Hantavirus infection is caused by a group of viruses that can infect humans with two serious illnesses: hemorrhagic fever with renal syndrome (HFRS), and Hantavirus pulmonary syndrome (HPS).
Hantaviruses are found without causing symptoms within various species of rodents and are passed to humans by exposure to the urine, feces, or saliva of those infected rodents. Ten different hantaviruses have been identified as important in humans. Each is found in specific geographic regions, and therefore is spread by different rodent carriers. Further, each type of virus causes a slightly different form of illness in its human hosts:
- Hantaan virus is carried by the striped field mouse, and exists in Korea, China, Eastern Russia, and the Balkans. Hantaan virus causes a severe form of hemorrhagic fever with renal syndrome (HFRS).
- Puumula virus is carried by bank voles, and exists in Scandinavia, western Russia, and Europe. Puumula virus causes a milder form of HFRS, usually termed nephropathia epidemica.
- Seoul virus is carried by a type of rat called the Norway rat, and exists worldwide, but causes disease almost exclusively in Asia. Seoul virus causes a form of HFRS that is slightly milder than that caused by Hantaan virus, but results in liver complications.
- Prospect Hill virus is carried by meadow voles and exists in the United States, but has not been found to cause human disease.
- Sin Nombre virus, the most predominant strain in the United States, is carried by the deer mouse. This virus was responsible for severe cases of HPS that occurred in the Southwestern United States in 1993.
- Black Creek Canal virus has been found in Florida. It is predominantly carried by cotton rats.
- New York virus strain has been documented in New York State. The vectors for this virus seem to be deer mice and white-footed mice.
- Bayou virus has been reported in Louisiana and Texas and is carried by the marsh rice rat.
- Blue River virus has been found in Indiana and Oklahoma and seems to be associated with the white-footed mouse.
- Monongahela virus, discovered in 2000, has been found in Pennsylvania and is transmitted by the white-footed mouse.
Causes and symptoms
Hemorrhagic fever with renal syndrome (HFRS)
Hantaviruses that produce forms of hemorrhagic fever with renal syndrome (HFRS) cause a classic group of symptoms, including fever, malfunction of the kidneys, and low platelet count. Because platelets are blood cells important in proper clotting, low numbers of circulating platelets can result in spontaneous bleeding, or hemorrhage.
Patients with HFRS have pain in the head, abdomen, and lower back, and may report bloodshot eyes and blurry vision. Tiny pinpoint hemorrhages, called petechiae, may appear on the upper body and the soft palate in the mouth. The patient's face, chest, abdomen, and back often appear flushed and red, as if sunburned.
After about five days, the patient may have a sudden drop in blood pressure; often it drops low enough to cause the clinical syndrome called shock. Shock is a state in which blood circulation throughout the body is insufficient to deliver proper quantities of oxygen. Lengthy shock can result in permanent damage to the body's organs, particularly the brain, which is very sensitive to oxygen deprivation.
Around day eight of HFRS, kidney involvement results in multiple derangements of the body chemistry. Simultaneously, the hemorrhagic features of the illness begin to cause spontaneous bleeding, as demonstrated by bloody urine, bloody vomit, and in very serious cases, brain hemorrhages with resulting changes in consciousness.
Day eleven often brings further chemical derangements, with associated confusion, hallucinations, seizures, and lung complications. Those who survive this final phase usually begin to turn the corner toward recovery at this time, although recovery takes approximately six weeks.
Hantavirus pulmonary syndrome (HPS)
Hantavirus pulmonary syndrome (HPS) develops in four stages. They are:
- The incubation period. This lasts from one to five weeks from exposure. Here, the patient may exhibit no symptoms.
- The prodrome, or warning signs, stage. Symptoms begin with a fever, muscle aches, headache, dizziness, and abdominal pain and upset. Sometimes there is vomiting and diarrhea.
- The cardiopulmonary stage. The patient slips into this stage rapidly, sometimes within a day or two of initial symptoms; sometimes as long as 10 days later. There is a drop in blood pressure, shock, and leaking of the blood vessels of the lungs, which results in fluid accumulation in the lungs, and subsequent shortness of breath. The fluid accumulation can be so rapid and so severe as to put the patient in respiratory failure within only a few hours. Some patients experience severe abdominal tenderness.
- The convalescent stage. If the patient survives the respiratory complications of the previous stage, there is a rapid recovery, usually within a day or two. However, abnormal liver and lung functioning may persist for six months.
Serologic techniques help diagnose a hantavirus infection. The patient's blood is drawn, and the ELISA (enzyme-linked immunosorbent assay) is done in a laboratory to identify the presence of specific immune substances (antibodies)—substances which an individual's body would only produce in response to the hantavirus.
It is very difficult to demonstrate the actual virus in human tissue, or to grow cultures of the virus within the laboratory, so the majority of diagnostic tests use indirect means to demonstrate the presence of the virus.
Treatment of hantavirus infections is primarily supportive, because there are no agents available to kill the viruses and interrupt the infection. Broad-spectrum antibiotics are given until the diagnosis is confirmed. Supportive care consists of providing treatment in response to the patient's symptoms. Because both HFRS and HPS progress so rapidly, patients must be closely monitored, so that treatment may be started at the first sign of a particular problem. Low blood pressure is treated with medications. Blood transfusions are given for both hemorrhage and shock states. Hemodialysis is used in kidney failure. (Hemodialysis involves mechanically cleansing the blood outside of the body, to replace the kidney's normal function of removing various toxins form the blood.) Rapid respiratory assistance is critical, often requiring intubation.
The anti-viral agent ribavirin has been approved for use in early treatment of hantavirus infections.
The diseases caused by hantaviruses are extraordinarily lethal. About 6-15% of people who contract HFRS have died. Almost half of all people who contract HPS will die. This gives HPS one of the highest fatality rates of any acute viral disease. It is essential that people living in areas where the hantaviruses exist seek quick medical treatment should they begin to develop an illness that might be due to a hantavirus.
There are no immunizations currently available against any of the hantaviruses. In 2003, developments in genetic science were helping researchers work on a possible vaccination and therapy for several versions of hantavirus, including the Sin Nombre virus that causes HPS. With further work, a gene-based vaccine could become available in the future. However, the only known forms of hantavirus prevention involve rodent control within the community and within individual households. The following is a list of preventive measures:
- Avoiding areas known to be infested by rodents is essential.
- Keeping a clean home and keeping food in rodent-proof containers.
- Disposing of garbage and emptying pet food dishes at night.
- Setting rodent traps around baseboards and in tight places. Disposing of dead animals with gloves and disinfecting the area with bleach.
- Using rodenticide as necessary.
- Sealing any entry holes 0.25 inch wide or wider around foundations with screen, cement, or metal flashing.
- Clearing brush and junk from house foundations.
- Putting metal flashing around house foundations.
- Elevating hay, woodpiles, and refuse containers.
- Airing out all sealed outbuildings or cabins 30 minutes before cleaning for the season.
- When camping, avoiding sleeping on the bare ground. It is advised to sleep on a cot or in a tent with a floor.
Harper, David R., and Andrea S. Meyer. Of Mice, Men, and Microbes: Hantavirus. San Diego: Academic Press, 1999.
"DNA Vaccine Protects Against Hantavirus Pulmonary Syndrome." Heart Disease Weekly November 2, 2003: 31.
Jones, Amy. "Setting a Trap for Hantavirus." Nursing September 2000: 20.
Monroe, Martha C., Sergey P. Morzunov, Angela M. Johnson, Michael De. Bowen, et al. "Genetic Diversity and Distribution of Peromyscus-Borne Hantaviruses in North America." Nursing January-February 1999: 75-86.
Naughton, Laurie. "Hantavirus Infection in the United States: Are We Prepared?" Physician Assistant May 2000: 33.
Rhodes III, Luther V., Cinnia Huang, Angela J. Sanchez, Stuart T. Nichol, et al. "Hantavirus Pulmonary Syndrome Associated with Monongahela Virus, Pennsylvania." Emerging Infectious Diseases November 2000: 616.
Van Bevern, Pamela A. "Hantavirus Pulmonary Syndrome." Clinician Reviews July 2000: 108.
Hemodialysis— A method of mechanically cleansing the blood outside of the body, in order to remove various substances that would normally be cleared by the kidneys. Hemodialysis is used when an individual is in relative, or complete, kidney failure.
Hemorrhagic— A condition resulting in massive, difficult-to-control bleeding.
Petechiae— Pinpoint size red spots caused by hemorrhaging under the skin.
Platelets— Circulating blood cells that are crucial to the mechanism of clotting.
Prodrome— Early symptoms or warning signs
Pulmonary— Referring to the lungs.
Renal— Referring to the kidneys.
Shock— Shock is a state in which blood circulation is insufficient to deliver adequate oxygen to vital organs.
"Hantavirus Infections." Gale Encyclopedia of Medicine, 3rd ed.. . Encyclopedia.com. (December 15, 2017). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/hantavirus-infections
"Hantavirus Infections." Gale Encyclopedia of Medicine, 3rd ed.. . Retrieved December 15, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/hantavirus-infections
hantavirus, any of a genus (Hantavirus) of single-stranded RNA viruses that are carried by rodents and transmitted to humans when they inhale vapors from contaminated rodent urine, saliva, or feces. There are many strains of hantavirus. The first to be isolated (1976) was the Hantaan virus (from the Han River in South Korea, which also gives the species its name). Hantaan virus and its related strains, Seoul virus and Puulmala virus, cause Korean hemorrhagic fever (more correctly, hemorrhagic fever with renal syndrome), a condition in which the capillaries of the circulatory system begin to leak blood. Although some people with the disease are nearly asymptomatic, in others it can lead to shock, acute kidney failure, and, in 10% of cases, death.
A second disease, hantavirus pulmonary syndrome, was identified in the United States in 1993 and is caused by at least three strains of the virus. It is known to be carried by deer mice, white-footed mice, and cotton rats. This disease is much more deadly, causing flulike symptoms that can lead to fluid accumulation in the lungs and death. One of the pulmonary strains, the Sin Nombre virus (named for a Spanish massacre of Native Americans that occurred in the canyon where it was discovered), was the cause of a 1993 outbreak in the Four Corners area of the SW United States that killed 32 of 53 people known to have been infected. Hantavirus pulmonary syndrome occurs sporadically in North America, with roughly one third of those known to be infected dying from the disease. Outbreaks of a hantavirus strain that apparently can be spread from person to person occurred in South America in 1996 and 1997. There is no vaccination for pulmonary hantavirus. Treatment includes respiratory and hemodynamic support; the antiviral drug ribavirin has been effective in some cases.
"hantavirus." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (December 15, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/hantavirus
"hantavirus." The Columbia Encyclopedia, 6th ed.. . Retrieved December 15, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/hantavirus
HANTAVIRUS refers both to a family of biological viruses that can be transmitted from animals to humans and to hantavirus pulmonary syndrome—the highly fatal infection caused by the viruses. Most often transmitted by exposure to the droppings of rodents, especially deer mice, infected individuals experience fever, nausea, vomiting, muscle and head aches, and, if left untreated, respiratory distress that can result in death. Other hantaviruses produce kidney disease.
As of 2003, an effective treatment for hantavirus was not yet available. Although long recognized in other countries, the disease was fairly rare in the United States, and the likelihood of infection was low. The first outbreak in the United States occurred in May 1993 in the Four Corners area of Arizona, Colorado, New Mexico, and Utah, and by April 2001, 283 cases of the disease had been reported in thirty-one states.
Hjelle, B., S. Jenison, G. Mertz, et al. "Emergence of Hantaviral Disease in the Southwestern United States." Western Journal of Medicine 161, no. 5 (1994): 467–473.
Schmaljohn, C. S., and S. T. Nichol, eds. Hantaviruses. Berlin and New York: Springer Verlag, 2001.
See alsoEpidemics and Public Health .
"Hantavirus." Dictionary of American History. . Encyclopedia.com. (December 15, 2017). http://www.encyclopedia.com/history/dictionaries-thesauruses-pictures-and-press-releases/hantavirus
"Hantavirus." Dictionary of American History. . Retrieved December 15, 2017 from Encyclopedia.com: http://www.encyclopedia.com/history/dictionaries-thesauruses-pictures-and-press-releases/hantavirus
Hantavirus infections are caused by a group of viruses known as hantaviruses. These viruses cause two serious illnesses in humans. They are hemorrhagic (pronounced heh-meh-RA-jik) fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS).
Hantaviruses live in rodents, such as rats and mice, without causing any symptoms. The viruses can be transmitted (passed on to) humans by way of urine, feces, or saliva from the rodents. Five different kinds of hantaviruses have been discovered so far. Each is found in a different geographical region and in different kinds of rodents. As an example, the virus known as the hantaan virus is carried by the striped field mouse. It is found primarily in Korea, China, East Russia, and the Balkans. This virus causes HFRS. Another type of hantavirus is called the Sin Nombre virus. It is carried by the deer mouse and found primarily in southwestern United States and causes severe cases of HPS.
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 Infections: Words to Know
- A mechanical method for cleansing blood outside the body.
- Relating to a condition in which there is massive, difficult-to-control bleeding.
- Blood cells that have a role in the process of blood clotting.
- Relating to the lungs.
- Relating to the kidneys.
- A condition in which blood pressure drops suddenly and the flow of blood to cells is dramatically reduced. Because of this reduced flow, cells are not able to get the oxygen they need.
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
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.
FOR MORE INFORMATION
Harper, David R. and Andrea S. Meyer. Of Mice, Men, and Microbes; Hantavirus. New York: Academic Press Inc., 1999.
Stoffman, Phyllis. The Family Guide to Preventing and Treating 100 Infectious Diseases. New York: John Wiley & Sons, 1995.
"Outbreak of Hantavirus Is Unusual." The New York Times (June 17, 1997): pp. C4+.
"Hantavirus Infections." UXL Complete Health Resource. . Encyclopedia.com. (December 15, 2017). http://www.encyclopedia.com/medicine/news-wires-white-papers-and-books/hantavirus-infections
"Hantavirus Infections." UXL Complete Health Resource. . Retrieved December 15, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/news-wires-white-papers-and-books/hantavirus-infections
Hantavirus Pulmonary Syndrome
Hantavirus Pulmonary Syndrome
Hantavirus pulmonary syndrome (HAN-tuh-vy-rus PUL-mo-nar-ee SIN-drome) is a lung disease that causes respiratory distress (breathing difficulty) and, in some cases, death. Hantavirus, the virus that causes the disease, is carried by rodents.
for searching the Internet and other reference sources
Sin Nombre virus
Hantavirus pulmonary syndrome, or HPS, is a potentially deadly disease that attacks the lungs. A family of viruses called hantavirus causes HPS. These viruses live in rodents but do not make them sick. The Sin Nombre virus (SNV) hantavirus causes most HPS in the United States, but some cases have come from the Bayou, the New York, and the Black Creek Canal viruses.
Camp with Care
The great outdoors is home for most rodents, and many of them carry hantavirus. Campers can help keep camping and hiking trips safe by following a few simple precautions:
- using a tent with a built-in floor and pitching it away from woodpiles or any rodent nests or burrows
- sleeping on a raised surface, at least 12 inches off the floor
- airing out cabins that have not been used for a half hour or more, then checking for rodent droppings
- using water and disinfectant to wipe out the area (no sweeping!)
- keeping all food in rodent-proof containers
- burying or burning trash
- using bottled water for drinking, cooking, and all washing
- staying away from mice, rats, chipmunks, and all other rodents.
Rodents, usually mice and rats, shed hantavirus in their saliva, urine, and droppings. Humans catch the virus when they disturb dried droppings (by sweeping, for example) and inhale the particles that are sent into the air. People can also contract hantavirus by touching an infected animal or its droppings and then touching their nose or mouth. Eating food or drinking water contaminated by rodent droppings is another source of infection. Rodent bites, although rare, can also spread the disease.
The most common carriers of hantavirus are deer mice (found almost everywhere in North America), cotton rats and rice rats (found in the southeastern United States and Central and South America), and white-footed mice (found in most parts of the United States and Mexico). Cats and dogs do not carry hantavirus and they cannot catch it from rodents. However, cats and dogs can spread hantavirus to humans if they bring an infected rodent into a home or other buildings where people live or work.
HPS is rare. Health authorities first recognized the disease in the United States in 1993, and the U.S. Centers for Disease Control and Prevention (CDC) recorded only 333 reported cases through early 2003. Although HPS occurs in people throughout North and South America, most cases in the United States appear in the Southwest and in places that are infested with rodents.
People of every age, sex, and race can contract HPS, but it is not contagious and cannot be spread by sneezing, coughing, kissing, or having other bodily contact.
The first symptoms of HPS usually appear 1 to 5 weeks after a person has been exposed to the virus. HPS can be difficult to diagnose because the early signs, such as fever, tiredness, and body aches, are similar to those of the flu. About half of the people who catch HPS also may experience dizziness, chills, nausea, vomiting, abdominal* pain, or headaches.
- (ab-DAH-mih-nul) refers to the area of the body below the ribs and above the hips that contains the stomach, intestines, and other organs.
From 2 to 5 days after the first symptoms, a person infected with hantavirus starts coughing and experiences shortness of breath. The disease quickly becomes more severe, and people who do not receive immediate treatment may become extremely ill and go into shock*, needing intensive care in a hospital.
- is a serious condition in which blood pressure is very low and not enough blood flows to the body’s organs and tissues. Untreated, shock may result in death.
A doctor may suspect HPS if a person with flulike symptoms complains about difficulty breathing, especially if the person has been exposed to rodents or rodent droppings. To confirm the diagnosis, the doctor uses blood tests to see if the person has developed antibodies* to a strain* of hantavirus. Chest X rays or ultrasound* images can help the doctor check the condition of a person’s heart and lungs.
- (AN-tih-bah-deez) are protein molecules produced by the body’s immune system to help fight specific infections caused by microorganisms, such as bacteria and viruses.
- are various subtypes of organisms, such as viruses or bacteria.
- *ultrasound ,
- also called a sonogram, is a diagnostic test in which sound waves passing through the body create images on a computer screen.
HPS is a serious disease, and someone who has it needs treatment in a hospital’s intensive care unit. There he might be given fluids, have his blood pressure monitored, and have a tube inserted in his throat to help him breathe. Because a virus causes HPS, antibiotics do not work against it, although an antiviral drug may help some patients. According to the CDC, 38 percent of reported cases of HPS have been fatal.
Doctors today know more about the disease and are quicker to get patients into treatment. The earlier people with HPS receive help, the better their chances of survival. Recovery from HPS is fairly fast, although patients may feel worn out for several months.
There is no vaccination available for HPS. The best way to avoid contracting the virus is to get rid of possible sources of infection, which means avoiding woodpiles and other places where rodents live outdoors and keeping homes and workplaces free of mice and rats. Experts also recommend sealing holes where rodents can enter (they can squeeze through spaces as small as .25 inch in diameter) and wearing a mask and gloves when cleaning out areas with rodent droppings.
National Center for Infectious Diseases, U.S. Centers for Disease Control and Prevention, Mailstop C-14, 1600 Clifton Road, Atlanta, GA 30333. The website for this government agency provides an extensive look at HPS, including advice on preventing the disease.
Telephone 800-311-3435 http://www.cdc.gov/ncidod
Discovery Online. Death in the Desert. This article, which can be found through the site’s Plague Patrol page, describes how researchers found hantavirus in the American Southwest in 1993, solving several mysterious deaths.
"Hantavirus Pulmonary Syndrome." Complete Human Diseases and Conditions. . Encyclopedia.com. (December 15, 2017). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/hantavirus-pulmonary-syndrome
"Hantavirus Pulmonary Syndrome." Complete Human Diseases and Conditions. . Retrieved December 15, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/hantavirus-pulmonary-syndrome
"hantavirus." A Dictionary of Nursing. . Encyclopedia.com. (December 15, 2017). http://www.encyclopedia.com/caregiving/dictionaries-thesauruses-pictures-and-press-releases/hantavirus
"hantavirus." A Dictionary of Nursing. . Retrieved December 15, 2017 from Encyclopedia.com: http://www.encyclopedia.com/caregiving/dictionaries-thesauruses-pictures-and-press-releases/hantavirus