VGTI/ONPRC Research Demonstrates Security Vulnerabilities In Infectious Disease Outbreak Protection

04/02/11  Portland, Ore.

Research by scientists at Oregon Health & Science University reveals the 2003 outbreak of monkeypox in the Midwest may have been larger than reported. This is due to the fact that at least one case, and possibly more, caused atypical, less obvious symptoms. The study raises questions regarding current abilities to detect a serious infectious disease outbreak and prevent its spread. The research is printed in the May 17 edition of The New England Journal of Medicine.

"The monkeypox outbreak of 2003 was eventually traced to a shipment of infected rodents imported from Africa and was considered a very serious threat to residents in the Midwest at the time," said Mark Slifka, Ph.D., an associate scientist at the OHSU Vaccine and Gene Therapy Institute, with joint appointments at the Oregon National Primate Research Center, and the Department of Molecular Microbiology and Immunology in the OHSU School of Medicine.  He is also president and chief science officer of Najit Technologies, Inc. a local biotech company that is developing improved diagnostics and vaccines for infectious diseases.

Monkeypox typically is considered a fatal disease for about 5 percent to 10 percent of the infected population – a number that varies depending on the age of the patients and the level of available health services in the region. In this particular outbreak, there were 72 suspect cases, and 37 cases that were officially confirmed, including some very serious cases that were nearly fatal. However, thankfully there were no deaths as a result of the 2003 outbreak. At the time, Slifka and his colleague Matt Lewis traveled to Wisconsin to investigate the aftermath of the outbreak.  There, they identified a patient who had presented all of the diagnostic disease symptoms of monkeypox except one. This patient had been infected with monkeypox but the most obvious sign, the skin lesions or the 'pox' that the disease is named for, were missing.

The case demonstrates a serious scenario wherein a patient could become infected with a potentially fatal disease that either goes undetected or is diagnosed incorrectly because it does not represent a "textbook version" of the ailment. If the outbreak involved smallpox instead of monkeypox, then this individual could have potentially infected others and extended the reach and death toll of the outbreak. Misdiagnosis of poxvirus infections could be more common than previously thought, especially according to a 2004 emergency drill published by K.R. Klein and colleagues. The study showed that six of 13 patients with simulated cases of smallpox were diagnosed with other, much less serious diseases, and the faux smallpox patients were discharged from the hospital instead of being quarantined.

"These monkeypox cases help to remind us that we can always aim to improve our disease detection methods," explained Slifka. "We need to develop better tests to correctly identify an infection. We also need to better educate physicians about the disease warning signs that can be both obvious and not so obvious."

Potential conflicts of interest involving OHSU investigators and OHSU start-up companies are reviewed and managed by the OHSU Conflict of Interest in Research Committee and the Integrity Program Oversight Council.