Respiratory syncytial virus infection
Respiratory syncytial virus (RSV) is a virus that can cause severe lower respiratory infections in children under the age of two, and milder upper respiratory infections in older children and adults. RSV infection is also called bronchiolitis, because it is marked in young children by inflammation of the bronchioles. Bronchioles are the narrow airways that lead from the bronchi to the tiny air sacs (alveoli) in the lungs. The result is wheezing, difficulty breathing, and sometimes fatal respiratory failure.
RSV infection is caused by a group of viruses found worldwide. There are twodifferent subtypes with numerous different strains. Taken together, these viruses account for a significant number of deaths in infants.
RSV infection is primarily a disease of winter or early spring, with waves ofillness sweeping through a community. The rate of RSV infection is estimatedto be 11.4 cases in every 100 children during their first year of life. In the United States, RSV infection occurs most frequently in infants between theages of two and six months.
RSV infection shows distinctly different symptoms, depending on the age of the infected person. In children under two, the virus causes a serious lower respiratory infection in the lungs. In older children and healthy adults, it causes a mild upper respiratory infection often mistaken for the common cold.
Although anyone can get this disease, infants suffer the most serious symptoms and complications. Breast feeding seems to provide partial protection fromthe virus. Conditions in infants that increase their risk of infection include:
- Premature birth
- Lower socio-economic environment
- Congenital heart disease
- Chronic lung diseases, such as cystic fibrosis
- Immune system deficiencies, including HIV infection
- Immunosuppressive therapy given to organ transplant patients.
Many older children and adults get RSV infection, but the symptoms are so similar to the common cold that the true cause often goes undiagnosed. People ofany age with weakened immune systems, either from such diseases as AIDS or leukemia, or as the result of chemotherapy or corticosteroid medications, aremore at risk for serious RSV infections. So are people with chronic lung disease.
RSV is spread through close contact with an infected person. It has been shown that if a person with RSV infection sneezes, the virus can be carried to others within a radius of six feet. This group of viruses is hardy. They can live on the hands for up to half an hour and on toys or other inanimate objectsfor several hours.
Scientists have yet to understand why RSV viruses attack the lower respiratory system in infants and the upper respiratory system in adults. In infants, RSV begins with such cold symptoms as a low fever, runny nose, and sore throat. Soon, other symptoms appear that suggest an infection which involves the lower airways. Some of these symptoms resemble those of asthma. RSV infection is suggested by:
- Wheezing and high-pitched, whistling breathing
- Rapid breathing (more than 40 breaths per minute)
- Shortness of breath
- Labored breathing out (exhalations)
- Bluish tinge to the skin (cyanosis)
- Croupy, seal-like, barking cough
- High fever.
Breathing problems occur in RSV infections because the bronchioles swell, making it difficult for air to get in and out of the lungs. If the child is having trouble breathing, immediate medical care is needed. Breathing problems are most common in infants under one year of age; they can develop rapidly.
RSV infection is usually diagnosed during a physical examination by the pediatrician or primary care doctor. The doctor listens with a stethoscope for wheezing and other abnormal lung sounds in the patient's chest. The doctor willalso take into consideration whether there is a known outbreak of RSV infection in the area. Chest x rays give some indication of whether the lungs are over-inflated from an effort to move air in and out. X rays may also show the presence of a secondary bacterial infection, such as pneumonia.
A blood test can also detect RSV infection. This test measures the level of antibodies (infection fighters) the body has formed against the virus. The blood test is less reliable in infants than in older children because antibodiesin the infant's blood may have come from the mother during pregnancy. If infants are hospitalized, other tests such as an arterial blood gas analysis aredone to determine if the child is receiving enough oxygen.
Home care for keeping a child with RSV comfortable and breathing more easilyincludes:
- Use a cool mist room humidifier to ease congestion and sorethroat.
- Raise the baby's head by putting books under the head end ofthe crib.
- Give acetaminophen (Tylenol, Panadol, Tempra) for fever.Aspirin should not be given to children because of its association with Reye's syndrome, a serious disease.
- For babies too young to blow their noses, suction away any mucus with an infant nasal aspirator.
Dehydration can be a problem, so children should be encouraged to drink plenty of fluids. Antibiotics have no effect on viral illnesses, therefore, the body must make antibodies to fight the infection and return itself to health.
In the United States, RSV infections are responsible for more than 90,000 hospitalizations and 4,500 deaths each year. Children who are hospitalized receive oxygen and humidity through a mist tent or vaporizer. They also are givenintravenous fluids to prevent dehydration. Mechanical ventilation may be necessary, and blood gases are monitored to assure that the child is receiving enough oxygen.
Bronchodilators, such as albuterol (Proventil, Ventilin), may be used to keepthe airways open. Ribavirin (Virazole) is used for desperately ill childrento stop the growth of the virus. Ribavirin is both expensive and has toxic side effects, so its use is restricted to the most severe cases.
Alternative medicine has little to say specifically about bronchiolitis, especially in very young children. However, practitioners emphasize that people get viral illnesses because their immune systems are weak. Prevention focuseson strengthening the immune system by eating a healthy diet low in sugars andhigh in fresh fruits and vegetables, reducing stress, and getting regular, moderate exercise. Like traditional practitioners, alternative practitioners recommend breast feeding infants so that the child may benefit from the positive state of health of the mother. Inhaling a steaming mixture of lemon oil, thyme oil, eucalyptus, and tea tree oil (aromatherapy) may make breathing easier.
RSV infection usually runs its course in 7-14 days. The cough may linger weeks longer. There are no medications that can speed the body's production of antibodies against the virus. Bacterial infections that take advantage of a weakened respiratory system may cause ear, sinus, and throat infections or pneumonia. These can be treated with antibiotics.
Hospitalization and death are much more likely to occur in children whose immune systems are weakened or who have underlying diseases of the lungs and heart. People do not gain permanent immunity to respiratory syncytial virus andcan be infected many times. Children who suffer repeated infections seem to be more likely to develop asthma in later life.
As of 1998 there were no vaccines against RSV. The infection is so common that prevention is impossible. However, steps can be taken to reduce a child's contact with the disease. People with RSV symptoms should stay at least six feet away from young children; frequent hand washing, especially after contactwith respiratory secretions, and the correct disposal of used tissues, help keep the disease from spreading; parents should try to keep their children under 18 months old away from crowded environments such as shopping malls duringholiday seasons--where they are likely to come in contact with older peoplewho have only mild symptoms of the disease; and child care centers should regularly disinfect surfaces that children touch.