Viral Hemorrhagic Fevers

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Viral

Hemorrhagic

Fevers

Viral Hemorrhagic Fevers

Objectives

• Describe the natural geographic distribution of VHF and scenarios suggestive of bioterrorism

• Describe the clinical manifestations of VHF in general

• List exposure classification of contact for cases of VHF

• Describe infection control precautions for personnel caring for patients with VHF

• List therapeutic options for patients with VHF

Viral Hemorrhagic Fevers

Case Presentation

• 38 yo business man returned from West

Africa via London, ill for 3 days

– new onset fever

– chills

– severe sore throat

– diarrhea

– back pain

• PE: T103.6 BP 90/60, alert

– Skin with diffuse ecchymosis and a maculopapular rash on the extremities

MMWR 2004;53(38):891-897 Viral Hemorrhagic Fevers

Differential Diagnosis

• Fever in a traveler

– Malaria

– Typhoid fever

• Other Differential Diagnoses

– Meningococcemia

– Rickettsial infection

– Leptospirosis

– Acute leukemia

– Idiopathic or thrombotic thrombocytopenic purpura

Viral Hemorrhagic Fevers

Hospital Course

• Hospital Day #4

– Despite empiric antibiotics including antimalarials, pt develops acute respiratory distress syndrome (ARDS)

– Required intubation

Viral Hemorrhagic Fevers

Differential Diagnosis

• Fever in a traveler

– Malaria

– Typhoid fever

– Yellow fever

– Lassa fever

Viral Hemorrhagic Fevers

Hospital Course

• Hospital Day #4

– Despite empiric antibiotics including antimalarials, pt develops ARDS

– Required intubation

• Hospital Day #5

– Local and state health departments notified

– Investigational new drug (IND) protocol to administer IV ribavirin

– Patient died before administration of any drug

Viral Hemorrhagic Fevers

Diagnosis

• Clinical and post-mortem specimens sent to CDC

• Lassa virus confirmed

– Serum antigen detection

– Immunohistochemical staining liver tissue

– Virus isolation in cell culture

– RT-PCR sequencing of virus

Viral Hemorrhagic Fevers

FAMILY/GEOGRAPHY

Filoviridae

Sub-saharan Africa

Ebola

Marburg

AGENT CASE-FATALITY

50-75%

25%

Arenaviridae

West Africa (Lassa)

South America,

California (Whitewater)

Bunyaviridae

Sub-saharan Africa

Egypt, Yemen

SW US (Hantavirus)

Flaviviridae

Sub-saharan Africa

Central Asia

Viral Hemorrhagic Fevers

Old World: Lassa

New World: Junin,

Machupo, Guanarito

Sabia, Whitewater arroyo

Phlebovirus: Rift Valley

Nairovirus: Crimean Congo

Hantavirus: Sin Nombre

Lassa:1-2% (up to 25% in hospitalized pts)

30% for New World

Rift Valley: <1% overall

50% in hemorrhagic

Yellow fever

Dengue

Omsk

Kyasanur

Yellow Fever: 5-7% overall

50% in hemorrhagic www.cidrap.umn.edu/index.html

accessed 2/4/05

Epidemiology

• Incubation period

– 2 days to 3 weeks for most VHF

– Lassa fever: 21 days

• Endemic regions

– Sub-saharan Africa

• Lassa fever causes 100-300,000 infections and 5,000 deaths each year

• 20 imported cases reported worldwide

• Human to human transmission has occured

– South America

Viral Hemorrhagic Fevers

Why do VHFs make good Bioweapons?

• Disseminate through aerosols

• Low infectious dose

• High morbidity and mortality

• Cause fear and panic in the public

• No effective vaccine

• Available and can be produced in large quantity

• Research on weaponization has been conducted

Viral Hemorrhagic Fevers

Clinical Presentation

• Initial:

– High grade fever, headache, myalgias, fatigue, abdominal pain

• Advanced disease:

– Bleeding

– Maculopapular rash

– Exudative Pharyngitis (Lassa)

– Meningoencephalitis

– Jaundice

Viral Hemorrhagic Fevers

Viral Hemorrhagic Fevers

Viral Hemorrhagic Fevers

Viral Hemorrhagic Fevers

Viral Hemorrhagic Fevers

Transmission

• Direct contact with blood/body fluids/cadavers

• Aerosol spray (droplet v. airborne)

• Sexual transmission

• Percutaneous

• Bite of infected tick or mosquito

Viral Hemorrhagic Fevers

Infection Control

• Lassa Fever in New Jersey Investigation:

– 5 high risk contacts (wife, kids, visitor)

– 183 low risk contacts

• 9 other family members

• 139 HCW at hospital: 42 labworkers, 32 RN, 11 MD

• 16 labworkers in Virginia and California

• 19 passengers on flight from London to Newark

• No additional cases occurred

Viral Hemorrhagic Fevers

Infection Control

Risk Category Description Surveillance

Casual Contacts Remote contact with index case (eg, stayed in same hotel)

VHF not spread by casual contact, no special surveillance

Close Contacts More than casual (eg, living with contact, caretaker, shook hands with contact)

Place under surveillance once index case confirmed

High-Risk Contacts Mucous membrane contact (eg, kissing, or penetrating injury involving contact with index case’s blood such as needlestick)

Place under surveillance as soon as consider diagnosis of VHF in index case

VHF Personal Protective Equipment

• Airborne and Contact isolation for patients with respiratory symptoms

– N-95 or PAPR mask

– Negative pressure isolation

– Gloves

– Gown

– Fitted eye protection and shoe covers if going to be exposed to splash body fluids

• Droplet and Contact isolation for patients without respiratory symptoms

– Surgical mask

– Gloves

– Gown

– Fitted eye protection and shoe covers if going to be exposed to splash body fluids

• Environmental surfaces

– Cleaned with hospital approved disinfectant

– Linen incinerated, autoclaved, double-bagged for wash

Viral Hemorrhagic Fevers

Treatment

• Supportive care:

– Fluid and electrolyte management

– Hemodynamic monitoring

– Ventilation and/or dialysis support

– Steroids for adrenal crisis

– Anticoagulants, IM injections, ASA,

NSAIDS are contraindicated

– Treat secondary bacterial infections

Viral Hemorrhagic Fevers

Treatment

• Manage severe bleeding complications

– Cryoprecipitate (concentrated clotting factors)

– Platelets

– Fresh Frozen Plasma

– Heparin for DIC

• Ribavirin in vitro activity vs.

– Lassa fever

– New World Hemorrhagic fevers

– Rift Valley Fever

– No evidence to support use in Filovirus or

Flavivirus infections

Viral Hemorrhagic Fevers

Vaccination

• Argentine and Bolivian HF

– PASSIVE IMMUNIZATION

• Treat with convalescent serum containing neutralizing antibody or immune globulin

• Yellow Fever

– ACTIVE IMMUNIZATION

• Travelers to Africa and South America

This completes the current presentation.

Viral Hemorrhagic Fevers

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