Ebola Virus Disease(EVD)

Transcription

1 Yemeni International Congress of Infectious Diseases December 2014 University of Science & Technology Hospital Faculty of Medicine & Health Sciences Ebola Virus Disease(EVD)

2 Presented by: Dr Ahmed Ali Qaid Pandemic and Epidemic Disease Officer,WHO Professor of Community Medicine Dr Abdullah Abdu Almikhlafy Assistant Professor of Community Medicine UST FOM

3 Ebola The Deadly African Virus

4 Ebola Virus Introduction First appeared in Africa 1976 African Hemorrhagic Fever acute,mostly fatal disease causes blood vessel bursting systemic (all organs/tissues) humans and nonhuman primates Excluding 2000 outbreak 1,500 cases over 1,000 deaths

5 Ebola Taxonomy Scientific Classification Order: Mononegavirales Family: Filoviridae Genus: Ebola like viruses Species: Ebola Subtypes Ebola-Zaire, Ebola-Sudan,Ebola-Ivory Coast disease in humans Ebola-Reston disease in nonhuman primates

6 Learning Objectives To Recognize the Epidemiological Pattern of Ebola Virus Disease. To Understand Prevention and Control Methods for Ebola Virus Disease.

7 Filoviridae or Filoviruses Most mysterious virus group Pathogenesis poorly understood Ebola Image courtesy of the Centers for Disease Control natural history/reservoirs unknown exist throughout the world endemic to Africa

8 Ebola Pathogenesis Enters Bloodstream skin, membranes,open wounds Copyright: Russell Kightley Media, Australia Cell Level docks with cell membrane Viral RNA released into cytoplasm production new viral proteins/ genetic material New viral genomes rapidly coated in protein create cores

9 Ebola Virus Zoonotic virus bats the most likely reservoir, although species unknown Spillover event from infected wild animals (e.g., fruit bats, monkey, duiker) to humans, followed by human-human transmission 9

10 Ebola Epidemiology Reservoirs in Nature largely unknown possibly infected animals (primates?) Transmission direct contact blood/secretions of infected person possible airborne (Reston primate facility) Onset of illness abrupt incubation period: 2 to 21 days infections are acute and mostly deadly

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12 EVD in West Africa up to Epi-Week 45 Source: (i) World Health Organization, (ii) WHO Ebola Response Team: the first 9 months of epidemic and forward projection. N Eng J Med, 2014 Sep 22 {Epub ahead of print]

13 History of EVD Outbreaks (1) In 1976, Ebola Virus Disease (EVD) (formerly known as Ebola Haemorrhagic Fever) was first appeared in 2 simultaneous outbreaks in Sudan and in Democratic Republic of Congo (DRC). Twenty three outbreaks (2388 human cases including 1590 deaths, CFR 67%) have been reported since the first discovery of EVD in 1976 and up to 2013.

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15 Ebola haemorrhagic fevers in Africa Countries at risk Countries with serological evidence Countries w/o serological evidence Epidemics (n) = number of cases Côte d Ivoire 1994 (1) Gabon, 1994 (44) 1996 (37), 1996 (61) (65) Congo, (57) 2002 (13) 2003 (143) (35) South Africa 1996 (1) Sudan, 1976 (284), 1979 (34) Uganda, 2000 (425) DRC (ex-zaire), 1976 (318) 1977 (1) 1995 (316)

16 EVD: Current Situation in EMR Rumours of EVD have been reported from Egypt, Lebanon, Morocco, KSA, Sudan and UAE. Sudan remains the only country in the region that has experienced previous outbreaks from EVD The risk of the spread of EVD to the region region is possible owing to international travel

17 Possible EVD importation Route (1) International travel by air Traders and businessmen from affected countries in West Africa Transit passengers Returnee UN Peacekeepers from Western Africa Religious pilgrims.

18 Potential of spreading internationally by air travel: These were the final destinations of airline travelers in the month of August-September 2014 departing from the affected countries by WHO Region Source: Assessing the international spreading risk associated with 2014 Western African Ebola Outbreak. PLOS Current Outbreaks, 2014 Sep2 Edition 1

19 Possible EVD importation Route (2) International travel by land and/or sea Illegal economic migrants to Europe Pilgrims from West Africa Job seekers and seasonal workers

20 Transmission mode

21 How contagious is EVD??

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23 H2H Transmission : familial and nosocomial Most human infections due to direct or indirect contact with damaged skin, mucous membranes, body fluids of infected patients (blood, saliva, vomitus, urine, stool, semen)

24 Amplification : 584 HCWs infected in the current outbreak of which 329 have died Hospital: health care workers, in-patients, care givers, unsafe injections Community: contacts when caring for ill, funeral

25 Symptoms and Diagnostic Tests Early symptoms muscle aches, fever, vomiting red eyes, skin rash, diarrhea, stomach pain Acute symptoms bleeding/hemorrhaging from skin, orifices, internal organs Early Diagnosis very difficult signs & symptoms very similar to other infections Laboratory Test PCR detection ELISA (enzyme-linked immuno-absorbant) assay

26 Treatment No Standard Treatment available Patients receive supportive therapy treating complicating infections balancing patient s fluids and electrolytes maintaining oxygen status and blood pressure

27 Clinical Features Incubation period 2 to 21 days (3-12). Sudden onset of fever, weakness, muscle pain, headache and sore throat, conjunctivitis, hiccups, dysphagia. followed by vomiting, diarrhea, rash. internal & external bleeding often absent or minimal

28 Late features Confusion and irritability Seizures easy bleeding; Rash e.g. ecchymosis, petechiae, purpura bleeding from the gums, conjunctival hemorrhage oozing from puncture sites

29 Late features --epistaxis Hematemesis hemoptysis Melaena -unexplained vaginal bleeding in women haematuria Fever may be absent in late stages Shock (compounded by dehydration)

30 Table 3: Ebola case-classification criteria Classification Suspected Criteria Any person, alive or dead, who has (or had) sudden onset of high fever and had contact with a suspected, probable or confirmed EVD case, or a dead or sick animal OR any person with sudden onset of high fever and at least three of the following symptoms: headache, vomiting, anorexia/ loss of appetite, diarrhoea, lethargy, stomach pain, aching muscles or joints, difficulty swallowing, breathing difficulties, or hiccup; or any person with unexplained bleeding OR any sudden, unexplained death. Probable Confirmed Any suspected case evaluated by a clinician OR any person who died from suspected EVD and had an epidemiological link to a confirmed case but was not tested and did not have laboratory confirmation of the disease. A probable or suspected case is classified as confirmed when a sample from that person tests positive for EVD in the laboratory.

31 WHO response WHO aims to prevent Ebola outbreaks by maintaining surveillance for Ebola virus disease and supporting at-risk countries to developed preparedness plans. The document provides overall guidance for control of Ebola and Marburg virus outbreaks: Ebola and Marburg virus disease epidemics: preparedness, alert, control, and evaluation

32 WHO response When an outbreak is detected WHO responds by supporting surveillance, community engagement, case management, laboratory services, contact tracing, infection control, logistical support and training and assistance with safe burial practices. WHO has developed detailed advice on Ebola infection prevention and control: Infection prevention and control guidance for care of patients with suspected or confirmed Filovirus haemorrhagic fever in health-care settings, with focus on Ebola

33 WHO Ebola Response- Overview The first case of the current Ebola Virus Disease (EVD) was reported in Guinea in March Since then the outbreak has spread to Sierra Leone, Liberia, Nigeria and Senegal. A separate Ebola outbreak in the Democratic Republic of Congo was also reported in August 2014.

34 8 countries affected High transmission: Guinea, Liberia, Sierra Leone Recently introduced / low transmission: Mali, Spain, US Ebola free: Nigeria, Senegal

35 Prevention No vaccines! Patients are isolated Medical Staff Training western sanitation practices intake care during stay after patient dies Infection-control Measures complete equipment and area sterilization

36 Prevention After Death Virus contagious in fluids for days Burial use extreme caution handling and transport cultural practices/ religious belief incinerate all waste!!!!

37 INFECTION PREVENTION Consider every person (client or staff) infectious Wash hands Wear gloves Use physical barriers: (protective goggles facemasks and aprons)

38 To Prevent Ebola The suspected reservoirs for Ebola are fruit bats. Transmission to humans is thought to originat e from infected bats or primates that have b ecome infected by bats. Undercooked infected bat and primate (bush) meat transmits the virus to humans.

39 To Prevent Ebola Human to human transmission is only achieved by phys ical contact with a person who is acutely and gravely il l from the Ebola virus or their body fluids Transmission among humans is almost exclusively amon g caregiver family members or health care workers ten ding to the very ill. The virus is easily killed by contact with soap, bleach, sunlight, or drying. A washing machine will kill the vir us in clothing saturated with infected body fluids.

40 To Prevent Ebola A person can incubate the virus without sympto ms for 2 21 days, the average being five to eigh t days before becoming ill. THEY ARE NOT CONT AGIOUS until they are acutely ill. Only when ill, does the viral load express itself fi rst in the blood and then in other bodily fluids (t o include vomit, feces, urine, breast milk, semen and sweat).

41 If you are walking around you are not infecious to others.. As always practice good hand washing techniq ues. You will not contract Ebola if you do not tou ch a dying person with it.

42 Take-home messages Ebola virus disease (EVD), formerly known as Ebola haemorrhagic fever, is a severe, often fatal illness in humans. The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission. The average EVD case fatality rate is around 50%. Case fatality rates have varied from 25% to 90% in past outbreaks.

43 Take-home messages Community engagement is key to successfully controlling outbreaks. Good outbreak control relies on applying a package of interventions, namely case management, surveillance and contact tracing, a good laboratory service, safe burials and social mobilisation.

44 Take-home messages Early supportive care with rehydration, symptomatic treatment improves survival. There is as yet no licensed treatment proven to neutralise the virus but a range of blood, immunological and drug therapies are under development. There are currently no licensed Ebola vaccines but 2 potential candidates are undergoing evaluation.

45 Thank You For your Attention And Listening