CDC: New influenza A subtypes now reportable

Washington -- Infections caused by novel influenza A subtypes, which can cause pandemic flu, now have a place on the Centers for Disease Control and Prevention's list of reportable diseases -- falling alphabetically between mumps and pertussis.

Although this latest addition doesn't signal a major change in physicians' ongoing role as lookouts for an incipient pandemic, it does add emphasis and importance to a potential emerging disease threat, said Kathleen F. Gensheimer, MD, MPH, state epidemiologist with the Maine Dept. of Public Health.

The list of reportable diseases, published by the CDC's National Notifiable Diseases Surveillance System, now totals more than 60, ranging from AIDS to yellow fever. The number reportable in each state varies according to state laws and regulations.

This early warning system is intended to give the nation's medical community time to prepare for outbreaks and, while it seems to be working well -- the detection of monkeypox and anthrax cases in recent years are among its successes -- some public health physicians are concerned that not all of the reportable diseases are, in fact, reported.

And they aren't. As a matter of fact, only about one in seven diseases that should be reported actually is, said Jonathan L. Temte, MD, PhD, associate professor of family medicine at the University of Wisconsin in Madison.

That some states have long lists of reportable diseases contributes to this problem. Wisconsin, for instance, has 86. Plus, the list changes, and some of the diseases are difficult to identify. It would be hard for an individual physician seeing a case of food- or water-borne illness to tell whether the case is a chance happening or a reportable disease, said Dr. Temte.

Heightened attention

Nonetheless, with many experts warning that the influenza A subtype known as H5N1 could cause the next pandemic, physicians have been asked to be vigilant for unusual respiratory symptoms, especially among patients who recently returned from trips to areas where avian flu is endemic. Now they are being asked to report such cases, and states may soon mandate this step.

Nasal and/or throat swabs should be obtained from such patients and sent to a lab for identification. If the lab is unable to identify the strain as one in current circulation, reporting this finding to the state public health department is crucial. The state lab will, in turn, send the information to the CDC for verification.

The timing of the changed reporting status for the flu subtypes results from the United States signing on to the World Health Organization's International Health Regulations, drafted in 2005 and adopted late last year. A provision of the regulations calls for the prompt notification of human influenza cases caused by a new virus subtype.

"We aren't asking physicians to do anything different," said David Shay, MD, MPH, medical epidemiologist with the CDC in Atlanta. "Recommendations for testing people who have returned from travel to Southeast Asia and concerns for infection with H5N1 haven't changed," he said. "We are just making a more formal notification process."