Chronicle down memory lane: India's sixty years of plague experience.

BACKGROUND: This perspective documents the historical aspects of outbreaks of plague of last six decades, establishment of plague surveillance network in India with detailed insights about its activities and recent developments requiring focus on plague surveillance. Human plague was reported in Mulbagal area of Karnataka in 1966-67 only to re-emerge in the country in 1994 in Beed district (Maharashtra) and subsequently in Surat (Gujarat). Later Plague outbreak has been reported in the year 2002 with index case from Village Hatkoti, Shimla District in Himachal Pradesh. The last outbreak reported from India was in 2004 from Village Dangaud, Uttarkashi District in Uttarakhand followed by a period of quiescent since last 17 years. OBJECTIVES: During the last few decades, at least three geographical areas experienced outbreaks of plague after silent period of 28 years. We recapitulate the response mechanism for containing outbreaks during the last three outbreaks of plague held in Maharashtra & Gujarat (1994), Himachal Pradesh (2002) and Uttarakhand (2004). We also document the Plague surveillance network of India and its activities which is a comprehensive surveillance system comprising of rodent, flea, canine and human surveillance whose foundation was started in 1964. The recent developments of last decade in terms of revised Human plague surveillance case definitions, Plague surveillance sites, vector control, novel diagnostics and vaccines in our country are also mentioned. CONCLUSION: The thrust areas in control of plague outbreak are early detection and isolation of cases, timely effective antibiotic treatment, chemoprophylaxis to contacts, strengthening of surveillance system and massive IEC campaign in infected areas. Yersinia pestis (causative agent of Plague) also being an important bioterrorism agent, clinicians need to pay special attention to diagnose and microbiologists must be provided skilled training for laboratory confirmation to this pestilential disease for effective and timely management.

Green biomimetic preparation of efficient Ag-ZnO heterojunctions with excellent photocatalytic performance under solar light irradiation: a novel biogenic-deposition-precipitation approach.

Herein, we report a unique single-step biogenic deposition precipitation (BDP) approach as a straightforward route for producing efficient Schottky contact between noble metal nanoparticles and wide-band-gap semiconductors. Successful preparation of Ag-ZnO heterojunctions using fennel seed extract (FSE) has been described. The effective biomolecules available in the seeds functioned as novel biogenic materials for the precipitation of adsorbed silver ions (Ag+) on ZnO particles as metallic silver (Ag0). The as-prepared composite materials were characterized using diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX) study, X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL) and high-resolution transmission electron microscopy (HR-TEM). The biogenically prepared Ag-ZnO nanocomposites exhibited excellent photocatalytic activity towards reduction/degradation of colored (rhodamine B (Rh-B) dye) as well as colorless (chlorpyrifos pesticide) pollutants when irradiated under solar light. Among the prepared photocatalysts, 3 wt% Ag-ZnO hybrid composite showed the best photocatalytic activity by efficiently degrading hazardous organic pollutants within a very short time. The superior photocatalytic performance of biogenically prepared Ag-ZnO heterojunctions can be ascribed to the clean production of steady and efficient Schottky contact between plasmonic AgNPs and semiconducting ZnO NPs.