Here are some of the latest health and medical news developments, compiled by editors of HealthDay:
U.S. Rate of New HIV Infections May Be Much Higher
Federal estimates of the number of Americans newly infected with HIV may be 50 percent higher than previously assumed, the Washington Post reported on Saturday, which is World AIDS Day.
The U.S. Centers for Disease Control and Prevention (CDC) has for the past decade estimated the number of new HIV infections nationwide at about 40,000 cases annually. But sources close to scientists who are finalizing the new numbers say the number is closer to 50,000 or 60,000, the Post said.
The rise in estimated infections is due to a change in blood sampling, which can now identify people who were infected within the past five months. This allows scientists to better differentiate new infections from longstanding ones. The new data comes from large cities and 19 states, the Post reported.
The new numbers -- as yet unannounced by the CDC -- may not mean that the HIV epidemic is growing in the US, merely that it is larger than experts had previously assumed. At least two years of follow-up are needed to confirm if there is any trend toward increasing cases, the Post said.
In related news, President Bush on Friday urged Congress to approve another $30 billion over the next five years for the global fight against AIDS, the Associated Press reported. He said he plans a visit to Africa early in 2008 to help focus on the epidemic there and to rally support for the administration's efforts.
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Contaminated Food Killed More Than 300 Pets
Contaminated pet food may have killed about 225 cats and 112 dogs earlier this year, according to a new Michigan State University study. The researchers said the pets' deaths may have been due to a deadly combination of melamine and cyanuric acid contaminants, the Associated Press reported.
"When combined, they form crystals which can block the kidneys. Unfortunately, these crystals don't dissolve easily. They go away slowly, if at all, so there is the potential for chronic toxicity," said Wilson Rumbeiha, an associate professor at MSU's Diagnostic Center for Population and Animal Health.
The findings of the study, commissioned by the American Association of Veterinary Laboratory Diagnosticians, were based on data gathered from veterinarians and other animal health workers from April 5 through June 6, the AP reported.
More cats and smaller dogs got sick than larger dogs after eating the contaminated food. Most of the sick pets were in Texas, Illinois and Michigan.
About one-quarter of pets that became sick after eating the contaminated food already had health problems such as kidney or cardiovascular disease, the study found.
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Pilots Taking Antidepressants as Capable as Other Pilots: Study
Pilots taking antidepressants aren't any more likely to commit errors than other pilots, according to an Australian study that compared 481 pilots on antidepressants and the same number of pilots who weren't taking the medications.
Unlike some other nations, Australia allows pilots to fly while taking an antidepressant drug.
Between 1993 and 2004, each group of pilots had a total of five accidents involving serious injury, death or major aircraft damage. There were 18 incidents of pilot error among the medicated pilots, compared with 15 among non-medicated pilots, which the study authors said was not a statistically significant difference, Agence France-Presse reported.
"There was virtually no difference in the number of incidents or accidents. But importantly, there was a tendency for more accidents in the period prior to pilots going on to antidepressants, but not once they were on them," said Australian National University mental health researcher Kathy Griffiths.
The findings were presented Friday at a World Psychiatric Association meeting in Melbourne.
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WHO Concerned About New Ebola Strain
World Health Organization officials are concerned about a new form of the deadly Ebola virus that's killed 16 people in an outbreak in western Uganda, the Associated Press reported.
Tests indicate the virus belongs to a different subtype than the four already known.
"We are very concerned about this because it does not present (symptoms) in exactly the same way as other Ebola strains," WHO spokesman Gregory Hartl said. He noted the new subtype appears to be associated with vomiting, something that normally doesn't occur in Ebola patients, the AP reported.
So far, there have been 51 confirmed Ebola cases (including the 16 patients who died) in the outbreak in western Uganda. The first case was reported on Nov. 10.
Improved disease surveillance was bound to uncover new forms of Ebola, Pierre Formenty, a WHO expert on hemorrhagic fevers, told the AP.
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Doctor Warns About Consumer Genetic Tests
Consumer genetic testing is poorly regulated and may pose problems for doctors and patients, a Massachusetts General Hospital physician warns in the December issue of the journal Obstetrics & Gynecology.
Dr. Erin Tracy noted that direct-to-consumer advertising for genetic tests is increasing and may mislead patients. Ads for the tests commonly attempt to exploit people's emotions and fears, and some even give the erroneous impression that a certain genetic test is mandatory, she said.
"Some of the tests that are being offered have no proven clinical validity whatsoever and are quite costly," Tracy noted. "So patients spend money trying to identify a particular gene to figure out if their child is prone to addictive behavior, for example. If the test comes back positive, parents are often not adequately counseled as to what those results might mean, whether the tests have any proven value, or what resources are available for follow up."
Most DNA tests are "home brews" that aren't regulated by the U.S. Food and Drug Administration, Tracy explained. Increased funding for the FDA could help regulate genetic testing in the United States, she said, but the agency can't oversee genetic testing companies in other countries.
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ACEP Challenges CT Scan Study
A study that linked a dramatic rise in the use of CT scans to increased risk of radiation-related cancer had a number of flaws, the American College of Emergency Physicians (ACEP) said Friday.
The group is concerned that people who hear about the study may be less likely to get CT scans, which can put their lives at risk in emergency care situations.
The Columbia University study, published Thursday in the New England Journal of Medicine, noted that more than 62 million CT scans are performed each year in the United States, compared with 3 million in 1980. A CT scan can have radiation doses 50 to 250 times greater than a dose of a conventional X-ray, the study authors said.
But the ACEP contends that the researchers used input from a limited number of doctors and outdated data to assess physician understanding about the risks of CT-related radiation. ACEP President Dr. Linda Lawrence said they study included a survey of fewer than 100 doctors, and was conducted more than five years ago.
"CT scanning is done more often in emergency departments for many very important reasons," Lawrence said in a prepared statement. "Emergency patients by definition are more in need of emergency care than other patients and diagnostic imaging often is critical to determining the course of treatment. In many cases, the risk of not testing can be more dangerous than testing."
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