Emerging infections includes identified diseases that have increased in incidence within the past 20 years as well as diseases that are expected to increase in prevalence in the near future. Examples of emerging infections are West Nile virus, Legionnaires' disease, Lyme disease, hantavirus pulmonary syndrome, Ebola and Marburg viruses, and severe acute respiratory syndrome (SARS). Two emerging infections—SARS and Legionnaires' disease—will be covered in this section.
Severe acute respiratory syndrome is a pneumonia caused by a newly recognized coronavirus (CoV). The first human coronavirus, isolated in 1965, is responsible for about one-third of all colds. The virus is spread by droplets as well as contact with surface objects contaminated by droplets. Most cases of SARS have been in China, Taiwan, Singapore, Hong Kong, and Vietnam; however, limited cases have been identified in other areas. Symptoms include cough, shortness of breath or increased shortness of breath, and fever. Chest x-ray reveals the presence of pneumonia, which can develop into acute respiratory distress. Lab studies include immunofluorescent antibody testing (IgM and IgG), and reverse transcriptase polyermerase chain reaction to detect RNA on the SARS CoV. Care of the client with SARS includes isolation and quarantine. The client should be placed in a negative-pressure isolation room and caregivers should use airborne and contact precautions, including N95 masks and eye shields. Antibiotics and antiviral medications are ordered. The client is closely monitored for signs of acute respiratory distress. Figure 5.6 illustrates the symptoms indicative of SARS.
Figure 5.6 Severe acute respiratory syndrome (SARS) symptoms.
Legionnaires' disease is caused by Legionella pneumophilia, a gram negative bacteria found in both natural and man-made water sources. The organism grows best in water temperatures between 77° F and 107° F and is enhanced by water storage. Risk factors include immunosuppression, advanced age, alcoholism, and pulmonary disease. Legionnaires' primarily affects the lungs and other organs and produces symptoms that include malaise, myalgia, headache, dry cough, chest pain, fever, diarrhea, and gastrointestinal complaints. Legionnaires' is diagnosed by routine culture, antibody titer, and urinary antigen for Legionella pneumophilia serotype I. Management of the client with Legionnaires' disease is the same as those used for clients with pneumonia. No special isolation technique is used because there is no evidence of transmission between humans. Antibiotic therapy includes the use of Zithromax (azithromycin), Biaxin (clarithromycin), Ilotycin (erythromycin), and Levaquin (levofloxacin). Zithromax (azithromycin) is considered to be the drug of choice for the client with Legionnaires' disease.