Title: Viral Hemorrhagic Fevers
1Viral Hemorrhagic Fevers
- Paige Jordan RN, BSN
- Region II Epidemiologist
- January 9, 2004
2Objectives
- To describe the epidemiology of VHFs
- To describe the public health action of VHFs
- To describe prevention and control procedures
including employee health
3What are Viral Hemorrhagic Fevers (VHFs)?
- A group of illnesses that are caused by several
distinct families of viruses. - A severe multisystem syndrome (multiple organ
systems in the body are affected). - Vascular system damaged
- Bodys ability to regulate itself is impaired.
- Many cause severe and life-threatening disease.
4What are Viral Hemorrhagic Fevers (VHF)? Cont.
- Classified as biosafety level four (BSL4)
pathogens. - Classified as Category A Agent
5How are VHF grouped?
- 4 distinct families
- Arenaviridae
- Filoviridae
- Bunyaviridae
- Flaviviridae
6(No Transcript)
7(No Transcript)
8(No Transcript)
9HFVs as potential biological weapons
- HFVs weaponized by the Russia and US
- Yellow fever may have been weaponized by North
Korea - Source JAMA, 2002 2872393
10Epidemiology of HFVs
- All RNA viruses, and all are covered, or
enveloped, in a fatty (lipid) coating - Survival depend on an animal or insect host (the
natural reservoir) - Geographically restricted to areas where their
host species live - Humans - not the natural reservoir but are
infected via contact with infected hosts or
arthropod vectors
11Epidemiology of HFVs cont.
- Naturally reside in an animal reservoir host or
arthropod vector - Rodents and arthropods main reservoirs for
viruses causing VHFs. - Ticks and mosquitoes vectors for some VHFs
- Ebola and Marburg unknown host factors
12Epidemiology of HFVs cont.
- Incubation
- Typical 5-10 days
- Range 2-16 days (except Hantavirus 9-35 days)
13Transmission to Humans
- Aerosols
- Desiccated rodent excreta Arenaviruses,
hantaviruses - Generated by field mice caught in agricultural
machinery New World arenaviruses - Generated during slaughter of infected livestock
CCHF, RVF - Contaminated food/water
- Arenavirus (Lassa)
14Transmission to Humans
- Arthropod vectors
- Mosquitoes
- Bunyavirus RVF
- Flaviviruses Dengue, Yellow fever
- Ticks
- Bunyavirus CCHF
- Flaviviruses Kyanasur Forest Disease, Omsk HF
- Hematophagous flies
- Bunyaviruses RVF
15Transmission to HumansBW Implications
- With exception of dengue, all VHF agents
transmitted by aerosol in laboratory (animal
models) - Stabilization in aerosols
16Infectious Period
- Viruses have been found in seminal fluid of
patients or sexually transmitted as follows - Ebola 82-101 days after symptom onset
- Marburg 83 days
- Lassa 90 days
- Junin 7-22 days
- Lassa fever virus in urine of patients 32 days
after symptom onset
17VHF Evolution
- Prostration
- Pharyngeal, chest or abdominal pain
- Mucous membrane bleeding, ecchymosis
- Shock
- Usually improving or moribund within a week
(except HFRS, arenaviruses) - Bleeding, CNS involvement, marked elevation SGOT
portend poor prognosis - Mortality agent dependent (lt10-90)
18VHF Sequelae
- Prolonged Convalescence
- Hair Loss, Furrowed Nails
- Deafness (Lassa, EBO)
- Retinitis (RVF, KFD)
- Uveitis (RVF, MBG)
- Encephalitis (AHF, BHF, RVF, KFD, OHF)
- Pericarditis (Lassa)
- Renal insufficiency (HFRS)
19VHF Clinical Lab
- Leukopenia is suggestive, but WBC may be normal,
elevated, or leukemoid - Thrombocytopenia is typical, but sometimes mild
or absent - Hematocrit normal or increased early
- AST (SGOT) typically elevated prognostic value
- BUN/Cr related to circulatory status (except in
HFRS)
20VHF Clinical Lab (cont.)
- Bilirubin, amylase may be elevated
- Prothrombin/APTT usually prolonged
- FSP normal or modestly elevated
- Fibrinogen elevated, normal, or decreased
- Proteinuria usual
21VHF Differential Diagnosis
- Bacterial
- typhoid fever, meningoccemia, rickettsioses,
leptospirosis - Protozoal
- falciparum malaria
- Other
- vasculitis, TTP, HUS, heat stroke
22How are HFVs transmitted?
- Exposure of urine, fecal matter, saliva, or other
body excretions from infected reservoir hosts or
vectors, e.g. rodents - Vector
- From animals to humans
- Person to person e.g. Ebola, Marburg, Lassa and
Crimean-Congo hemorrhagic fever
23Arenaviridae
- Classification
- Old World and New World groups
- Life-long association with a rodent reservoir
- Found in 1956 as Tacaribe virus (New World virus)
and discovered new arenaviruses have been
discovered every one to three years
24(No Transcript)
25The Arenaviridae (Source Chapter 29, VHFs by
Peter B Jahrling)
26Arenaviridae
- Zoonotic
- Rodents located in Europe, Asia, Africa, and the
Americas - Some Old World arenaviruses - rodent population
generation after generation - Some New World arenaviruses transmitted among
adult rodents - Exception
- Tacaribe virus found in Trinidad isolated from
a bat
27Arenaviridae
- The viruses - shed into the environment in the
urine or droppings of the infected hosts - Human infection incidental
- contact with excretions
- materials contaminated with the excretions of an
infected rodent - ingestion of contaminated food,
- or by direct contact with broken skin with rodent
excrement - Aerosol transmission (inhalation of tiny
particles soiled with rodent urine or saliva - Agricultural work
- Human homes or other buildings domestic
settings
28Arenaviridae
- Lassa and Machupo viruses
- Associated with secondary person-to-person and
nosocomial (health-care setting) transmission - Contact with contaminated objects medical
equipment
29Filoviridae
- Filovirus
- Marburg 1967 in Marburg, Germany and Yugoslavia
- Ebola 1976 in Zaire and Sudan
- 4 species identified Ivory Coast, Sudan, Zaire,
Reston - 18 reports of human outbreak due to Ebola or
Marburg viruses approximately 1500 cases to
date - Most in Africa
- Source of Human infection Unknown
- Incubation Period 3-16 days
30Filoviridae
(Source CDC)
31Filoviridae
- High mortality rate especially percutaneous
transmission - Transmission due to needle stick injuries or use
of contaminated syringes - Require low inocula for infection
32Filoviridae
- Transmission by mucosal exposure in experimental
animals - Human infections through contact of
contaminated fingers with oral mucosa or
conjunctiva - Person to person by small droplet airborne nuclei
33Bunyaviridae
34Flaviridae
35Epidemiology of HFVs cont.
- Symptoms
- Fever, headache, malaise, dizziness
- Myalgias
- Nausea/vomiting
- Initial Signs
- Flushing, conjunctival injection
- Periorbital edema
- Petechiae
- Positive tourniquet test
- Hypotension
36Clinical Manifestations of VHFs
- Nonspecific
- May not be possible to differentiate by clinical
grounds alone - Overall incubation period 2 21 days
- Initially nonspecific prodrome lasts less than
a week - High fever, malaise, headache, arthralgias,
myalgias, nausea, abdominal pain, and nonbloody
diarrhea
37Clinical Manifestations of VHFs
- Filoviruses, Rift Valley fever, and flaviviruses
characterized by an abrupt onset - Arenaviruses more insidious onset
- Early signs typically include
- Fever, hypotension, relative bradycardia,
tachypnea, conjunctivitis, and pharyngitis - Cutaneous flushing or a skin rash
- Petechiae, mucous membrane and conjunctival
hemorrhage Hematuria, hematemesis, and melena - DIC and circulatory shock
- CNS dysfunction
-
38Maculopapular RashMarburg Disease
(Source JAMA 2872397)
39Erythematous RashBolivian Hemorrhagic Fever
(Source JAMA 2872397)
40Ocular Manifestation Bolivian Hemorrhagic Fever
(Source JAMA 2872397)
41Clinical Characteristics of Hemorrhagic Fever
Viruses
(Source JAMA, 2002 2872396)
42Clinical Characteristics of Hemorrhagic Fever
Viruses
(Source JAMA, 2002 2872396)
43Clinical Characteristics of Hemorrhagic Fever
Viruses (Source JAMA, 2002 2872396)
44Clinical Characteristics of Hemorrhagic Fever
Viruses
(Source JAMA, 2002 2872396)
45- Case Definition / Confirmation Suspect index
case - Temperature gt 101 of lt 3 weeks duration
- No predisposing factors for hemorrhagic symptoms
- Two or more hemorrhagic symptoms
- hemorrhagic or purple rash,
- Epistaxis (nosebleed),
- Hematemesis (vomiting of blood),
- Hemoptysis (spitting of blood derived from lung
or airways), - blood in stools,
- Other conjunctival hemorrhage, bleeding gums,
bleeding at puncture sites, hematuria(blood in
urine) - No established alternative diagnosis
- Laboratory confirmation _at_ CDC / USAMRIID
JAMA, 2002 2872391
46Differential Diagnosis of VHFs
- Influenza
- Viral hepatitis
- Staphylococcal or gram-negative sepsis
- Toxic shock syndrome
- Meningococcemia
- Salmonellosis
- Shigellosis
- Rickettsial diseases (e.g. Rocky Mountain Spotted
Fever) - Leptospirosis
- Borreliosis
- Psittacosis
- Dengue
- Hantavirus pulmonary syndrome
- Malaria
- Trypanosomiasis
- Septicemic plague
- Rubella
- Mealses
- Hemorrhagic smallpox
47Differential Diagnosis of VHFs cont.
- Noninfectious bleeding diathesis
- Idiopathic or thrombotic thrombocytopenic purpura
- Hemolytic uremic syndrome
- Acute leukemia
- Collagen-vascular diseases
48Lab Abnormalities
- Leukopenia (except in some cases of Lassa fever
leukocytosis) - Anemia or hemoconcentration
- Thrombocytopenia
- Elevated liver enzymes
49Lab Abnormalitiescont.
- Jaundice typical in Rift Valley fever and
yellow fever - Coagulation abnormalities prolonged bleeding
time, prothrombin time, and activated partial
thromboplastin time - Elevated fibrin degradation products
- Decreased fibrinogen
- Urinalysis proteinuria, and hematuria
50Lab Testing for VHFs
- Blood and serum specimens
- Environmental samples should be taken when
possible and appropriate for exposure assessment - Specimens should be sent to OLS which will
coordinate to submit to CDC - IgM ELISA, PCR, Viral Isolation, IgG ELISA
(recovered), Immunohistopathology testing for
deceased
51Public Health Action
- Protect employee health
- Identify high risk employees
- Educate high risk employees
- Personal Protective Equipment (PPE)
- Educate health care providers and the public in
the recognition and diagnosis of VHF - Educate providers and laboratories to report VHF
to the LHD immediately
52Public Health Action cont.
- When a VHF case is reported
- Isolation of case
- Confirm cases
- Obtain a complete clinical and lab history by
using VHF case investigation form - Assure to obtain appropriate lab specimens on
each suspected case and send it to OLS - Confirmation of an intentional or unintentional
exposure and notification procedure - Checking for natural exposures to HFV, contact of
a case or travel to an endemic area within last
21 days - If no clear source is identified, begin active
surveillance
53Public Health Action cont.
- Case Finding
- Develop a working case definition for the
outbreak investigation - Begin enhanced passive surveillance
- Issue a news release and provide alert to
increase health care providers and the public
recognition and diagnosis of VHF - Educate providers and lab to immediately report
possible VHF infections
54Public Health Action cont.
- Identify contact
- Contact Definition
- Direct Contacts any person who has had
face-to-face contact (within 6 feet) with a
suspected, probable, or confirmed case of VHFs
during the infectious period (onset of symptoms
until time of interview, recovery, or death and
burial of case).
55Public Health Action cont.
- Surveillance of case-contacts and exposed
population - Interview case-contacts and exposed individuals
assure that all case-contacts and exposed are
contacted within 24 hours and interview daily for
21 days after last exposure. - Determine if fevergt101F or VHF symptoms
- Refer symptomatic persons to a clinical center
for isolation and treatment
56Public Health Action cont.
- Surveillance of exposed
- If exposed does not have fever of 101? F or
higher or signs/symptoms of VHF by end of 21 days
discontinue surveillance - Interview all exposed individuals to verify they
have no symptoms indicate status of exposed
individual as closed on Exposed Individual Line
Listing Form
57Public Health Action cont.
- If exposed have fever 101F or higher, or
signs/symptoms of VHF, then assure referral to a
MD for diagnostic work-up - Implement appropriate infection control and
preventive interventions - Enter status of exposed individual as a case and
move to Case Line List Form - Begin contact tracing for this new case
58- Preventive Interventions
- Employee Health And Infection Control
- Hand hygiene wash
- Before donning protective equipment
- After removal of gown, leg and shoe covers,
gloves - Before removal of face and eye protection
- Double gloves
JAMA, 2002 2872391
59- Preventive Interventions
- Employee Health And Infection Control
- Impermeable gowns
- Negative pressure isolation room
- N-95 masks or powered air-purifying respirators
- Leg and shoe coverings
- Goggles / face shields
- Restricted access of non-essential staff /
visitors - Dedicated medical equipment
- Environmental disinfection with 1100 bleach
JAMA, 2002 2872391
60Infection Control(Arenavirus, Filovirus, CCHF)
- Single room w/ adjoining anteroom as only
entrance - Handwashing facility with decontamination
solution - 0.5 sodium hypochlorite, 2 glutaraldehyde,
phenolic detergent, soap - Changing area/protective equipment
- Negative air pressure air not recirculated
- Prominent hemorrhage, cough, vomiting, diarrhea
- Consider negative air flow room, if available, in
absense of these sxs/sxs to avoid having to
transfer pt later
61Infection Control(Arenavirus, Filovirus,
CCHF)(Contd)
- Strict barrier precautions
- gloves, gown, mask, shoe covers, protective
eyewear/faceshield - HEPA-filtered mask or respirator
- Prominent hemorrhage, cough, vomiting, diarrhea
62Infection ControlArenavirus, Filovirus, CCHF
(cont.)
- Chemical toilet
- All body fluids disinfected
- Disposable equipment sharps into rigid
containers containing disinfectant -gt autoclaved
or incinerated - Double-bag refuse
- outside bag disinfected then autoclaved or
incinerated
63Clinical Laboratory Procedures
- Strict barrier precautions
- gloves, gown, mask, shoe covers, protective
eye/faceshield - consider respirator with HEPA filter
- handle specimens in biosafety cabinet when
possible - Spills/splashes
- immediately cover with disinfectant, allow to
soak for 30 - wipe with absorbent towel soaked in disinfectant
- Waste disposal
- same as for patient isolation practices
64ExposuresFirst Aid
- Wash/irrigate wound/site immediately
- within 5 minutes of exposure
- Mucous membrane (eye, mouth, nose)
- continuous irrigation with rapidly flowing water
or sterile saline for gt 15 minutes - Skin
- scrub for at least 15 minutes while copiously
soaking the wound with soap or detergent solution - fresh Dakin's solution (0.5 hypochlorite)
dilute 1 part standard laundry bleach (5
hypochlorite) with 9 parts tap water
65- Treatment and ProphylaxisJAMA, 2002 2872391
- Prophylaxis none
- Treatment experimental use of ribavirin
- Arenaviridae
- Lassa hemorrhagic fever
- Bunyaviridae
- Rift Valley fever
66VHF Vaccines
- YELLOW FEVER
- licensed 17D vaccine safe and efficacious
- cannot be used in persons with egg allergy
- ARGENTINE HEMORRHAGIC FEVER
- live, attenuated
- safe and efficacious used in 150,000
- protects monkeys against Bolivian HF
67VHF Vaccines
- RIFT VALLEY FEVER
- formalin-inactivated
- safe but requires 3 shots, intermittent booster
- limited supply
- live, attenuated MP-12
- Phase II testing
- HFRS (HANTAAN)
- vaccinia vectored recombinant vaccine
68Treatment Recommendation
- The mainstay of treatment supportive
- Fluid maintenance of fluid and electrolyte
balance, circulatory volume, and blood pressure - No approved antiviral drugs or vaccines
- If a case is suspected, probable or confirmed the
following drug therapy is recommended - Initial supportive and ribavirin therapy
immediately while diagnostic confirmation is
pending - If infection with Arenaviruses or Bunyaviruses is
confirmed, continue 10-day course of ribavirin - If infection with Filovirus or Flavirus is
confirmed, or is the diagnosis of VHF is excluded
or an alternative diagnosis is established,
discontinue ribavirin.
Source JAMA, 2002 2872399
69VHF ManagementCardiovascular
- Hemodynamic resuscitation monitoring
- invasive (S-G catheter) as warranted and feasible
- Careful fluid management
- use of colloid
- hemodialysis or hemofiltration as needed
- esp. HFRS patients
- Vasopressors and cardiotonic drugs
- Cautious sedation and analgesia
70VHF ManagementHematologic
- Coagulation studies and clinical judgement as
guide - replacement of clotting factors
- platelet transfusions
- No antiplatelet drugs or IM injections
- DIC may be important in some VHFs (RVF, CCHF,
Filoviruses)
71VHF ManagementAnti-viral Therapy
- Ribavirin
- Arenaviridae (Lassa, AHF, BHF)
- Bunyaviridae (HFRS, RVF, CCHF)
- Immune (convalescent) plasma
- Arenaviridae (AHF, BHF, ?Lassa)
- Passive immunoprophylaxis post-exposure?
72VHF ManagementOther
- R/O or treat empirically for malaria, typhoid
fever, rickettsioses, etc. - vigilance against secondary bacterial infections
- nosocomial pneumonia, UTI, bacteremia
- ONLY INTENSIVE CARE WILL SALVAGE THE SICKEST
PATIENTS