Hantavirus

Answer 1

Definition

Hantavirus is a disease spread by rodents that is similar to the flu.

Alternative Names

Hantavirus pulmonary syndrome; Hemorrhagic fever with renal syndrome

Causes, incidence, and risk factors

Hantavirus has probably caused people to get sick for years in the United States, but it was not recognized until recently.

In 1993 there was an outbreak of fatal respiratory illness on an Indian reservation at the border of Utah, Colorado, New Mexico, and Arizona. Researchers discovered that hantavirus caused the epidemic. Since that discovery, hantavirus disease has been reported in every western state, and in many eastern states.

Hantavirus is carried by rodents, especially deer mice. The virus is in their urine and feces, but it does not make the carrier animal sick. Humans are thought to become infected when they are exposed to contaminated dust from mice nests or droppings.

The disease is not passed between humans. People may encounter contaminated dust when cleaning long-empty homes, sheds, or other enclosed areas.

The U.S. Centers for Disease Control and Prevention (CDC) reported that rodents carrying hantavirus have been found in at least twenty national parks. The CDC says it is possible that the virus is in all of the parks.

The CDC suspects that campers and hikers may be more likely to catch the disease than most people. This is because they pitch tents on the forest floor and lay their sleeping bags down in musty cabins.

So far, however, only a couple of cases have been directly linked to camping or hiking. Most people who are exposed to the virus have come in contact with rodent droppings in their own homes.

Symptoms

The early symptoms of hantavirus disease are flu-like (fever, chills, muscle aches). For a very short period of time, the infected person starts to feel better. Then, within 1 - 2 days, the person may develop shortness of breath. The disease gets worse quickly and leads to respiratory failure.

Other symptoms may include:

• Dry cough
• General ill feeling (malaise)
• Headache
• Nausea and vomiting
• Rapid shallow breathing

Signs and tests

A doctor may notice signs of:

• Acute respiratory distress syndrome (ARDS)
• Decreased blood pressure (hypotension)
• Decreased levels of oxygen in the blood (hypoxia), causing the skin to have a bluish color (cyanosis)
• Kidney failure

Tests include:

• Complete blood count (CBC)
• Hematocrit
• Liver enzymes
• Platelet count
• Serologicaltesting for hantavirus
• Serum albumin
• Serum chemistry
• X-ray of the chest

Treatment

An effective treatment for hantavirus infection involving the lungs is not yet available.

Hantavirus hemorrhagic fever that involves the kidneys (with renal syndrome) does respond to treatment with ribavirin given through a vein (intravenously). This medication shortens the illness and reduces the risk of death.

Treatment must be given in the hospital. Often patients are admitted to an intensive care unit.

Oxygen therapy is used. Blood gases are closely monitored. Severe cases will need respiratory support with a breathing tube (endotracheal tube) and ventilator.

Expectations (prognosis)

Hantavirus is a serious infection. Even with aggressive treatment, more than half of the cases are fatal.

Complications

• Cardiorespiratory failure
• Death
• Kidney failure

Calling your health care provider

Call your health care provider if you develop flu-like symptoms after being exposed to mouse urine or feces (excreta), or dust that may have been contaminated with mouse excreta.

Prevention

Avoid exposure to rodent urine and feces.

• When hiking and camping, pitch tents in areas where there are no rodent droppings.
• Avoid rodent dens.
• Drink disinfected water.
• Sleep on a ground cover and pad.
• Keep your home clean. Clear out potential nesting sites and clean your kitchen.

If you must work in an area where contact with rodent urine and feces is possible, follow these recommendations from the Centers for Disease Control and Prevention (CDC):

1. When opening an unused cabin, shed, or other building, open all the doors and windows, leave the building, and allow the space to air out for 30 minutes.
2. Return to the building and spray the surfaces, carpet, and other areas with a disinfectant. Leave the building for another 30 minutes.
3. Spray mouse nests and droppings with a 10% solution of chlorine bleach or similar disinfectant. Allow it to sit for 30 minutes. Using rubber gloves, place the materials in plastic bags. Seal the bags and throw them in the trash or an incinerator. Dispose of gloves and cleaning materials in the same way.
4. Wash all potentially contaminated hard surfaces with a bleach or disinfectant solution. Avoid vacuuming until the area has been thoroughly decontaminated. Then, vacuum the first few times with enough ventilation. Surgical masks may provide some protection.

References

Bell M. Viral hemorrhagic fevers. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 404.

Answer 2

Definition

Hantavirus is a life-threatning disease spread to humans by rodents that has symptoms similar to influenza.

Alternative Names

Hantavirus pulmonary syndrome; Hemorrhagic fever with renal syndrome

Causes, incidence, and risk factors

Hantavirus is carried by rodents, especially deer mice. The virus is found in their urine and feces, but it does not make the animal sick.

It is believed that humans can get sick with this virus if they come in contact with contaminated dust from mice nests or droppings. You may come in contact with such dust when cleaning homes, sheds, or other enclosed areas that have been empty for a long time.

Hantavirus does not spread between humans.

Rodents carrying the hantavirus have been found in many U.S. national parks. Campers and hikers may be more likely to catch the disease than most people. This is because they pitch tents on the forest floor and lay their sleeping bags down in musty cabins.

However, only a couple of cases have been directly linked to camping or hiking. Most people who are exposed to the virus have come in contact with rodent droppings in their own homes.

Symptoms

The early symptoms of hantavirus disease are similar to the flu and include:

• Chills
• Fever
• Muscle aches

People with hantavirus may begin to feel better for a very short amount of time, but within 1-2 days, it becomes hard to breathe. The disease gets worse quickly. Symptoms include:

• Dry cough
• General ill feeling (malaise)
• Headache
• Nausea and vomiting
• Shortness of breath

Signs and tests

The health care provider will perform a physical exam. This may reveal:

• Acute respiratory distress syndrome (ARDS)
• Kidney failure
• Low blood pressure (hypotension)
• Low blood oxygen levels, which cause the skin to turn a blue color

The folllowing tests may be done:

• Blood tests to check for signs of hantavirus
• Complete blood count (CBC)
• Complete metabolic panel
• Kidney and liver function tests
• X-ray of the chest

Treatment

People with hantavirus are admitted to the hospital, often to the intensive care unit (ICU).

Treatments will include:

• Oxygen
• Breathing tube or breathing machine in severe cases
• A medication called ribavirin to treat kidney-related problems and reduce the risk of death

There is no effective treatment for hantavirus infection involving the lungs.

Expectations (prognosis)

Hantavirus is a serious infection that gets worse quickly. Lung failure can occur and may lead to death. Even with aggressive treatment, more than half of people who have this disease in their lungs die.

Complications

Complications of hantavirus may include:

• Kidney failure
• Heart and lung failure

These complications can lead to death.

Calling your health care provider

Call your health care provider if you develop flu-like symptoms after you come in contact with rodent droppings or rodent urine, or dust that is contaminated with these substances.

Prevention

Avoid exposure to rodent urine and droppings.

• When hiking and camping, pitch tents in areas where there are no rodent droppings.
• Avoid rodent dens.
• Drink disinfected water.
• Sleep on a ground cover and pad.
• Keep your home clean. Clear out potential nesting sites and clean your kitchen.

If you must work in an area where contact with rodent urine or feces is possible, follow these recommendations from the Centers for Disease Control and Prevention (CDC):

1. When opening an unused cabin, shed, or other building, open all the doors and windows, leave the building, and allow the space to air out for 30 minutes.
2. Return to the building and spray the surfaces, carpet, and other areas with a disinfectant. Leave the building for another 30 minutes.
3. Spray mouse nests and droppings with a 10% solution of chlorine bleach or similar disinfectant. Allow it to sit for 30 minutes. Using rubber gloves, place the materials in plastic bags. Seal the bags and throw them in the trash or an incinerator. Dispose of gloves and cleaning materials in the same way.
4. Wash all potentially contaminated hard surfaces with a bleach or disinfectant solution. Avoid vacuuming until the area has been thoroughly decontaminated. Then, vacuum the first few times with enough ventilation. Surgical masks may provide some protection.

References

Bell M. Viral hemorrhagic fevers. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 404.

Peters CJ. California encephalitis, hantavirus pulmonary syndrome, and bunyavirid hemorrhagic fevers. In: Mandell GL, Bennett JE, Dolin R, eds. Douglas and Bennett's Principles and Practice of Infectious Disease. 7th ed. Philadelphia, Pa: Saunders Elsevier; 2009:chap 166.

Reviewed By

Review Date: 03/11/2011

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.