Viral hemorrhagic fever (patient information)

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Viral hemorrhagic fever
Overview
What are the symptoms?
What are the causes?
Who is at highest risk?
When to seek urgent medical care?
Diagnosis
Treatment options
Where to find medical care for Viral hemorrhagic fever?
What to expect (Outlook/Prognosis)?
Possible complications
Prevention
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]

Overview

Viral hemorrhagic fevers (VHFs) refer to a group of illnesses that are caused by several distinct families of viruses. The term "viral hemorrhagic fever" commonly describes a severe multi-organ syndrome. In this condition the vascular system is usually affected, diminishing the body's ability to regulate itself. The symptoms may include bleeding, however, this is seldom life-threatening. The severity of the disease will depend on the underlying virus causing it, and can range from mild to life-threatening. Geographically, these viruses are distributed over the globe. However, since each virus has its own host, some diseases are more commonly seen in certain areas than others.

What are the symptoms of Viral hemorrhagic fever?

Signs and symptoms may vary according to the disease, but in general, patients with VHF present with:

• Abrupt onset of fever
• Myalgias
• Prostration
• Coagulopathy with:

• Petechial rash
• Ecchymoses, sometimes with overt bleeding

• Vascular endothelial damage may lead to:

• Shock,
• Pulmonary edema
• Liver injury

Signs seen with specific viruses may include:

• Renal failure (HFRS)
• Ecchymoses (CCHF)
• Hearing loss
• Anasarca
• Shock in newborns (Lassa fever), and spontaneous abortion (Lassa and lymphocytic choriomeningitis viruses)

Because the incubation period may be as long as 21 days, patients may not develop illness until returning from travel; therefore, a thorough travel and exposure history are critical.

What causes Viral hemorrhagic fever?

Viral hemorrhagic fevers (VHFs) are caused by several families of enveloped RNA viruses, including:

• Filoviruses, such as Ebola and Marburg viruses
• Arenaviruses, such as Lassa fever, Lujo, Guanarito, Machupo, Junin, Sabia, and Chapare viruses
• Bunyaviruses, such as Rift Valley fever (RVF), Crimean-Congo hemorrhagic fever (CCHF
• Hantaviruses
• Flaviviruses, such as dengue, yellow fever, Omsk hemorrhagic fever, Kyasanur Forest disease, and Alkhurma viruses

These families of viruses share some common features, including:

• Are all RNA viruses, and all are covered, or enveloped, in a fatty coating
• The survival of the virus depends on an animal or insect host (natural reservoir)
• The viruses are restricted to their hosts' area
• The virus has human and animal hosts
• Humans can transmit the virus among them
• Outbreaks of theses viruses occur rarely and are not possible to predict
• There is generally no cure or established treatment for VHFs
• Seldom other viruses and bacteria can cause a hemorrhagic fever, such as scrub typhus

Transmission

The virus responsible for the VHF may be transmitted through:

• Contact with urine, fecal matter, saliva, or other body excretions from infected rodents
• Mosquito or tick bites
• When crushing a tick.
• Some of these vectors may spread the virus to animals, which will then transmit it to humans
• Person-to-person (Ebola, Margurg or Lassa), through direct contact or through infected surfaces

Who is at highest risk?

Some VHFs are spread on person to person basis, through direct contact with symptomatic patients, body fluids, cadavers or through inadequate infection control measures (filoviruses, arenaviruses, CCHF virus). Zoonotic spread includes the following:

• Livestock - via slaughter or consumption of raw milk or meat from infected animals (CCHF, RVF, Alkhurma viruses)
• Bushmeat - likely via slaughter or consumption of infected animals (Ebola, Marburg viruses)
• Rodent - (arenaviruses, hantaviruses) via inhalation or contact with contaminated materials
• Mosquitos (RVF virus) or ticks bites (CCHF, Omsk, Kyasanur Forest disease, Alkhurma viruses)
• Other reservoir species - such as bats (Ebola, Marburg viruses)

When to seek urgent medical care?

If you think you are developing symptoms of this disease contact your doctor. Common symptoms of Viral hemorrhagic fever include:

• Fever
• Bleeding, under the skin and/or through body orificies, such as: mouth, eyes, or ears
• Fatigue
• Dizziness
• Muscle pain
• Weakness
• Exhaustion
• Seizures
• Kidney problems

Diagnosis

US-based clinicians should notify CDC’s Viral Special Pathogens Branch immediately of any suspected cases of VHF occurring in patients residing in or requiring evacuation to the United States: 404-639-1115 or the CDC Emergency Operations Center at 770-488-7100 after hours. CDC also provides consultation for international clinicians and health ministries. Whole blood or serum may be tested for virologic (RT-PCR, antigen detection, virus isolation) and immunologic (IgM, IgG) evidence of infection. Tissue may be tested with the following tests:

• Immunohistochemistry
• RT-PCR
• Virus isolation

Postmortem skin biopsies fixed in formalin and blood collected within a few hours after death by cardiac puncture can be used for diagnosis. Samples should be sent for testing to a reference laboratory with biosafety level 3 and 4 capability.

Treatment options

In most cases there is no specific treatment, with supportive care being the only remaining alternative. Ribavirin, an anti-viral drug, has been effective for treating Lassa fever, New World arenaviruses, and likely CCHF. However, it is not approved by the Food and Drug Administration (FDA) for these indications. Convalescent-phase plasma is effective in treating Argentine hemorrhagic fever.

Where to find medical care for Viral hemorrhagic fever?

Directions to Hospitals Treating Viral hemorrhagic fever

What to expect (Outlook/Prognosis)?

Hemorrhagic fever varies in severity. Severe infections with internal bleeding and fever (hemorrhagic fever) are deadly in up to half of cases.

Prevention

The risk of acquiring VHF is very low for international travelers. Travelers at increased risk for exposure include:

• Those engaging in animal research
• Health care workers
• Others providing care for patients in the community, particularly where outbreaks of VHF are occurring

Prevention should focus on avoiding contact with host or vector species:

• Travelers should not visit locations where an outbreak is occurring
• Contact with rodents should be avoided
• Travelers should avoid contact with livestock in RVF- and CCHF-endemic areas, and they should use insecticide-treated bed nets and insect repellent to prevent vector borne disease
• Direct contact should be avoided with corpses of patients suspected of having died of Ebola, Marburg, or Old World arenavirus infection
• Standard precautions and contact and droplet precautions for suspected VHF case-patients are recommended to avoid transmission
• Contact with or consumption of primates, bats, and other bushmeat should be avoided
• Bat-inhabited caves or mines should be avoided
• If an infection does occur, all efforts should focus on preventing further transmission of the disease to other humans
• Because rodents are an important vehicle of transmission of some viruses, it is important to:

• Control rodent populations
• Discourage people from letting rodents enter or living in homes or workplaces
• Encourage safe cleanup of rodent nests and droppings

• For hemorrhagic fever viruses spread by arthropod vectors, prevention efforts should focus on:

• Community-wide insect and arthropod control
• Encourage the use of insect repellant, proper clothing, bednets, window screens, and other insect barriers to avoid being bitten

• For hemorrhagic fever viruses that can be transmitted from one person to another, avoidance of close physical contact with infected people and their body fluids
• Barrier nursing or infection control techniques include isolating infected individuals and wearing protective clothing
• Other infection control recommendations include:

• Desisinfection, and disposal of instruments and equipment used in treating or caring for patients with VHF

Investigational vaccines exist for Argentine hemorrhagic fever and RVF however, neither is approved by FDA or commonly available in the United States.
The CDC in conjunction with the WHO, has developed practical, hospital-based guidelines, titled Infection Control for Viral Haemorrhagic Fevers In the African Health Care Setting.

Possible complications

• Coma
• Death
• Disseminated intravascular coagulation (DIC)
• Kidney failure
• Liver failure
• Parotitis
• Secondary bacterial infections
• Shock

Sources

http://wwwnc.cdc.gov/travel/yellowbook/2012/chapter-3-infectious-diseases-related-to-travel/viral-hemorrhagic-fevers.htm
http://www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages/vhf.htm Template:WSTemplate:WH