Both isolation of suspected cases and quarantine of contacts have been used to control SARS. In the US, quarantine is usually implemented voluntarily, but, for certain conditions such as SARS, people can be quarantined involuntarily. In the case of a communicable disease such as SARS for which there is no known treatment and which can spread readily under certain circumstances, the strategies of isolation and quarantine are even more important.
A need for better defenses
As of early June, countries most affected were mainland China, Hong Kong, and Taiwan. These countries were subject to a CDC travel advisory, which means people should travel there only if they had essential business. In addition, the CDC issued a travel alert for Singapore, and re-issued one for Toronto after the city failed to contain the initial outbreak. Alerts advise travelers that if they have visited a specific SARS-affected area, they should seek medical attention if they get sick within 10 days.
Strategies against SARS. While SARS appears to have been brought under control in certain areas (Hanoi and maybe Singapore), this has not happened in others. To date, the US has been spared a serious outbreak. Use of strategies such as travel alerts and advisories, screening airline passengers from affected countries, and heightened vigilance in following up suspected cases and exposures have all helped.
Another emerging infection: monkeypox
As SARS was being contained, an infectious disease new to the US erupted: monkeypox. On June 16, when the number of cases stood at 82 persons An ELISA blood test is now available to identify antibodies to the presumed SARS virus in 5 states, the federal government banned the sale and distribution of prairie dogs and all rodents from Africa, in an effort to control the spread. Monkeypox is believed to have spread from an African rat imported by a pet store and housed with prairie dogs for sale to the public.
Most infected persons had direct contact with diseased prairie dogs that had been purchased as pets. In some instances, however, direct contact with infected animals could not be documented; therefore, health officials cannot rule out the possibility of human-to-human transmission of the monkeypox virus.
Monkeypox was first identified in monkeys in 1959, but certain African rodents were later identified as its real host. Outbreaks in people occurred in the Congo in the 1990s.
The Centers for Disease Control and Prevention issued an interim case definition for human cases of monkeypox and a recommendation that certain individuals be offered smallpox vaccination for protection (available at http://www.cdc.gov/ncidod/monkeypox/ casedefinition.htm).
Our best defense
Continued emergence of infectious diseases and the dramatic spread of SARS internationally through airline travel and close contact in hospitals should prompt us to strengthen our public health systems. A well functioning surveillance system coupled with the infrastructure to apply traditional techniques such as case finding, tracking, isolation, quarantine—and bans, as in the case of monkeypox—may be our best defense against communicable disease epidemics.
Correspondence
1601 Parkview Avenue, Rockford, IL 61107. E-mail: ehenley@uic.edu.