Genome fingerprinting of two populations of Aedes (Stegomyia) albopictus Skuse (Asian Tiger) using random primers (Diptera: Culicidae)

The present paper deals with RAPD-PCR based genomic characterization of two allopatric populations of Aedes (Stegomyia) albopictus Skuse which is a major vector of dengue fever and a source of many other pathogenic infections in man. For the present purpose one population was collected from village Dhunater, Distt. Hamirpur in Himachal Pradesh (pop.A) while the other was procured from Panjab University campus (pop.B). The genomic DNA from the legs of individual specimens was amplified by using three random primers viz: Primer I-5’TTTGCCCGGA-3’, Primer II- 5’-GTCCCGACGA-3’ and Primer III- 5’-CAGGCCCTTC-3’. The amplification of the DNA of pop.A with primer I, produced a total of 7 bands ranging from 230-880 bp while 3 bands ranging from 450-820 bp were produced from pop. B. Similarly, with primer II a total of 8 bands were produced from pop. A, which ranged from 220-800 bp while 9 were produced from the DNA of the individuals of pop. B, which ranged from 200-900 bp. With primer III, a total of 15 bands were produced from pop. A, with a base pair composition varying from 210-1031 bp while 5 were produced from pop. B with a range of 210-370 bp. From the hierarichial cluster sharing analysis of bands, primers I and II were found to ideal for the differentiation of the individuals at the population level studies of this species of considerable epidemiological significance

Insecticide Resistance in Vectors of Medically Important Parasitic Infections

Insecticide resistance is a major threat to vector control programmes as insecticides still remain the most effective method to control the vector-borne diseases. For effective management of insecticide resistance, a knowledge of the insecticides used along with their mode of action is a prerequisite to optimize their use. Nowadays, different detection methods, viz., phenotypic, genotypic and proteomic assays are used for assessment of insecticide resistance in vectors. An understanding of the phenotypic and genotypic variations present in the vectors help in implementation of these techniques to evaluate the usefulness of insecticides in an area and to determine the efficacy of an ongoing vector control programmes. The understanding of different factors involved in emergence of insecticide resistance and the alternative solutions to control this problem by the use of rotational, mixture of insecticides and use of piperonyl butoxide to increase the efficacy of indoor residual spray and insecticide treated bed nets are some of the steps taken to tackle the problem of insecticide resistance in vectors

Different Strategies for Mosquito Control: Challenges and Alternatives

Vector control is an imperative method for the control of vector borne diseases. Over the last few decades, many methods have been developed for their control and the main goal of these strategies is to reduce the number of mosquito populations to overcome the epidemic situations. Though despite continuous efforts of the present interventions being deployed in the vector control programs we are unable to control the disease transmission and outbreaks. Therefore, it highlights the importance of exploring the challenges which are hindering the success of these strategies and also alternative solutions for the same so as to boost the vector control interventions

Rapid identification of medically important mosquitoes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Abstract Background Accurate and rapid identification of dipteran vectors is integral for entomological surveys and is a vital component of control programs for mosquito-borne diseases. Conventionally, morphological features are used for mosquito identification, which suffer from biological and geographical variations and lack of standardization. We used matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for protein profiling of mosquito species from North India with the aim of creating a MALDI-TOF MS database and evaluating it. Methods Mosquito larvae were collected from different rural and urban areas and reared to adult stages. The adult mosquitoes of four medically important genera, Anopheles, Aedes, Culex and Armigerus, were morphologically identified to the species level and confirmed by ITS2-specific PCR sequencing. The cephalothoraces of the adult specimens were subjected to MALDI-TOF analysis and the signature peak spectra were selected for creation of database, which was then evaluated to identify 60 blinded mosquito specimens. Results Reproducible MALDI-TOF MS spectra spanning over 2–14 kDa m/z range were produced for nine mosquito species: Anopheles (An. stephensi, An. culicifacies and An. annularis); Aedes (Ae. aegypti and Ae. albopictus); Culex (Cx. quinquefasciatus, Cx. vishnui and Cx. tritaenorhynchus); and Armigerus (Ar. subalbatus). Genus- and species-specific peaks were identified to create the database and a score of > 1.8 was used to denote reliable identification. The average numbers of peaks obtained were 55–60 for Anopheles, 80–100 for Aedes, 30–60 for Culex and 45–50 peaks for Armigeres species. Of the 60 coded samples, 58 (96.67%) were correctly identified by MALDI-TOF MS with a score > 1.8, while there were two unreliable identifications (both Cx. quinquefasciatus with scores < 1.8). Conclusions MALDI-TOF MS appears to be a pragmatic technique for accurate and rapid identification of mosquito species. The database needs to be expanded to include species from different geographical regions and also different life-cycle stages to fully harness the technique for entomological surveillance programs

Prevalence of submicroscopic malaria in low transmission state of Punjab: A potential threat to malaria elimination

Background & objectives: Submicroscopic malaria infections with low parasite density serve as a silent reservoir for maintaining residual transmission in the population. These infections should be identified and targeted to be eliminated for sustained malaria control. The conventional methods of diagnosis such as light microscopy and rapid diagnostic kits often fail to detect low density infections. Therefore, the more sensitive molecular techniques should be employed to detect low density infections. The objectives of the study was to explore the prevalence of sub-microscopic infections in low transmission areas of Punjab using highly sensitive molecular tool. Methods: A total of 1114 finger prick blood samples were collected through active surveillance and tested for malaria diagnosis using light microscopy, RDT and PCR. Nested PCR amplification was performed using a pair of Plasmodium genus-specific primers from the 18S rRNA small subunit gene (18S rRNA). The amplified PCR products were analysed using a 2% agarose gel, stained with ethidium bromide and observed under transilluminator. Results: Test positive rate (TPR) by microscopy, RDT and PCR was 4.4, 3.95 and 5.75%, respectively. Microscopy and RDT failed to detect mixed infections whereas 0.26% cases were found to be mixed infection in PCR. Compared to LM and RDT, PCR has detected 1.3% additional positive cases. However, of the total positive cases detected by PCR, 23.4% infections were found to be submicroscopic, which could not be detected by conventional methods of diagnosis. Interpretation & conclusions: The molecular study revealed the existence of submicroscopic malaria cases in the study population which would have remained undetected by conventional methods of diagnosis. This is particularly important because Punjab state is in malaria elimination phase and targeted to achieve elimination in 2021. However, such undetected parasite positive cases may pose bigger problem any time due to continued transmission. Therefore, application of more sensitive diagnostic tools like PCR and LAMP with conventional methods may be much more useful in case detection particularly in low transmission settings for malaria elimination

Additional file 1: of Rapid identification of medically important mosquitoes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Figure S1. MALDI-TOF MS spectra of three representative specimens of An. stephensi. Figure S2. MALDI-TOF MS spectra of three representative specimens of An. culicifacies. Figure S3. MALDI-TOF MS spectra of three representative specimens of An. annularis. Figure S4. MALDI-TOF MS spectra of three representative specimens of Ae. aegypti. Figure S5. MALDI-TOF MS spectra of three representative specimens of Ae. albopictus. Figure S6. MALDI-TOF MS spectra of three representative specimens of Cx. tritaenorhynchus. Figure S7. MALDI-TOF MS spectra of three representative specimens of Cx. vishnui. Figure S8. MALDI-TOF MS spectra of three representative specimens of Cx. quinquefasciatus. Figure S9. MALDI-TOF MS spectra of three representative specimens of Ar. subalbatus. (PDF 2050 kb