by electron microscopic examination of the fluid specimen in a high-containment (BL-4)
facility. Definitive identification in the laboratory is accomplished with viral cell culture, PCR,
and restriction fragment–length polymorphism analysis (162).
Herpes Simplex
Herpes simplex virus type 1 (herpes labialis) commonly causes vesicular lesions of the oral
mucosa (163). The illness is characterized by the sudden appearance of multiple, often painful,
vesicular lesions on an erythematous base. The lesions last for 10 to 14 days. Recurrent
infections in the immunocompetent host are usually shorter than the primary infection. In the
immunocompromised host, infections can be much more serious. Aside from vesicular
eruptions on mucous membranes, the infection can cause keratitis, acute retinal necrosis,
hepatitis, esophagitis, pneumonitis, and neurological syndromes (163–172).
Herpes simplex virus type 1 can cause sporadic cases of encephalitis characterized by
rapid onset of fever, headache, seizures, focal neurological signs, and impaired mental
function. HSV-1 encephalitis has a high rate of mortality in the absence of treatment (173).
Diagnosis can infrequently be made by culture; PCR analysis of the CSF has become the gold-
standard technique for making the diagnosis (174).
Staphylococcus aureusBacteremia
S. aureuscan cause metastatic skin infections that often manifest as pustules (3). The pustular
skin eruption due to this organism is often widespread. Risk factors for bacteremia include
older age, diabetes, recent surgery, HIV, hemodialysis, neoplasm, neutropenia, and intrave-
nous drug use (175–180). Bacteremia can lead to metastatic complications, such as endocarditis
and arthritis. Risk factors for these metastatic complications include underlying valvular heart
disease and prosthetic implants.
Vibrio Vulnificus
V. vulnificusis a slightly curved, gram-negative bacillus that is endemic in warm coastal waters
around the world.V. vulnificusis the leading cause of seafood-related fatalities in the United
States (181). There are reports that virtually all oysters and 10 percent of crabs harvested in the
warmer summer months from the Gulf of Mexico are culture-positive forV. vulnificus(182).
Consequently, the illness presents mostly between March and November (183). In the United
States, most cases occur in states bordering the Gulf of Mexico or those that import oysters
Figure 9 Male patient with smallpox.Source: Courtesy of the CDC/Barbara Rice, Public Health Image Library.
38 Engel et al.