Hantavirus Infections - Symptoms

The two forms of hantavirus infections each have distinctive symptoms.

Hemorrhagic Fever with Renal Syndrome (HFRS)

The three most common symptoms of HFRS are mentioned in the name of the disease. The first of those symptoms is a fever. The second symptom is malfunction of the kidneys. The term renal means "relating to the kidneys." The third symptom is a low platelet count. Platelets are blood cells that promote the clotting of blood. When the number of platelets in blood is reduced, blood clotting does not occur properly. A person tends to hemorrhage (pronounced hem-ir-idj) or bleed easily.

Patients with HFRS have pain in the head, stomach, and lower back. They may also have bloodshot eyes and blurry vision. Hemorrhaging may occur through tiny openings on the upper body and in the mouth. The patient's face, chest, abdomen, and back often appear bright red, as if sunburned.

Five days into the disease, the patient may experience a sudden drop in blood pressure. He or she may go into shock. Shock occurs when the heart does not pump enough blood through the veins and arteries. Cells do not get blood and the needed oxygen it carries. Shock can cause damage to the body's organs, especially the brain.

After about eight days, kidney damage may taken place. The kidneys are responsible for filtering toxins (poisons) out of the blood. If the kidneys do not function properly, those toxins can damage cells throughout the body. Hemorrhaging may also become more serious throughout the body. Blood may begin to appear in the urine or when a person vomits. Hemorrhaging in the brain can cause the most serious problems that can include a loss of consciousness.

These symptoms can become even more serious about eleven days into the infection. A person may become very confused, begin to have hallucinations, and go into seizures. A person who hallucinates sees and hears things that are not really there. Problems can also develop with the lungs and the ability to breathe normally.

At this point, the patient faces a turning point. He or she may continue to become more and more ill, with death as the result. Or the infection may begin to clear up. In the latter case, full recovery may take up to six weeks.

Hantavirus Pulmonary Syndrome (HPS)

The first symptoms of HPS are fever and a sudden drop in blood pressure. These symptoms may be followed by shock and loss of blood in the lungs. When this happens, fluids may collect in the lungs, leading to shortness of breath. These symptoms can occur so quickly that the patient goes into respiratory failure in a matter of hours. Respiratory failure means that the patient has lost the ability to breathe on his or her own.

Blood tests are used to diagnose hantavirus infections. Blood taken from a patient is analyzed for the presence of certain hantavirus antibodies. Antibodies are substances produced by the blood when it has been infected by a foreign body, such as a bacterium or a virus. Antibodies are very specific. That is, a particular kind of antibody is produced to fight every different kind of infective agent (bacterium, fungus, virus, etc.). An analysis of a person's blood can tell whether he or she has been infected with a hantavirus and, if so, by what kind of hantavirus.

There is no way to kill the hantavirus. Treatments for hantavirus infections are designed, therefore, to relieve the symptoms of the disease. For example,

a person who has been hemorrhaging or who is in shock may require blood transfusions. Hemodialysis (pronounced HEE-mo-die-ali-sis) is used to remove toxins from the blood of a person whose kidneys have failed. Hemodialysis is a procedure by which a person's blood is passed through a machine to take out dangerous toxins (replacing the function of the kidneys).

Hantavirus infections progress very rapidly. It is important, therefore, to begin treatment as quickly as possible and to observe the patient very carefully.

An experimental drug being tested on hantavirus infections is called ribavirin (pronounced RI-buh-vih-rin). The drug has been shown to kill the hantavirus in laboratory tests. It is too soon to tell how well it will work in human beings.

Hantavirus infections are very lethal (capable of causing death). About 6 to 15 percent of those who develop HFRS will die of the disease. The death

The deer mouse is a carrier of one type of hantavirus that caused severe cases of HPS in the southwestern United States. (© 1997

S.R. Maglione

. Reproduced by permission of

Photo Researchers, Inc.

)

rate for those who contract (catch) HPS is about 50 percent. These numbers point out how important it is for people with symptoms of hantavirus infections to get treatment as quickly as possible.

There is no way to prevent a hantavirus infection. The best way to avoid getting the disease is to reduce one's exposure to the rodents that carry the virus. That means keeping one's living quarters as clean as possible.