Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:
Dick Van Dyke has Undiagnosed Neurological Disorder
Dick Van Dyke is struggling with fatigue and other symptoms of an unknown neurological disorder and has been ordered to rest at home.
"Tests and scans have yet to reveal a specific diagnosis. Various medications have not diminished the symptoms," Van Dyke's spokesman, Bob Palmer, told USA Today. The 87-year-old actor has canceled a public appearance scheduled for New York next week.
Palmer said that thanks to Van Dyke's "strong constitution and years on a daily fitness regimen Dick is otherwise in good physical condition but the fatigue factor has become acute. Until there is a specific diagnosis and treatment plan he is advised against travel by flight and is resting at home in Malibu."
On Twitter, Van Dyke outlined his situation: "My head bangs every time I lay down. I've had every test come back that I'm perfectly healthy. Anybody got any ideas?"
Possible causes suggested by people included sinus issues, allergies, acid reflux and ear problems, USA Today reported.
Infection Sends GMA Host Robin Roberts to Hospital
Television host Robin Roberts has been hospitalized with infection.
The "Good Morning America" host was diagnosed with a rare blood disorder about a year ago and had a bone marrow transplant in September. She returned to the show in February but hasn't been on the air this week, USA Today reported.
"Last week, in the middle of my Key West vacation, I began not to feel well. Nothing serious, just under the weather. I contacted my doctors and flew back to NYC. They felt it best to admit me into the hospital for a few days," Roberts said in a Facebook note.
"Seems my young immune system needed a little boost to fight off 'opportunistic infections,' " she explained.
"My doctors assured me that this was NOT because I was working or doing too much, too soon. It's extremely common, post bone marrow transplant, to have complications. I'm blessed that mine have not been severe," Roberts wrote, USA Today reported.
She added: "I'm feeling MUCH better, and will relax at home for the rest of the week. I'll be back on GMA next week...as my sweet momma would say: 'Good Lord willing, and the creek don't rise!'"
No 'Sustained' Evidence of Human-to-Human Transmission of H79N Bird Flu
Four possible cases of human-to-human transmission of the H7N9 bird flu in China are being investigated, but so far there is "no sustained" evidence of the virus being passed between people, according to the World Health Organization.
The investigation involves three families in Shanghai and two young boys in Beijing who may have infected each other, WHO spokesman Gregory Hartl told The New York Times.
"Even if two family members are positive, it is not necessarily the case they got it from each other. They may have gotten it from the same bird," Hartl noted.
He also said there is growing concern that the H7N9 virus -- which has killed 17 people so far -- may not originate in birds but in other animals and in environmental sources, The Times reported.
Gay 'Conversion Therapy' Case Heard by Appeals Court
A California law that forbids gay "conversion therapy" for children and teens is an unjustified infringement on free speech, according to opponents. Supporters say it prevents therapeutic malpractice.
Arguments for and against the ban were heard Wednesday by a federal appeals court in San Francisco. The law is being challenged by several therapists and some patients who say there were helped by the treatment, The New York Times reported.
The ban, which was adopted last year, bars licensed therapists from trying to change the sexual orientation of people under the age of 18. Mainstream professional associations say there is no proof that this therapy is effective and also say it can harm young patients.
In December, a federal district judge imposed an injunction on the law. After Wednesday's hearing, the three-judge United States Court of Appeals for the Ninth Circuit was to decide whether to continue the injunction or allow the law to take effect, The Times reported.