Vector-borne Viral Disease Research Articles

Herbal, Safe and effective Mosquito repellents: Recent Development and Opportunity

Most of today's rapidly spreading infectious diseases are arthropod-borne, and vaccinations are powerless to prevent them. Because insect repellents are effective topical barriers to the spread of arthropod-borne infectious illnesses. Plant-based (natural) and chemical-based products are both used (synthetic) as a mosquito repellents, which come in a variety of forms such as mosquito repeller coils, mosquito repeller oil, and so on, are becoming more popular around the world as vector-borne viral diseases such as Dengue, Chikungunya, and Malaria become more prevalent. The best alternative to the optimal formulation is determined by a number of elements, including the type of repellent (natural or synthetic), medicinal forms (spray, lotion, cream, gel), duration of action (short or long), exposure environment, and user (adult, pregnant women, children, newborn). DEET, IPicaridin, and essential oils are the most commonly utilised repellents, each with its own set of benefits and drawbacks. DEET is not suggested for children under the age of six months or pregnant women because of its toxicity. The current tendency is to employ pant-based repellent active compounds like essential oils, which have minimal toxicity, are environmentally friendly, but have a shorter repellent action period due to quick evaporation after skin contact. Repellents could be a visible option for people to reduce the risk of interaction with rare mosquito-borne diseases for mosquito borne diseases. The review highlights a summary of mosquito repellents, its novel discoveries, and areaof technicalstudies such as the novel and unique repellent formulations and their potentialfuture.

Evaluation of haematological, serum biochemical and oxidative stress parameters in cattle naturally infected with lumpy skin disease virus.

Lumpy skin disease (LSD) is a vector-borne viral transboundary disease of cattle caused by the LSD virus (LSDV). Despite investigations on clinical and outbreak features of LSDV, information on disease pathogenesis and alternative changes in blood parameters are scarce. Keeping this in view, the current study was designed to determine haematological, serum biochemical, and oxidative stress parameters in naturally infected cattle with LSDV during the recent surge of outbreaks in Punjab, Pakistan. A total of 35 blood samples was collected from polymerase chain reaction-confirmed LSDV-infected cattle for assessment of all parameters. The haematological examination of blood samples showed a significant reduction (p < 0.05) in different variables of erythrogram and leucogram. On the other hand, differences between levels of various serum biochemical parameters with the significant increase in levels of alkaline phosphatase, serum alanine aminotransferase, aspartate aminotransferase, and blood urea nitrogen were observed in LSDV naturally infected cattle. Moreover, malondialdehyde levels for lipid peroxidation and nitrate concentration were markedly elevated whereas glutathione S-transferase fluorescent and serum superoxide dismutase enzymes showed a decrease in levels. The current study suggests that alternations in haematological and serum biochemical parameters following LSDV infection stimulate oxidative stress and such findings may be useful for early and rapid diagnosis and improvement in the treatment strategy of the disease.

Pathological features of African horse sickness virus infection in IFNAR-/- mice.

African Horse Sickness (AHS) is a vector-borne viral disease of equids. The disease can be highly lethal with mortality rates of up to 90% in non-immune equine populations. The clinical presentation in the equine host varies, but the pathogenesis underlying this variation remains incompletely understood. Various small animal models of AHS have been developed over the years to overcome the financial, bio-safety and logistical constraints of studying the pathology of this disease in the target species. One of the most successful small animal models is based on the use of interferon-alpha gene knock-out (IFNAR-/-) mice. In order to increase our understanding of African Horse Sickness virus (AHSV) pathogenesis, we characterised the pathology lesions of AHSV infection in IFNAR-/- mice using a strain of AHSV serotype 4 (AHSV-4). We found AHSV-4 infection was correlated with lesions in various organs; necrosis in the spleen and lymphoid tissues, inflammatory infiltration in the liver and brain, and pneumonia. Significant viral antigen staining was only detected in the spleen and brain, however. Together these results confirm the value of the IFNAR-/- mouse model for the study of the immuno-biology of AHSV infections in this particular in vivo system, and its usefulness for evaluating protective efficacy of candidate vaccines in preclinical studies.

Emerging and re-emerging viral diseases, predisposing risk factors, and implications of international travel: a call for action for increasing vigilance and imposing restrictions under the current threats of recently emerging multiple Omicron subvariants.

Emerging and re-emerging viral diseases, predisposing risk factors, and implications of international travel: a call for action for increasing vigilance and imposing restrictions under the current threats of recently emerging multiple Omicron subvariants.

Evaluation of an Immunoglobulin E Capture Enzyme-Linked Immunosorbent Assay for the Early Diagnosis of Dengue.

Dengue virus (DENV) is the etiological agent of dengue, the most important mosquito-transmitted viral disease of humans worldwide. Enzyme-linked immunosorbent assays (ELISAs) designed to detect DENV IgM are commonly used for dengue diagnosis. However, DENV IgM is not reliably detected until ≥4 days after illness onset. Reverse transcription-polymerase chain reaction (RT-PCR) can diagnose early dengue but requires specialized equipment, reagents, and trained personnel. Additional diagnostic tools are needed. Limited work has been performed to determine whether IgE-based assays can be used for the early detection of vector-borne viral diseases, including dengue. In this study, we determined the efficacy of a DENV IgE capture ELISA for the detection of early dengue. Sera were collected within the first 4 days of illness onset from 117 patients with laboratory-confirmed dengue, as determined by DENV-specific RT-PCR. The serotypes responsible for the infections were DENV-1 and DENV-2 (57 and 60 patients, respectively). Sera were also collected from 113 dengue-negative individuals with febrile illness of undetermined etiology and 30 healthy controls. The capture ELISA detected DENV IgE in 97 (82.9%) confirmed dengue patients and none of the healthy controls. There was a high false positivity rate (22.1%) among the febrile non-dengue patients. In conclusion, we provide evidence that IgE capture assays have the potential to be explored for early diagnosis of dengue, but further research is necessary to address the possible false positivity rate among patients with other febrile illnesses.

Mucin Protein of Aedes aegypti Interacts with Dengue Virus 2 and Influences Viral Infection.

Dengue, caused by dengue virus (DENV), is the most prevalent vector-borne viral disease, posing a serious health concern to 2.5 billion people worldwide. DENV is primarily transmitted among humans by its mosquito vector Aedes aegypti; hence, the identification of a novel dengue virus receptor in mosquitoes is critical for the development of new anti-mosquito measures. In the current study, we have identified peptides which potentially interact with the surface of the virion particles and facilitate virus infection and movement during their life cycle in the mosquito vector. To identify these candidate proteins, we performed phage-display library screening against domain III of the envelope protein (EDIII), which plays an essential role during host cell receptor binding for viral entry. The mucin protein, which shared sequence similarity with the peptide identified in the screening, was cloned, expressed, and purified for in vitro interaction studies. Using in vitro pulldown and virus overlay protein-binding assay (VOPBA), we confirmed the positive interaction of mucin with purified EDIII and whole virion particles. Finally, blocking of mucin protein with anti-mucin antibodies partially reduced DENV titers in infected mosquitos. Moreover, mucin protein was found to be localized in the midgut of Ae. aegypti. IMPORTANCE Identification of interacting protein partners of DENV in the insect vector Aedes aegypti is crucial for designing vector control-based strategies and for understanding the molecular mechanism DENV uses to modulate the host, gain entry, and survive successfully. Similar proteins can be used in generating transmission-blocking vaccines.

Serum biomarkers and anti-flavivirus antibodies at presentation as indicators of severe dengue.

Dengue is the most common vector-borne viral disease worldwide. Most cases are mild, but some evolve into severe dengue (SD), with high lethality. Therefore, it is important to identify biomarkers of severe disease to improve outcomes and judiciously utilize resources. One hundred forty-five confirmed dengue cases (median age, 42; range <1-91 years), enrolled from February 2018 to March 2020, were selected from an ongoing study of suspected arboviral infections in metropolitan Asunción, Paraguay. Cases included dengue virus types 1, 2, and 4, and severity was categorized according to the 2009 World Health Organization guidelines. Testing for anti-dengue virus IgM and IgG and serum biomarkers (lipopolysaccharide binding protein and chymase) was performed on acute-phase sera in plate-based ELISAs; in addition, a multiplex ELISA platform was used to measure anti-dengue virus and anti-Zika virus IgM and IgG. Complete blood counts and chemistries were performed at the discretion of the care team. Age, gender, and pre-existing comorbidities were associated with SD vs. dengue with/without warning signs in logistic regression with odds ratios (ORs) of 1.07 (per year; 95% confidence interval, 1.03, 1.11), 0.20 (female; 0.05,0.77), and 2.09 (presence; 1.26, 3.48) respectively. In binary logistic regression, for every unit increase in anti-DENV IgG in the multiplex platform, odds of SD increased by 2.54 (1.19-5.42). Platelet count, lymphocyte percent, and elevated chymase were associated with SD in a combined logistic regression model with ORs of 0.99 (1,000/μL; 0.98,0.999), 0.92 (%; 0.86,0.98), and 1.17 (mg/mL; 1.03,1.33) respectively. Multiple, readily available factors were associated with SD in this population. These findings will aid in the early detection of potentially severe dengue cases and inform the development of new prognostics for use in acute-phase and serial samples from dengue cases.

Cross-reactivity of SARS-CoV-2 with other pathogens, especially dengue virus: A historical perspective.

Dengue is a vector-borne viral disease caused by a Flavivirus whereas the COVID-19 pandemic was caused by a highly contagious virus, SARS-CoV-2 belonging to the family Coronaviridae. However, COVID-19 severity was observably less in dengue-endemic countries and vice versa especially during the active years of the pandemic (2019-2021). We observed that dengue virus (DENV) antibodies (Abs) could cross-react with SARS-CoV-2 spike antigen. This resulted in SARS-CoV-2 false positivity by rapid Ab test kits. DENV Abs binding to SARS-CoV-2 receptor-binding domain (and the reverse scenario), as revealed by docking studies further validated DENV and SARS-CoV-2 cross-reactivity. Finally, SARS-CoV-2 Abs were found to cross-neutralize DENV1 and DENV2 in virus neutralization test (VNT). Abs to other pathogens like Plasmodiumwere also cross-reactive but non-neutralizing for SARS-CoV-2. Here, we analyze the existing data on SARS-CoV-2 cross-reactivity with other pathogens, especially dengue to assess its impact on health (cross-protection?) and differential sero-diagnosis/surveillance.

The Dengue Prevalence and Mortality Rate Surpass COVID-19 in Bangladesh: Possible Strategies to Fight Against a Double-Punch Attack.

Dengue is a vector-borne viral disease caused by multiple serotypes (DENV-1, DENV-2, DENV-3, and DENV-4) of the dengue virus. It has been a public health concern since 2000 in Bangladesh. However, Bangladesh experienced a higher prevalence and death rate in the year 2022 than the previous year surpassing the COVID-19 situation. While climatic factors had always been a prominent reason for dengue incidence, reports stated that DEN 4 serotype was identified for the first time in the country, which made the dengue cases worse. In this article, we presented the 5 years prevalence of hospitalization and death cases owing to dengue fever and also provided a comparison of death cases caused by dengue and COVID-19 in Bangladesh. We described the possible reasons for the sudden surges of dengue infection and mentioned the actions led by the government to deal with this dengue occurrence. Lastly, we recommend a few strategies to counter the future outbreak of dengue infection in the country.

Analysis and Bayesian estimation of a model for Chikungunya dynamics with relapse: An outbreak in Acapulco, Mexico.

Chikungunya is a vector-borne viral disease transmitted by Aedes aegypti and Aedes albopictus mosquitoes. It does not have any specific treatment, and there is no vaccine. Recent epidemiological data have indicated that a relapse of the infection can occur within three months of the initial infection; however, until now, mathematical models for the spread of the disease have not considered this factor. We propose a mathematical model for the transmission of the Chikungunya virus that considers relapse. We calculated the basic reproductive number $ (R_0) $ of the disease by using the next-generation operator method. We proved the existence of a forward bifurcation. We determined the existence and the global stability of the equilibrium points by using the Lyapunov function method. We fitted the model to data from an outbreak in 2015 in Acapulco, Mexico to estimate the model parameters and $ R_0 $ with the Bayesian approach via a Hamiltonian Monte Carlo method. In the local sensitivity analysis, we found that the fraction of infected individuals who become asymptomatic has a strong impact on the basic reproductive number and makes some control measures insufficient. The impact of the fraction of infected individuals who become asymptomatic should be considered in Chikungunya control strategies.

Dynamic behavior of a reaction-diffusion dengue model with spatial heterogeneity

Dengue is one of the most prevalent vector-borne viral diseases, which is transmitted through the bite of Aedes mosquitoes (Aedes albopictus). In this study, using the global exponential attraction theory, the dynamic behavior of the dengue model in a spatially heterogeneous environment was studied. The existence and uniqueness of positive global solutions were proven using the semigroup theory. The basic reproduction number was defined using the spectral radius of the next-generation operator. Furthermore, a global exponential attractor set was given, and the results of globally asymptotically stable and disease uniform persistence were obtained for the dengue model. A numerical simulation showed the dynamic behavior and revealed that increasing the diffusion coefficient and spatial heterogeneity rate is beneficial for disease control.

Serological evidence of bluetongue virus and associated factors in small ruminants of Bangladesh

Bluetongue (BT) is an infectious, vector-borne viral disease of animals having a substantial economic impact and it is endemic in the bordering states of the Indian subcontinent. Livestock enters frequently from India into Bangladesh without any screening. Hence, this study aimed to estimate the seroprevalence of Bluetongue virus (BTV) and associated risk factors in small ruminants of Bangladesh. We conducted a cross-sectional study in the Dhaka, Chattogram, and Faridpur districts of Bangladesh between 2017 and 2018. The team collected 333 serum samples from 123 goats and 210 sheep and tested them for the presence of antibodies against BTV using a competitive enzyme linked immunosorbent assay (c-ELISA). A mixed multivariable logistic regression model was built to identify risk factors. Sample collection location was included as a random effect and husbandry and demographic variables as fixed effects to identify the potential risk factors. The BTV seroprevalence was found to be 55.3% (n = 184; 95% CI: 49.74–60.68). In the mixed-effect logistic regression analysis, animal species (AOR: 4.69; 95% CI: 2.49–8.82; p = 0.001) and vector control measurement (AOR: 9.01; 95% CI: 4.01–20.00; p = 0.0001) were significantly associated with BTV seropositivity. However, no significant association was found in multivariable mixed-effect logistic regression for the variables age, body condition score (BCS), vaccination against PPR (p > 0.05). The study found evidence of high seroprevalence of BTV in both sheep and goats in different districts of Bangladesh, indicating natural exposure of the virus and the animals can serve as a potential threat for other animals. Further research is needed to isolate and identify the circulating virus serotype(s) of BTV in Bangladesh as well as longitudinal studies for epidemiological investigations to formulate sound control programs and to enhance the awareness about the possible impacts of this disease on the livelihood of the people.

A next generation targeted amplicon sequencing method to screen for insecticide resistance mutations in Aedes aegypti populations reveals a rdl mutation in mosquitoes from Cabo Verde.

Aedes mosquito vectors transmit many viruses of global health concern, including dengue, chikungunya and Zika. These vector-borne viral diseases have a limited number of treatment options, and vaccines vary in their effectiveness. Consequently, integrated vector management is a primary strategy for disease control. However, the increasing emergence and spread of insecticide resistance is threatening the efficacy of vector control methods. Identifying mutations associated with resistance in vector populations is important to monitor the occurrence and evolution of insecticide resistance and inform control strategies. Rapid and cost-effective genome sequencing approaches are urgently needed. Here we present an adaptable targeted amplicon approach for cost-effective implementation within next generation sequencing platforms. This approach can identify single nucleotide polymorphisms (SNPs) and small insertions and deletions (indels) in genes involved in insecticide resistance in Aedes aegypti mosquitoes. We designed and tested eleven amplicons, which included segments of the ace-1 (carbamate target), the Voltage-Gated Sodium Channel (vgsc; pyrethroids, DDT and organochlorines), and rdl (dieldrin) genes; thereby covering established knockdown resistance (kdr) mutations (e.g., S989P, I1011M/V, V1016G/I and F1534C), with the potential to identify novel ones. The amplicon assays were designed with internal barcodes, to facilitate multiplexing of large numbers of mosquitoes at low cost, and were sequenced using an Illumina platform. Our approach was evaluated on 152 Ae. aegypti mosquitoes collected in Cabo Verde, an archipelago with a history of arbovirus outbreaks. The amplicon sequence data revealed 146 SNPs, including four non-synonymous polymorphisms in the vgsc gene, one in ace-1 and the 296S rdl mutation previously associated with resistance to organochlorines. The 296S rdl mutation was identified in 98% of mosquitoes screened, consistent with the past use of an organochlorine compound (e.g., DDT). Overall, our work shows that targeted amplicon sequencing is a rapid, robust, and cost-effective tool that can be used to perform high throughput monitoring of insecticide resistance.

Detection of Crimean-Congo Hemorrhagic Fever Virus Antibodies in Cattle in Plateau State, Nigeria

Crimean-Congo hemorrhagic fever (CCHF) is a vector-borne viral hemorrhagic disease with global clinical significance. Certain species of ticks are vectors of CCHF, which can be transmitted from animals to humans and humans to humans by direct exposure to blood or other body fluids. The zoonotic transmission at the human-animal interface from viremic animal hosts to humans is a public health concern with a paucity of data in Nigeria. Samples from 184 pastoral cattle from three local government areas (LGAs) of Plateau state, Nigeria, were screened for CCHF virus using a commercial enzyme-linked immunosorbent assay (ID Screen® CCHF Double Antigen for Multi-Species). Overall seropositivity of 30.4% (n = 56) (95% CI: 23.88%, 37.63%) was recorded from the study areas in Plateau State, while 48/126 (38.1%, 95% CI: 29.59%, 47.17%) sampled cows tested positive for CCHFV antibodies. Seropositivity was significantly higher (p < 0.001) among older cattle greater than two years, 54.69% (95% CI: 2.88%, 11.24%) compared to cattle younger than two years, 17.5% (95% CI: 11.17%, 25.50%). The location of farms played a significant role in the seropositivity of CCHF with the least risk observed in Wase LGA. CCHF is an important zoonotic disease in different parts of the globe with a high risk of transmission to pastoralists, livestock keepers/slaughterhouse workers, and veterinarians who handle animals. There is a need for a collaborative one-health approach with various stakeholders to unravel the dynamics of CCHFV epidemiology in Nigeria.

Spatial association of Aedes aegypti with dengue fever hotspots in an endemic region

Background and objectiveDengue is a vector-borne viral disease usually transmitted by Aedes mosquitoes. Around the world, the relationship between local vector density and frequency of dengue cases is being explored and needs further evidence. This study aimed to analyze the potential spatial relationships between the dengue vector (Aedes aegypti) and dengue cases in the megacity of Bangladesh during the 2019 dengue outbreak. MethodsVector density measures were used to estimate spatial associations with dengue case distribution. Location was determined for 364 dengue cases who were admitted to Dhaka Medical College Hospital over a period of 4 months. Data were collected using a semi-structured questionnaire, and prior consent was ensured before participation. The Moran global index, Getis-Ord Gi∗, ordinary least squares regression, geographically weighted regression and count data regression methods were used for spatial analysis. ResultsWe found that dengue case distribution was not associated with immature Aedes aegypti mosquito (larvae) density across the city. The relationship between larval density measured by the Breteau Index (BI) and House Index (HI) with dengue cases was nonstationary and not statistically significant. ConclusionThe location of dengue cases appears to be unrelated to vector distribution and vector density. These findings should prompt the search for other transmission risk factors.

Evidence for overwintering and autochthonous transmission of Usutu virus to wild birds following its redetection in the United Kingdom.

Usutu virus (USUV) is an emerging zoonotic arbovirus in Europe, where it primarily impacts Eurasian blackbirds (Turdus merula). For mosquito-borne viruses to persist in temperate areas, transovarial transmission in vectors or overwintering in either hosts or diapausing vectors must occur to facilitate autochthonous transmission. We undertook surveillance of hosts and vectors in 2021 to elucidate whether USUV had overwintered in the United Kingdom (UK) following its initial detection there in 2020. From 175 dead bird submissions, we detected 1 case of USUV infection, in a blackbird, from which a full USUV genome was derived. Using a molecular clock analysis, we demonstrate that the 2021 detection shared a most recent common ancestor with the 2020 Greater London, UK, USUV sequence. In addition, we identified USUV-specific neutralizing antibodies in 10 out of 86 serum samples taken from captive birds at the index site, demonstrating in situ cryptic infection and potential sustained transmission. However, from 4966 mosquitoes, we detected no USUV RNAsuggesting that prevalence in the vector community was absent or low during sampling. Combined, these results suggest that USUV overwintered in the UK, thus providing empirical evidence for the continued northward expansion of this vector-borne viral disease. Currently, our detection indicates geographically restricted virus persistence. Further detections over time will be required to demonstrate long-term establishment. It remains unclear whether the UK, and by extension other high-latitude regions, can support endemic USUV infection.

A Numerical Study of the Dynamics of Vector-Born Viral Plant Disorders Using a Hybrid Artificial Neural Network Approach.

Most plant viral infections are vector-borne. There is a latent period of disease inside the vector after obtaining the virus from the infected plant. Thus, after interacting with an infected vector, the plant demonstrates an incubation time before becoming diseased. This paper analyzes a mathematical model for persistent vector-borne viral plant disease dynamics. The backpropagated neural network based on the Levenberg-Marquardt algorithm (NN-BLMA) is used to study approximate solutions for fluctuations in natural plant mortality and vector mortality rates. A state-of-the-art numerical technique is utilized to generate reference data for obtaining surrogate solutions for multiple cases through NN-BLMA. Curve fitting, regression analysis, error histograms, and convergence analysis are used to assess accuracy of the calculated solutions. It is evident from our simulations that NN-BLMA is accurate and reliable.

A Review of Vector-Borne Rice Viruses.

Rice (Oryza sativa L.) is one of the major staple foods for global consumption. A major roadblock to global rice production is persistent loss of crops caused by plant diseases, including rice blast, sheath blight, bacterial blight, and particularly various vector-borne rice viral diseases. Since the late 19th century, 19 species of rice viruses have been recorded in rice-producing areas worldwide and cause varying degrees of damage on the rice production. Among them, southern rice black-streaked dwarf virus (SRBSDV) and rice black-streaked dwarf virus (RBSDV) in Asia, rice yellow mottle virus (RYMV) in Africa, and rice stripe necrosis virus (RSNV) in America currently pose serious threats to rice yields. This review systematizes the emergence and damage of rice viral diseases, the symptomatology and transmission biology of rice viruses, the arm races between viruses and rice plants as well as their insect vectors, and the strategies for the prevention and control of rice viral diseases.

Points to consider in seeking biosafety approval for research, testing, and environmental release of experimental genetically modified biocontrol products during research and development

Novel genetically modified biological control products (referred to as “GM biocontrol products”) are being considered to address a range of complex problems in public health, conservation, and agriculture, including preventing the transmission of vector-borne parasitic and viral diseases as well as the spread of invasive plant and animal species. These interventions involve release of genetically modified organisms (GMOs) into the environment, sometimes with intentional dissemination of the modification within the local population of the targeted species, which presents new challenges and opportunities for regulatory review and decision-making. Practices developed for GMOs, primarily applied to date for GM crops may need to be adapted to accommodate different types of organisms, such as insects, and different technologies, such as gene drive. Developers of new GM biocontrol products would benefit from an early understanding of safety data and information that are likely to be required within the regulatory dossier for regulatory evaluation and decision making. Here a generalizable tool drawing from existing GM crop dossier requirements, forms, and relevant experience is proposed to assist researchers and developers organize and plan their research and trialing. This tool requires considering specifics of each investigational product, their intended use, and country specific requirements at various phases of potential product development, from laboratory research through contained field testing and experimental release into the environment. This may also be helpful to risk assessors and regulators in supporting their systematic and rigorous evaluation of new biocontrol products.

A Case Report of Dengue Shock Syndrome Complicated with Multi-Organ Failure and Hepatitis E Virus Superinfection

Dengue fever is a vector borne viral disease. It is more prevalent in Southeast Asia. The main symptoms include myalgia, nausea, vomiting and rash, hence, subsequently lead to dengue hemorrhagic fever and dengue shock syndrome. In the current report, we are presenting a case of a 50-year-old female patient who was presented in hospital with the symptoms of fever, vomiting, abdominal pain, productive cough and sore throat. Her serology came positive for dengue NSP1, and she was shifted to intensive care unit because of her aggravating condition. On day 4, the hepatitis E virus infection also was detected and she died after developing hepatic shock and multi-organ failure. This report states the superinfection of hepatitis E and dengue virus and highlights the significance of its early detection for better clinical management.