Hantavirus pulmonary syndrome

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at July 29, 2016
StartDiseasesHantavirus pulmonary syndrome

As the name suggests, hantavirus pulmonary syndrome (HPS for short) is caused by an infection with the hantavirus. The Centers for Disease Control and Prevention (CDC) describes this disease as severe and sometimes fatal. The principle cause of hantavirus pulmonary syndrome is contact with an infected rodent.

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Definition & Facts

Hantavirus pulmonary syndrome was first identified in 1993 after an outbreak in the Four Corners region of the United States (Colorado, Utah, Arizona, and New Mexico). However, scientists found that the disease dates back to 1959 after having examined historical tissue samples of people who had died of unknown respiratory disease and finding the same virus. In addition to North America, hantavirus pulmonary syndrome also strikes people in South America though is limited to the western hemisphere.

Hantavirus pulmonary syndrome has a similar presentation to acute respiratory distress syndrome which severely limits a person's capacity to breathe. Without diagnosis and prompt treatment, an individual with fluid in the lungs can die in a matter of hours. To date, the death toll from hantavirus pulmonary syndrome is high with up to 40 percent of infected individuals succumbing to the condition.

Symptoms & Complaints

During the first few days after hantavirus infection, symptoms are typically slight and are often mistaken for flu or the common cold. Such flu-like symptoms during the first few days following infection often include the following:

Starting around day four of infection, the symptoms begin to worsen rapidly. Bouts of increasingly intense coughing occur, and the lungs begin to fill up with fluid (pulmonary edema) upon which the individual begins to experience shortness of breath.

Heartbeat speeds up and breathing becomes shallow and fast. Some individuals report feeling like they are being slowly suffocated from within.

Causes

The hantavirus is spread through contact with rodents. Rodents are attracted to larger urban areas where scraps and garbage make for a plentiful food supply. Hantavirus pulmonary syndrome is primarily linked to deer mice, white-footed mice, rice rats and cotton rats.

The risk of contracting the syndrome is high or low depending on the different species of rodents present in the area. There are several different strains of hantavirus that can cause hantavirus pulmonary syndrome. Different rodents will be carriers for different strains as follows:

  • Deer mouse carries the Sin Nombre hantavirus, which is the primary cause of hantavirus pulmonary syndrome in America and Canada.
  • White-footed mouse carries the New York hantavirus. This virus is responsible for cases in the northeastern parts of North America.
  • Cotton rat and rice rat carry the Black Creek hantavirus which is responsible for cases in the southeastern areas of North America. 

The virus takes up residence in the urine, saliva and/or droppings of an infected rodent, where it can then be passed along to other rodents and to humans. There are several ways that an infected rodent can transmit hantavirus to humans:

  • Through a rodent bite.
  • Through skin contact with rodent urine or droppings followed by touching the eyes, mouth, or nose.
  • Through breathing in air saturated with hantavirus when a rodent's nest material gets stirred up and releases the hantavirus into the air supply.

To date, no known cases of human-to-human transmission of hantavirus pulmonary syndrome have been reported to the Centers for Disease Control.

Diagnosis & Tests

Prompt and accurate diagnosis of hantavirus pulmonary syndrome is vital, as this disease can be fatal if left untreated. The best course of action is to recollect any recent rodent contact and seek medical treatment immediately. 

The best method physicians have for diagnosing HPS at this time is to take a medical history and symptom history and match it to recent rodent exposure. If diagnostic questions remain, blood tests, chest X-rays and an oxygen saturation test (performed by using a device called an oximeter to measure the level of oxygen in the red blood cells) may be ordered.

Treatment & Therapy

Unfortunately, there is no vaccine available for hantavirus pulmonary syndrome at this time, and there is no single treatment that is guaranteed to cure an individual of hantavirus pulmonary syndrome once symptoms have begun.

The earlier an accurate diagnosis is sought, the more successful treatment is likely to be, but even then there are no guarantees. Treatment usually involves hospitalizing the infected individual and intubating them (putting a tube down their trachea to keep the air passages open for treatment) so they can receive oxygen therapy. Treatment can also involve a ventilator to deliver oxygen-rich air to the individual's body.

Medications and fluids may also be administered to keep the individual from becoming dangerously dehydrated or malnourished. If caught in time and treated promptly, the prognosis for recovery from hantavirus pulmonary syndrome is very good. The long-term patient outlook is also good with no lingering complications.

Prevention & Prophylaxis

The best method (and really the only method) of prevention is to ensure there is no contact with a rodent that might be infected with any strain of hantavirus. This includes ensuring that household pets do not bring home rodents that may be infected with hantavirus.

For individuals planning to camp or explore outdoors, it is important to steer clear of enclosed spaces or let them air out first before entering. Hand washing or using hand sanitizer before eating or drinking and drinking only purified water can also be a useful preventative measure. At home, ensuring any rodents are promptly removed from the property can drastically reduce the risk of contracting hantavirus in any of its forms. Commonsense rodent-prevention tactics include the following:

  • Tightly bag and enclose all garbage.
  • Block any areas where rodents may enter the home or outlying spaces.
  • Call in a professional exterminator when rodent dwellings/nests are discovered to ensure there is no direct contact with rodents during removal.