Ebola Virus Disease and Clinical Care Part I: History, Transmission, and Clinical Presentation This lecture is on Ebola virus disease (EVD) and clinical care. This is part one of a three-part lecture on this topic. Preparing Healthcare Workers to Work in Ebola Treatment Units (ETUs) in Africa This lecture will focus on EVD in the West African setting. Ebola Virus Disease and Clinical Care: The training and information you receive in this course will Part I: History, Transmission, and Clinical not cover the use of certain interventions such as intubation Presentation or dialysis which are not available in West African Ebola Treatment Units (ETUs). You will need supplemental training This presentation is current as of December 2014. This presentation contains materials from Centers for Disease Control and to care for patients appropriately in countries where advanced Prevention (CDC), Médecins Sans Frontières (MSF), and World Health Organization (WHO). care is available. U.S. Department of Health and Human Services U.S. Department of Health and Human Services Centers for Disease Control and Prevention Centers for Disease Control and Prevention version 12.03.2014 The learning objectives for this lecture are to: Learning Objectives ▶ Describe the routes of Ebola virus transmission Describe the routes of Ebola virus transmission Explain when and how patients are infectious ▶ Explain when and how patients are infectious Describe the clinical features of patients with Ebola ▶ Describe screening criteria for Ebola virus disease Describe the clinical features of patients with Ebola (EVD) used in West Africa Explain how to identify patients with suspected ▶ Describe screening criteria for EVD used in West Africa EVD who present to the ETU ▶ Explain how to identify patients with suspected EVD who present to the ETU This presentation contains materials from CDC, MSF, and WHO 2 A number of different viruses cause viral hemorrhagic fever. Viral Hemorrhagic Fevers Some illness from these infections, such as Lassa fever, dengue, Arenaviridae Bunyaviridae Filoviridae Flaviviridae or yellow fever, may be encountered in West Africa and can easily be confused with Ebola virus because symptoms are • Lassa HF • Hantavirus Genus • Ebola • Dengue similar. • Argentine HF • Congo-Crimean • Marburg • Yellow fever • Bolivian HF HF • Lloviu • Kyasanur For example, because Lassa fever is endemic in West Africa • Venezuelan • Rift Valley Fever • Omsk and an accepted drug treatment (Ribavirin) exists, it is HF important to differentiate this from Ebola virus. • Brazilian HF This presentation contains materials from CDC, MSF, and WHO 3 29 Course Lectures and Scripts > Ebola Virus Disease and Clinical Care Part I Ebola Virus This is an electron micrograph of an Ebola virus particle, demonstrating the characteristic filamentous structure of the virus. It is sometimes described as a shepherd’s crook or “U” or a “6”. The virus has a lipid envelope and the genome only encodes for 7 genes. As you can see from this picture the virus has an exceptionally large surface area because of its filamentous area. This makes it more susceptible to disruption of the lipid envelope which results in deactivation of the virus. This presentation contains materials from CDC, MSF, and WHO 4 Let’s address transmission of the Ebola virus. Ebola Transmission This presentation contains materials from CDC, MSF, and WHO 5 Ebola virus belongs to a family of zoonotic RNA viruses, Ebola Virus Filoviridae called Filoviridae, which also includes Marburg virus, another Family of zoonotic RNA viruses: hemorrhagic fever virus with similar symptoms and case Marburg virus and Ebola virus species fatality rates. >20 previous Ebola and Marburg outbreaks In previous outbreaks, the case- The first Ebola virus species was discovered in 1976 in fatality rates have varied by subtype: E. Zaire (57%-90%), E. Sudan (approximately 50%), E. Yambuku, Zaire, now known as the Democratic Republic of Bundibugyo (32%), and E. Reston (0%--evidence of infection but no clinical illness). the Congo, along the Ebola River, as shown here on the map. Previous West African case: Tai Forest Virus, Côte d’Ivoire In this first recognized outbreak, there were 318 cases, with a case fatality rate of 88%. Since 1976, there have been more This presentation contains materials from CDC, MSF, and WHO 6 than 20 outbreaks of Ebola and Marburg viruses. Ebola virus species now include Zaire, responsible for this outbreak, Sudan, Bundibugyo, Tai Forest, and Reston. Different fatality rates have been associated with the several species. Ebola Zaire is the most virulent, having a case fatality of 88-99%, while Ebola Reston is not associated with any human deaths. 30 Course Lectures and Scripts > Ebola Virus Disease and Clinical Care Part I Based on evidence and the known transmission cycles of other Ebola Virus Transmission Cycle similar viruses, researchers believe that Ebola virus is animal- Zoonotic virus– bats are the most likely reservoir, borne. Bats are the most likely reservoir although the exact although species unknown Spillover event from infected animals to humans, species is unknown. followed by person-to-person transmission This slide depicts the hypothesized natural life cycle of Ebola virus in bats on the left, and spillover infections of other mammals, including humans, that can occur on the right. Preparation of “bush meat,” a term used to describe meat from any wild animal, including monkeys and bats, might be an important opportunity for a spillover event. The event could This presentation contains materials from CDC, MSF, and WHO 7 then start a person-to-person chain of Ebola virus transmission through contact with blood or body fluids. Transmission occurs via direct or indirect contact with body Ebola Virus Transmission fluids from Ebola virus infected persons or animals. Sources Transmission occurs via direct or indirect contact with body fluids from Ebola-infected persons or animals Potentially infectious body fluids include: Potentially infectious body fluids include blood, respiratory . Blood . Respiratory secretions secretions, urine, feces, vomit, saliva, sweat, breast milk, semen, . Urine . Feces and vaginal secretions. Vomit . Saliva . Sweat Detection in semen by viral culture (up to day 82) or by reverse . Breast milk . Semen, vaginal secretions transcriptase polymerase chain reaction (RT-PCR) (up to day Prolonged detection by PCR in semen (up to 101 days after infection and recovery) 101) has been reported after illness onset and recovery. The . Transmission risk uncertain transmission risk from semen after recovery is uncertain. This presentation contains materials from CDC, MSF, and WHO 8 However, seminal fluid is an immunologically protected site, meaning that antibodies might not have access to virus present in semen. Hence, it is recommended men use condoms for three months after the Ebola virus is no longer detectable in the patient’s blood. 31 Course Lectures and Scripts > Ebola Virus Disease and Clinical Care Part I Ebola Virus Transmission Important concepts about Ebola virus transmission include: Key Concepts ▶ Infected persons are not contagious until onset Infected persons are not contagious until onset of symptoms. of symptoms ▶ Infectiousness of body fluids (e.g., viral load) Infectiousness of body fluids (e.g., viral load) increases as increases as patients become more ill patients becomes more ill. Corpses are highly infectious Direct contact with an infected person or recently ▶ Corpses are highly infectious even though viral load stops deceased person are the most common routes of transmission increasing after death. Fresh corpses are a major problem Transmission also occurs through contact with with customary West African body preparation and burial objects or surfaces contaminated by blood or other body fluids containing virus practices. This presentation contains materials from CDC, MSF, and WHO 9 ▶ Direct contact with ill persons or recently deceased persons are the most common routes of transmission. ▶ Transmission also occurs through contact with objects or surfaces contaminated by blood or body fluids containing virus. Evidence from this epidemic and previous outbreaks indicates Ebola Virus Transmission Routes of Virus Entry direct contact with blood or other body fluids from an infected Established route – direct contact with blood or other body fluids person or corpse are the major routes of transmission. Levels . Eyes or other mucous membranes of Ebola virus in blood and other body fluids are very high, . Breaks in the skin . Percutaneous injuries from objects contaminated with infectious especially when patients are sickest and near death. Since the materials (e.g., needlestick injury) Possible routes infectious dose is very low, even small amounts of blood or . Sexual contact other body fluids are potentially very infectious. Virus from . Breastfeeding Aerosol transmission is unlikely contaminated hands or fomites, including contaminated . Person-to-person transmission of Ebola virus via inhalation (aerosols) has not been demonstrated personal protective equipment (PPE), can enter through the . Epidemiology is not consistent with aerosol transmission eyes or other mucous membranes, or breaks in skin that might This presentation contains materials from CDC, MSF, and WHO 10 not be visible. Percutaneous injuries such as a needlestick can also transmit virus. Other possible routes of transmission include sexual contact or breastfeeding. However, it is hard