Fleas (Insecta, Siphonaptera) are important vectors of plague and murine typhus in many parts of the world. Currently, about 2700 flea species were described in the world. The most common vector flea Xenopsylla cheopis is found throughout India, but X. astia, and X. brasiliensis are found less and limited in distribution associated with the domestic rats such as Rattus rattus, R. norvegicus, Mus musculus, and Bandicota bengalensis. Bubonic plague is a major flea-borne disease caused by the bacterial pathogen Yersinia pestis, transmitted from rats to humans via the rodent flea, X. cheopis. A major outbreak of plague and high mortality occurred in India. After 1966 with the 3 decadal intervals, plague cases occurred only during the year 1994 reported in 5 different states (Gujarat, Maharashtra, Karnataka, Uttar Pradesh, Madhya Pradesh and New Delhi and subsequently plague cases occurred during 2002 and 2004 after the one-decade interval in Himachal Pradesh (2002). Another outbreak of bubonic plague was reported in Dangud village, Barkhot tehsil, Uttarkashi district, Uttarakhand during October 2004. Ctenocephalides fleas are common in cats and dogs, which are the main vectors of bacteria rickettsiae, such as Rickettsia typhi, R. felis, R. conorii, and Bartonella henselae. Molecular and serological evidence also confirms the presence of R. typhi, R. conorii R. felis and B. henselae pathogens in cats and other fleas in India. Flea bites and flea-borne dermatitis are common in men and pet animals. Because of the re-emergence of the plague, updated information on fleas and flea-borne diseases are essential to control the flea vectors and flea-borne diseases in India. Hence, this comprehensive review updates the available information on fleas and fleas transmitted diseases in India.

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Malaria is a vector borne disease, considered to be one of the most serious public health problems. The present review focused on the blocking of parasite development in mosquito vectors; one broad strategy for achieving this is Transmission Blocking Vaccines (TBV). The TBVs usually rely on immunization of vertebrate hosts with molecules derived from the vector or pathogen to reduce pathogen transmission from infected to uninfected hosts. Most of the studies on the TBVs are based on the antibodies targeted against the surface antigens of sexual stages of malaria parasite, but it is meagre to develop mosquito-based vaccine in this regard. Vector-based TBVs include surface proteins that are expressed by the mosquito midgut digestive enzymes which are induced upon blood-feeding, and receptors expressed on the epithelial line of the tissue. Many proteins are reported that can act as candidates for transmission-blocking vaccines. This review aims to summarize the vector midgut-based proteins identified till date, that can block the development and maturity of sexual stages of the parasite within mosquitoes as targets for transmission-blocking vaccine development. The TBVs intervention can block transmission of different malaria parasite species in various species of mosquitoes with future application perspective worldwide.

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Background & objectives: Accurate mosquito species identification is the basis of entomological surveys and effective vector control. Mosquito identification is either done morphologically using diagnostic features mentioned in taxonomic keys or by molecular methods using cytochrome oxidase subunit 1 (coxI) and Internal transcribed spacer 2 (ITS2). Methods: We performed a larval survey for Aedes mosquitoes from eight different geographical regions in Tamil Nadu, India. The mosquitoes collected during the survey were characterized using both morphological and molecular markers. Results: During an entomological survey from eight different geographical regions in Southern India, a morphological variety named Aedes aegypti var. luciensis was observed. The variant mosquitoes were characterized using both morphological and molecular markers. The variant mosquitoes differed only in the dark scaling of 5^th segment of hind-tarsi. Around one third to two third of the 5^th segment in variant mosquitoes was dark which has been described as white in identification keys. No other significant difference was observed in adults or immature stages. The variation was heritable and coexisting in the field with the type form mosquitoes. Comparison of the genetic profile of coxI and ITS2 were similar in variant and the type form indicating both of them to be conspecific. Interpretation & conclusion: The morphological variant mosquitoes were found genetically similar to the Ae. aegypti type form. However, considering its high prevalence and coexistence with Ae. aegypti type form in different geographical regions, detailed studies on bionomics, ecology, genetics, behavior as well as its plausible role in disease transmission are warranted.

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Diagnosis of malaria is a prominent challenge due to the endemic nature of infection. Malaria poses a great threat to global public health. The disease can be diagnosed by several techniques out of which microscopy is a known gold standard. High sensitivity of molecular techniques is making them more reliable and popular as tools for diagnosis of malaria. However, new methods are required which can fulfill the criteria of being Point of Care Test (POCT) as defined by WHO. Loop-mediated isothermal amplification (LAMP) technique amplifies DNA in an isothermal condition, and surpasses the disadvantages of conventional molecular techniques such as polymerase chain reaction. Multiplex LAMP, a modification of LAMP may emerge as a new POC for malaria diagnosis. This review deals with the use of LAMP and multiplex LAMP in diagnosis of malaria and its prospective use as point of care techniques.

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Zika virus disease is a great concern in different parts of the world, and it has become a Public Health Emergency of International Concern. The global pandemic of ZIKV in 2015 prompted concern among scientific community. Zika is a flavivirus of the family Flaviviridae transmitted by mosquitoes. Natural vertical transmission is an ecological strategy that arboviruses adopt to ensure their survival inside the mosquito vector during harsh conditions or interepidemic periods when horizontal transmission is difficult. ZIKV is vertically transmitted from infected females to its offspring. This review has concluded various studies regarding the vertical transmission ability of different mosquito species for ZIKV. Previously Aedes aegypti was considered to be a major vector, however Aedes albopictus and Culex quinquifasciatus are discovered to have the similar vertical transmission potential. Different studies shown that natural vertical transmission has been detected in mosquito species which are not implicated as possible vectors. It leads to the possibility that many other mosquito species may be potential ZIKV vectors.

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The recently described Triatoma huehuetenanguensis, has been reported in Mexico, Guatemala, Belize and Honduras. In Mexico, the species has been collected primarily in rural areas; it has the potential to colonize human dwellings, however, its contribution to Chagas outbreaks remains unclear. In 2021, T. huehuetenanguensis was first observed at Tuxtla Gutierrez city, Chiapas; then a collection for the species was performed. A total of 308 houses were inspected in the intra and peridomestic structures. Only 3 houses (0.97%) were infested. Triatoma huehuetenangensis was the only triatomine specie recorded and four males were collected. None of the bugs tested positive for Trypanosoma infection. We do not have evidence to suggest that urban human-vector contact still limited, and a possible domestication process is possible. The presence of reservoirs, the vector species and the parasite demonstrate that Tuxtla Gutierrez could be at risk of a Chagas disease outbreak.

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Background & objectives: Microscopy is considered as the gold standard for malaria diagnosis, however sub-microscopic infections can only be detected by Polymerase chain reaction, which demands high cost and elaborate laboratory setup. The Micro-chip PCR based Truenat Malaria Pv-Pf and Pf assay is a portable solution for detection of sub-microscopic/asymptomatic cases of malaria in the field, three lots of which were evaluated for P. falciparum and P. vivax malaria. Methods: Three lots of Truenat® Malaria Pv-Pf and Pf assay (kits) were assessed using blood samples of P. vivax and P. falciparum as well as malaria negative blood samples. DNA was extracted from the blood samples using the Trueprep Auto v2 Universal Cartridge based sample prep device and real time qPCR was performed using Truelab DUO micro PCR Analyzer with three lots of Truenat® Malaria Pv-Pf and Pf Assays. Mean, Standard deviation and one-way analysis of variance (ANOVA) was used to assess the significance of inter-lot variability in Cycle threshold values. Results: The Truenat® Malaria Pv-Pf and Pf assays identified the malaria parasites with 100% accuracy. Based on the test for variance (ANOVA) the inter-lot variability in cycle threshold values were not significant, indicating a high degree of precision. Interpretation & conclusion: Based on high accuracy and precision between different lots, the Truenat® Malaria Pv-Pf and Pf assays were found to be suitable for the diagnosis of sub-microscopic infections in field conditions to provide support in elimination of malaria.

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Background & objectives: In India, Kyasanur Forest Disease has been reported from the states of Karnataka, Kerala, Goa, and Maharashtra. The relationship between climatic factors and transmission of KFD remains untouched, therefore, the present study was undertaken. Methods: Based on the occurrence of cases, Shivamogga district (Karnataka) and Wayanad district in Kerala and northern Goa (Goa state) were selected for the study. Data on the incidence of KFD and climate factors were collected from concerned authorities. To determine the relationship between dependent and independent variables, spearman’s correlation was calculated for monthly as well as with lag months. Results: KFD cases and temperature (°C) were found significantly correlated up to 1 months’ lag period (p<0.05) while with precipitation relationship was found negatively significant for 0-3 months’ lag. The range of suitable temperature for KFD in Shivamogga, Goa and Wayanad was found as 20-31°C, 25-29°C and 27-31°C respectively. The cumulative precipitation during transmission months (November–May) ranged from <150-500mm, while in non-transmission months (June-October) from >1100-2400mm. Interpretation & conclusion: The analysis of three sites revealed that with the increase in temperature, the intensity of KFD transmission decreases as corroborated by the seasonal fluctuations in Shivamogga, Goa and Wayanad. High precipitation from June to October rovides suitable ecology to tick vector and sets in transmission season from November to May when cumulative precipitation is <500 mm.

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Background & objectives: Attractive toxic sugar baits (ATSB) is a novel tool which employs mosquito sugar feeding behaviour to kill them. The potential of ATSB against mosquito vectors has been demonstrated in limited scope around the world including Israel, some of the African countries and USA. But their efficacy against mosquito vectors of India is yet to be ascertained. Therefore, current study was planned to evaluate the efficacy of TSB (without attractant) against two important malaria vectors Anopheles culicifacies and An. stephensi along with major dengue vector Aedes aegypti. Methods: TSB solution was prepared by dissolving different concentrations of boric acid in glucose and tested against each of the mosquito species. Another experiment was done by spraying this boric acid sugar solution on to Calendula officinalis plant. It served as a sole source of mosquito feed and mortality of mosquitoes was counted after 24 hours. Results: The TSB resulted in 100% mortality of Ae. aegypti and An. stephensi at 4% concentration of boric acid while in An. culicifacies 100% mortality was achieved at 3% concentration TSB solution. TSB solution with 2% boric acid, resulted in 99.1% mortality in An. culicifacies while ~95 % mortality of An. stephensi and Ae. aegypti. When TSB solution with 2% boric acid was sprayed on plant, ~89-94% mortality was observed in both An. stephensi and An. culicifacies. Interpretation & conclusion: Based on the results, boric acid based toxic sugar bait solution could be a promising tool for vector control. Further studies are needed to find out its toxicity of TSB against non-target organisms and residual efficacy in field trials in different ecotypes.

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Aedes (Ochlerotatus) melanimon Dyar 1924 has been considered an important pest in agricultural and rural communities. Aedes melanimon is a vector of WEEV and CEV and is a competent laboratory vector of WNV. The known range of Ae. melanimon extends throughout Southwest Canada, part of Central and most of Western USA. Here we report the first record of Ae. melanimon in Mexico, at Ciudad Juárez, Chihuahua. The collect represents the southernmost distributional record for this species. Its indigenous presence in a highly urbanized and dry area was not expected. A permanent surveillance program to detect and determine the species in border-crossing cities is encouraged.

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Background & objectives: Kyasanur Forest Disease (KFD) is a vector borne haemorrhagic fever that is endemic in the Wayanad region located in Northern part of Kerala, India. The region is managing the outbreak well ever since the major epidemic of 2015. This was because of the successful implementation of One Health (OH) initiative concentrating on multisectoral collaboration between regional institutions involved in public, animal and environmental health domains. The article presents how OH was implemented for the first time in the district in the year 2015 and evaluates the degree OH-ness of the Initiative. Methods: The OH approach involved trans-disciplinary stakeholder meetings and reviews, outbreak management and integrated surveillance targeting ticks, monkeys and humans. The degree of OH-ness used for addressing KFD during the year 2015 was evaluated following the protocol developed by the Network for Evaluation of One Health (NEOH). In detail, we (i) described the OH initiative and its system (Aim, stakeholders, action strategy) and (ii) scored different aspects of this initiative (i.e., OH-thinking, -planning, -working, -sharing, -learning, -organization), with values from 0 (=no OH approach) to 1 (=perfect OH approach). Results: We obtained a median score for each aspect evaluated. We reached high scores for OH systemic organization (1.0), OH thinking (0.83) and OH working (0.83). Lower scores were attributed to OH planning (0.58), OH sharing (0.50) and OH learning (0.33). The OH index was 0.36 and OH ratio was 0.95, indicating a balance between the OH operations and supporting infrastructures. Interpretation & conclusion: With this we could high-light some critical issues related to communication on sharing data as well as learning gaps for consideration to control future outbreaks. The strengths and weaknesses detected may be used to refine the initiative, aiming to provide a basis for the development of shared recommendations in a more OH-oriented perspective. This model of evaluation criteria will serve to create a database of OH success stories in India that will in turn help to institutionalize the approach at ministerial level. Future India is moving towards implementing a One Health, hence, this study data will provide an ideal opportunity for all sectors to control any vector borne diseases.

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Malaria and typhoid co-infections can be a serious public health issue in tropical countries leading to incorrect diagnosis due to overlapping clinical presentations of malaria and typhoid and hence, causing a delay in implementing the appropriate treatment regimen for these concurrent infections. This study reports a case of six-year-old female child co-infected with severe malaria (Plasmodium falciparum) and typhoid (Salmonella typhi) diagnosed by rapid malaria antigen test (RMAT) and blood culture respectively. Further, analysis of the chloroquine resistance gene Pfcrt for the falciparum demonstrated the presence of K76T mutant allele in pfcrt gene with high IC50 (150nM) for chloroquine (CQ) drug. The present case highlights the significance of timely identification and treatment of co-infections and also provides information about the circulating P. falciparum clinical strains.

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Dengue, a vector-borne disease remains as one of the most serious public health problems globally. Incidence of this disease is on an increasing trend and currently over a billion people in tropical and subtropical regions are at risk. In the absence of an operational vaccine, prevention of dengue virus (DENV) is primarily focused upon controlling mosquito vectors. Mosquito vector surveillance programmes require simple and rapid tools to detect mosquitoes infected with DENV. Here, we tested the commercially available DENV Detect™ NS1 ELISA kit (InBios International, Inc.) for detection of recombinant DENV-NS1 protein in Aedes mosquito samples. The kit was evaluated to find out the minimum detection limit of recombinant DENV-2 NS1 protein following the manufacturer’s instructions. Initially, the NS1 protein detection threshold of the kit was determined and later the assay was standardized for detection of NS1 protein in Aedes aegypti mosquito pools containing 5, 10 and 25 mosquitoes. The ELISA kit displayed high sensitivity towards detection of recombinant dengue virus-2 NS1 protein in mosquito pools (up to 25 mosquitoes per pool) at 25 pico gram concentration. Since the commercial NS1 ELISA is highly sensitive and follows a very simple procedure, it could be employed for DENV surveillance in Aedes aegypti mosquitoes, after carrying out laboratory and field bioassays with DENV infected specimens.

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Background & objectives: Malaria affects around 228 million people all over the globe. Malaria causing parasite Plasmodium infection leads to activation of immune responses. The growth of parasite and immune activation requires semi essential amino acids like L-arginine. Malaria infection leads to condition of hyperargininemia and low availability of nitric oxide. However, the effect of L-arginine supplementation in malaria infected mice has not been explored in in-vivo studies. In this study we have compared the effect of oral supplementation of nitric oxide donor, L-arginine and L-citrulline, in malaria infected mice Methods: To examine the effect of oral supplementation of L-arginine and L-citrulline, Plasmodium berghei infected mice were divided in different groups and respective groups were fed with L- arginine and L-citrulline, parasitemia was measured on different days. Mice was sacrificed and immunophenotyping was done on 10 days post infection. Results: our results show that supplementation of L-arginine induces conducive environment for Plasmodium growth due to which the infected mice dies earlier than control wild type infected mice whereas L-citrulline supplementation inhibits parasite growth and mice survives for longer period of time. Flow cytometric analysis shows that supplementation of L-arginine increases cTLA-4 on T cell population, increases Treg cells leading to immunosuppression while supplementation of L-citrulline does not have effect on T cells population and number of Treg cell decrease compared to P. berghei infected mice. Interpretation & conclusion: our results show that L-citrulline can be a better alternative than L-arginine because of lower expression of inhibitory molecules and lower parasitemia as well as increased survival of infected mice.

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Background & objectives: Sand fly saliva contains proteins that modulate the host immune system and it plays an important role in both blood feeding and the outcome of Leishmania infections. The profile of the salivary proteins was examined and analyzed from an endemic focus of zoonotic cutaneous leishmaniasis by wild P. papatasi to find local and suitable antigens as potential proteins for developing Leishmania vaccine alongside the development of a new extraction technique. Methods: Specimens were caught from Bojnord, using funnel and CDC traps. Different methods of protein extraction were employed and a new technique was developed. The proteins were extracted from the salivary glands tissues with a lysis buffer. Purification was performed using RP-HPLC, with a linear gradient protocol from 0-60 % of acetonitrile. PpSP15 was characterized by SDS-PAGE. Results: The concentration of extracted protein content was 0.5 and 0.03 μg/μl in chemical and physical methods, respectively. PpSP15 was isolated at a weight of 15kDa in 80–85 min of run time. SDS-PAGE was able to characterize PpSP15. The crude extract of the chemical method, revealed 15 separated bands, ranging from 11–100 KDa. Tajima D index was positive. Interpretation & conclusion: PpSP15 was characterized from Iranian specimens; it is a very highly hydrophobic protein of salivary glands among SP15- like proteins. The chemical method of extraction was found to be more effective than physical methods (P < 0.05). For developing a vaccine against leishmaniasis, depending on the location, choosing suitable proteins should be considered and an efficient extraction method should be used.

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Sardar Sarovar Irrigation Canal system was constructed by Narmada Valley Development Authority (NVDA) to cater to drinking water as well as for irrigation purposes in Jalore and Barmer districts of Western Rajasthan. To cater to the needs of water for the villagers in the command areas, ‘Diggies’ (surface water tanks) with ‘Sumpwells’ (water supply surface tanks) were installed. In a health impact assessment study of the irrigation canals from December 2010 to February 2016, the breeding of two major malaria vectors. An. culicifacies and An. stephensi were observed in diggies and sumpwells. As a biological control, Gambusia affanis fishes were employed for larval control in such stagnated water sites during the intervention phase viz. February 2012 in 251 diggies and 251 sumpwells. A significant reduction of breeding in diggies (99.54%) and sumpwells (97.81%) was observed. The positivity and larval density (dip index) were monitored in the control from up to February 2016 for their sustainability.

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