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Viral Haemorrhagic Fevers Images www.google/images.co.za.

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Presentation on theme: "Viral Haemorrhagic Fevers Images www.google/images.co.za."— Presentation transcript:

1 Viral Haemorrhagic Fevers Images

2 No vaccine for killer virus Images

3 S Africa fear over killer disease More than 100 people in South Africa are under medical observation after coming into contact with people who died from suspected haemorrhagic fever. Images

4 Viral Haemorrhagic Fevers  Group of febrile illnesses  RNA viruses from 4 families  Highly infectious viruses  Potential lethal syndrome  Fever, malaise, vomiting, mucosal and GIT bleeding, hypotension, edema  Most notorious Ebola case fatality rate 90%, 1995 Kikwik, Zaire  Contracted from infected animal or arthropod vector  International travel, nosocomial outbreaks

5 Images

6 Shared features  Lipid envelope  Survival and perpetuation depend on animal host: natural reservoir  Distributed all over the world, higher occurrence tropical areas e.g. South America, Africa, Pacific Islands Images

7 Shared features  Transmitted 2 categories natural reservoirs: rodents or arthropods  Transmission occurs through contact with:  Natural reservoirs (mosquito bites, rodent bites)  Excretions, secretions, blood reservoirs, intermediate hosts  Person-to-person nosocomial infections Images

8 Pathophysiology  Vascular bed attacked, microvascular damage and increased vascular permeability  Specific pathophysiologic findings can vary depending on virus family and species  Initial febrile illness, haemorrhaging skin and mucous membranes, orifices, effusions  Widespread necrosis, may present any organ, modest and focal to massive in extent  Liver, lymphoid system extensively involved  Lung varying degrees interstitial pneumonitis, diffuse alveolar damage and haemorrhage  ATN, microvascular thrombosis  Minimal inflammatory response  thromocytopaenia, leucocytosis

9 Morbidity and Mortality  Ebola, Marburg  % mortality, pregnancy universally fatal  High infection rate, especially Zaire type  South-American HF  case-infection ratio > 50% exposed  Mortality rate 15-30%  Lassa fever  Fatality rate 2-15%  Rift Valley Fever  1% exposed infected, mortality rate 50%  Congo Fever  Infection rate %, Fatality rate 15-30%

10 History  Not all patients present with bleeding  Travel history, contact vectors, patient, bioterrorist attack  Incubation period 2-14 d  Initial symptoms non-specific  Progressive fever, biphasic  Chills  Malaise  Generalized myalgias, arthralgias  Headache, anorexia,cough  Severe sore throat  Nausea, vomiting, diarrhoea, epigastric pain

11 Physical examination Findings not distinctive  Nonspecific conjunctival injection  Facial/truncal flushing  Petechiae, purpura,ecchymoses  Icterus  Epistaxis;GIT,GUT bleeding  Lymphadenopathy  Hypotension, shock, bradycardia, pneumonitis, pleural and pericardial effusions, haemorrhage  Encephalopathy, seizures, coma, death Images

12 Arenaviridae  Conjunctivitis, pharyngeal enanthema and petechiae, no exudate  Sore throat  Retrosternal pain  Lassa fever: classic signs meningitis  Swollen baby syndrome  Infants toddlers; Lassa fever anasarca, abdominasl distension, bleeding Images

13 Bunyaviridae  Retinal vasculitis, blindness  Cotton wool spots macula  Severe disease bleeding, icterus, anuria, shock  Encephalitis  Congo fever most severe bleeding and ecchymosis Images

14 Filoviridae  Ebola similar clinically more severe disease Marburg  5 th day distinct morbiliform rash trunk, expressionless ghost-like facies  Haemorrhage mucous membranes, venipuncture sites, body orifices  DIC late disease Images

15 Flaviviridae  Yellow fever  Midzone necrosis liver, jaundice d3, flushing face, congested conjunctivae, reddening edges tongue  Heart, kidney damaged  Early haemorrhage, swelling bleeding gums prominent Images

16 Differential diagnosis  Rickettsial infections  Bacterial infections  Salmonella, shigella, gram negative infections  Septicaemia  Meningococcal, staph, strep, typhoid  Leptospirosis  Malaria  Viral: Chikungunya, Sinbis, Herpes, influenza  EBV  Acute anemia  Acute Leukemia, promyelocytic leukemia  DIC  Encephalitis  HUS  TTP  Meningitis  Sepsis  Collagen vascular diseases

17 Lab studies  FBC  Leucopenia, leucocytosis, thrombocytopenia, hemoconcentration, DIC  Liver enzymes  Alb   Proteinuria universal  Serological tests – Ab not detected acute phase; Direct examination blood/tissues for viral Ag enzyme immunoassay, virions EM specific and sensitive  PCR  MassTag PCR Images

18 Treatment  Supportive, ICU  Blood, platelets, plasma  Ribavirin – arenaviruses Congo, Lassa  Vaccination: Yellow fever  Electrolyte and fluid balance Images

19 VHF isolation precautions WHO and CDC guidelines  Wash hands as needed  Isolate the patient  Wear protective clothing  Dispose of needles and syringes safely  Dispose of waste safely  Use safe burial practices

20 Decontamination and isolation  Contain disease  Appropriate barrier mechanisms and negative pressure isolation  Report infection control of hospital as well as local and state public health officials, notify laboratory directors  CDC – expedite virus specific diagnosis (beyond scope local lab) and mobilization resources containment

21 Specific infection control recommendations  Strict adherence to hand washing  Double gloving, impermeable gowns  N-95 masks or air- purifying respirators  Negative pressure isolation 6-12 air changes per hour  Leg and shoe coverings  Face shields or goggles Images

22 Specific infection control recommendations  Restricted access  Dedicated equipment  Point-of-care analysers  Environmental disinfection 1:100 bleach solution  Multiple infected patients same part hospital  Portable high-efficiency particulate air filtered forced-air equipment  Survivors remain contagious extended periods of time  Fatalities promptly buried/cremated  Contacts medical surveillance 21 d

23 Lab samples  Specially handled and packaged for shipment to authorized labs  Biosafety level 3 and 4 facilities

24 References  Clare DJ, Ricketti AJ et al.  Clare DJ, Ricketti AJ et al. Viral Hemorrhagic Fevers: Currentb Status of Endemic Disease and Strategies for Control. Infect Dis Clin N Am 20 (2006) 359–393.   Marty AM,Jahrling PB, Geisbert TW. Hemorrhagic Fevers. Clin Lab Med 26 (2006) 345–386   Pigott DC.Hemorrhagic Fever Viruses. Crit Care Clin 21 (2005) 765– 783 All Images:


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