A pinboard by
Anja Ruether

Postdoctoral Researcher, Monash University


Babesia, a parasite similar to the malaria parasite Plasmodium, is the second most common bloodstream parasite found in mammals.[1] It is transmitted to its vertebrate host by tick bites. Babesia bovis infects cattle herds in tropical regions worldwide and leads to mortalities, abortions and a reduction in meat and milk production. Tick control, prevention and treatment are expensive and only cost-intensive (polymerase chain reaction) or human error-prone (microscopy) diagnosis methods are available.[2] Thus, a sensitive and reliable method for the diagnosis of babesiosis is highly desired. A number of optical spectroscopic techniques to detect the human malaria parasite were explored in our lab, including Attenuated Total Reflection Fourier transform infrared (ATR-FTIR) spectroscopy as a non-subjective diagnosic tool.[3] Here, we demonstrate the applicability of spectroscopic methods for the detection of B. bovis. 1) First, we established ATR-FTIR spectroscopy as a method for the detection of B. bovis. As ATR-FTIR on blood samples is usually challenged by the background absorbance of blood components, blood samples were lysed thereby removing blood components. This increased the detection sensitivity from 77.3% to 92.0% for 0.25% parasitemia. 2) Using atomic force microscopy (AFM) IR, which allows for the collection IR spectra with a nanoscale spatial resolution, we could assign spectral features that are characteristic for parasites, i.e. DNA and lipid IR-bands, for example. 3) Synchrotron-based FPA-IR allows for IR imaging with the high intensity of synchrotron radiation. Averaging over the pixels in an image of B. bovis infected cattle red blood cells (cRBCs) and uninfected cRBCs yielded spectra corresponding to a whole infected or uninfected cRBC, respectively. The spectral changes from ATR-FTIR that account for the presence of B. bovis in cRBCs were confirmed by the use of AFM-IR directly on the parasite inside of a cRBC and by synchrotron-based FPA-IR on B. bovis infected and uninfected cRBCs. This proves that the diagnosis of B. bovis using ATR-FTIR spectroscopy is based on real changes in the biological composition of infected RBCs. Thus we show here the proof of principle of using IR spectroscopic techniques for diagnosing the threatening disease babesiosis.

[1.] L. Schnittger et al. Infec Genet and Evol. 12, 1788–1809 (2012) [2.] R. Bock et al. Parasitology, 129, S247–S269 (2004) [3.] Khoshmanesh, A. et al. Anal Chem, 86, 4379 (2014)