The Unsuspected Patients

SARS patients with chronic illnesses occurring concurrently with fever and/or pneumonia and who have a plausible diagnosis are the most challenging to the public health and healthcare systems (MMWR 52: 405-11).

Unrecognized cases of SARS have been implicated in recent outbreaks in Singapore (MMWR 52: 405-11), Taiwan (MMWR 52: 461- 5), and Toronto. Despite efforts to implement extensive control measures, these cases led to nosocomial clusters and subsequent spread to other healthcare facilities and/or community settings. Several factors might contribute to difficulties in recognizing cases of SARS. Early symptoms of SARS are non-specific and are associated with other more common illnesses. Patients with SARS who are immunocompromised or who have chronic conditions (e.g., diabetes mellitus or chronic renal insufficiency) might not have fever when acutely ill or have symptoms attributable to the underlying disease, delaying the diagnosis of SARS (MMWR 52: 405-11). Finally, some patients might not reveal useful contact information (e.g., exposure to an im- plicated healthcare facility) for fear of being stigmatized by the local community or causing their friends and families to be quarantined (MMWR 52: 405-11).

These experiences demonstrate that spread among health care workers can occur despite knowledge about the epidemiology and transmission of SARS. To reduce the number of unrecognized cases, the Singapore Ministry of Health recommends a strategy to quickly identify febrile or symptomatic persons with chronic illnesses or any recent healthcare facility contact as suspected cases for isolation (MMWR 52: 405-11; see also Chapter 5: Prevention).