Bird flu hard to detect until too late - studies

WASHINGTON, Nov 23 (Reuters) Quick tests that can tell if patients have influenza do not detect bird flu, so despite heroic efforts, they can die before anyone knows what killed them, doctors reported.

The H5N1 bird flu virus also causes a range of symptoms in people, making it that much harder to diagnose, experts said in two separate reports from Indonesia and Turkey yesterday.

In Turkey, repeated testing failed to diagnose H5N1 avian influenza in eight patients, one team of doctors reported in the New England Journal of Medicine.

In Turkey and in Indonesia, patients turned up with a wide variety of symptoms, even in family clusters, making it hard to distinguish H5N1 from a range of other common infections, another team said.

Dr Ahmet Faik Oner, Dr Mehmet Ceyhan, and colleagues at Yuzuncu Yil University Hospital in Van, Turkey said they hope their detailed findings can help other experts battling avian influenza, which remains largely a disease of birds but which occasionally infects humans.

Bird flu has infected 258 people in 10 countries and killed 153 of them. Experts say the danger is that the virus will evolve and spark a pandemic that could kill millions.

''There is no question that there will be another influenza pandemic someday. We simply don't know when it will occur or whether it will be caused by the H5N1 avian influenza virus,'' Dr Robert Webster and Dr Elena Govorkova of the Memphis, Tennessee-based St Jude Children's Research Hospital wrote in a commentary on the two reports.

Dr Anthony Fauci of the US National Institute of Allergy and Infectious Diseases, who was not involved in the studies, said they gave useful details about the newer strain, called clade 2, of the virus.

''It's important that as these viruses evolve from one clade to another that we get a good, clear description of the type of disease, the transmission of the disease and ability of diagnostics to pick it up,'' Fauci said in a telephone interview.

TURKISH CHILDREN Oner's team fought an outbreak of H5N1 in children in Turkey between Dec. 31, 2005, and Jan. 10, 2006.

They said 32 separate tests failed to detect the virus -- not only quick tests, but time-consuming polymerase chain reaction or PCR tests and ELISA tests, which look for specific proteins from viruses or bacteria.

Eventually, eight patients were diagnosed using real-time PCR, the researchers said. Four died.

''In our series, fever was a major symptom, and most of our patients had pneumonia on admission,'' they wrote. Most had cough and sore throat, but only half reported muscle aches and only one had a runny nose. About a third had diarrhea.

Certain blood enzyme levels were elevated in most of the patients and that may be an important clue, they said.

In a second report, a team of researchers from the World Health Organization, the US Centers for Disease Control and Prevention, the Ministry of Health in Jakarta and elsewhere said rapid tests also failed to detect the virus when they fought three family clusters of H5N1 in 2005.

The clusters ''included mild, severe, and fatal cases among family members,'' they wrote. Despite the use of multiple antibiotics, breathing assistance and other care, half the patients died.

Last week, a team at the University of Colorado at Boulder and the CDC reported they had developed an inexpensive and quick ''gene chip'' test that might identify flu viruses, including H5N1. Fauci said that test would have helped in Turkey and Indonesia.

Reuters SBA VP0430