Bird Flu: Diagnosis
Central to the problem of dealing with bird flu is diagnosis. A number of upper respiratory infections have similar symptoms?at least at the onset of the illness, including the common cold, seasonal influenza, and bird flu. Seasonal flu and bird flu have almost identical symptoms?including fever, cough, malaise (feeling unwell), nausea, vomiting, and diarrhea. This is, needless to say, a gigantic problem in accurately diagnosing bird flu?which is critical to beginning appropriate treatment as well as initiating infection control procedures and public health measures.
Currently, accurate testing for bird flu and other vial infections that can cause similar symptoms is difficult and requires specialized testing. This testing is time consuming and only available in specialized reference laboratories, which are few and far between. Fortunately, this may change in the near future.
According to Richard Janeczko, Ph.D., executive vice-president and chief scientific officer, Tm Bioscience, located In Toronto, Canada, is feverishly working to complete the final stage of development of an amazing test?not only for bird flu, but for more than 15 other viral infections (including severe acute respiratory syndrome or SARS), many of which can mimic the symptoms of bird flu (personal communication). (Tm Bioscience is a DNA-based diagnostics company developing a suite of genetic tests. Tm Bioscience?s product pipeline includes tests for genetic disorders, drug metabolism, and infectious diseases.
The test, called the Multiplexed Respiratory Test, discriminates influenza A from influenza B and identifies the H5-subtype of influenza A (bird flu is ?H5N1?) from all other H subtypes. In addition, it can identify almost all the other common?and some uncommon?viruses that cause influenza-like illnesses. This is extremely important in managing patients, communities and economic issues. Other tests have lower clinical sensitivities and specificities which can lead to both false positives and false negatives.
By incorrectly identifying an outbreak as due to H5N1, patients could be treated with anti-virals unnecessarily (thus raising the chances of selecting for drug-resistant strains), unneeded vaccination programs in asymptomatic individuals could be initiated, and damage to local and national economies?through such measures as culling of commercial poultry operations?could occur. Conversely a false-negative test result could lead to catastrophic outcomes, including a pandemic.
The assay utilizes swab specimens taken from the nose and takes less than 5 hours to perform. It was developed for use as a diagnostic tool and for infection control in hospitals. The assay has been slated for expedited review by the Food and Drug Administration (FDA), and TM Bioscience is hoping to have an FDA-cleared test available by the end of January 2006. If this assay delivers what it claims, it will have huge applicability on a global basis and save many lives.
About the Author: Bradford Frank, M.D., M.P.H., M.B.A. The Frank Group. P.O. Box 138 Lakewood, NY 14750