston ebolavirus (disease only in nonhuman primates)
Ebola outbreak in Guinea, Liberia and Sierra Leone, Epicurve by week of onset, December 2013 to 19 July 2014 (n=1002) 23 March WHO deployed multi-diciplinary international experts 23 March Mobile laboratory deployed through EDPLN Outbreak response operations started 21 March Labortory Confirmation 26 May Sierra Leone declared outbreak Alert 13 March 15 cases inc. 9 deaths 31 March Liberia declared outbreak Alert from Méliandou 26 January 5 death w diarrhoea
Case Definitions Suspected (clinical) case: Any person ill or deceased with fever and hemorrhage. Documented prior contact with an EVD case is not required • Confirmed Case A case with laboratory confirmed diagnostic evidence of ebola virus infection.
Probable case (with or without bleeding): Any person (living or dead) with contact with a clinical case of EVD and a history of acute fever. OR Any person (living or dead) with a history of acute fever and three or more of the following - headache/ vomiting/nausea/ loss of appetite/ diarrhea/ intense fatigue/ abdominal pain/ general muscular or articular pain/ difficulty in swallowing/ difficulty in breathing/ hiccoughs OR Any unexplained death. • Distinction between a suspected case and a probable case in practice relatively unimportant as far as outbreak control is concerned.
Definition of contact • A person without any symptoms has had physical contact with a case or the body fluids of a case within the last three weeks. The notion of physical contact may be proven or highly suspected such as having shared the same room/bed, cared for a patient, touched body fluids, or closely participated in a burial ceremony (physical contact with the corpse).
Current Status by August 9, 2014 (WHO) *New cases were reported between 7 and 9 August, 2014.
Transmission Cycles • Animal to Man • Initial source of outbreak in human populations • Often occurs in rural areas • Man to Man • Source of epidemic propagation in human populations • All body fluids are infected • Infected humans only transmit the virus AFTER THEY BECOME SICK!!! • Risk is increased during hospital care of infected individuals • Improper disposal of dead bodies also transmits disease
Routes of Transmission • Direct contact • Blood or secretions of infected person • Infected needles and other equipments contaminated with infected secretions • Others • Through families and friends contact with infectious secretions of ill person • Virus can still be present in semen 6 weeks after illness • Factors aiding transmission • Hospital settings: inappropriate use of PPE; Lack of point of care risk assessment • Community settings: burial rites; treatment seeking delays/denials
Transmission dynamics • Natural reservoir not conclusive • However, WHO believes fruit bats may be the natural host • First patient in outbreaks most likely infected by animal • Health workers more susceptible to infection • Higher risk of transmission (high viral loads) • Later stages : vomiting, diarrhoea, shock, haemorrhage
Hypothesis of Ebola Virus transmission at the human-animal interface
Symptoms of Ebola Virus Disease MAIN • Fever – at least 38C • Weakness • Diarrhoea • Vomiting • Headache • Joint and muscle aches • Stomach pain • Lack of appetite ADDITIONAL • A Rash • Red Eyes • Hiccups • Cough • Sore throat • Chest pain • Difficulty breathing • Difficulty swallowing • Bleeding inside and outside of the body
Definitive Diagnosis • LABORATORY BASED • Antibody-capture enzyme-linked immunosorbent assay (ELISA) • Antigen detection tests • Serum neutralization test • Reverse transcriptase polymerase chain reaction (RT-PCR) assay • Electron microscopy • Virus isolation by cell culture
Facts about the Virus? • Easily destroyed – soaps, detergent, chlorine, heat. • Highly infectious • Highly pathogenic – causes a serious disease with high risk of death • Humans only become infectious when sick • Virus shed in ALL body fluids • No evidence of air borne transmission • No licensed vaccine or specific treatment • Can only be diagnosed via specialised lab tests
Prevention Strategies • Prevention of Community infections/HE • Prevention of new infections • Early recognition of infected individuals • Tracing and surveillance of contacts of infected individuals • Prevention of hospital infections • Isolation of infected individuals • Supportive treatment of infected individuals
Community Prevention during Outbreaks • Reducing the risk of wildlife-to-human transmission from contact with infected fruit bats or monkeys/apes/other bush meats and the consumption of their raw meat. • Animals should be handled with gloves and other appropriate protective clothing. • Animal products (blood and meat) should be thoroughly cooked before consumption.
Community Prevention during Outbreaks • Close physical contact with Ebola patients should be avoided. • Gloves and appropriate personal protective equipment should be worn when taking care of ill patients at home. • Regular hand washing is required after visiting patients in hospital, as well as after taking care of patients at home
Community Prevention during Outbreaks • Communities affected by Ebola should inform the population about the nature of the disease and about outbreak containment measures, including burial of the dead. • People who have died from Ebola should be promptly and safely buried • Manage rumours during outbreak • Do not hide cases or contacts
Control in Hospital Settings • Ebola is highly infectious and must be treated in specialised isolation centres • Standard precautions for all patients • Infection based precautions for probable or confirmed cases • Proper decontamination of all surfaces
Summary • Ebola causes a serious disease with high risk of death • Cases present with fever and other symptoms diagnosis requires specialised lab tests • Prevention strategies • Practice good personal hygiene, frequent hand washing with soap and water • Avoid close contact with possibly infected individuals • Proper investigation and isolation of all cases • Tracing and surveillance of contacts of Ebola patients