Research on monitoring the epidemiological situation of parasitic diseases in farm animals has been conducted in the world for many years. One of the most common diseases is toxoplasmosis, which is a serious problem due to the reproductive and economic losses it causes. The current methods of detecting infection with the protozoan causing toxoplasmosis are long-lasting (usually the waiting time for the result is about a day) and require a professional laboratory and trained laboratory technicians. The most common method of infection detection is a serum blood test for antitoxoplasma antibodies. Unfortunately, it is expensive and due to the price it has not been widely used. Therefore, there is a need to look for an alternative diagnostic solution that would enable a diagnosis to be made simply, quickly and cheaply. Such a solution can be optical fiber sensors, which with their properties exceed conventional methods of measurement. Optical fiber sensors are characterized by high sensitivity and a wide dynamic range of measurement. They are attractive because of their small size, lightness and mobility. Access to a diagnostic device that allows farm animal veterinarians to make a diagnosis quickly and simply can be of great economic importance. Preventing the spread of the parasite thanks to a quick diagnosis and response to its appearance will protect many animals from the effects of the disease, and the owners of farms from losses generated in this way. The advantages of the proposed solution are the speed of measurement, simplicity of the sensor, versatility and low cost of the test. Such a device can be very popular among breeders, as it fills the market gap