The virus had been sent to IAH Pirbright by the European Commission, as IAH Pirbright is the European Community Reference Laboratory for bluetongue.
After confirming that the disease in the Netherlands was bluetongue, the IAH Pirbright scientists worked to identify the serotype of the virus.
Having eliminated that possibility that the virus was one of the 5 serotypes previously detected in southern Europe (types 1, 2, 4, 9, and 16), they developed tests for the other 19 types.
The identification of the serotype was done by PCR tests late on Friday night (25 Aug). The test involves the gene for protein VP2 of the virus.
VP2 unequivocally specifies the serotype of the virus. The PCR result was confirmed by sequencing most of genome segment 2 of the virus, on Saturday (26 Aug).
Professor Philip Mellor, head of the European Community Reference Laboratory (CRL) for bluetongue said `The isolation of a bluetongue virus serotype new to the region, by Professor Peter Mertens` group at Pirbright,
within only 8 days of receipt of the first infected sheep material from the
Netherlands, is an astonishing feat.`
The quick turn-around time was achieved by using serotype-specific reverse transcriptase polymerase chain reactions (RT-PCRs) followed by sequencing, rather than by virus neutralisation tests that have been used in the past, and which take 3 times longer to achieve a result.
Typing of the virus is important in tracking where the BTV-8 virus came from.
The results show that the Dutch isolate is NOT descended from vaccine forms of the bluetongue virus that have been used in many parts of southern Europe including Bulgaria, Italy, Corsica, Spain, and also in South Africa,
in recent years.
The gene sequence data points to an origin in sub-Saharan Africa.
Source: www.promedmail.org
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