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Viral Haemorrhagic Fevers

Viral Haemorrhagic Fevers. Images www.google/images.co.za. No vaccine for killer virus. Images www.google/images.co.za. S Africa fear over killer disease .

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Viral Haemorrhagic Fevers

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

  2. No vaccine for killer virus Images www.google/images.co.za

  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 www.google/images.co.za

  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 www.google/images.co.za

  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 www.google/images.co.za

  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 www.google/images.co.za

  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 • 25-100% 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 20-100%, 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 Images www.google/images.co.za • Hypotension, shock, bradycardia, pneumonitis, pleural and pericardial effusions, haemorrhage • Encephalopathy, seizures, coma, death

  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 www.google/images.co.za

  13. Bunyaviridae • Retinal vasculitis, blindness • Cotton wool spots macula • Severe disease bleeding, icterus, anuria, shock • Encephalitis • Congo fever most severe bleeding and ecchymosis Images www.google/images.co.za

  14. Filoviridae • Ebola similar clinically more severe disease Marburg • 5th day distinct morbiliform rash trunk, expressionless ghost-like facies • Haemorrhage mucous membranes, venipuncture sites, body orifices • DIC late disease Images www.google/images.co.za

  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 www.google/images.co.za

  16. 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 Differential diagnosis

  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 www.google/images.co.za

  18. Treatment • Supportive, ICU • Blood, platelets, plasma • Ribavirin – arenaviruses Congo, Lassa • Vaccination: Yellow fever • Electrolyte and fluid balance Images www.google/images.co.za

  19. VHF isolation precautionsWHO 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 www.google/images.co.za

  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. 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: www.google/images.co.za

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