Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:
New Research May Help Lead to HIV/AIDS Vaccine
In what may be an important advance in efforts to develop an HIV vaccine, scientists have analyzed one person's immune response to the virus to determine how a series of mutations created an antibody that can conquer many strains of HIV, which is the virus that causes AIDS.
The team examined numerous sequential samples of blood from an African man. The samples were collected from shortly after he was infected with HIV until about two years later, when his immune system began to produce "broadly neutralizing antibodies" against HIV, The New York Times reported.
The antibodies produced by the man's immune system were able to defeat about 55 percent of all known HIV strains, according to the study published online in the journal Nature.
While an HIV vaccine still remains far off, this research could prove important in attempts to reach that goal.
"The beauty of this is that it's a big clue as to the sequential steps the virus and the antibody take as they evolve," said Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, which financed the research, The Times reported.
Experts reacted cautiously to the study.
The findings are "a road map to vaccine development, yes -- but it's like one of those maps of the world from the year 1400. We still don't know how to turn this into a vaccine," Dr. Louis Picker, an HIV vaccine specialist at Oregon Health & Science University, told The Times.
It's not clear if one patient's immune process could be applied to others, noted Dr. Joseph McCune III, head of experimental medicine at the University of California, San Francisco.
One major reason why efforts to create an HIV vaccine have so far failed is because the virus mutates so rapidly. Flu viruses mutate so often that flu vaccines must be reformulated every year. In one day, HIV mutates as much as flu viruses do in a year, The Times reported.
Worldwide, 34 million have HIV and 2.5 million are newly infected each year, including 50,000 in the United States.
Organ Recipients Out of Danger After Completing Rabies Treatment: CDC
Three people who received organs from a rabies-infected donor in 2011 are no longer in danger of developing the deadly disease, according to the U.S. Centers for Disease Control and Prevention.
The agency said the organ recipients in Florida, Georgia and Illinois have all completed post-exposure rabies treatment and are doing well, the Associated Press reported.
A Maryland man who received a kidney from the same Florida donor died of rabies in February.
Health officials conducted a search for any people who may have had close contact with any of the patients, and 36 people in Florida, Georgia, Illinois, Maryland and North Carolina were advised to get the rabies vaccine. So far, 28 have done so, the AP reported.
H7N9 Bird Flu Virus Could be Hard to Track: Scientists
The H7N9 bird flu virus that recently killed two people and sickened five others in China could prove hard to track because it might be able to spread among poultry without causing any symptoms, scientists say.
They also noted that the virus, which previously infected only birds, appears to have mutated in a way that allows it to more easily infect other animals. This includes pigs, which could serve as hosts that spread the virus more widely among humans, the Associated Press reported.
The findings from the scientists at several research institutions around the world are preliminary and further research is required to gain a full understanding of the H7N9 virus causing human deaths and illnesses in China.
While they try to learn more about the virus, the scientists recommended that Chinese veterinary officials conduct widespread testing of animals and birds in affected regions in order to detect and eliminate the virus before it becomes widespread, the AP reported.
Okla. Dentist Should Face Criminal Charges: Dental Chief
Prosecutors should consider criminal charges against an Oklahoma oral surgeon at the center of a health scare involving thousands of patients who may be infected with hepatitis B and C or HIV, the head of the Oklahoma Board of Dentistry says.
Susan Rogers said she has talked with Tulsa County District Attorney Tim Harris about whether Dr. W. Scott Harrington is criminally liable. Harrington was a dentist for 36 years before voluntarily giving up his license on March 20.
"We're looking for the witnesses and individuals who can testify for us that this is what happened to me in (Harrington's) office," Rogers told the Associated Press.
Letters have been sent to 7,000 of Harrington's patients advising them to get tested for hepatitis B and C as well as HIV, the virus that causes AIDS. The testing is free. So far, nearly 1,000 people have been tested.
People who get tested should receive their results within two weeks, Kaitlin Snider, a spokeswoman for the Tulsa Health Department, told the AP.
Patients were urged to get tested after officials discovered improper sterilization, rusty instruments, and potentially contaminated drug vials at Harrington's two Tulsa-area offices.
New Plan Would Eradicate Polio by 2018: Health Officials
About $5.5 billion is needed for a new global plan to end most cases of polio by late next year and eradicate the disease by 2018, health officials say.
However, they acknowledge that it may be difficult to secure the funding in these tough economic times. The money is needed for vaccinations as well as the monitoring required to ensure that the paralyzing disease has been eliminated, the Associated Press reported.
Under the plan, the long-used oral vaccine would be replaced by a more expensive but safer injection version.
Last year, there were 223 cases of polio worldwide, a historic low. This means it is an ideal time for an "endgame" strategy against polio, Dr. Rebecca Martin of the U.S. Centers for Disease Control and Prevention told the AP.
Officials Say Mandela's Health is Improving
Nelson Mandela is improving after spending nearly a week in hospital being treated for pneumonia, the South African government reported Wednesday.
The 94-year-old former president "continues to make steady improvement in hospital," said a statement released Wednesday by the office of President Jacob Zuma, The New York Times reported. "His doctors say he continues to respond satisfactorily to treatment and is much better now than he was when he was admitted to hospital."
The statement did not say when Mandela might be discharged.
Mandela has been hospitalized three times in the past four months. That included a 19-day stay in December when he was treated for a lung infection and underwent gallstone surgery, The Times reported.