Wild Bird Surveillance Results

Samples taken from wild birds are initially tested by the Polymerase Chain Reaction (PCR) laboratory test; this detects genetic material (RNA) specific to all influenza A viruses including those from avian species.

This is a very sensitive screening test. If this test gives a positive result, the samples are subjected to further confirmatory tests to identify and characterise the virus. This involves attempts to grow (or culture) the virus; when this is successful the virus can usually be fully characterised.

Sometimes it is only possible to detect parts of the virus, not an entire virus. In this case the virus may be incomplete (partially destroyed); these viruses are not viable. Laboratory results may therefore involve only partial identification of the virus i.e. detection of genetic material or the haemagglutinin (H) subtype only (and not the neuraminidase (N)).

These further tests also involve determining whether the virus is a highly pathogenic avian influenza (HPAI) virus or a low pathogenic avian influenza (LPAI) virus, again this may not be possible if there is not enough viable virus present in the sample.

Positive results: A positive result is a laboratory result where there is at least correct identification of the virus by haemagglutinin (H) subtype. Results that are only positive by M gene screening test are not reported as positive on the web site.

Only final positive laboratory results will be reported on the web page, this is when the complete suite of laboratory tests has been completed on the sample(s).