The CDC (1994) defines emerging infections as diseases of infectious origin with human incidences occurring within the past two decades. Emerging illnesses are likely to increase in incidence in the near future. Two respiratory conditions listed as emerging infections are Severe Acute Respiratory Syndrome (SARS) and Legionnaire's disease.
Severe Acute Respiratory Syndrome
Severe Acute Respiratory Syndrome (SARS) is caused by a coronavirus. Symptoms include
- Dry cough
In identifying SARS, a chest x-ray reveals "ground glass" infiltrates with bilateral consolidation occurring sometimes within 24–48 hours, thus suggesting the rapid development of acute respiratory failure. SARS has occurred with greater frequency in Asia, although cases have also been confirmed in Canada, Switzerland, and Germany; therefore, a history of recent travel is significant
The SARS virus can be found in nasopharyngeal and oropharyngeal secretions, blood, and stool. Diagnostic tests for SARS include
- Sputum cultures for Influenza A, B, and RSV
- Serum tests to detect antibodies IgM and IgG
- Reverse transcriptase polymerase chain reaction tests performed to detect RNA of SARS CoV
Two tests on two different specimens must be positive to confirm the diagnosis. Test results are considered negative if no SARS CoV antibodies are found 28 days after the onset of symptoms.
The client suspected of having SARS should be cared for using airborne and contact precautions. Management includes the use of antibiotics to treat secondary or atypical pneumonia. Antivirals or retrovirals can be used to inhibit replication. Respiratory support, closed system for suctioning, and the use of surfactant replacement may be ordered.
Legionnaire's disease is caused by gram negative bacteria found in both natural and manmade water sources. Bacterial growth is greater in stored water maintained at temperatures ranging from 77° to 107° F. Risk factors include
- Pulmonary disease
Legionnaire's involves the lungs and other organs. The symptoms include
- Productive cough
- Chest pain
Diagnostic tests include a urinary antigen test that remains positive after initial antibiotic therapy. Management includes the use of antibiotics, oxygen, provision of nutrition, and hydration. The drug of choice for treating Legionnaire's disease is Zithromax (azithromycin). Transmission-based precautions are not necessary when caring for the client with Legionnaire's disease because there is no indication of human-to-human transmission.