Symptoms

Signs and symptoms of viral hemorrhagic fevers vary by disease. In general, initial symptoms may include:

• High fever
• Fatigue
• Dizziness
• Muscle aches
• Weakness

Symptoms can become life-threatening Severe cases of some types of viral hemorrhagic fevers may cause bleeding:

• Under the skin
• In internal organs
• From the mouth, eyes or ears

Other signs and symptoms of severe infections can include:

• Shock
• Nervous system malfunctions
• Coma
• Delirium
• Seizures
• Kidney failure

When to see a doctor The best time to see a doctor is before you travel to a developing country to ensure you've received any available vaccinations and pre-travel advice for staying healthy. If you develop signs and symptoms once you return home, consider consulting a doctor who focuses on international medicine or infectious diseases. A specialist may be able to recognize and treat your illness faster. Be sure to let your doctor know what areas you've visited.

Causes

The viruses that cause viral hemorrhagic fevers live naturally in a variety of animal and insect hosts — most commonly mosquitoes, ticks, rodents or bats.

Each of these hosts typically lives in a specific geographic area, so each particular disease usually occurs only where that virus's host normally lives. Some viral hemorrhagic fevers also can be transmitted from person to person.

How is it transmitted? The route of transmission varies by specific virus. Some viral hemorrhagic fevers are spread by mosquito or tick bites. Others are transmitted by contact with infected blood or semen. A few varieties are breathed in if you're around infected rat feces or urine.

If you travel to an area where a particular hemorrhagic fever is common, you may become infected there and then develop symptoms after you return home.

Risk factors

Simply living in or traveling to an area where a particular viral hemorrhagic fever is common will increase your risk of becoming infected with that particular virus. Several other factors can increase your risk even more, including:

• Working with the sick
• Slaughtering infected animals
• Sharing needles to use intravenous drugs
• Having unprotected sex
• Working outdoors or in rat-infested buildings

Complications

Viral hemorrhagic fevers can damage your:

• Brain
• Eyes
• Heart
• Kidneys
• Liver
• Lungs
• Spleen

In some cases, the damage is severe enough to cause death.

Tests and diagnosis

Diagnosing specific viral hemorrhagic fevers in the first few days of illness can be difficult because the initial signs and symptoms — high fever, muscle aches, headaches and extreme fatigue — are common to many other diseases.

To reach an accurate diagnosis, your doctor is likely to ask about your medical and travel history and any exposure to rodents or mosquitoes. Be sure to describe international trips in detail, including the countries you visited and the dates, as well as any contact you may have had with possible sources of infection.

Laboratory tests, usually using a sample of your blood, are needed to confirm a diagnosis. Because viral hemorrhagic fevers are particularly virulent and contagious, these tests are usually performed in specially designated laboratories using strict precautions.

Treatments and drugs

MedicationsWhile no specific treatment exists for most viral hemorrhagic fevers, the antiviral drug ribavirin (Virazole, Rebetol) may help shorten the course of infection and prevent complications in some cases.

Therapy Supportive care is essential. To prevent dehydration, you may need fluids to help maintain your balance of electrolytes — minerals that are critical to nerve and muscle function.

Surgical and other procedures Some people may benefit from kidney dialysis, an artificial way of cleaning wastes from your blood when your kidneys fail.

Prevention

Preventing viral hemorrhagic fevers, especially in developing nations, presents enormous challenges. Many of the social, economic and ecological factors that contribute to the sudden appearance and spread of infectious diseases — war, displacement, destruction of habitat, lack of sanitation and proper medical care — are problems that have no easy or quick solutions.

If you live in or travel to areas where viral hemorrhagic fevers are common, you should take precautions to protect yourself from infection.

Get vaccinated The yellow fever vaccine is generally considered safe and effective, although in rare cases, serious side effects can occur. Check with the Centers for Disease Control and Prevention about the status of the countries you're visiting — some require certificates of vaccination for entry. The yellow fever vaccine isn't recommended for children under 9 months of age or for pregnant women, especially during the first trimester. Vaccines for several less common types of viral hemorrhagic fevers are currently in development.

Avoid mosquitoes and ticks Wear light-colored long pants and long-sleeved shirts or, better yet, permethrin-coated clothing. Don't apply permethrin directly to the skin. Avoid unnecessary activities at dusk and dawn when mosquitoes are most active and apply mosquito repellent with a 20 to 25 percent concentration of DEET to your skin and clothing. If you're staying in tented camps or local hotels, use bed nets and mosquito coils.

Guard against rodents To prevent rodent infestations in your home:

• Keep pet food covered and stored in rodent-proof containers.
• Store trash in rodent-proof containers, and clean the containers often.
• Dispose of garbage on a regular basis.
• Make sure doors and windows have tightfitting screens.
• Place woodpiles and stacks of bricks and other materials at least 100 feet from your house.
• Mow your grass closely and keep brush trimmed to within 100 feet from your house.