Here are some of the latest health and medical news developments, compiled by editors of HealthDay:
Nine Cows Tracked to Sick Animal
Investigators say they have tracked nine cows to a herd that included one that was infected with mad cow disease in December.
The Washington Post reports that the animals were exported from a farm in Alberta, Canada, to one in Washington state. Finding these animals is critical because of concerns that the animals may have eaten that same contaminated feed that sickened the Holstein diagnosed with mad cow disease.
According to the Post, the farm in Mabton, Wash., has quarantined 4,000 cattle since the one cow was infected. A case of mad cow disease was reported in Alberta earlier in 2003, raising concerns that both cases may be tied to the same source of contaminated feed.
The discovery came a day after the United States Department of Agriculture announced that the United States banned "downer" cows, those that can no longer walk, from the food supply.
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Brain Scan May Ease Depression
A novel brain scan may help ease bipolar disorder because its magnetic fields affect the electrical workings of the patients' brains.
The Boston Globe reports that researchers at McLean Hospital in Belmont, Mass., are trying to develop a much smaller version of a magnetic resonance imaging device that hospitals use to scan patients.
According to the Globe, the researchers stumbled on to the discovery. A research assistant found that patients who got the scan for other reasons emerged in better moods than they were before the scan.
One patient was so depressed that she couldn't even answer questions. After a 20-minute scan, she was astounded by how much better she felt. "What happened? What did you do?" the researcher, Aimee Parow, told the newspaper. Another emerged joking with Parow, which was completely out of character.
Researchers suspect that the magnets in the brain scan affect the brain, and that the mood-lifting can last for weeks, according to the Globe.
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Vision Tests Required for Elderly Fla. Drivers
Beginning Friday, Florida drivers over the age of 79 will have to pass a vision test every time they renew their licenses.
The Miami Herald reports that some find the new law discriminatory against older people, but that others say it will cut down on crashes.
According to the newspaper, people 75 and older comprise 7.9 percent of Florida's drivers, but account for 10.6 percent of those who die in a crash.
The new law doesn't mean that everyone that age needs to take an eye exam now. However, they must pass the test when their license comes up for renewal, which is every six years in Florida.
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Hepatitis B Rates Continue to Drop
Rates of acute hepatitis B continue their march downward, especially among children, and the government is crediting a vaccine that protects against the liver disease.
The Centers for Disease Control and Prevention reported Wednesday that, between 1990 and 2002, the overall rate of hepatitis B declined by 67 percent, from 8.5 per 100,000 people to 2.8 per 100,000. The sharpest drop, 89 percent, was seen among people 19 years of age and under.
The government in 1991 began a campaign to eliminate hepatitis B transmission to infants through a universal vaccination campaign; it was widened in 1995 to include adolescents. No such program exists for adults, who accounted for the slowest decline in the disease, though the CDC says some programs ought to be implemented for those at highest risk.
Hepatitis B is a bloodborne virus spread via exposure to the skin or bodily fluids of infected people. About 1.2 million Americans have it, according to the CDC publication Morbidity and Mortality Weekly Report. Those at highest risk are men who have sex with men and those who use needles to inject drugs.
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Flu Activity Widespread in 45 States
The flu is beginning to wane in Western-South Central states but is still widespread in 45 states, the Centers for Disease Control and Prevention reported Wednesday.
As of Dec. 20, hospital visits declined in Western and South Central states that were hit hard early, the CDC reported. The highest activity was seen in Indiana, Illinois, Michigan, and Wisconsin, according to a report in the CDC publication Morbidity and Mortality Weekly Report.
Also as of Dec. 20, flu and pneumonia accounted for 7.8 percent of all deaths in the United States, reaching the epidemic threshold, according to the CDC.
The only states spared widespread activity so far are Florida, New Hampshire, Louisiana, and Oklahoma, each of which had regional activity. Hawaii reported only local flu activity.
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Powell Back at Work After Prostate Surgery
Secretary of State Colin Powell reported back to work Wednesday, two weeks after undergoing surgery to remove a cancerous prostate gland.
Agence France-Presse reports that Powell chaired a staff meeting and had a telephone conversation with International Atomic Energy Agency Mohamed El Baradei, who has just finished a visit to Libya, according to State Department spokesman Adam Ereli.
According to AFP, Powell isn't expected to resume a full schedule until after the new year.
Powell, 66, had been resting at his home in northern Virginia since being released from Walter Reed Army Medical Center on Dec. 18, according to AFP.
