Respiratory Syncytial Virus Infection

Respiratory syncytial virus infection occurs almost exclusively in infants and young children. It's the leading cause of lower respiratory tract infections, pneumonia, tracheobronchitis, and bronchiolitis in this age group. It's also a suspected cause of the fatal respiratory diseases of infancy.

Rates of illness are highest among infants age 1 to 6 months; incidence peaks betWeen 2 and 3 months. Those in day-care settings are especially susceptible. This virus creates annual epidemics during winter and spring.

Causes

Respiratory syncytial virus infection results from a subgroup of the myxoviruses that resemble paramyxovirus. The organism is transmitted from person to person by respiratory secretions and has an incubation period of 4 to 5 days.

Reinfection is common, producing milder symptoms than the primary infection. School-age children, adolescents, and young adults with mild reinfections are probably the sources of infection for infants and young children.

Signs and symptoms

The following are the most common symptoms of RSV. However, each baby may experience symptoms differently. Symptoms may include:

• runny nose
• apnea
• listlessness
• fever
• poor feeding
• wheezing
• retractions (pulling in) of the chest wall
• rapid breathing
• cough

The symptoms of RSV may resemble other conditions or medical problems. Always consult your baby's physician for a diagnosis.

Diagnostic tests 

Cultures of nasal and pharyngeal secretions may show respiratory syncytial virus; however, the virus is very labile, so cultures aren't always reliable.

Serum antibody titers may be elevated, but in infants under age 4 months, maternal antibodies may impair test results.

Two serologic techniques that give rapid results are indirect immunofluorescence and the enzyme­linked immunosorbent assay (ELISA). However, these tests are an impractical diagnostic tool because serum specimens aren't obtained until 4 weeks after the onset of illness. They're mainly used for epidemiologic studies.

Treatment

Appropriate treatment aims to support respiratory function, maintain fluid balance, and relieve symptoms. Ribavirin, a broad-spectrum antiviral agent, is being used successfully to treat infants with severe lower respiratory tract infection caused by the respiratory syncytial virus. The aerosol form of the drug is given by way of tent, oxygen hood, mask, or ventilator for 2 to 5 days, 12 to 18 hours a day. With this drug therapy, patients show less severe symptoms and improvements in arterial oxygen saturation.

Prevention

No vaccine exists for respiratory syncytial virus. But common-sense precautions can help prevent the spread of this infection:

• Wash your hands frequently. Do so particularly before touching your baby, and teach your children the importance of hand washing.
• Avoid exposure. Limit your infant's contact with people who have fevers or colds.
• Keep things clean. Make sure countertops are clean in the kitchen and bathrooms, especially when someone in your family has a cold. Discard used tissues right away.
• Be aware that kissing the baby can spread RSV infection.
• Do not smoke inside your house, car or anywhere near your baby. Exposure to tobacco smoke increases the risk of RSV illness.