Browsing by Author "Shukla, Ashish"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Publication
    Assessing insecticide susceptibility, diagnostic dose and time for the sand fly Phlebotomus argentipes, the vector of visceral leishmaniasis in India, using the CDC bottle bioassay
    (Public Library of Science, 2023) Chaubey, Rahul; Shukla, Ashish; Kushwaha, Anurag Kumar; Tiwary, Puja; Singh, Shakti Kumar; Hennings, Shawna; Singh, Om Praksh; Lawyer, Phillip; Rowton, Edgar; Petersen, Christine A.; Bernhardt, Scott A.; Sundar, Shyam
    Visceral leishmaniasis (VL) is a vector-borne protozoan disease, which can be fatal if left untreated. Synthetic chemical insecticides are very effective tools for controlling of insect vec-tors, including the sand fly Phlebotomus argentipes, the vector of VL in the Indian subconti-nent. However, repeated use of the same insecticide with increasing doses potentially can create high selection pressure and lead to tolerance and resistance development. The objec-tive of this study was to determine the lethal concentrations and assess levels of susceptibility, diagnostic doses and times to death of laboratory-reared P. argentipes to five insecticides that are used worldwide to control vectors. Using the Center for Disease Control and Prevention (CDC) bottle bioassay, 20�30 sand flies were exposed in insecticide-coated 500-ml glass bot-tles. Flies were then observed for 24 hours and mortality was recorded. Dose-response survival curves were generated for each insecticide using QCal software and lethal concentrations causing 50%, 90% and 95% mortality were determined. A bioassay was also conducted to determine diagnostic doses and diagnostic times by exposing 20�30 flies in each bottle containing set concentrations of insecticide. Mortality was recorded at 10-minute intervals for 120 minutes to generate the survival curve. Phlebotomus argentipes are highly susceptible to alpha-cypermethrin, followed by deltamethrin, malathion, chlorpyrifos, and least susceptible to DDT. Also, the lowest diagnostic doses and diagnostic times were established for alpha-cypermethrin (3?g/ml for 40 minutes) to kill 100% of the flies. The susceptibility data, diagnostic doses and diagnostic times presented here will be useful as baseline reference points for future studies to assess insecticide susceptibility and resistance monitoring of field caught sand flies and to assist in surveillance as VL elimination is achieved in the region. � 2023 Chaubey et al.
  • Thumbnail Image
    Publication
    Livestock and rodents within an endemic focus of Visceral Leishmaniasis are not reservoir hosts for Leishmania donovani
    (Public Library of Science, 2022) Kushwaha, Anurag Kumar; Shukla, Ashish; Scorza, Breanna M.; Rai, Tulika Kumari; Chaubey, Rahul; Maurya, Dharmendra Kumar; Srivastva, Shweta; Upadhyay, Shreya; Singh, Abhishek Kumar; Malviya, Paritosh; Singh, Om Prakash; Scholar, Vivek Kumar; Tiwary, Puja; Singh, Shakti Kumar; Lawyer, Phillip; Rowton, Edgar; Bernhardt, Scott A.; Petersen, Christine A.; Sundar, Shyam
    Leishmaniasis on the Indian subcontinent is thought to have an anthroponotic transmission cycle. There is no direct evidence that a mammalian host other than humans can be infected with Leishmania donovani and transmit infection to the sand fly vector. The aim of the present study was to evaluate the impact of sand fly feeding on other domestic species and provide clinical evidence regarding possible non-human reservoirs through experimental sand fly feeding on cows, water buffalo goats and rodents. We performed xenodiagnosis using colonized Phlebotomus argentipes sand flies to feed on animals residing in villages with active Leishmania transmission based on current human cases. Xenodiagnoses on mammals within the endemic area were performed and blood-fed flies were analyzed for the presence of Leishmania via qPCR 48hrs after feeding. Blood samples were also collected from these mammals for qPCR and serology. Although we found evidence of Leishmania infection within some domestic mammals, they were not infectious to vector sand flies. Monitoring infection in sand flies and non-human blood meal sources in endemic villages leads to scientific proof of exposure and parasitemia in resident mammals. Lack of infectiousness of these domestic mammals to vector sand flies indicates that they likely play no role, or a very limited role in Leishmania donovani transmission to people in Bihar. Therefore, a surveillance system in the peri-/post-elimination phase of visceral leishmaniasis (VL) must monitor absence of transmission. Continued surveillance of domestic mammals in outbreak villages is necessary to ensure that a non-human reservoir is not established, including domestic mammals not present in this study, specifically dogs. � 2022 Kushwaha et al.
  • Thumbnail Image
    Publication
    Nanodiagnostics in leishmaniasis: A new frontiers for early elimination
    (Wiley-Blackwell, 2021) Gedda, Mallikarjuna Rao; Madhukar, Prasoon; Shukla, Ashish; Mudavath, Shyam Lal; Srivastava, Onkar Nath; Singh, Om Prakash; Sundar, Shyam
    Visceral leishmaniasis (VL) is still a major public health concern in developing countries having the highest outbreak and mortality potential. While the treatment of VL has greatly improved in recent times, the current diagnostic tools are limited for use in the post-elimination setting. Although conventional serological methods of detection are rapid, they can only differentiate between active disease in strict combination with clinical criteria, and thus are not sufficient enough to diagnose relapse patients. Therefore, there is a dire need for a portable, authentic, and reliable assay that does not require large space, specialized instrument facilities, or highly trained laboratory personnel and can be carried out in primary health care settings. Advances in the nanodiagnostic approaches have led to the expansion of new frontiers in the concerned area. The nanosized particles are blessed with an ability to interact one-on-one with the biomolecules because of their unique optical and physicochemical properties and high surface area to volume ratio. Biomolecular detection systems based on nanoparticles (NPs) are cost-effective, rapid, nongel, non-PCR, and nonculture based that provide fast, one-step, and reliable results with acceptable sensitivity and specificity. In this review, we discuss different NPs that are being used for the identification of molecular markers and other biomarkers, such as toxins and antigens associated with leishmaniasis. The most promising diagnostic approaches have been included in the article, and the ability of biomolecular recognition, advantages, and disadvantages have been discussed in detail to showcase the enormous potential of nanodiagnostics in human and veterinary medicine. This article is categorized under: Diagnostic Tools > Diagnostic Nanodevices Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Diagnostic Tools > Biosensing. � 2020 Wiley Periodicals LLC.