Arthropod-borne Disease Research Articles

Repellency of Veratraldehyde (3,4-Dimethoxy Benzaldehyde) against Mosquito Females and Tick Nymphs

Arthropod-borne infectious diseases cause many deaths and a major economic burden worldwide. Repellents play an important role in protecting people from infectious biting arthropods. The repellency of veratraldehyde, a known food additive, and the WJ-1041 formulation containing 10% veratraldehyde was tested against Aedes albopictus and Culex pipiens pallens females and Haemaphysalis longicornis nymphs using arm-in-cage, indoor or filter paper tests. Veratraldehyde exhibited repellency similar to or lower than that of n,n-diethyl-meta-toluamide (DEET) against A. albopictus, but in H. longicornis, the activity of veratraldehyde was better than that of DEET. The repellency of the 10% veratraldehyde solution was comparable to that of 20% DEET against the two mosquitoes. When comparing repellency between the WJ-1041 formulation (10% veratraldehyde) and 10% DEET against C. pipiens pallens, A. Albopictus and H. longicornis, the two showed similar repellency and complete protection time (CPT) values. However, there was a small difference depending on the tested insects. The absorption of veratraldehyde via skin was minimal, if at all. The pharmacokinetic parameters (Cmax and Tmax) of veratraldehyde in blood samples of rats were not different from those of the control group. Based on these results, veratraldehyde has high potential to be commercialized as a repellent agent against infectious disease-borne pests in the near future.

A study on predictors of severe dengue in pediatric patients in a tertiary care hospital in Telangana

Background: Dengue is an emerging arthropod borne disease with increasing incidence in recent years in several countries, especially India. Early recognition of progression of disease helps in triage and timely management of fluids to decrease mortality. Objective: The objective of the study was to identify the predictive factors for severe dengue in pediatric patients for hospitalization for close monitoring. Methods: This was a prospective observational study conducted in the department of pediatrics in a tertiary care hospital in Mahbubnagar from June 2019 to May 2020. One hundred and four children between the age group of 0 and 15 years with probable dengue symptoms who were willing to get admitted were included in the study cohort. Thorough history and clinical examination, basic laboratory investigations such as complete blood picture, hematocrit, liver function tests, renal function tests (RFTs), serum electrolytes, serum ferritin, and coagulation profile were done as needed. All the patients were grouped into two groups – non-severe dengue (dengue fever without warning signs and dengue fever with warning signs) and severe dengue as per the World Health Organization guidelines. All the variables were analyzed using SPSS software. Results: Out of 104 confirmed cases, majority of the admissions were in 5–10 years age group (51.9%). Male children were 61.5%. Mean duration of hospitalization was 4.79±2.96 days. Fever (97.1%) was the most common symptom followed by anorexia (86.5%) and lethargy (82.7%). Symptoms such as lethargy, vomiting, abdominal pain/epigastric tenderness, epistaxis, edema, and altered sensorium were more commonly associated with severe dengue. Hepatomegaly (53.9%) was the most common clinical sign followed by epigastric tenderness (58.7%). Hepatomegaly, splenomegaly, ascites, gallbladder edema, pleural effusion, low pulse pressure, hypotension, oliguria, and significant gastrointestinal bleeds were more common in severe dengue group. Platelet count <50,000/mm3, increase in hematocrit more than 20% from baseline, raised transaminases, raised ferritin, decrease in serum sodium, decrease in serum albumin, abnormal coagulation profile, and abnormal RFTs were significantly associated with severe dengue. Mean platelet recovery time was 3–5 days. Conclusion: Dengue is a dynamic disease and progression of dengue with or without warning signs into severe dengue can be appropriately identified by close monitoring of certain clinical signs and symptoms.

Tetraspanins as Potential Therapeutic Candidates for Targeting Flaviviruses.

Tetraspanin family of proteins participates in numerous fundamental signaling pathways involved in viral transmission, virus-specific immunity, and virus-mediated vesicular trafficking. Studies in the identification of novel therapeutic candidates and strategies to target West Nile virus, dengue and Zika viruses are highly warranted due to the failure in development of vaccines. Recent evidences have shown that the widely distributed tetraspanin proteins may provide a platform for the development of novel therapeutic approaches. In this review, we discuss the diversified and important functions of tetraspanins in exosome/extracellular vesicle biology, virus-host interactions, virus-mediated vesicular trafficking, modulation of immune mechanism(s), and their possible role(s) in host antiviral defense mechanism(s) through interactions with noncoding RNAs. We also highlight the role of tetraspanins in the development of novel therapeutics to target arthropod-borne flaviviral diseases.

Comparison Between the SD BIOLINE Dengue Duo and Two InBios Prototype Dengue Immunochromatographic Tests

Dengue fever, caused by any of the four serotypes of dengue viruses (DENV1-4), is the most important arthropod-borne viral disease in the world. Although dengue diagnostic tests based on polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) have received the U.S. Food and Drug Administration (FDA) clearance, these assays require specialized equipment and highly trained personnel, and thus not suitable for resource-limited settings. Two immunochromatographic test (ICT) prototypes (traditional and multiplex formats) were recently developed by InBios International Inc. (Seattle, WA) to detect the presence of dengue viral non-structural protein 1 (NS1) antigen or anti-DENV IgG and IgM antibodies in serum.

Mosquito survey reveals the first record of Aedes (Diptera: Culicidae) species in urban area, Annaba district, Northeastern Algeria

The diversity, distribution and ecology of mosquitoes, especially arbovirus vectors are important indices for arthropod-borne diseases control. The mosquito larvae were collected in different habitats in four sites of Annaba district, Algeria, during the period of March 2018 to February 2019 and the properties of larval habitats were recorded for each site. The systematic study revealed the presence of 8 species belonging to 4 genera; including Culex pipiens (Linnaeus, 1758), Culex modestus (Ficalbi, 1889), Culex theileri (Theobald, 1903), Culiseta longiareolata (Macquart, 1838), Anopheles labranchiae (Falleroni, 1926), Anopheles claviger (Meigen, 1804), Aedes aegypti (Linnaeus, 1762) and Aedes albopictus (Skuse, 1894). Among the species, C. pipiens presented the highest species abundance (RA %) (55.23%) followed by C. longiareolata (20.21%). The Aedes species are recorded for the first time in the study urban area. Variation of diversity in different sites depends on the type of breeding habitat. These results provided important information on species diversity, distribution and factors associated with breeding habitats. They could be used for the mosquito control and to prevent the spread of mosquito-borne diseases to the population of the region.

Surveillance and Epidemiology of Dengue in Medellín, Colombia from 2009 to 2017.

Dengue is the most prevalent arthropod-borne viral disease in humans, primarily transmitted by the Aedes aegypti mosquito. We conducted a descriptive analysis of dengue cases from 2009 to 2017 in Medellín, Colombia, using data available from the Secretariat of Health. We analyzed the burden of outbreak years on the healthcare system, risk of cases exhibiting severe illness, potential disease surveillance problems, gender and age as risk factors, and spatiotemporal patterns of disease occurrence. Our data consisted of 50,083 cases, separated based on whether they were diagnostic test negative, diagnostic test positive (primarily IgM ELISA), clinically confirmed, epidemiologically linked, or probable. We used dengue incidence to analyze epidemiological trends between our study years, related to human movement patterns, between gender and age-groups, and spatiotemporally. We used risk to analyze the severity of dengue cases between the study years. We identified human movement could contributed to dengue spread, and male individuals (incidence rate: 0.86; 95% CI: 0.76-0.96) and individuals younger than 15 years (incidence rate: 1.24; 95% CI: 1.13-1.34) have higher incidence of dengue and located critical parts of the city where dengue incidence was high. Analysis was limited by participant diagnostic information, data concerning circulating strains, and a lack of phylogenetic information. Understanding the characteristics of dengue is a fundamental part of improving the health outcomes of at-risk populations. This analysis will be useful to support studies and initiatives to counteract dengue and provide context to the surveillance data collected by the health authorities in Medellín.

Occurrence of Phlebotomine sand flies (Diptera: Psychodidae) in the northeastern plain of Italy

BackgroundRecent climate and environmental changes have resulted in the geographical expansion of Mediterranean Leishmania infantum vectors towards northern latitudes and higher altitudes in different European countries, including Italy, where new foci of canine leishmaniasis have been observed in the northern part of the country. Northern Italy is also an endemic area for mosquito-borne diseases. During entomological surveillance for West Nile virus, mosquitoes and other hematophagous insects were collected, including Phlebotomine sand flies. In this study, we report the results of Phlebotomine sand fly identification during the entomological surveillance conducted from 2017 to 2019.MethodsThe northeastern plain of Italy was divided by a grid with a length of 15 km, and a CO2-CDC trap was placed in each geographical unit. The traps were placed ~ 15 km apart. For each sampling site, geographical coordinates were recorded. The traps were operated every two weeks, from May to November. Sand flies collected by CO2-CDC traps were identified by morphological and molecular analysis.ResultsFrom 2017 to 2019, a total of 303 sand flies belonging to the species Phlebotomus perniciosus (n = 273), Sergentomyia minuta (n = 5), P. mascittii (n = 2) and P. perfiliewi (n = 2) were collected, along with 21 unidentified specimens. The trend for P. perniciosus collected during the entomological surveillance showed two peaks, one in July and a smaller one in September. Sand flies were collected at different altitudes, from −2 m above sea level (a.s.l.) to 145 m a.s.l. No correlation was observed between altitude and sand fly abundance.ConclusionsFour Phlebotomine sand fly species are reported for the first time from the northeastern plain of Italy. Except for S. minuta, the sand fly species are competent vectors of Leishmania parasites and other arboviruses in the Mediterranean Basin. These findings demonstrate the ability of sand flies to colonize new environments previously considered unsuitable for these insects. Even though the density of the Phlebotomine sand fly population in the plain areas is consistently lower than that observed in hilly and low mountainous areas, the presence of these vectors could herald the onset of epidemic outbreaks of leishmaniasis and other arthropod-borne diseases in areas previously considered non-endemic.Graphical

Larvicidal activities of essential oils of indigenous medicinal plants, Mentha pulegium L., Satureja hortensis L., and Thymus vulgaris L. against malaria vector, Anopheles stephensi

According to World Health Organization report, malaria is the main important arthropod-borne disease in the World . There is several chemical control of mosquito. Due to resistant of vectors to different insecticides, this research was aim to evaluate the larvicidal activities of three native plants, Mentha pulegium L., Satureja hortensis L., and Thymus vulgaris L. against 3th-4th instar larvae of Anopheles stephensi.Medicinal plants were collected from different localities in East Azerbaijan province, Iran. The plant samples were dried in shaded place and the chopped plants were hydro-distilled in a Clevenger-type apparatus for 2–4 h and the EOs dried over anhydrous sodium sulfate. The EOs was maintained in the dark sealed vials at 4 °C until conduction of the larvicidal tests. The larvicidal tests were carried out based on the guideline of WHO.The values of LC50 of EOs of Mentha pulegiumL., Satureja hortensis L, and Thymus vulgaris L. were 40.1324, 34.1527, 53.1063 ppm respectively . The LC90 of EOs of Mentha pulegium L., Satureja hortensis L., and Thymus vulgaris L. were 122.1340,98.9910,96.4527 respectively. Satureja hortensis L. had the lowest LC50 and the Thymus vulgaris the highest one.More efforts are recommended for trade formulation, semi-field and field evaluations of EOs are strongly recommended at the malarious area, southern Iran.

Field Evaluation of Selected Common Household Containers as Oviposition Attractants of <em>Aedes Albopictus</em> (Diptera: Culicidae

Dengue is a fatal arthropod-borne disease that affects humans worldwide. The mosquito Aedes albopictus (Skuse) is the secondary vector of dengue in Sri Lanka, however, studies on oviposition preferences of Ae. albopictus is scarce. The objective of the current study was to investigate the oviposition attraction of Aedes albopictus to selected household containers; black colour basins, metal cans, rain gutter parts, curd pots, coconut shells and yoghurt cups. For this, water containers for oviposition were placed in three outdoor shady sites and at three different heights. The mosquito larvae were collected after 5 days. The larvae were reared to adult stage and then they were identified and enumerated. Wing lengths of adult female mosquitoes that developed in different containers were measured. In the meantime, temperature, pH, dissolved oxygen (DO) and total dissolved solids (TDS) were measured in each container. The Ae. albopictus larval density was higher in coconut shells. The maximum mean number of mosquito larvae was observed in the containers at ground level. The oviposition attraction of Ae. albopictus was increased with the aging of coconut shells and old coconut shells were preferred than new coconut shells. Highest TDS level and neutral pH were observed in coconut shells which support the mosquito oviposition. The highest wing lengths were observed in female Ae. albopictus that developed in curd pots, representing higher fecundity. In conclusion, discarded coconut shells and curd pots should be carefully managed as means of eliminating dengue vector mosquito breeding sites.

Current Arboviral Threats and Their Potential Vectors in Thailand.

Arthropod-borne viral diseases (arboviruses) are a public-health concern in many regions of the world, including Thailand. This review describes the potential vectors and important human and/or veterinary arboviruses in Thailand. The medically important arboviruses affect humans, while veterinary arboviruses affect livestock and the economy. The main vectors described are mosquitoes, but other arthropods have been reported. Important mosquito-borne arboviruses are transmitted mainly by members of the genus Aedes (e.g., dengue, chikungunya, and Zika virus) and Culex (e.g., Japanese encephalitis, Tembusu and West Nile virus). While mosquitoes are important vectors, arboviruses are transmitted via other vectors, such as sand flies, ticks, cimicids (Family Cimicidae) and Culicoides. Veterinary arboviruses are reported in this review, e.g., duck Tembusu virus (DTMUV), Kaeng Khoi virus (KKV), and African horse sickness virus (AHSV). During arbovirus outbreaks, to target control interventions appropriately, it is critical to identify the vector(s) involved and their ecology. Knowledge of the prevalence of these viruses, and the potential for viral infections to co-circulate in mosquitoes, is also important for outbreak prediction.

Articles of Significant Interest In This Issue

The deer tick Ixodes scapularis is the most important vector of arthropod-borne diseases to humans in North America, with tens of thousands of cases of Lyme disease reported annually. The symbiont Rickettsia buchneri is found in the ovaries of female ticks and is transmitted transovarially to the offspring. In this article, Oliver et al. (e01672-20) describe the reproductive dynamics of R. buchneri throughout the lifecycle of I. scapularis and describe methods for its elimination using antibiotics. Removing R. buchneri will allow future researchers to determine the fitness effects of the symbiont on the host and evaluate its interactions with pathogenic microorganisms responsible for I. scapularis-borne diseases.

Drivers of spatio-temporal variation in mosquito submissions to the citizen science project \u2018M\xfcckenatlas\u2019

Intensified travel activities of humans and the ever growing global trade create opportunities of arthropod-borne disease agents and their vectors, such as mosquitoes, to establish in new regions. To update the knowledge of mosquito occurrence and distribution, a national mosquito monitoring programme was initiated in Germany in 2011, which has been complemented by a citizen science project, the ‘Mückenatlas’ since 2012. We analysed the ‘Mückenatlas’ dataset to (1) investigate causes of variation in submission numbers from the start of the project until 2017 and to (2) reveal biases induced by opportunistic data collection. Our results show that the temporal variation of submissions over the years is driven by fluctuating topicality of mosquito-borne diseases in the media and large-scale climate conditions. Hurdle models suggest a positive association of submission numbers with human population, catch location in the former political East Germany and the presence of water bodies, whereas precipitation and wind speed are negative predictors. We conclude that most anthropogenic and environmental effects on submission patterns are associated with the participants’ (recording) behaviour. Understanding how the citizen scientists’ behaviour shape opportunistic datasets help to take full advantage of the available information.

A selectable, plasmid-based system to generate CRISPR/Cas9 gene edited and knock-in mosquito cell lines

Aedes (Ae.) aegypti and Ae. albopictus mosquitoes transmit arthropod-borne diseases around the globe, causing ~ 700,000 deaths each year. Genetic mutants are valuable tools to interrogate both fundamental vector biology and mosquito host factors important for viral infection. However, very few genetic mutants have been described in mosquitoes in comparison to model organisms. The relative ease of applying CRISPR/Cas9-based gene editing has transformed genome engineering and has rapidly increased the number of available gene mutants in mosquitoes. Yet, in vivo studies may not be practical for screening large sets of mutants or possible for laboratories that lack insectaries. Thus, it would be useful to adapt CRISPR/Cas9 systems to common mosquito cell lines. In this study, we generated and characterized a mosquito optimized, plasmid-based CRISPR/Cas9 system for use in U4.4 (Ae. albopictus) and Aag2 (Ae. aegypti) cell lines. We demonstrated highly efficient editing of the AGO1 locus and isolated U4.4 and Aag2 cell lines with reduced AGO1 expression. Further, we used homology-directed repair to establish knock-in Aag2 cell lines with a 3xFLAG-tag at the N-terminus of endogenous AGO1. These experimentally verified plasmids are versatile, cost-effective, and efficiently edit immune competent mosquito cell lines that are widely used in arbovirus studies.

Independent Evaluation of Two Prototype Immunochromatographic Tests for Dengue Fever Developed by InBios

Dengue fever, caused by any of the four dengue viruses (DENV1-4), is endemic in more than 100 countries around the world. Each year, up to 400 million people get infected with dengue virus. It is one of the most important arthropod-borne viral diseases. Dengue's global presence poses a medical threat to deploying military personnel and their dependents. An accurate diagnosis followed by attentive supportive care can improve outcomes in patients with severe dengue disease. Dengue diagnostic tests based on PCR and ELISA platforms have been developed and cleared by the U.S. FDA. However, these diagnostic assays are laborious and usually require highly trained personnel and specialized equipment, which presents a significant challenge when conducting operations in austere and resource-constrained areas. InBios International, Inc. (Seattle, WA) has developed two rapid and instrument-free immunochromatographic test prototype devices (multiplex and traditional formats) for dengue diagnosis. To determine the performance of the InBios immunochromatographic tests, 183 clinical samples were tested on both prototype devices. Both assays were performed without any instruments and the results were read in 20 minutes. The traditional format had better overall performance (sensitivity: 97.4%; specificity: 90%) than the multiplex format (sensitivity: 86.9%; specificity: 63.3%). The traditional format was superior in serotype-specific detection with 100% overall sensitivity for DENV1, DENV3, and DENV4 and 93.3% sensitivity for DENV2 compared to the multiplex format (91.7%, 78.3%, 83.3%, and 96.3% for DENV1, 2, 3, and 4, respectively). The traditional format was easier to read than the multiplex format. The multiplex format was simpler and faster to set up than the traditional format. The InBios traditional format had a better overall performance and readability profile than the multiplex format, while the multiplex format was easier to set up. Both formats were highly sensitive and specific, were easy to perform, and did not require sophisticated equipment. They are ideal for use in resource-limited settings where dengue is endemic. Based on our overall assessment, the traditional format should be considered for further development and used in the upcoming multicenter clinical trial toward FDA clearance.

Assessing the efficacy of oral intake of insecticides on mortality of fleas and ticks on commensal Rattus species

Many rodent-borne pathogens can be transmitted via their ectoparasites to humans and can cause severe zoonotic diseases (e.g. plague, tick-borne encephalitis, typhus). Managing relevant ectoparasites in rodents may reduce human infection risk. The purpose of this laboratory study was to screen potential insecticides for their palatability to commensal rat species and their efficacy against fleas and ticks feeding on rats. The preferences shown by Norway rats (Rattus norvegicus) for four insecticides (fipronil, cythioate, thiamethoxam and ivermectin) were assessed when presented as a choice in cereal-based pellets. Subsequently, specific doses of insecticide-containing cereal pellets were fed to rats to determine the ability of each insecticide, over time, to kill cat fleas (Ctenocephalides felis), stickfast fleas (Echidnophaga gallinacea) feeding on Norway rats, and possum ticks (Ixodes trichosuri) feeding on Norway rats and black rats (R. rattus). Fipronil, cythioate and thiamethoxam were similarly palatable to rats, but ivermectin was avoided at high concentration. Fipronil was the most effective in killing cat fleas, stickfast fleas and ticks feeding on rats. Cythioate and ivermectin performed similarly against two flea species, while the effects of ivermectin and fipronil were comparable against ticks. Cythioate was not efficacious against ticks at the doses tested. Fipronil should be tested as a systemic compound to minimise arthropod infestation in small mammals to reduce adverse effects of arthropod-borne disease on humans. This insecticide should also be tested in combination with a rodenticide to prevent migration of arthropods with zoonotic relevance from rodent carcasses to humans.

Phytoconstituents as Lead Compounds for Anti-Dengue Drug Discovery.

Dengue is an arthropod-borne viral disease common in subtropical and tropical regions. The widespread use of traditional medicines in these regions for dengue fever (DF) has encouraged researchers to explore the therapeutic effect of herbs and their phytochemicals in dengue infection. Phytochemicals such as quercetin, baicalein, luteolin, oxindole alkaloids, celastrol and geraniin have shown significant inhibition of dengue virus in vitro. Many phytoconstituents have better selectivity index supporting their safety profile for future development. However, in vivo studies supporting therapeutic potency for these active phytoconstituents are limited. There is a need for studies translating anti-dengue profile of active phytoconstituents to find successful anti-dengue compounds.

High-Throughput Screening Assays for Dengue Antiviral Drug Development.

Dengue is an arthropod-borne viral disease that has become endemic and a global threat in over 100 countries. The increase in prevalence would require a long-term measure to control outbreaks. Sanofi Pasteur has licensed the tetravalent dengue vaccine (Dengvaxia) in certain dengue endemic countries. However, the efficacy of the vaccine is limited against certain dengue serotypes and can only be used for individuals from the age from 9 to 45years old. Over the years, there has been intense research conducted on the development of antivirals against dengue virus (DENV) through either inhibiting the virus replication or targeting the host cell mechanism to block the virus entry. However, no approved antiviral drug against dengue is yet available. In this chapter, we describe the dengue antiviral development workflow including (i) prophylactic, (ii) virucidal, and (iii) postinfection assays that are employed in the antiviral drug screening process against DENV. Further, we demonstrate different methods that can be used to enumerate the reduction in virus foci number including foci-forming unit reduction assay (FFURA), estimation of viral RNA copy number through quantitative real-time PCR, and a high-throughput enzyme linked immunosorbent assay (ELISA)-based quantification of virus particles.

Environmental Mapping of Potential Habitats for Anthropod Vectors of Trypanosomiasis in Northern Nigeria

This paper presents analysis of a cost effective methodology using remotely sensed data analysed within a geographical systems (GIS) environment for mapping out potential habitats of anthropod vectors responsible for trypanosomiasis in northern Nigeria. These geographical locations are areas with high population of livestock in Nigeria. Animal Trypanosomiasis is considered as an arthropod-borne viral disease which is endemic in about 37 countries of the sub-Saharan Africa and in particular northern Nigeria. This anthropod-borne viral disease remains a threat to both humans and livestock in many communities, and the outbreak of such diseases is shown to relate to fluctuations in the changing climate mostly experienced whenever there are changes in global precipitation which also relates to changes in sea surface temperatures otherwise known as “El Niňo Southern Oscillations” (ENSO). Monthly Satellite imageries in the form of Normalised Difference Vegetation Index (NDVI) at 250 meters spatial resolution obtained from NASA-MODIS/CMD were subjected to principal component analysis utilizing the standardized principal components within a GIS environment and supplemented with Digital Elevation Model (DEM) data in the analysis. Results from the maps showed that pockets of probable habitats of these anthropod vectors responsible for trypanosomiasis mostly located around forest islands characterized by dry woodland and savanna, and in some cases around gallery forests and few lowland and riverine areas. This study provides baseline information for policy makers in Nigeria and other stakeholders as a cost effective measure for mapping potential habitats for anthropod vectors responsible for trypanosomiasis in Northern Nigeria. Further studies are encouraged so as to clearly understand the magnitude and actual locations of the habitat of this vector and find ways of targeting their locations for minimizing or even eradicating these vectors.

Steroidal saponins from the roots of Solanum sisymbriifolium Lam. (Solanaceae) have inhibitory activity against dengue virus and yellow fever virus.

Dengue is the most important arthropod-borne viral disease worldwide. Infection with any of the four dengue virus (DENV) serotypes can be asymptomatic or lead to disease with clinical symptoms ranging from undifferentiated and self-limiting fever to severe dengue disease, which can be fatal in some cases. Currently, no specific antiviral compound is available for treating DENV. The aim of this study was to identify compounds in plants from Paraguayan folk medicine with inhibitory effects against DENV. We found high virucidal activity (50% maximal effective concentration (EC50) value of 24.97 µg/mL) against DENV-2 in the ethanolic extract of the roots of Solanum sisymbriifolium Lam. (Solanaceae) without an evident cytotoxic effect on Vero E6 cells. Three saponins isolated from the root extract showed virucidal effects (EC50 values ranging from 24.9 to 35.1 µg/mL) against DENV-2. Additionally, the saponins showed inhibitory activity against yellow fever virus (EC50 values ranging from 126 to 302.6 µg/mL), the prototype virus of the Flavivirus genus, suggesting that they may also be effective against other members of this genus. Consequently, these saponins may be lead compounds for the development of antiviral agents.

Co-existence of Malaria and Dengue: An Incidental Observation

Introduction: Malaria and dengue are two most important arthropod borne diseases responsible for high morbidity and mortality across the globe. Both these communicable diseases have been a major threat to the public health not only in India but also in other tropical and sub-tropical regions of the world. Aim: To study the prevalence of Dengue and Malaria along with the cases of co-infection among the patients visiting a tertiary care hospital located in central India. Materials and Methods: The present prospective study was conducted for a period of two years from January 2019 to December 2020, in the serology section of the Department of Microbiology of a teaching tertiary care hospital. Three to five millilitres (mL) of venous blood samples from 1519 patients were tested for both dengue (NS1 antigen, IgM and IgG antibodies) by Enzyme Linked Immunosorebent Assay (ELISA) method and malaria peripheral smear and antigen by immunochromatographic method. All demographic parameters were simultaneously analysed. Statistical analysis was performed with the help of Chi-square test. Results: Out of 1519 blood samples tested, 267 (17.5%) samples were positive for dengue and six (0.39%) samples were positive for malaria. No case of co-infection was detected. Maximum dengue cases were detected during post monsoon period while malaria cases were detected in monsoon and post monsoon period. Among the various dengue positive cases, 185 (69.2%) patients were diagnosed with recent primary infection while 20 (7.49%) patients had primary infection. Conclusion: The present study concluded that seroprevalence of dengue was high in our geographical region with malaria being negligible. Present study incidentally recorded the fact that the two diseases may co-exist in an individual but both the vectors rarely share the same geographical site.