Research Projects

Scrub typhus is a deadly disease transmitted by mites and caused by the bacteria Orientia tsutsugamushi (O. tsutsugamushi). It is a reappearing disease of the tsutsugamushi triangle transmitted by the bite of chiggers (larval stage). Recent studies have shown that the number of patients suffering from this infection is increasing daily, especially in the northern part of the country (mostly Himachal Pradesh, Times of India report). In addition, scrub typhus is known to be prevalent in the foot hills of the Himalayas, viz. Jammu & Kashmir, Sikkim, Manipur, Nagaland, Meghalaya, Himachal Pradesh, etc. (NCDC Newsletter., 2013), and the mortality rate of the disease is quite high. A vast majority of cases (81.7%) reside in rural areas, whereas 18.3% reside in urban areas, with mortality rates ranging from 7% to 30%, in addition to malaria, which is an infectious disease (Devasagayam et al. 2021). Scrub typhus is difficult to diagnose, as its symptoms are similar to those of other fever-related illnesses. Enzyme-linked immunosorbent assay (ELISA), immunofluorescence assay (IFA), immunochromatographic test (ICT), Weil-Felix, polymerase chain reaction (PCR), and loop-mediated isothermal amplification (LAMP) are effective diagnostic procedures for scrub typhus. The Weil-Felix test was first employed in poor nations to screen for scrub typhus, but it was not recommended because of its lack of specificity and sensitivity. Other antibody-based methods, such as IFA and ELISA, are mostly used in the diagnosis of scrub typhus because of their high sensitivity and specificity, but they do not have the ability to detect infection in the early stages and require convalescent sampling for confirmation. In addition, PCR-based methods overcome the limitations of current diagnostic methods and are able to detect infection at early stages with high precision and sensitivity. The only limitation with this method is the lower recovery of bacterial GDNA from patient samples and the genetic variations among its serotypes. Our laboratory has been working on the diagnostic aspects of Scrub Typhus for the past 7 years and has successfully developed electrochemical DNA sensors that can detect particular bacteria in only 20 mins. In this sensor, different nanocomposites have been used to increase the sensitivity of the device. However, some limitations in terms of the stability of commercial electrodes, cost of the developed sensor, specificity issues and lack of user-friendliness make commercialization and its availability to common people very difficult. Here, we propose the development of a user-friendly (in-house-developed prototype and android software), economical (in-house-synthesized screen-printed electrodes), portable, sensitive and specific point-of-care technology using electrochemical CRISPR-CAS and fluorescence-based diagnostic technology. CRISPR-based electrochemical sensors offer significant advantages over traditional electrochemical sensors, primarily due to their enhanced sensitivity, specificity, and adaptability for multiplexed and point-of-care (POC) applications. In this context, CRISPR/Cas12a-driven fluorescent and electrochemical dual-mode biosensors for the detection of Orientia tsutsugamushi will be developed and commercialized.