LYMPHATIC FILARIASIS (LF) is a parasitic infection spread by mosquitoes. This disabling and disfiguring disease is caused by thread-like parasitic worms. To accomplish the earlier detection of LF, a microwave method has been presented by Anil Lonappan, Vinu Thomas, G. Bindu, Joe Jacob, and K.T. Mathew from the Department of Electronics, Microwave Tomography, and Materials Research Laboratory at India's Cochin University of Science and Technology together with C. Rajasekaran from the Department of Medicine at Medical College (Trivandrum, India).
In this solution, in-vitro blood analysis was performed based on dielectric properties at microwave frequencies. A rectangular-cavity-perturbation technique was used at the S-band with samples of blood obtained from both healthy donors and patients who were already suffering from LF. The technique was used at the frequency range of 2 to 3 GHz. Compared to the healthy blood samples, the LF patient samples exhibited a higher dielectric constant. This increased conductivity stems from the presence of a higher level of electrolytes and complete blood cell count.
The cavity-perturbation technique only requires minute volumes of blood for the measurement. In addition, this approach does not suffer from the time restrictions of more traditional methods. This feature is key for LF, as its parasites tend to exhibit "nocturnal periodicity" that restricts their appearance in the blood to only the hours of 10 p.m. to 2 a.m. The measurement approach that was used relied upon a transmission-type, S-band rectangular cavity resonator, the HP 8714 ET network analyzer from Agilent (www.agilent.com). See "New Method of Detecting Lymphatic Disease Using Microwaves," Microwave and Optical Technology Letters, December 2007, p. 3166.