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Epidemiology, drug resistance, and pathophysiology of Plasmodium vivax malaria
Kiran K Dayananda, Rajeshwara N Achur, D Channe Gowda
January-March 2018, 55(1):1-8
DOI:10.4103/0972-9062.234620  PMID:29916441
Malaria, caused by the protozoan parasites of the genus Plasmodium, is a major health problem in many countries of the world. Five parasite species namely, Plasmodium falciparum, P. vivax, P. malariae, P. ovale, and P. knowlesi, cause malaria in humans. Of these, P. falciparum and P. vivax are the most prevalent and account for the majority of the global malaria cases. In most areas of Africa, P. vivax infection is essentially absent because of the inherited lack of Duffy antigen receptor for chemokines on the surface of red blood cells that is involved in the parasite invasion of erythrocytes. Therefore, in Africa, most malaria infections are by P. falciparum and the highest burden of P. vivax infection is in Southeast Asia and South America. Plasmodium falciparum is the most virulent and as such, it is responsible for the majority of malarial mortality, particularly in Africa. Although, P. vivax infection has long been considered to be benign, recent studies have reported life-threatening consequences, including acute respiratory distress syndrome, cerebral malaria, multi-organ failure, dyserythropoiesis and anaemia. Despite exhibiting low parasite biomass in infected people due to parasite’s specificity to infect only reticulocytes, P. vivax infection triggers higher inflammatory responses and exacerbated clinical symptoms than P. falciparum, such as fever and chills. Another characteristic feature of P. vivax infection, compared to P. falciparum infection, is persistence of the parasite as dormant liver-stage hypnozoites, causing recurrent episodes of malaria. This review article summarizes the published information on P. vivax epidemiology, drug resistance and pathophysiology.
  4,215 1,123 1
Insights into the early liver stage biology of Plasmodium
Lokesh D Kori, Neena Valecha, Anupkumar R Anvikar
January-March 2018, 55(1):9-13
DOI:10.4103/0972-9062.234631  PMID:29916442
Even though malaria is preventable and curable, it has become a serious threat to mankind. In 2016, there were an estimated 216 million cases of malaria across the world. The biology of its causative agent, i.e. Plasmodium parasite is full of complex mechanisms. There are five Plasmodium species responsible for malaria in humans, viz. Plasmodium falciparum, P. vivax, P. malariae, P. ovale and recently identified P. knowlesi that normally infect apes. In humans, malaria is spread by the injection of Plasmodium sporozoites through the bite of infectious Anopheles’ female mosquito during their blood meal. From the time of entry into human skin till the development into the asexual forms, the parasite undergoes several transformations. This review attempts to understand the science behind the pre-erythrocytic liver stage of Plasmodium. Research articles explaining parasite biology, cell-traversal, transformation stages, cell-egress process, etc. were retrieved from PubMed and google scholar database. Various known and unknown mechanisms and strategies used by the malaria parasite P. berghei in rodent models have been discussed in this review. Limited or no information was available for humans, due to technical feasibility and complexity of parasite’s life cycle. Hence, it was concluded that there is an urgent need to investigate the hepatic invasion, traversal and egress mechanism of P. falciparum and P. vivax for developing novel therapeutics to fight against malaria.
  2,385 675 -
Role of gut inhabitants on vectorial capacity of mosquitoes
Lekshmi Jayakrishnan, Ambalaparambil Vasu Sudhikumar, Embalil Mathachan Aneesh
April-June 2018, 55(2):69-78
DOI:10.4103/0972-9062.242567  PMID:30280704
Mosquito-borne diseases are spreading at an alarming rate. Globally millions of deaths occur due to the diseases transmitted by mosquitoes, next to AIDS and tuberculosis. Several methods have been used to control these vectors and the diseases caused by them. Earlier studies have shown the potential role of mosquito gut inhabitants on disease transmission. Their findings can be used as an innovative approach for devising strategies to modify the survival of mosquitoes by reducing their lifespan, reproduction and disease transmission abilities. In this study, microbiome of the three genera of mosquitoes, namely Aedes, Anopheles, and Culex along with their vectorial capacity have been reviewed for assessing their role in mosquito control and transmission. Relevant articles were accessed using different databases, including LILACS, Embase, Science Direct and PubMed from inception to June 2017. The search keywords included “Aedes”, “Anopheles”, “Culex”, “gut inhabitants”, “vectors”, and “mosquito”. The titles, abstract, and keywords of the retrieved articles were screened, and eligible research articles were sorted. The review indicates that paratransgenesis may be considered as a versatile and effective strategy to eradicate the spurt of mosquito transmitting diseases. Enterobacter species is the most common type of gram-negative bacteria associated with the gut of all the three genera of mosquitoes. It was found to have a beneficial effect on humans as it helps in destroying dreadful disease-transmitting vectors. These symbiotic qualities of the microbes need to be thoroughly investigated further to reveal their antipathogenic effect on the vector.
  2,306 588 2
Malaria elimination in India—The way forward
Susanta K Ghosh, Manju Rahi
January-March 2019, 56(1):32-40
DOI:10.4103/0972-9062.257771  PMID:31070163
The World Malaria Report 2018 published by the World Health Organization highlights that no significant progress in reducing global malaria cases was achieved for the period 2015–2017. India carries 4% of the global malaria burden and contributes 87% of the total malaria cases in South-East Asia. India is in malaria elimination mode, and set targets for malaria-free status by 2030. Diagnosis and treatment of asymptomatic falciparum malaria cases continues to be a challenge for health care providers. To overcome these hurdles innovative solutions along with the existing tools and strategies involving vector control, mass drug administration, disease surveillance hold the key to solve this gigantic health problem.
  2,453 352 1
Aedes vittatus (Bigot) mosquito: An emerging threat to public health
AB Sudeep, P Shil
October-December 2017, 54(4):295-300
DOI:10.4103/0972-9062.225833  PMID:29460858
Aedes vittatus (Bigot) mosquito is a voracious biter of humans and has a geographical distribution throughout tropical Asia, Africa and the Mediterranean region of Europe. It is predominantly a rock-hole breeder, though it can breed in diverse macro- and micro-habitats. The mosquito plays an important role in the maintenance and transmission of yellow fever (YFV), dengue (DENV), chikungunya (CHIKV) and Zika (ZIKV) viruses. It has been implicated as an important vector of YFV in several African countries as evidenced by repeated virus isolations from the mosquito and its potential to transmit the virus experimentally. Similarly, DENV-2 has been isolated from wild caught Ae. vittatus mosquitoes in Senegal, Africa which has been shown to circulate the virus in sylvatic populations without causing human infection. Experimental studies have shown replication of the virus at a low scale in naturally infected mosquitoes while high rate of infection and dissemination have been reported in parenterally infected mosquitoes. Natural isolation of ZIKV has been reported from Senegal and Cote d’Ivoire from these mosquitoes. They were found highly competent to transmit the virus experimentally and the transmission rate is at par with Ae. leuteocephalus, the primary vector of ZIKV. A few CHIKV isolations have also been reported from the mosquitoes in Senegal and other countries in Africa. Experimental studies have demonstrated high susceptibility, early dissemination and efficient transmission of CHIKV by Ae. vittatus mosquitoes. The mosquitoes with their high susceptibility and competence to transmit important viruses, viz. YFV, DENV, CHIKV and ZIKV pose a major threat to public health due to their abundance and anthropophilic behaviour.
  2,093 485 1
Anopheline mosquitoes behaviour and entomological monitoring in southwestern Ethiopia
Kidane Lelisa, Abebe Asale, Behailu Taye, Daniel Emana, Delenasaw Yewhalaw
July-September 2017, 54(3):240-248
DOI:10.4103/0972-9062.217615  PMID:29097639
Background & objectives: Despite a tremendous expansion in the financing and coverage of malaria control programmes, the disease continues to be a global health threat. This study was conducted to assess the entomological parameters of anopheline mosquitoes, viz. species composition, abundance, longevity, behaviour and infectivity rates in Kersa district, Jimma zone, southwestern Ethiopia. Methods: Mosquito collection was carried out from each selected household in each of the nine selected study villages of Kersa district, using CDC light-traps and pyrethrum spray catches (PSCs) for seven months (June to December 2014). Mosquito count data were log transformed before analysis and the data were analyzed using SPSS software package version 16.0. Analysis of variance (ANOVA) was employed to compare means and Tukey’s post-hoc test was used for mean separation. Results: In total, 1559 adult female anopheline mosquitoes, representing at least three species were collected from the study villages. Of these, 1122 were collected by CDC light-traps and the rest 437 were collected by PSCs. Anopheles gambiae s.l. (71.8%) was the most abundant species, followed by An. coustani s.l. (22%) and An. pharoensis (6.2%). The mean monthly density of anopheline mosquito species was highly significant (p < 0.001). Significantly (p <0.05) higher population of An. gambiae s.l. were trapped indoor than outdoor. However, outdoor mean densities ofAn. pharoensis and An. coustani s.l. were significantly (p < 0.001) higher than indoor mean densities. The longevity of An. gambiae s.l. was higher in the months of June, July and August (mean 7.32 days) and lower in the months of October, November and December (mean 2.94 days). Two An. gambiae s.l. specimens were found positive for Plasmodium vivax 210 polymorphs and the overall infectivity rate was estimated to be 1.04%. Interpretation & conclusion: This study could contribute to the understanding of anopheline mosquitoes with respect to their composition, dynamics, distribution and behaviour in Kersa district, for evidence based malaria vector control programmes, mainly in the appropriate timing of the indoor residual spray programme.
  2,080 356 2
Geographic distribution and spatial analysis of Leishmania infantum infection in domestic and wild animal reservoir hosts of zoonotic visceral leishmaniasis in Iran: A systematic review
M Mohebali, E Moradi-Asl, Y Rassi
July-September 2018, 55(3):173-183
DOI:10.4103/0972-9062.249125  PMID:30618442
Visceral leishmaniasis (VL) is an important parasitic disease which is endemic in different parts of Iran; and domestic and wild canines are principal reservoir hosts of the disease. The objective of this study was to review the spatial distribution of canine VL (CVL) caused by Leishmania infantum in domestic and wild canines in different geographical areas of Iran. An extensive literature search was conducted in different international and national databases, including Cochrane, MEDLINE/PubMed, Scopus, Web of Science and Iran Medex to find articles with the words “visceral leishmaniasis in Iran” in their titles and “canine visceral leishmaniasis in Iran” or “feline visceral leishmaniasis in Iran” or “accidental reservoir hosts of visceral leishmaniasis in Iran” in their subtitles, irrespective of the type and duration of study. Screening of the irrelevant articles from total 36,342, yielded 61 eligible articles. More than 93% of the studies were carried out on domestic dogs (Canis familiaris, n = 57) and the remaining were on other carnivores such as wild canines including foxes (Vulpes vulpes, n = 4), jackals (C. aureus, n = 6) and wolves (C. lupus, n = 6); while studies on domestic cats (Felis catus, n = 3) as well as desert rodents (n = 2) were rare. The average rate of L. infantum infections reported among domestic dogs using direct agglutination test (DAT) in Iran was 12.5%. The highest prevalence rate (14%) was reported from the northwest regions of the country where VL is endemic. The review indicates that CVL is endemic in various parts of Iran and domestic dogs are the main and potential reservoir hosts of the disease. Other carnivores, such as domestic cats and some species of desert rodents (Cricetulus migratorius, Mesocricetus auratus and Meriones persicus) seem to be playing a role in the maintenance of transmission cycle of L. infantum in the endemic areas of the disease.
  1,910 478 -
Improving vector-borne pathogen surveillance: A laboratory-based study exploring the potential to detect dengue virus and malaria parasites in mosquito saliva
Vanessa R Melanson, Ryan Jochim, Michael Yarnell, Karen Bingham Ferlez, Soumya Shashikumar, Jason H Richardson
October-December 2017, 54(4):301-310
DOI:10.4103/0972-9062.225834  PMID:29460859
Background & objectives: Vector-borne pathogen surveillance programmes typically rely on the collection of large numbers of potential vectors followed by screening protocols focused on detecting pathogens in the arthropods. These processes are laborious, time consuming, expensive, and require screening of large numbers of samples. To streamline the surveillance process, increase sample throughput, and improve cost-effectiveness, a method to detect dengue virus and malaria parasites (Plasmodium falciparum) by leveraging the sugar-feeding behaviour of mosquitoes and their habit of expectorating infectious agents in their saliva during feeding was investigated in this study. Methods: Dengue virus 2 (DENV-2) infected female Aedes aegypti mosquitoes and P. falciparum infected female Anopheles stephensi mosquitoes were allowed to feed on honey coated Flinders Technical Associates —FTA® cards dyed with blue food colouring. The feeding resulted in deposition of saliva containing either DENV-2 particles or P. falciparum sporozoites onto the FTA card. Nucleic acid was extracted from each card and the appropriate real-time PCR (qPCR) assay was run to detect the pathogen of interest. Results: As little as one plaque forming unit (PFU) of DENV-2 and as few as 60 P. falciparum parasites deposited on FTA cards from infected mosquitoes were detected via qPCR. Hence, their use to collect mosquito saliva for pathogen detection is a relevant technique for vector surveillance. Interpretation & conclusion: This study provides laboratory confirmation that FTA cards can be used to capture and stabilize expectorated DENV-2 particles and P. falciparum sporozoites from infectious, sugar-feeding mosquitoes in very low numbers. Thus, the FTA card-based mosquito saliva capture method offers promise to overcome current limitations and revolutionize traditional mosquito-based pathogen surveillance programmes. Field testing and further method development are required to optimize this strategy.
  1,849 465 2
Aetiology of acute encephalitis syndrome in Uttar Pradesh, India from 2014 to 2016
Parul Jain, Shantanu Prakash, Danish N Khan, Ravindra Kumar Garg, Rashmi Kumar, Amit Bhagat, V Ramakrishna, Amita Jain
October-December 2017, 54(4):311-316
DOI:10.4103/0972-9062.225835  PMID:29460860
Background & objectives: It is imperative to know the aetiology of acute encephalitis syndrome (AES) for patient management and policy making. The present study was carried out to determine the prevalence of common aetiological agents of AES in Uttar Pradesh (UP) state of India. Methods: Serum and/or CSF samples were collected from AES patients admitted at Gandhi Memorial and Associated Hospital, King George's Medical University, Lucknow, a tertiary care centre, UP during 2014–16. Cerebrospinal fluid (CSF) and serum samples from cases were tested for IgM antibodies against Japanese encephalitis virus (anti-JEV), and dengue virus (anti-DENV) by ELISA; and for enterovirus, herpes simplex virus (HSV) and varicella zoster virus (VZV) by real-time PCR. Serum samples of cases having sufficient CSF volume, were also tested for anti-scrub typhus IgM antibodies and for Neisseria meningitides, Streptococcus pneumoniae and Haemophilus influenzae. Results: JEV and DENV (8% each) were the most common identified aetiology from the 4092 enrolled patients. Enterovirus, HSV and VZV, each were detected in <1% AES cases. Co-positivity occurred in 48 cases. Scrub typhus (31.8%) was the most common aetiology detected. Haemophilus influenzae and S. pneumoniae were detected in 0.97 and 0.94% cases, respectively, however, N. meningitides was not detected in any of the cases. About 40% of the JEV/DENV positive AES cases were adults. The gap between the total number of AES cases and those with JEV/ DENV infection increased during monsoon and post-monsoon seasons. Interpretation & conclusion: Scrub typhus, JEV and DENV are the main aetiological agents of AES in UP. DENV and JEV can no longer be considered paediatric diseases. The prevalence of non-JEV/DENV aetiology of AES increases in the monsoon and post-monsoon seasons.
  1,928 368 3
The impact of Zika virus infection on human neuroblastoma (SH-SY5Y) cell line
Natthanej Luplertlop, San Suwanmanee, Watcharamat Muangkaew, Sumate Ampawong, Thitinan Kitisin, Yong Poovorawan
July-September 2017, 54(3):207-214
DOI:10.4103/0972-9062.217611  PMID:29097635
Background & objectives: An increase in Zika virus (ZIKV) epidemic during the last decade has become a major global concern as the virus affects both newborns and adult humans. Earlier studies have shown the impact of ZIKV infection in developing human foetus. However, effective in vitro model of target cells for studying the ZIKV infection in adult human neurons is not available. This study aimed to establish the use of human neuroblastoma cell line (SH-SY5Y) for studying an infection of ZIKV in vitro. Methods: ZIKV growth kinetics, viral toxicity, and SH-SY5Y cell vialibity were determined after ZIKV infection in SH-SY5Y cells in vitro. ZIKV-infected SH-SY5Y cells were morphologically analysed and compared with nonhuman primate Vero cells. Furthermore, the susceptibility of SH-SY5Y cells to ZIKV infection was also determined. Results: The results showed that ZIKV efficiently infects SH-SY5Y cell lines in vitro. Gradual changes of several cellular homeostasis parameters including cell viability, cytotoxicity, and cell morphology were observed in ZIKV-infected SH-SY5Y cells when compared to mock-treated or non-human primate cells. Interestingly, ZIKV particles were detected in the nucleoplasmic compartment of the infected SH-SY5Y cells. Interpretation & conclusion: The results suggest that ZIKV particle can be detected in the nucleoplasmic compartment of the infected SH-SY5Y cells beside the known viral replicating cytoplasmic area. Hence, SH-SY5Y cells can be used as an in vitro adult human neuronal cell-based model, for further elucidating the ZIKV biology, and highlight other possible significance of Zika virus distribution through nuclear localization, which may correlate to the neuropathological defects in ZIKV-infected adult humans.
  1,412 834 5
Native larvivorous fish diversity as a biological control agent against mosquito larvae in an endemic malarious region of Ranchi district in Jharkhand, India
Manoj Kumar Das, M Rajesh Kumar Rao, AK Kulsreshtha
January-March 2018, 55(1):34-41
DOI:10.4103/0972-9062.234624  PMID:29916446
Background & objectives: Mosquitoes are responsible for transmitting several diseases, including malaria, dengue, chikungunya, filariasis, and yellow fever, etc. Release of larvivorous fishes is one of the cheapest method of vector management approach, with long suppression of mosquito population. The present study identifies the native larvivorous fishes and evaluates their potential larvivoracity for biological control of mosquito larvae in an endemic malarious region. Methods: During the year 2012–13, an ecological descriptive study was carried out in diverse aquatic habitats of fish species found in different areas of Ranchi district, in Jharkhand state of India. Fishes were captured using fishing nets, and identified and classified according to the available keys. Their larvivorous potential was graded according to their feeding potential. Data on current conservation status as well as their abundance were also recorded and analysed. Results: In total, 30 larvivorous fish species belonging to seven orders, 10 families and 21 genera were identified. Order Cypriniformes and the family Cyprinidae were the most ascendant group constituting 66.7 and 60%, respectively. The grading assessment of larvivorous potential for different fish species revealed that, Colisa fasciatus possess maximum larvivoracity (+ + + + +). According to the conservation, assessment and management plan (CAMP, 1998), 60% species were at lower risk near threat (LRnt), while 86.7% species were at least concerned (LC) as per the IUCN, 2017 categorisation. All fish species preferred to inhabit in freshwater. Maximum species occurrence was found in the river (63.3%). Only 30% species were bottom feeders (BF). Interpretation & conclusion: The larvivoracity and habitat distribution analysis indicated that C. fasciatus, Oreochromis mossambica, Esomus danricus, Oryzias melastigma, Puntius sophore, P. ticto, Rasbora daniconius, R. elegans, Aplocheilus panchax, and Danio (B) rerio possess high-level larvivorous potentiality in nature and are recommended for malaria control in the study area. There is an increasing pressure on the fish fauna, of facing several threats, such as fishing, human interference, loss of habitat, overexploitation, pollution, siltation, trade, and diseases. Therefore, periodic survey and monitoring of fish biodiversity, demarcation of breeding sites, field level research study on the efficacy of these fishes, and public awareness on establishment of larvivorous fish ponds should be adopted as a part of the vector management approach in the endemic malarious region of Ranchi district in Jharkhand, India.
  1,991 228 -
Repellent effect of microencapsulated essential oil in lotion formulation against mosquito bites
Norashiqin Misni, Zurainee Mohamed Nor, Rohani Ahmad
January-March 2017, 54(1):44-53
Background & objectives: Many essential oils have been reported as natural sources of insect repellents; however, due to high volatility, they present low repellent effect. Formulation technique by using microencapsulation enables to control the volatility of essential oil and thereby extends the duration of repellency. In this study, the effectiveness of microencapsulated essential oils of Alpinia galanga, Citrus grandis and C. aurantifolia in the lotion formulations were evaluated against mosquito bites. Methods: Essential oils and W,W-Diethyl-3-methylbenzamide (DEET) were encapsulated by using interfacial precipitation techniques before incorporation into lotion base to form microencapsulated (ME) formulation. The pure essential oil and DEET were also prepared into lotion base to produce non-encapsulated (NE) formulation. All the prepared formulations were assessed for their repellent activity against Culex quinquefasciatus under laboratory condition. Field evaluations also were conducted in three different study sites in Peninsular Malaysia. In addition, Citriodiol® (Mosiquard®) and citronella-based repellents (KAPS®, MozAway® and BioZ Natural®) were also included for comparison. Results: In laboratory conditions, the ME formulations of the essential oils showed no significant difference with regard to the duration of repellent effect compared to the microencapsulated DEET used at the highest concentration (20%). It exhibited >98% repellent effect for duration of 4 h (p = 0.06). In the field conditions, these formulations demonstrated comparable repellent effect (100% for a duration of 3 h) to Citriodiol® based repellent (Mosiguard®) (p = 0.07). In both test conditions, the ME formulations of the essential oils presented longer duration of 100% repellent effect (between 1 and 2 h) compared to NE formulations. Interpretation & conclusion: The findings of the study demonstrate that the application of the microencapsulation technique during the preparation of the formulations significantly increases the duration of the repellent effect of the essential oils, suggesting that the ME formulation of essential oils have potential to be commercialized as an alternative plant-based repellent in the market against the mosquitoes.
  1,592 608 -
MERA India: Malaria Elimination Research Alliance India
Manju Rahi, Anupkumar R Anvikar, OP Singh, P Jambulingam, P Vijayachari, Aparup Das, Sanghamitra Pati, Kanwar Narain, RR Gangakhedkar, Neeraj Dhingra, Balram Bhargava
January-March 2019, 56(1):1-3
DOI:10.4103/0972-9062.257766  PMID:31070158
  1,848 298 -
Computer-aided analysis of phytochemicals as potential dengue virus inhibitors based on molecular docking, ADMET and DFT studies
Iqra Qaddir, Nouman Rasool, Waqar Hussain, Sajid Mahmood
July-September 2017, 54(3):255-262
DOI:10.4103/0972-9062.217617  PMID:29097641
Background & objectives: Dengue fever, caused by dengue virus (DENV), has become a serious threat to human lives. Phytochemicals are known to have great potential to eradicate viral, bacterial and fungal-borne diseases in human beings. This study was aimed at in silico drug development against nonstructural protein 4B (NS4B) of dengue virus 4 (DENV4). Methods: A total of 2750 phytochemicals from different medicinal plants were selected for this study. These plants grow naturally in the climate of Pakistan and India and have been used for the treatment of various pathologies in human for long-time. The ADMET studies, molecular docking and density functional theory (DFT) based analysis were carried out to determine the potential inhibitory properties of these phytochemicals. Results: The ADMET analysis and docking results revealed nine phytochemicals, i.e. Silymarin, Flavobion, Derrisin, Isosilybin, Mundulinol, Silydianin, Isopomiferin, Narlumicine and Oxysanguinarine to have potential inhibitory properties against DENV and can be considered for additional in vitro and in vivo studies to assess their inhibitory effects against DENV replication. They exhibited binding affinity ≥−8 kcal/mol against DENV4-NS4B. Furthermore, DFT based analysis revealed high reactivity for these nine phytochemicals in the binding pocket of DENV4-NS4B, based on ELUMO, EHOMO and band energy gap. Interpretation & conclusion: Five out of nine phytochemicals are reported for the first time as novel DENV inhibitors. These included three phytochemicals from Silybum marianum, i.e. Derrisin, Mundulinol, Isopomiferin, and two phytochemicals from Fumaria indica, i.e. Narlumicine and Oxysanguinarine. However, all the nine phytochemicals can be considered for in vitro and in vivo analysis for the development of potential DENV inhibitors.
  1,626 453 5
Prevalence of disease vectors in Lakshadweep Islands during post-monsoon season
Jayalakshmi Krishnan, L Mathiarasan
July-September 2018, 55(3):189-196
DOI:10.4103/0972-9062.249127  PMID:30618444
Background & objectives: Increase of vector-borne diseases (VBDs) in India has posed a question on the situation in Lakshadweep Islands, where VBDs are reported from time-to-time. The present investigation was aimed to assess the faunastic situation of the prevailing vectors along with their breeding sites in different islands of the Lakshadweep. Methods: Extensive surveys were carried out from November 2017 to January 2018 (post-monsoon season) randomly in the nine inhabited islands of Lakshadweep for conducting faunastic studies on mosquitoes and to know the basic binomics like breeding and resting preference of mosquitoes. The study islands included, Kavaratti, Agatti, Chetlat, Bitra, Amini, Kadmath, Andrott, Kalpeni and Kiltan. Both immature and adult collections were carried out by standard/appropriate sampling techniques. The obtained data were calculated and analysed in terms of different entomological indices Results: A total of 3356 mosquitoes were collected during the study period which comprised of 16 species from nine genera. Out of the 16 species, six belonged to mosquito vectors. The collection included malaria vector, Anopheles stephensi; Japanese encephalitis vector, Culex tritaeniorhynchus; Bancroftian filariasis vector, Cx. quinquefasciatus; Brugian filariasis vector, Mansonia uniformis; and dengue and chikungunya vectors, Stegomya albopicta and St. aegypti. Stegomya albopicta was the most predominant species observed constituting 54% of the catch, followed by Cx. quinquefasciatus, An. stephensi, Cx. tritaeniorhynchus, and St. aegypti constituting 10.5, 6, 3 and 1.2%, respectively. Apart from vector species many non-vectors such as Heizmannia chandi, An. subpictus, An. varuna, Cx. sitiens, Cx. minutissimus, Cx. rubithoracis, Fredwardsius vittatus, Lutzia fuscana, Malaya genurostris and Armigeres subalbatus were also present in the study area. In Kavaratti Island, the capital of Lakshadweep, a non-vector species of sandfly, Sergentomyia (Parrotomyia) babu was observed during the indoor resting collection. The major breeding sites which supported various mosquito species included, discarded plastic containers, tree holes, open sintex tanks (water storage tanks), unused wells, discarded tyres, discarded iron pots, unused and damaged boats, cement tanks, pleated plastic sheets, coral holes, pits and irrigation canals, discarded washing machines, and Colocasia plant leaf axils. Breteau index ranged between 65.3 and 110, CI ranged between 63.64 and 72.41; and HI ranged between 38.46 and 70 among the various islands. Interpretation & conclusion: Entomological indices such as house index (HI), breteau index (BI) and pupal index (PI) were high in all the nine islands and exceeded the threshold levels specified by WHO, indicating high risk for dengue virus transmission in case of outbreaks. Occurrence of vector as well as non-vector species indicates that the global change in climate is causing notable changes in terms of breeding of vector and non-vector species in the islands. With the reported cases of VBDs and the presence of vectors species in Lakshadweep Islands, a stringent control measure needs to be implemented at the Lakshadweep Islands.
  1,730 336 -
Antiplasmodial efficacy of Calotropis gigantea (L.) against Plasmodium falciparum (3D7 strain) and Plasmodium berghei (ANKA)
P.V.V. Satish, D Santha Kumari, K Sunita
July-September 2017, 54(3):215-225
DOI:10.4103/0972-9062.217612  PMID:29097636
Background & objectives: Malaria is a deadly parasitic disease, having a high rate of incidence and mortality across the world. The spread and development of resistance against chemical insecticides is one of the major problems associated with malaria treatment and control. Hence, plant based formulations may serve as an alternative source towards development of new drugs for treatment of malaria. The present study was aimed to evaluate the in vitro antiplasmodial activities of leaf, stem and flower of Calotropis gigantea against chloroquine-sensitive Plasmodium falciparum (3D7 strain) and its cytotoxicity against THP-1 cell lines. The plant extract which showed highest potency, in the in vitro antimalarial activity was further tested in vivo against P. berghei (ANKA strain) for validating its efficacy. Methods: The crude extracts of methanol, ethyl acetate and chloroform from leaves, stem and flowers of C. gigantea were prepared using Soxhlet apparatus. These extracts were screened for in vitro antimalarial activity against P. falciparum 3D7 strain. The cytotoxicity studies of crude extracts were conducted against THP-1 cell line. Phytochemical analysis of these extracts was carried out by following the standard methods. The damage to erythrocytes due to the plant extracts was tested. The in vivo study was conducted in P. berghei (ANKA) infected BALB/c albino mice by following the 4-day suppressive test. Results: The phytochemical screening of the crude extracts showed the presence of alkaloids, flavonoids, triter-penes, tannins, carbohydrates, phenols, coumarins, saponins, phlobatannins and steroids. Out of all the extracts, the methanolic extract of leaves showed highest antimalarial activity with IC50 value of 12.17 μg/ml. In cytotoxicity evaluation, none of the crude extracts, showed cytotoxicity on THP-1 cell line. Since, methanolic leaf extract of C. gigantea showed good antimalarial activity in vitro, it was tested in vivo. In the in vivo results, the methanolic leaf extract of C. gigantea exhibited an excellent activity against P. berghei malaria parasite, wherein the decrement of parasite counts was moderately low and dose-dependent (p < 0.05) in comparison to the P. berghei infected control group, which showed a daily increase of parasitaemia unlike the chloroquine-treated group. Interpretation & conclusion: The methanolic leaf extract of C. gigantea may act as potent alternative source for development of new medicines or drugs for the treatment of drug-resistant malaria. Thus, further research is needed to characterize the bioactive molecules of the extracts of C. gigantea that are responsible for inhibition of malaria parasite.
  1,336 437 -
Longitudinally extensive transverse myelitis (LETM) in a case of Japanese encephalitis with an unexpected complication
Srikant Mohta, Animesh Ray, SK Sharma, Surabhi Vyas
July-September 2017, 54(3):291-293
DOI:10.4103/0972-9062.217623  PMID:29097647
  1,598 171 2
Asymptomatic plasmodial infection in pregnant women: A global scenario
Jaime Carmona-Fonseca, Eliana M Arango
July-September 2017, 54(3):201-206
DOI:10.4103/0972-9062.217610  PMID:29097634
Though asymptomatic plasmodial infection (API) is well known phenomenon and play an important role in different populations and malaria transmission settings, it has received less attention in malaria intervention strategies. This review was aimed to estimate the prevalence of API in pregnant women across the world. The bibliography records relevant to the study were searched on PubMed and Lilacs, till August 15, 2016, without restriction of language. A total of 78 references were identified, of which 29 met the inclusion criteria. The study of the identified reports revealed that the mean prevalence of API in pregnant women was 10.8% (3382/31186), with wide variation among countries and transmission settings. The reports showed that APIs are very common even in low malaria transmission areas, and most of the APIs are due to submicroscopic plasmodial infection (SPI). More sensitive diagnostic tools are required to address API and SPI in such areas. Every malaria endemic region/country should carry out systematic studies for accurate estimation of frequency for both these events (API and SPI) in different populations for planning appropriate intervention measures.
  1,394 369 4
Safety of weekly primaquine in G6PD deficient patient with relapsing vivax malaria: A case report
Deepali Savargaonkar, Md. Zohaib Ahmed, Anupkumar R Anvikar, Neena Valecha
July-September 2017, 54(3):287-290
DOI:10.4103/0972-9062.217622  PMID:29097646
  1,448 239 -
Salinity tolerant Aedes aegypti and Ae. albopictus—Infection with dengue virus and contribution to dengue transmission in a coastal peninsula
SN Surendran, T Veluppillai, T Eswaramohan, K Sivabalakrishnan, F Noordeen, R Ramasamy
January-March 2018, 55(1):26-33
DOI:10.4103/0972-9062.234623  PMID:29916445
Background & objectives: Aedes aegypti and Ae. albopictus are major arboviral vectors that are considered to lay eggs, and undergo preimaginal development only in fresh water collections. However, recently they have been also shown to develop in coastal brackish water habitats. The ability of the biologically variant salinity-tolerant Aedes vectors to transmit arboviral diseases is unknown. We therefore, investigated the infection of salinity-tolerant Aedes mosquitoes with dengue virus (DENV) and analysed dengue incidence and rainfall data to assess the contribution of salinity-tolerant Aedes vectors to dengue transmission in the coastal Jaffna peninsula in Sri Lanka. Methods: Brackish and fresh water developing female Ae. aegypti and Ae. albopictus were tested for their ability to become infected with DENV through in vitro blood feeding and then transmit DENV vertically to their progeny. An immunochromatographic test for the NS1 antigen was used to detect DENV. Temporal variation in dengue incidence in relation to rainfall was analysed for the peninsula and other parts of Sri Lanka. Results: Aedes aegypti and Ae. albopictus developing in brackish water, became infected with DENV through in vitro blood feeding and the infected mosquitoes were able to vertically transmit DENV to their progeny. Monsoonal rainfall was the discernible factor responsible for the seasonal increase in dengue incidence in the peninsula and elsewhere in Sri Lanka. Interpretation & conclusion: Fresh water Aedes vectors are main contributors to the increased dengue incidence that typically follows monsoons in the Jaffna peninsula and elsewhere in Sri Lanka. It is possible however, that brackish water-developing Aedes constitute a perennial reservoir for DENV to maintain a basal level of dengue transmission in coastal areas of the peninsula during the dry season, and this supports increased transmission when monsoonal rains expand populations of fresh water Aedes.
  1,393 279 2
Comparative proteomics of salivary glands of Anopheles culicifacies mosquitoes using tandem mass tag (TMT) mass spectrometry
Ritu Rawal, Sonam Vijay, Kavita Kadian, Tridibesh Adak, Veena Pande, Arun Sharma
April-June 2018, 55(2):98-110
DOI:10.4103/0972-9062.242570  PMID:30280707
Background & objectives: Salivary gland proteins play a pivotal role in blood feeding, epithelial interactions, and parasite transmission in mosquito vectors. Anopheles culicifacies is a complex of five sibling species, viz. A, B, C, D, and E, with diverse geographical distribution patterns. Among these, sibling species B has been identified as poor vector. Exploring the differentially expressed salivary proteins in An. culicifacies may potentially identify refractoriness factors during malaria parasite maturation and may help to elucidate the mechanism of refractoriness. Methods: A comparative proteomic analysis was carried out using tandem mass tag (TMT) technology combined with LC-MS/MS mass spectrometry and bioinformatics analysis, to identify the differentially expressed salivary gland proteins among An. culicifacies species A (susceptible) and An. culicifacies species B (refractory) mosquitoes. Results: A total of 82 proteins were found to be differentially expressed. Out of these, seven proteins including TRIO, translation initiation factor 5C, glutathione S-transferase, and 5’ nucleotidase were up-regulated, and 75 proteins including calreticulin, elongation factors, fructose biphosphatase, isocitrate dehydrogenase, histone proteins and anti-platelet proteins, etc. were down-regulated in refractory species. Analysis of KEGG pathways showed that the up-regulated proteins were related to fatty acid metabolism and RNA transport pathways. Interpretation & conclusion: This comparative proteomic analysis of susceptible and refractory An. culicifacies salivary gland proteins identifies the plausible role of the differential proteome in immune responses, digestion, energy, and carbon metabolic pathways. This information may serve as a basis for future work concerning the possible role of these proteins in refractoriness dependent metabolic function of mosquitoes.
  1,397 271 -
Predictive and diagnostic test accuracy of ultrasonography in differentiating severe dengue from nonsevere dengue
Gary Kim-Kuan Low, Sing-Yan Looi, Mun-Hin Yong, Deepali Sharma
April-June 2018, 55(2):79-88
DOI:10.4103/0972-9062.242568  PMID:30280705
Diagnosing severe dengue from those who do not develop complication is important to prevent death. The objective of this systematic review was to evaluate the diagnostic test accuracy of ultrasonography in differentiating severe dengue from nonsevere dengue; and to assess if ultrasonography/ultrasound can be used as a predictive (screening) and diagnostic tool in the course of dengue infection. An electronic search was conducted in different databases via OvidSP platform. The included studies were cohort studies between 1995 and 2016 wherein cases were confirmed by dengue blood test. Severity of dengue was assessed and compared using standard WHO references. The methodological quality of the paper was assessed by two independent reviewers by using QUADAS-2 tool. In total 12 studies were included in this review after suitable screening. Overall, the studies included had a low and unclear risk of bias. Seven out of nine studies that compared severe dengue and nonsevere dengue, performed an ultrasonography on gallbladder (wall thickness cutoff–3 mm) with a sensitivity of 24.2–100% and a specificity of 13.2–98.7%. Other parameters such as splenic subcapsular fluid collection, pericardial fluid and hepatic subcapsular fluid collection had a specificity of >90%, though the sensitivity was poor. There were insufficient evidence that ultrasonography is able to differentiate severe dengue from nonsevere dengue accurately. The predictive and diagnostic value of ultrasonography could not be concluded due to insufficient reporting on the temporality of the ultrasonography performed with regard to the diagnosis. However, it might serve as an adjunct investigation to support the clinical diagnosis.
  1,355 274 -
Host preferences and feeding patterns of Anopheles sinensis Wiedemann in three sites of Shandong province, China
Chongxing Zhang, Guihong Shi, Peng Cheng, Lijuan Liu, Maoqing Gong
October-December 2017, 54(4):328-333
DOI:10.4103/0972-9062.225837  PMID:29460862
Background & objectives: Anopheles sinensis Wiedemann is a major vector of malaria and is among the dominant species in Shandong province of China. Knowledge of the blood-feeding patterns of mosquitoes is crucial for elimination of malaria vectors. However, little information is available on the blood-feeding behaviour of An. sinensis mosquitoes in Shandong province. This study was carried out to compare the blood-feeding behaviour of An. sinensis in malaria-endemic areas of Shandong province China. Methods: Adult Anopheles mosquitoes were collected from three malaria-endemic areas (Jimo, Yinan and Shanxian), during the peak months of mosquito population (August and September) from 2014 to 2015. Indoor-resting mosquitoes and outdoor-resting blood-fed females were sampled in the morning hours (0600 to 0900 hrs) from 10 randomly selected houses using pyrethrum spray catch method, and sweeping with an insect net. ELISA was used for the identification of blood meal. The blood meal of each mosquito was tested against antisera specific to human, pig, dog, cow, goat, horse (mule) and fowl. Results: At all indoor study locations of Jimo, Yinan and Shanxian, 59.4, 68.1 and 98.8% blood-engorged female An. sinensis collected from cattle sheds fed almost exclusively on bovines, respectively. For outdoor locations, at Jimo site, 27.27 and 49.55% An. sinensis fed on cattle and pigs; at Yinan, 30.42% fed on cattle and 36.88% fed both on cattle and goats, while no pig antibodies were detected. At Shanxian, percent of An. sinensis that fed on cattle, pigs and cattle-goat was 20.72, 27.62 and 21.78%, respectively. Interpretation & conclusion: The analysis of An. sinensis blood meals in all the three studied areas from human houses, cattle sheds, pig sheds and mixed dwellings revealed that An. sinensis prefers cattle hosts, and can feed on other available animal hosts if the cattle hosts are absent, and the mosquitoes readily feed on humans when domestic animals (cattle and pigs) are not nearby for feeding. The analysis of blood meal revealed that An. sinensis follow opportunistic feeding in Shandong province, China.
  1,369 190 2
Identification of Leishmania species using N-acetylglucosamine-1-phosphate transferase gene in a zoonotic cutaneous leishmaniasis focus of Iran
Reza Saberi, Vahideh Moin-Vaziri, Homa Hajjaran, Maryam Niyyati, Niloofar Taghipour, Farnaz Kheirandish, Alireza Abadi
January-March 2018, 55(1):14-19
DOI:10.4103/0972-9062.234621  PMID:29916443
Background & objectives: Ilam province is one of the oldest known endemic foci of zoonotic cutaneous leishmani- asis (CL) in Iran; and the recent studies have shown an increasing trend in the number of cases from the region. This study was aimed to investigate the parasite species and genetic diversity of isolates obtained from CL patients based on the N-acetylglucosamine-1-phosphate transferase (nagt) gene. Methods: Exudate materials were collected from the swollen margin of the skin lesions of the patients suspected with CL who were referred to health centers laboratory of Mehran, Dehloran, Ilam and Malekshahi cities in the Ilam province. Demographic data were collected through a questionnaire. Smears were stained and examined microscopically. In total, 62 parasitologically positive samples were subjected to PCR-RFLP of nagt gene for identification of Leishmania species, in addition to genetic diversity investigation. Results: Nearly, half of the positive cases were referred from Mehran followed by Dehloran City (40.4%). These included people from different age groups (1 to 73 yr), with majority being male (66.1%). The common site of lesions was hand (48.4%). Half of the patients had multiple lesions; most of them were wet ulcerative type. A 1450-60 bp band of the nagt gene was amplified from all the samples. Digestion patterns of acetyl-coenzyme A carboxylase 1 (ACC1) enzyme were similar to what expected for Leishmania major. No difference was observed at the nucleotide acid level or resulting amino acid in nine sequenced samples on the basis of phylogenetic analyses. However, intra- species differences (0.0015) were observed amongst the L. major isolates of present study and the other parts of Iran. Interpretation & conclusion: The findings of this study demonstrated that the main causative agent of CL in Ilam Province is L. major, and there is no considerable heterogeneity among the L. major isolates. Moreover, nagt gene proved to be an efficient marker for differentiating Leishmania species. Further studies with more samples need to be carried out to achieve a more comprehensive result on the genetic variation of L. major isolates.
  1,270 267 -
Immunogenicity of OmpA and OmpB antigens from Rickettsia rickettsii on mononuclear cells from Rickettsia positive Mexican patients
Karla Dzul-Rosado, Javier Balam-Romero, Guillermo Valencia-Pacheco, Cesar Lugo-Caballero, Juan Arias-León, Gaspar Peniche-Lara, Jorge Zavala-Castro
October-December 2017, 54(4):317-327
DOI:10.4103/0972-9062.225836  PMID:29460861
Background & objectives: The nature of the rickettsial antigens and the immune response generated by them, have been the subject of exhaustive research so that a suitable vaccine can be developed. Till date evaluations of Rickettsia rickettsii antigens that induce both humoral and cellular responses in animal models have only shown partial protection and short-term immunological memory. This study was aimed to evaluate the immune response induced by DNA plasmids generated from the OmpA and OmpB genes of R. rickettsii in peripheral blood mononuclear cells of rickettsial (sensitized) patients compared to healthy subjects. Methods: Plasmids OmpA-49, OmpB-15 and OmpB-24 were generated in the pVAX vector. Macrophages derived from the THP-1 cell line were transfected in vitro with the plasmids and were co-cultured with T-lymphocytes from sensitized subjects and healthy subjects to evaluate cell proliferation and cytokine production. Results: The OmpB-24 plasmid induced proliferative response in human lymphocytes, with production of IL-2, IFN-γ, IL-12p70, IL-6 and TNF-α, likely due to the presence of conserved epitopes among R. rickettsii, R. typhi and R. felis (differing from 1 to 3 amino acids) during the construction of the plasmids. Interpretation & conclusion: DNA sequences of rickettsial epitopes can be cloned into the pVAX vector. Constructed plasmids can generate a proliferative response and produce cytokines in vitro, in co-culture of transfected macrophages with sensitized human lymphocytes. Plasmid OmpB-24 proved to be the most immunogenic with respect to plasmids OmpA-49 and OmpB-15.
  1,280 256 -