Feline herpesvirus 1 (FHV-1) infection causes feline viral rhinotracheitis (FVR) and is one of the most widespread viral infections in cats. It can cause severe disease, including death from pneumonia in young kittens, and it accounts for approximately half of all diagnosed feline viral upper respiratory infections. FVR is usually diagnosed by clinical signs. However, for a definitive diagnosis laboratory techniques such as PCR (polymerase chain reaction) or virus isolation are required; diagnostic methods that are relatively expensive or require well-trained personnel. Therefore, the development of a biosensing method that can deliver concrete, same-day results in a simple and inexpensive manner can elevate the prompt response to infection cases. In this work, we propose a novel biosensing system (Fig. 1) in which the pathogens are labelled with streptavidin coated magnetic markers (MPs). Video microscopy in combination with a particle tracking software are used for their detection. The virus sample under investigation is mixed with commercially available MPs (Dynabeads Streptavidin MyOne T1) and suspended in DI water. If virions are present they will bind to the surface of these MPs forming compounds (MLPs –magnetically labelled pathogens). When the liquid containing the MLPs is introduced into the developed, microfluidic platform the MLPs are accelerated towards the outlet by means of a magnetic field gradient generated by integrated microconductors, which are sequentially switched ON and OFF by a microcontroller. The velocities of the MLPs and that of reference MPs are calculated and compared in real time by a digital camera mounted on a conventional optical microscope in combination with a particle trajectory tracking software. The MLPs will be slower than the reference MPs due to the enhanced Stokes´ drag force exerted on them, resulting from their greater volume and altered hydrodynamic shape. A registered difference in velocity indicates the presence of the FHV-1