Bluetongue diagnosis
Clinical diagnosis for Bluetongue relies on the basic presentation of edema, ulcerations, and epithelial lesions. Generally, these clinical signs and lesions are not pathognomonic, and they could be confused with those of other ruminant diseases, such as Contagious ecthyma, Malignant catarrhal fever, or even other relevant notifiable diseases as Foot-and-mouth disease or Peste de petit ruminants. Therefore, laboratory diagnosis is essential.
Despite advances in molecular biology techniques, some traditional diagnostic methods for the detection and identification of BTV remain in force. Although different assays have been developed for the detection of BTV infection, based on either antibody or virus detection, just some of them comprehensively validated, are massively used by official laboratories to control purpose.
From the point of view of disease surveillance and control, serogroup diagnosis is the first step to carry out. Real time RT-PCR and ELISA are the minimum techniques recommended by the EURL to be stablished in the EU National reference laboratories.
Second challenge in the diagnosis is differentiation of the different BTV serotypes, to implement vaccination program as soon as possible, considering that commercial available vaccines are serotype specific.
Finally, a further characterization, mainly based in genome sequence, should be performed to determinate the specific strain.
Because of the intense BT surveillance in the last years, some BTV atypical strains (not notifiable) have been detected, being a challenge for the diagnosis and understanding of the BTV infection.
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