Mosquito-borne Infectious Disease Research Articles

Analysis and interpretation of Malaria disease model in crisp and fuzzy environment

Malaria is a mosquito-borne infectious disease caused by the Plasmodium parasite. It is prevalent in many regions of the globe, particularly in sub-Saharan Africa, where it is a major cause of illness and death. Mathematical models can aid in understanding the dynamics of malaria transmission and guiding disease-control interventions. The authors discuss a mathematical model and focus on severely infected people of malaria transmission in both crisp and fuzzy environments in this article. A parameter pertaining to the cases where relapse of the disease has occurred is considered. This study discusses the stability of the model in both crisp and fuzzy environments and also considered numerical illustrations to validate the said model.

Impact of Human Activities on Disease-Spreading Mosquitoes in Urban Areas.

Urbanization is one of the leading global trends of the twenty-first century that has a significant impact on health. Among health challenges caused by urbanization, the relationship of urbanization between emergence and the spread of mosquito-borne infectious diseases (MBIDs) is a great public health concern. Urbanization processes encompass social, economic, and environmental changes that directly impact the biology of mosquito species. In particular, urbanized areas experience higher temperatures and pollution levels than outlying areas but also favor the development of infrastructures and objects that are favorable to mosquito development. All these modifications may influence mosquito life history traits and their ability to transmit diseases. This review aimed to summarize the impact of urbanization on mosquito spreading in urban areas and the risk associated with the emergence of MBIDs. Moreover, mosquitoes are considered as holobionts, as evidenced by numerous studies highlighting the role of mosquito-microbiota interactions in mosquito biology. Taking into account this new paradigm, this review also represents an initial synthesis on how human-driven transformations impact microbial communities in larval habitats and further interfere with mosquito behavior and life cycle in urban areas.

A systematic self-study and analysis in prevalence of malaria across the world

Malaria is a febrile mosquito borne infectious disease which is caused by plasmodium. Malaria is one of the most deadliest and serious tropical disease ever witnessed by humanity. There are five species of plasmodium which are reported to infect humans. Out of the five species plasmodium falciparum has been reported to be the most deadliest form of plasmodium.A systemic self-study was planned to analyze and study the current prevalence of malaria globally. With the application of electronic databases we searched PubMed, Google Scholar, Web of Science, WHO website, Medline Plus, Health line & Cleveland Clinic web which were published in English language. This systemic self-study have reviewed the facts which were published earlier to determine the current scenario by vast study of statistics and derivation of facts. Vast analysis and along with proper examination of data were made to evaluate with final conclusion.We observed and analyzed various surveys and studies conducted by World Health Organization which has stated that malaria have affected 90 countries and also territories in tropical and subtropical regions. In 2019 World Malaria Report documented over 96% of malarial death has occurred in African region. According to World Malarial Report, India also accounts for 3% of global burden of malaria. We also have observed in over 50% of estimated cases of malaria in India Plasmodium vivax have been the most infectious type of plasmodium. Irrespective of any country in the world India has by far the greatest plasmodium vivax incidences.We hereby conclude our systematic self-study and vast analysis by stating these following facts that malaria is a mosquito borne infectious disease which is highly infectious and is caused by a unicellular microorganism known as plasmodium. Malaria is one of the most serious and fatal tropical disease ever witnessed by humanity. We analysed several studies and found that World Health Organization have estimated globally about 241 million clinical cases of malaria followed by 6,27,000 deaths of people. We also derive the fact that most of this death related malaria occurred in the African region. In 2019 World Malarial Report also confirmed that 96% of global death has occurred from the African continent. We further studied that India have also accounted 3% of total global burden of malaria. We further inferred based on our observational analysis that over 50% of urban malaria in India is caused by plasmodium vivax. We studied that there are five types of malaria along with the prevalence and inferred that plasmodium falciparum is the most fatal form of malaria and have accounted over 95% of death caused due to malaria in African region at 100% in sub-Saharan African region. We hereby positively conclude our self-study on prevalence of malaria across the world by drawing a report given by World Health Organization stating that global mortality rate has significantly reduced by 90% in the end of 20th century.

Effects of temperature, relative humidity, and illumination on the entomological parameters of Aedes albopictus: an experimental study.

Aedes albopictus (Diptera: Culicidae) is a mosquito from Asia that can transmit a variety of diseases. This paper aimed to explore the effects of temperature, relative humidity, and illumination on the entomological parameters related to the population growth of Aedes albopictus, and provide specific parameters for developing dynamic models of mosquito-borne infectious disease. We used artificial simulation lab experiments, and set 27 different meteorological conditions to observe and record mosquito's hatching time, emergence time, longevity of adult females, and oviposition amount. We then applied generalized additive model (GAM) and polynomial regression to formulate the effects of temperature, relative humidity, and illumination on the biological characteristics of Aedes albopictus. Our results showed that hatchability closely related to temperature and illumination. The immature stage and the survival time of adult female mosquitoes were associated with temperature and relative humidity. The oviposition rate related to temperature, relative humidity, and illumination. Under the control of relative humidity and illumination, ecological characteristics of mosquitoes such as hatching rate, transition rate, longevity, and oviposition rate had an inverted J shape with temperature, and the thresholds were 31.2°C, 32.1°C, 17.7°C, and 25.7°C, respectively. The parameter expressions of Aedes albopictus using meteorological factors as predictors under different stages were established. Meteorological factors especially temperature significantly influence the development of Aedes albopictus under different physiological stages. The established formulas of ecological parameters can provide important information for modeling mosquito-borne infectious diseases.

Epidemiologi Kasus Malaria Terkonfirmasi Positif di Kabupaten Muna

<p><em><span lang="EN-US">Malaria is one of the most common mosquito-borne infectious diseases in the world. Globally, deaths due to malaria infection reported in 2019 amounted to 405,000 deaths with a total number of sufferers of around 228 million cases. Although malaria cases have continued to decline in the last five years, including in Southeast Sulawesi Province, there are still regencies/cities in Southeast Sulawesi that have not been free from malaria. Therefore this disease continues to be a burden of pain. This study is a descriptive study using secondary data on positive confirmed malaria cases from the Southeast Sulawesi Provincial Health Office.This study aims to describe malaria cases in Muna Regency during the period from 2016 to 2020 based on epidemiological variables, namely people and time. The results showed that positive confirmed malaria cases in Muna Regency from 2016 to 2020 showed a significant decline. From the people variable, the majority 56.95% of positive confirmed malaria cases were men and only 43.05% were women. Meanwhile, based on the time in five years of observation, the highest prevalence of confirmed positive malaria occurred in 2016 and the lowest in 2020. Malaria prevention and control programs need to be carried out strictly to reduce morbidity and achieve malaria elimination programs in Muna Regency</span></em></p><p><strong><em>Key words</em></strong><em>: Malaria, confirmed positive, people, time. </em><em></em></p><p><em><br /></em></p>

Seasonal metabolic profiling of Valencia orange leaf essential oil using GC coupled with chemometrics, nano-formulation, and insecticidal evaluation: in vivo and in silico.

Mosquitoes and mosquito-borne infectious diseases are a global challenge, especially with increased resistance to synthetic insecticides. The foregoing study aimed to utilize the essential oil of leaves of Citrus sinensis var. Valencia as a cheap, safe, eco-friendly (green), and effective alternative to chemical insecticides. Essential oil samples were collected from fresh and dried leaves across different seasons. They are subjected to hydrodistillation and then GC analysis to be compared. Seventy-seven compounds were detected in all samples where monoterpene hydrocarbons represented the most abundant class of hydrocarbons in fresh leaves (52.6-74.4%) and dried leaves (58.6-66.9%). Sabinene (8.26-29.2%), delta-3-carene (8.23-16.4%), d-limonene (2.50-11.2%), and β-myrcene (2.40-4.93%) were the major monoterpene hydrocarbons in all seasons. Oxygenated monoterpenes comprising β-linalool, citronellal, terpinen-4-ol, β-citral, and α-citral exhibited also appreciable percentages in fresh (21.2-43.4%) and dried leaves (23.4-33.0%). Hierarchical cluster analysis (HCA) and principal component analysis (PCA) effectively segregated all samples into three discriminate clusters where, β-linalool, terpinen-4-ol, β-elemene enantiomer, sabinene, and β-phellandrene constitute the main discriminatory biomarkers. Essential oil of fresh spring leaves (FS) was chosen for nano-formulation adopting the hot emulsification method. Both FS sample and the prepared nano-hexosomal formula were screened against the 3rd instar larvae Culex pipiens L. (common house mosquito). LC50 and LC95 values of FS and oil loaded nano-formula were (48 and 30 552 mg L-1) and (30 and 1830 mg L-1) respectively. α-Citral followed by citronellal showed the best fitting within the binding sites of acetylcholine esterase enzyme utilizing molecular docking. Thus, it can be concluded that Valencia orange leaf as a nano-formulation could serve as an effective and sustainable insecticidal agent.

Spin-Enhanced Lateral Flow Immunoassay for High-Sensitivity Detection of Nonstructural Protein NS1 Serotypes of the Dengue Virus.

Dengue fever is a global mosquito-borne viral infectious disease that has, in recent years, rapidly spread to almost all regions of the world. Lack of vaccination and directed treatment makes detection at the infection's early stages extremely important for disease prevention and clinical care. In this paper, we developed a rapid and highly sensitive dengue detection tool using a novel platform of diagnosis, called spin-enhanced lateral flow immunoassay (SELFIA) with a fluorescent nanodiamond (FND) as a reporter. Taking advantage of the unique magneto-optical properties of negatively charged nitrogen-vacancy centers in the FND, the SELFIA platform utilizes alternating electromagnetic fields to modulate signals from FND's fluorescence to provide sensitive and specific results. With sandwich SELFIA, we could efficiently detect all four dengue non-structural protein (NS1) serotypes (DV1, DV2, DV3, and DV4). The lowest detection concentration of the dengue NS1 antigens varied from 0.1 to 1.3 ng/mL, which is among the lowest limits of detection to date. The FND-based SELFIA technique is up to 500 and 5000 times more sensitive than carbon black and conventional gold nanoparticles, respectively. By using different anti-NS1 antibodies, we could differentiate the NS1 antigen serotypes contained in the tested samples via three simultaneous assays. Proposed SELFIA allows for both qualitative and quantitative differentiation between different NS1 protein serotypes, which will assist in the development of a highly sensitive and specific detection platform for dengue screening that has the potential to detect the disease at its early stages, especially in high-risk and limited-resource areas.

Elevated plasma α1-antichymotrypsin is a biomarker candidate for malaria patients

Advancements in the field of proteomics have provided opportunities to develop diagnostic and therapeutic strategies against various diseases. About half of the world's population remains at risk of malaria. Caused by protozoan parasites of the genus Plasmodium, malaria is one of the oldest and largest risk factors responsible for the global burden of infectious diseases with an estimated 3.2 billion persons at risk of infection. For epidemiological surveillance and appropriate treatment of individuals infected with Plasmodium spp., timely detection is critical. In this study, we used combinations of depletion of abundant plasma proteins, 2-dimensional gel electrophoresis (2-DE), image analysis, LC-MS/MS and western blot analysis on the plasma of healthy donors (100 individuals) and vivax and falciparum malaria patients (100 vivax malaria patients and 8 falciparum malaria patients). These analyses revealed that α1-antichymotrypsin (AACT) protein levels were elevated in vivax malaria patient plasma samples (mean fold-change ± standard error: 2.83 ± 0.11, based on band intensities), but not in plasma from patients with other mosquito-borne infectious diseases. The results of AACT immunoblot analyses showed that AACT protein was significantly elevated in vivax and falciparum malaria patient plasma samples (≥ 2-fold) compared to healthy control donor plasma samples, which has not been previously reported. [BMB Reports 2022; 55(11): 571-576].

Development and application of an indirect ELISA for detecting equine IgG antibodies against Getah virus with recombinant E2 domain protein

Getah virus (GETV) disease is a mosquito-borne infectious disease that causes fever, aseptic meningitis, and abortion in a variety of animals. Currently, the epidemic trend of GETV disease increases seriously worldwide, especially in China, posing a potential threat to animal safety and public health. However, there are few reports about the epidemiological investigation of GETV disease in China as well as a lack of commercial diagnostic kit for GETV antibody. Therefore, the establishment of a rapid, sensitive and suitable GETV antibody detection method for large-scale samples is an urgent request to fully understand the prevalence of GETV disease. Here, a recombinant plasmid pET22b-GETV-E2d that contained the domain of GETV-E2 (E2d) fused to His-tag was constructed to express recombinant protein E2d (rE2d) in Escherichia coli. The rE2d was mainly expressed in inclusion bodies. And it was purified successfully by nickel affinity column so that it could be used to develop an indirect ELISA (rE2d-ELISA). After optimizing reaction conditions of rE2d-ELISA, the cut-off value was determined as 0.396 with 100 equine sera tested by virus neutralization test (VNT). Furthermore, rE2d-ELISA method showed the positive rate of IgG antibodies against GETV was 54.3% based on testing 646 clinical serum samples obtained in Xinjiang whereas the overall coincidence rate between rE2d-ELISA and VNT was 94.0%, with 98.2% sensitivity and 92.6% specificity. The findings suggest that the developed IgG ELISA employing recombinant E2d promises was an efficient and low-cost type of antibody detection method for horse, which will benefit for prevention of GETV outbreaks in horses.

Transdermal Transmission Blocking Vaccine for Malaria using a Solid-in-Oil Dispersion

Malaria is a mosquito-borne infectious disease that is widespread in developing countries. Malaria vaccines are important in efforts to eradicate malaria; however, vaccines are usually administered by injection, which requires medical personnel and has a risk of causing infection. Transdermal vaccines can be administered without damaging the skin and thus are ideal for the prevention of malaria. However, the stratum corneum forms a "brick and mortar" like structure in which stratum corneum cells are embedded in a hydrophobic matrix composed of lipids, which strongly inhibits the permeation of hydrophilic substances. In the present study, we designed a transdermal vaccine against vivax malaria using a solid-in-oil (S/O) dispersion. The S/O dispersion of a transmission blocking vaccine candidate, Pvs25 from Plasmodium vivax, showed higher skin penetration than that of the aqueous solution. Mice immunized with the S/O dispersion generated antibodies at similar titers as the mice immunized by injection, over the mid- to long-term. These results provide information for the development of transdermally administered malaria vaccines toward the eradication of malaria.

Pyp25α is required for male gametocyte exflagellation.

Malaria, a mosquito-borne infectious disease, is caused by the unicellular apicomplexan protozoa of the genus Plasmodium. For malaria parasite transmission, the essential sexual stage includes production of gametocytes through gametocytogenesis in vertebrate hosts and formation of gametes from gametocytes through gametogenesis in mosquito vectors. Whereas each female gametocyte forms a single immotile macrogamete, a male gametocyte produces eight flagella-like microgametes in a process called exflagellation. We identified a conserved protein named as Py05543 (Pyp25α), required for male gametocyte exflagellation in Plasmodium yoelii, which is the ortholog of PFL1770c (PF3D7_1236600). Interestingly, PF3D7_1236600 was previously phenotypically screened to be gametocyte-essential genes during gametocytogenesis of Plasmodium falciparum, using piggyBac transposon-mediated insertional mutagenesis. In this study, using CRISPR/Cas9-mediated genome editing, the Pyp25α¯ (KO) parasite line was successfully established. We found that the KO parasites proliferated asexually in mouse blood normally. In addition, compared with that of the parental parasites, the KO parasites displayed similar levels of gametocytes formation. Unexpectedly, the KO parasites showed considerable deficiency in exflagellation of male gametes, by observing exflagellation centre formation. Taken together, our data suggested that Pyp25α gene, the ortholog of PF3D7_1236600, was nonessential for the growth of asexual parasites, required for male gametocyte exflagellation in P. yoelii.

Dephospho-Coenzyme A Kinase Is an Exploitable Drug Target against Plasmodium falciparum: Identification of Selective Inhibitors by High-Throughput Screening of a Large Chemical Compound Library.

Malaria is a mosquito-borne fatal infectious disease that affects humans and is caused by Plasmodium parasites, primarily Plasmodium falciparum. Widespread drug resistance compels us to discover novel compounds and alternative drug discovery targets. The coenzyme A (CoA) biosynthesis pathway is essential for the malaria parasite P. falciparum. The last enzyme in CoA biosynthesis, dephospho-CoA kinase (DPCK), is essential to the major life cycle development stages but has not yet been exploited as a drug target in antimalarial drug discovery. We performed a high-throughput screen of a 210,000-compound library using recombinant P. falciparum DPCK (PfDPCK). A high-throughput enzymatic assay using a 1,536-well platform was developed to identify potential PfDPCK inhibitors. PfDPCK inhibitors also inhibited parasite growth in a P. falciparum whole-cell asexual blood-stage assay in both drug-sensitive and drug-resistant strains. Hit compounds were selected based on their potency in cell-free (PfDPCK) and whole-cell (Pf3D7 and PfDd2) assays, selectivity over the human orthologue (HsCOASY) and no cytotoxicity (HepG2). The compounds were ranked using a multiparameter optimization (MPO) scoring model, and the specific binding and the mechanism of inhibition were investigated for the most promising compounds.

Impact of temperature on infection with Japanese encephalitis virus of three potential urban vectors in Taiwan; Aedes albopictus, Armigeres subalbatus, and Culex quinquefasciatus

Japanese encephalitis (JE) is an important mosquito-borne infectious disease in rural areas of Asia that is caused by Japanese encephalitis virus (JEV). Culex tritaeniorhynchus is the major vector of JEV, nevertheless there are other mosquitoes that may be able to transmit JEV. This study confirms that the midgut, head tissue, salivary glands, and reproductive tissue of Aedes albopictus, Armigeres subalbatus, and Culex quinquefasciatus are all able to be infected with JEV after a virus-containing blood meal was ingested by female mosquitoes. Even though the susceptibility to JEV of the different tissues varies, the virus-positive rate increased with the number of days after JEV infection. Moreover, once JEV escapes the midgut barrier, the oral transmission rates of JEV were 16%, 2%, and 21% for Ae. albopictus, Ar. subalbatus, and Cx. quinquefasciatus at 14 days after infection at 30 °C, respectively. There is no supporting evidence to suggest vertical transmission of JEV by the tested mosquitoes. Collectively, raising the temperature enhances JEV replication in the salivary gland of the three mosquito species, suggesting that global warming will enhance mosquito vector competence and that this is likely to lead to an increase in the probability of JEV transmission.

Anti-plasmodial and mosquitocidal potential of metallic nanoparticles: a perspective

The incidence of malaria, a mosquito-borne infectious disease exists throughout the tropical and subtropical regions. Various factors restrict the effective control of malaria including their increasingly resistance to existing anti-malarial drugs. New strategies for malaria management are needed at both the fronts for the search of new anti-malarial agent and control of vector anopheles in order to restrict the transmission of malaria. Mosquitoes are the most important single group of insects in terms of public health importance, which transmit a number of diseases, such as malaria, filariasis, dengue, Japanese encephalitis, etc., causing millions of deaths every year. Although many strategies including chemicals and phytochemicals has been well explored for parasite and vector control, in recent years, metal nanoparticles are gaining attention as potential material in this domain. This review has summarized, the present status of some metallic nanoparticles as anti-plasmodial and mosquitocidal activities in perspective of malaria management.Graphical abstractFig. Metallic nanoparticles potential with Anti-plasmodial and Mosquitocidal activity

COMMUNITY AWARENESS OF MOSQUITOES BORNE DISEASES IN ONE URBAN AND ONE RURAL AREA IN ODISHA, INDIA

Prevention and control strategies for mosquitoes borne diseases require community involvement to successes. Knowledge, Attitude and Practice (KAP) study was conducted in an urban and rural area in Odisha state of India to determine the perceived risk by the community of mosquito borne infectious diseases and the level of knowledge regarding mosquitoes. Drawing on data collected in Dec-2021 to June-2022, we explore the role of community participation and the factors that inuenced its failure in the prevention and control of mosquitoes-borne disease in Odisha. Approaches based on social and mobilization and communication aimed at bringing behavior change in the communities are in stressed. Community should be encouraged to take appropriate actions at household level to prevent mosquito borne diseases and the doctors and physicians should be encouraged to provide health education to the patients about the appropriate and affordable preventive measures.

Changes in CD and Correlation with Hepatic Insulin Resistance Index and Triacylglycerol 36 Level in Liver of Malarial Infected Mice Treated with Phyllanthus amarus

Phyllanthus amarus is an herb for the treatment of various ailments including malaria. Its antiplasmodial properties and antioxidant capacity have been reported, but very little is known about its effect on CD36 in relation to hepatic insulin resistance and triacylglycerol level. Hence, this study was undertaken to evaluate the changes in soluble CD36 concentrations and correlation with hepatic insulin resistance index and triacylglycerol levels in liver of Plasmodium berghei malarial parasite infected mice treated with graded doses of Phyllanthus amarus ethanolic leaf extract. Thirty (30) adult Swiss albino mice of both sexes weighing between 20-30g were assigned into six (6) groups (n=5/grp). Crude ethanolic leaf extract of Phyllanthus amarus was administered at 150, 300 and 450mg/kg/d as single daily dose for 7 days. On the 8th day of study, the mice were sacrificed under chloroform anaesthesia after an overnight fast. Blood sample was collected by cardiac puncture and centrifuged to obtain serum which was used for the assay of serum CD36, glucose and insulin, while, liver of each mouse was excised and processed for the assay of varying doses (150, 300 and 450mg/kg/d) of Phyllanthus amarus crude ethanolic leaf extract to experimental mice infected with P. berghei malarial parasite for seven days maintained serum soluble CD36 (3.40±0.52pg/ml, 3.47±0.46pg/ml and 3.37±0.46pg/ml), hepatic insulin resistance index (0.85±0.10, 0.77±0.17 and 0.82±0.13) and liver triacylglycerol (134.33±15.95mg/dl, 174.00±11.27mg/dl and 163.67±11.02mg/dl) levels, respectively, in trends that compared well with the Control and chloroquine – treated data ( C D 3 6 = 3.03±0.12pg/ml, liver TAG = 139.33±12.01, HIR index = 0.64±0.07). Correlation of CD36 with liver triacylglycerol for the malarial infected group without treatment was strongly positive, while, that with hepatic insulin resistance index was strongly negative. The control and chloroquine treated groups produced similar correlation pattern, but those for the extract-treated were weaker. Malarial infection in experimental mice significantly (p<0.05) increased serum soluble CD36 and this impacted HIR index and liver TAG. However, extract and chloroquine treatments ameliorated the malaria-induced level of serum soluble CD36 and hepatic triacylglycerol, using documented methods. Results indicate that infection of mice with Plasmodium berghei malarial parasite yielded significant increase in level of CD36 (5.40±0.70pg/ml) and liver triacylglycerol, TAG (259.00±7.21mg/dl), but abnormal reduced (p<0.05) hepatic insulin resistance, HIR index (0.37±0.05) when compared with the control mice (CD36 = 3.47±0.46pg/ml, liver TAG = 161.00±10.00, HIR index = 0.68±0.18) at the 5% probability level. However, administration of as starting materials for drugs (Sofowora, 1993). Plants have provided an alternative strategy in research for new drugs. It is likely that plants will continue to be a valuable source of new molecules which may after possible chemical manipulations provide new and improved drugs (Shan et al., 2006). One of such plants is Phyllanthus amarus.Phyllanthus amarus belongs to the family Euphorbiaceae (the spurge family) from which the largest genus is the Euphorbia. It has about eight hundred (800) species which are found in tropical and subtropical countries of the world (Mazumder et al., 2005). Phytochemicals identified in the leaf extract include alkaloids, flavonoids, tannins, saponins, anthraquinone and glycosides (Onyesom et al., 2015). The antimalarial activity of P. amarus has been observed (Onyesom and Adu, 2015). Malaria is a mosquito borne infectious disease of humans caused by eukaryotic protists of the genus Plasmodium. It is widespread in tropical and subtropical regions of the world including much of the sub-Saharan Africa. In Nigeria, malaria is mostly caused by Plasmodium falciparum. The association with HIR index and liver TAG in manners that were similar to the control trend.

Progress and Development of Three Types of Live Attenuated Vaccines for Dengue Fever

Dengue fever is a disease spread by mosquitoes infected with the dengue virus (DENV) that bite people. It is produced by any of the four serotypes of DENV. Dengue fever has become one of the most widespread mosquito-borne infectious diseases in the world. According to the World Health Organization (WHO) dengue fever is a serious global public health concern. To suppress the spread of dengue fever and reduce the social, medical, and economic burden brought by dengue fever, vaccination is an effective measure to prevent the disease. Research teams around the world have worked on the development of a dengue vaccine for many years. At present, three live attenuated vaccines have made great progress and entered the final stage of clinical trials. In order to enable dengue vaccine researchers to grasp the latest research status and promote faster development of the dengue vaccine, this paper provided a comprehensive overview of the research progress of three different live attenuated vaccines: CYD-TDV, TAK-003, and TV003/005.

Detection and persistence of environmental DNA (eDNA) of the different developmental stages of a vector mosquito, Culex pipiens pallens.

Preventing mosquito-borne infectious diseases requires that vector mosquitoes are monitored and controlled. Targeting immature mosquitoes (eggs, larvae, and pupae), which have less mobility than adults, is an effective management approach. However, conducting these surveys is often difficult due to the limitations of morphological classification and survey costs. The application of environmental DNA (eDNA) analysis can solve these issues because it allows easy estimation of species distribution and morphology-independent species identification. Although a few previous studies have reported mosquito eDNA detection, there is a gap in knowledge regarding the dynamics related to the persistence of immature mosquito eDNA. We used Culex pipiens pallens, a vector of West Nile fever, as a model species. First, we developed a species-specific detection assay and confirmed its specificity using in silico and in vitro tests. Next, we conducted laboratory experiments using breeding tanks. Water samples were collected at each developmental stage. In addition, water samples were collected daily until the seventh day after emergence from the pupae. We quantified eDNA using real-time PCR with the developed assay to investigate the dynamics of mosquito eDNA. The specificity of the developed assay was confirmed by in silico and in vitro tests. Mosquito eDNA was detected at all developmental stages and detected up to seven days after emergence of pupae. In particular, high concentrations of eDNA were detected immediately after hatching from eggs and after emergence from pupae. Highly frequent positive eDNA signals were continuously detected between egg hatching and pupa hatching. Mosquito eDNA was detected immediately after the eggs were introduced, and eDNA-positive detections continued until pupae emergence, suggesting that eDNA analysis is useful for monitoring mosquito larvae. In the future, monitoring immature mosquitoes using eDNA analysis will contribute to prevent mosquito-borne infectious diseases.

Modeling optimal vaccination strategy for dengue epidemic model: a case study of India

Dengue fever is a mosquito-borne infectious disease which is transmitted through Aedes aegypti mosquitoes. It is one of the major global health issues in the tropical and subtropical regions of the world. Its dynamics are very complicated owing to the coupling among multiple transmission pathways and various components in pathogen. Due to absence of proper medicine or vaccination, mathematical modeling plays an important role in understanding the disease dynamics and in designing strategies to control the spread of dengue virus. In this paper, we studied a non-linear vector-host model to investigate the transmission dynamics of dengue virus which can be controlled by vaccination as well as treatment. Analysis of model start with the basic reproduction number , when it is less than one, the system become locally asymptotically stable about the virus-free equilibrium point. We calibrated our proposed model corresponding to transmission of dengue virus using real data for six Indian states, namely Tamil Nadu, Kerala, Delhi, Gujarat, Rajasthan and Karnataka by using the least square method. Moreover, we performed normalized forward sensitivity analysis of the basic reproduction number and obtained that mitigating the disease transmission rate of mosquito and human population is the most important factor in achieving dengue control. Finally, an objective functional has been developed to minimize the cost of the vaccination and solved with the aid of the Pontryagin’s Maximum Principle. The implementation of the optimal treatment policy shows a significant reduction of the hospitalized individuals as well as infected individuals. We then performed extensive numerical simulations to validate our theoretical analysis with aid of the estimated model parameters.

ApiAP2 Gene-Network Regulates Gametocytogenesis in Plasmodium Parasites

Malaria is a mosquito-borne infectious disease, caused by unicellular Apicomplexan protozoa of the genus Plasmodium. The sexual stage of Plasmodium is one of the most fascinating aspects of the Plasmodium life cycle, yet relatively less explored until now. The production of sexually fit gametocytes through gametocytogenesis is essential to the transmission of the Plasmodium parasite into an anopheline mosquito vector. Understanding how gametocytogenesis is regulated promotes the identification of novel drug targets and also the development of transmission-blocking vaccines that would help reduce the disease burden in endemic areas. Transcriptional regulation in Plasmodium parasites is primarily controlled by a family of twenty-seven Apicomplexan Apetela 2 (ApiAP2) genes which act in a cascade to enable the parasite to progress through its asexual replication as well as gametocytogenesis. Here, we review the latest progress made on members of the ApiAP2 family characterized as key players of the transcriptional machinery of gametocytes. Further, we will highlight the transcriptional regulation network of ApiAP2 genes at each stage of gametocytogenesis.