Bite Of Infected Aedes Mosquitoes Research Articles

Dengue-Related Hemophagocytic Lymphohistiocytosis in an Adult: A Case Report and Brief Update

AbstractDengue virus is an arbovirus transmitted through the bite of infected Aedes mosquitoes. Many unusual clinical features are being reported in dengue. Dengue complicated with hemophagocytic lymphohistiocytosis (HLH) is a rare but potentially fatal condition. Here, we report an 18-year-old otherwise healthy female with dengue fever complicated with HLH. The diagnosis was made by fulfilling the clinical and laboratory criteria of HLH. She was managed successfully with a methylprednisolone pulse regimen. Our case highlights the importance of early recognition of complications and prompt treatment for a better outcome.

Performance of Fujifilm Dengue NS1 Antigen Rapid Diagnosis Kit Compared to Quantitative Real-Time Polymerase Chain Reaction.

Dengue is a viral infection caused by the dengue virus (DENV), transmitted to humans through the bite of infected Aedes mosquitoes. About half of the world's population is now at risk of dengue, which represents a global public health concern, especially in tropical and subtropical countries. Early detection of the viral infection is crucial to manage the disease; hence, effective rapid diagnostic tests are essential. In this study, we evaluated the performance between the new Fujifilm Dengue non-structural antigen diagnosis kit (FF NS1 kit) and the SD Bioline NS1 antigen test kit (SD NS1 kit) against the quantitative real-time polymerase chain reaction (qRT-PCR) assays. The 140 acute serum samples collected from the Yangon General Hospital and Yangon Children's Hospital, Myanmar, from 2017 to 2019 were characterised by the three assays. With the qRT-PCR as the standard, the FF NS1 kit and the SD NS1 kit exhibited sensitivity of 94.3% and 88.6%, respectively, and specificity of 100% in both kits. Moreover, the positivity rates of the FF NS1 kit and the SD NS1 kit were 97.5% and 95% in primary infection and 90% and 80% in secondary infection, respectively. Our overall results suggest that the FF NS1 kit is reliable and accurate for detecting DENV infection.

Antiviral Activity of Kappaphycus alvarezii Seaweed against ZIKV.

Zika virus (ZIKV) is a flavivirus transmitted through the bites of infected Aedes mosquitoes. These viruses can also be transmitted through sexual contact, vertical transmission, and possibly transfusion. Most cases are asymptomatic, but symptoms can include rash, conjunctivitis, fever, and arthralgia, which are characteristic of other arboviruses. Zika infection can lead to complications such as microcephaly, miscarriage, brain abnormalities, and Guillain-Barré syndrome (GBS). The aim is to determine the inhibitory potential of the algae Kappaphycus alvarezii (K. alvarezii) on ZIKV replication. Cytotoxicity experiments were performed using Vero cells to determine the CC50, and ZIKV replication inhibition assays (ATCC® VR-1839™) were conducted to determine the EC50. The mechanism of action was also studied to assess any synergistic effect with Ribavirin. K. alvarezii demonstrated low toxicity with a CC50 of 423 μg/mL and a potent effect on ZIKV replication with an EC50 of 0.65 μg/mL and a Selectivity Index (SI) of 651, indicating the extract's safety. Virucidal effect assays were carried out to evaluate the possible mechanism of action, and the compound addition time was studied, showing the potential to delay the treatment of infected cells by up to 6 hours. A potential synergistic effect was observed when K. alvarezii extract was combined with suboptimal concentrations of Ribavirin, resulting in 99% inhibition of viral replication. Our data demonstrate the significant potential of K. alvarezii extract and highlight the need for further studies to investigate its mechanism of action. We propose this extract as a potential anti-Zika compound.

Antiviral activity of pimecrolimus against dengue virus type 2 infection in vitro and in vivo

Dengue virus (DENV) infection is a public health concern in several countries and is associated with severe diseases, such as dengue hemorrhagic fever and dengue shock syndrome. DENVs are transmitted to humans via the bites of infected Aedes mosquitoes, and no antiviral therapeutics are currently available. In this work, we aimed to identify antiviral drugs against DENV type 2 (DENV2) infections and selected pimecrolimus as a potential antiviral drug candidate. Pimecrolimus significantly inhibited DENV2-mediated cell death and replication in vitro. We also confirmed a decrease in the number of plaques formed as well as in the envelope protein levels of DENV2. The time-of-addition and course experiments revealed that pimecrolimus inhibited DENV2 infection during the early stages of the virus replication cycle. In an experimental mouse model, orally administered pimecrolimus alleviated body weight loss and lethality caused by DENV2 infection, which we used as readouts of the drug’s antiviral potency. Furthermore, pimecrolimus significantly inhibited the DENV2 load and ameliorated focal necrosis in the liver and spleen. Taken together, our in vitro and in vivo findings suggest that pimecrolimus is a promising antiviral drug candidate for the treatment of DENV2 infection.

Knowledge and practices on dengue prevention among the people of Buddhabhumi Municipality of Nepal: a cross-sectional study

Dengue infection is transmitted to humans through the bite of infected Aedes mosquitoes and about half of the world’s population now in risk of the dengue infection. The objective of the study was to assess the level of knowledge and practices on dengue prevention among the people of Buddhabhumi Municipality of Kapilvastu district of Nepal. A Cross-sectional study was done among randomly selected 181 households. Head of the households were the respondents for face to face interview. Pretested and validated tool was used for data collection. Statistical Package for Social Sciences version 20 used for data analysis. Percentages, frequency, mean the calculated and Chi-square test applied to measure level of association. Overall knowledge about dengue was good among 30.9% and overall 38.1% of the respondents had good dengue prevention practices. Caste/ethnicity and family type of the respondents are the factors associated with overall knowledge on dengue. Caste/ethnicity and educational status of respondents are associated with dengue prevention practices. For success of dengue prevention, programs should be designed to increase level of knowledge and also the translation of knowledge domain into real preventive measures.

Human-Biting Activity, Resting Behavior and Yellow Fever Virus Transmission Potential of Aedes Mosquitoes in Southwest Ethiopia

Yellow fever (YF) is an emerging and re-emerging arboviral disease transmitted through the bites of infected Aedes mosquitoes, primarily in the genus Aedes. Several outbreaks of yellow fever have been documented in southern Ethiopia. Four outbreaks have been documented since 2012, suggesting that southern Ethiopia is prone to YF outbreaks. Understanding the transmission cycle is pivotal to managing arboviral disease outbreaks, and the aims of the present study were to investigate the mosquito species that most likely contributed to the recent YF outbreaks and to study their behaviors. Therefore, the present study aimed to evaluate which species of Aedes mosquitoes contribute to the YF virus transmission, the outbreaks that have occurred and their behaviors (biting and resting) in the region. Two districts were selected on the basis of recent YF outbreak history. A longitudinal entomological survey was conducted to collect adult mosquitoes by using human landing catches (HLC), mechanical mouth aspirators and pyrethrum sprays. Collections were conducted twice a month for six months, from February 2019 to July 2020. The mosquitoes were identified by species by using morphological keys and molecular techniques. A total of 1689 mosquitoes were collected, of which 93.7% (1582/1689) were members of the genus Aedes and 6.3% (107/1689) of the genus Culex. A total of 58.7% (991/1689) of the mosquitoes were captured in the Ofa District and 41.3% (698/1689) from the Boko Dawula District. The largest number of mosquitoes, 97.9% (1653/1689), were collected during the wet season. A total of 1582 members of the Aedes simpsoni complex were collected, where 57.7% (913/1582) were from the Ofa District and 42.3% (669/1582) were from the Boko Dawula District. Molecular identification showed that members of the Aedes simpsoni complex accounted for 99.5% (404/406), while Aedes aegypti, detected only in the Ofa District, accounted for only 0.5% (2/406). The mosquitoes were pooled and tested for YFV, dengue virus (DENV, serotype 1–4) and chikungunya virus (CHKV) by using qPCR. None of the 934 Aedes simpsoni tested were positive for any arboviruses. The human-biting activities of Ae. simpsoni complex were peaked between 8:00–9:00 and 16:00–17:00, mostly outdoors, both within the villages and the forests. The largest numbers of Aedes simpsoni complex resting mosquitoes were collected from the leaves of the Abyssinian banana, Ensete ventricosum, suggesting that they are the preferred resting places. Although the tested Ae. simpsoni complex was negative for arboviruses; the morning and afternoon activities of the species complex coincide with peak human outdoor activities in these areas and may therefore pose the highest risk of transmitting YFV to humans. The extremely low abundance of Aedes aegypti suggests a minor role in arbovirus transmission in southern Ethiopia. It is of great importance that expanded surveillance activities of arboviruses to include reservoir hosts and sylvatic vectors to the chances of devising and implementing effective control measures.

Treatment Dilemma in an Unusual Case of Dengue Fever with Cardiomyopathy and Nephropathy: A Case Report

Dengue is a viral illness in humans caused by the bite of infected Aedes mosquitoes, mostly Aedes aegypti and also Aedes albopictus. There are four serotypes of the Dengue virus that cause infection in humans and may lead to a variety of complications. Myocarditis and cardiomyopathy can occur in several viral and non viral infections, increasing morbidity and mortality. Nephropathy may also arise in dengue fever, causing complications. The case presented here involved both complications, nephropathy and cardiomyopathy, posing treatment challenges in terms of altering fluid and electrolyte status, which hindered fluid therapy as fluid overload would be detrimental. However, the complications were reversible with the normalisation of echocardiography and urea and creatinine levels. Long-term follow-up is necessary to monitor cardiac and renal function, as some patients may progress to Chronic Kidney Disease (CKD). The patient presented with fever, headache, vomiting, and haematuria, along with signs of fluid overload. There was a past history of fever, and since both Immunoglobulin G (IgG) and IgM Dengue antibodies were positive, this may be a case of a second episode of dengue fever causing complications. This case report emphasises the diagnostic and treatment challenges in a dengue patient with cardiomyopathy and nephropathy, where excessive fluid replacement may increase morbidity and mortality. Additionally, long-term follow-up of these patients is necessary.

Cross sectional study on the relationship between serum calcium level and severity of dengue fever

Background: Dengue is the most rapidly spreading mosquito borne disease in the world. An estimated 50 million dengue infections occur annually. It is caused by a small, single stranded RNA virus belonging to the genus Flavivirus, family Flaviviridae and is divided into four serotypes (DEN-1 to DEN-4). These various serotypes are transmitted to humans through the bites of infected Aedes mosquitoes, primarily Aedes aegypti. Materials & Methods: A cross sectional study was conducted on 72 patients with dengue fever, for a period of 12 months in the medicine wards of Government Medical College, Kottayam. All cases fulfilling the inclusion criteria during the study period were included after SRC and IRB approval. Results: Mean age of patients in the present study was 32.6 in dengue fever and 32.1 in severe dengue. There was no significant correlation between age and serum corrected calcium level (Pearson correlation coefficient – 0.074, p value 0.539). In patients with dengue fever, mean hematocrit was 39.2 %, while in those with severe dengue, it was 40.5 %. There was no significant correlation between hematocrit and serum corrected calcium level (Pearson correlation coefficient – 0.147, p value 0.219).

A mathematical analysis of Zika virus transmission with optimal control strategies

This paper presents a mathematical model for transmission dynamics of Zika virus by considering standard incidence type interaction for the human to human transmission. The model involves the transmission through the bite of infected Aedes mosquitoes and human to human sexual transmission. The equilibria of the proposed model are found and the basic reproduction number R0 is computed. If R0 1. The sensitivity analysis is performed to identify the key parameters that affect the basic reproduction number, which can be regulated to control the transmission dynamics of the Zika. Further, this model is extended to the optimal control model and to reveals the optimal control strategies we used the Pontryagin’s Maximum Principle. It has been noticed that the optimal control gives better result than without the optimal control model. Numerical simulation is presented to support our mathematical findings.

A mathematical analysis and simulation for Zika virus model with time fractional derivative

Zika is a flavivirus that is transmitted to humans either through the bites of infected Aedes mosquitoes or through sexual transmission. Zika has been associated with congenital anomalies, like microcephalus. We developed and analyzed the fractional‐order Zika virus model in this paper, considering the vector transmission route with human influence. The model consists of four compartments: susceptible individuals are x1(t), infected individuals are x2(t), x3(t) shows susceptible mosquitos, and x4(t) shows the infected mosquitos. The fractional parameter is used to develop the system of complex nonlinear differential equations by using Caputo and Atangana–Baleanu derivative. The stability analysis as well as qualitative analysis of the fractional‐order model has been made and verify the non‐negative unique solution. Finally, numerical simulations of the model with Caputo and Atangana Baleanu are discussed to present the graphical results for different fractional‐order values as well as for the classical model. A comparison has been made to check the accuracy and effectiveness of the developed technique for our obtained results. This investigative research leads to the latest information sector included in the evolution of the Zika virus with the application of fractional analysis in population dynamics.

Community awareness on dengue and practices of mosquito bite prevention in urban residents of a central Indian city, Sagar, Madhya Pradesh

Background: Dengue is an arboviral, mosquito borne illness caused by bite of infected aedes mosquitoes which breed commonly on household water containers like cooler tank, fridge trays and flower pots. Though dengue is non fatal illness but it may lead to deaths from dengue hemorrhagic fever and dengue shock syndrome. The objective of the study was to assess the community awareness regarding dengue and practices primarily being used as personal protection measures against mosquito bites and abolition of household breeding sites of mosquitoes.Methods: A cross sectional observational study done in 5 randomly selected wards of the municipal corporation Sagar. 400 households were studied, selecting 80 houses from each ward randomly. Pretested structured questionnaire was used for interview with the head of family/adult member of the family. The data collected was analysed using SPSS software and chi square test was applied as test of significance.Results: The households studied were mostly (28.2%) of lower middle class (modified B G Prasad scale). the dengue awareness in the community was fair (44.25%) and satisfactory (46.25) in Likert scale. Awareness regarding household breeding sites of mosquitoes was absolute (100%) but the use of personal protective measures was partial (50%).Conclusions: The knowledge and awareness to stop the mosquito breeding, biting should be enhanced and should be turned into action.

Mathematics of a model for Zika transmission dynamics.

Zika is a flavivirus transmitted to humans through either the bite of infected Aedes mosquitoes or sexual intercourse with infected individuals. In this paper, we present a mathematical model based on these two modes of transmission. Using the next-generation matrix method, a threshold parameter called basic reproduction number is determined. Sensitivity analysis of the basic reproduction number in terms of parameters involved in its formulation is discussed. A dynamically consistent nonstandard finite difference scheme is designed to replicate the properties of the continuous model. Numerical simulations of the nonstandard finite difference scheme that we have constructed show the number of infected humans due to sexual intercourse with Zika virus infectious individuals. The numerical simulations also support the theoretical analysis of the model.

Diagnosis of Zika Virus Infection by Peptide Array and Enzyme-Linked Immunosorbent Assay.

ABSTRACTZika virus (ZIKV) is implicated in fetal stillbirth, microcephaly, intracranial calcifications, and ocular anomalies following vertical transmission from infected mothers. In adults, infection may trigger autoimmune inflammatory polyneuropathy. Transmission most commonly follows the bite of infected Aedes mosquitoes but may also occur through sexual intercourse or receipt of blood products. Definitive diagnosis through detection of viral RNA is possible in serum or plasma within 10 days of disease onset, in whole blood within 3 weeks of onset, and in semen for up to 3 months. Serological diagnosis is nonetheless critical because few patients have access to molecular diagnostics during the acute phase of infection and infection may be associated with only mild or inapparent disease that does not prompt molecular testing. Serological diagnosis is confounded by cross-reactivity of immune sera with other flaviviruses endemic in the areas where ZIKV has recently emerged. Accordingly, we built a high-density microarray comprising nonredundant 12-mer peptides that tile, with one-residue overlap, the proteomes of Zika, dengue, yellow fever, West Nile, Ilheus, Oropouche, and chikungunya viruses. Serological analysis enabled discovery of a ZIKV NS2B 20-residue peptide that had high sensitivity (96.0%) and specificity (95.9%) versus natural infection with or vaccination against dengue, chikungunya, yellow fever, West Nile, tick-borne encephalitis, or Japanese encephalitis virus in a microarray assay and an enzyme-linked immunosorbent assay (ELISA) of early-convalescent-phase sera (2 to 3 weeks after onset of symptomatic infection).

Persistence of Zika virus in semen 93 days after the onset of symptoms

IntroductionZika virus is mainly transmitted through the bites of infected Aedes mosquitoes, although mother-to-child and sexual transmission have also been described. The presence of Zika virus in semen after infection seems to be not uncommon, but the duration of viral persistence has not been well-determined. MethodsMolecular, serological and cell culture methods were used for the diagnosis and follow up of a case of Zika virus infection imported from Venezuela. Serial samples of serum, urine and semen were analyzed to investigate the persistence of the Zika virus. ResultsZika virus was detected in semen samples up to 93 days after the onset of symptoms. ConclusionsOur results confirm the persistence of Zika virus in semen samples for long periods after infection.

A Retrospective Single-center Analysis of 16 Cases of Imported Chikungunya Fever in Japan.

Objective Chikungunya fever (CHIK) is a re-emerging arboviral disease that is transmitted through the bite of infected Aedes mosquitoes. There is limited information regarding the epidemiology and clinical information of imported CHIK in Japan. The objective of this study was to review the epidemiology and clinical information of imported CHIK patients treated at the National Center for Global Health and Medicine (NCGM). Methods We evaluated all patients (n=16) who were diagnosed with imported CHIK and treated at the NCGM between October 1, 2005 and March 31, 2016. Results The primary complaint of 7 patients who presented to the NCGM after 31 days from disease onset was persistent arthritis, and the primary complaints of 9 patients who presented within 30 days after disease onset were a fever, headache, arthralgia, and rash. Eleven patients experienced a rash during the first week of illness. The median duration of the arthralgia was 75 days, and the joint pain lasted for >2 months in 8 patients and >6 months in 3 patients. Persistent arthralgia was not significantly associated with an age of >35 years (p=0.13) or patient sex (p=0.69). All 16 patients exhibited positive results for CHIK IgM, although only 4 exhibited positive real-time polymerase chain reaction results. Conclusion Physicians should consider CHIK in patients with a fever who have returned from areas where CHIK is endemic.

TRAVEL ASSOCIATED CASES OF CHIKUNGUNYA FEVER (CHIKF) IN ISLAMABAD DECEMBER, 2016

Due to significant climate changes in Pakistan and other Asian countries, the rising temperature has supported outbreak of many Arboviral illnesses. Cases of Chikungunya, an arboviral disease, started to surface in the second week of November, 2016. Karachi being the largest city of Pakistan, a large number of people travel from Karachi to other areas of Pakistan every day. Two cases travelled from Karachi to Islamabad and developed flu like illness with high grade fever and body aches. Both cases were hospitalized and investigated for conclusive diagnosis. Investigations revealed that both cases were positive for Chikungunya fever. These were first travel associated cases in Islamabad, originated from Karachi. After identification of these cases, necessary preventive & control measures were taken by local health authorities to contain the spread of disease. Dengue and Chikungunya transmitted through the bites of infected Aedes mosquitoes (Aedes aegypti and Aedes albopictus) and there is an urgent need to take appropriate measures in all dengue endemic areas because there is a potential risk of massive Chikungunya outbreaks in areas where the vector is populated.

La Crosse Virus Vectors Are Host-Seeking and Ovipositing After 1700 H in Eastern Tennessee.

La Crosse virus (LACV) is transmitted via the bites of infected Aedes mosquitoes (Ae. triseriatus, Ae. albopictus, and Ae. japonicus) and causes La Crosse encephalitis, which is the most commonly diagnosed arbovirus in eastern Tennessee children. This study identified host-seeking and oviposition activity of LACV vectors over a diel period, as it relates to traditional working hours. Nineteen sites in Knox County, TN, were monitored with host-seeking (Centers for Disease Control and Prevention [CDC] miniature light traps) and oviposition traps (CDC gravid traps) during 2 diel periods (0900-1700 h and 1700-900 h). We collected 2,444 adult mosquitoes, comprising 19 different species of which 1,337 (54.7%) were LACV vectors: Ae. albopictus (1,207 specimens), Ae. triseriatus (85 specimens), and Ae. japonicus (45 specimens). These species were active throughout the sampling period, but significantly more were collected from 1700-0900 h. The CDC gravid trap was the most effective method for monitoring Ae. japonicus; there were no trap effects or trap × time interactive effects for Ae. albopictus or Ae. triseriatus. Overall, significantly more LACV vectors were collected from 1700-0900 h compared to 0900-1700 h. Information gathered in this study improves vector surveillance, helps communities control mosquito populations, and minimizes nontarget effects.

Mathematical model of Zika virus with vertical transmission.

Zika is a flavivirus transmitted to humans through either the bites of infected Aedes mosquitoes or sexual transmission. Zika has been linked to congenital anomalies such as microcephaly. In this paper, we analyze a new system of ordinary differential equations which incorporates human vertical transmission of Zika virus, the birth of babies with microcephaly and asymptomatically infected individuals. The Zika model is locally and globally asymptotically stable when the basic reproduction number is less than unity. Our model shows that asymptomatic individuals amplify the disease burden in the community, and the most important parameters for ZIKV spread are the death rate of mosquitoes, the mosquito biting rate, the mosquito recruitment rate, and the transmission per contact to mosquitoes and to adult humans. Scenario exploration indicates that personal-protection is a more effective control strategy than mosquito-reduction strategy. It also shows that delaying conception reduces the number of microcephaly cases, although this does little to prevent Zika transmission in the broader community. However, by coupling aggressive vector control and personal protection use, it is possible to reduce both microcephaly and Zika transmission. 2000 Mathematics Subject Classifications: 92B05, 93A30, 93C15.

A large-scale stochastic spatiotemporal model for Aedes albopictus-borne chikungunya epidemiology.

Chikungunya is a viral disease transmitted to humans primarily via the bites of infected Aedes mosquitoes. The virus caused a major epidemic in the Indian Ocean in 2004, affecting millions of inhabitants, while cases have also been observed in Europe since 2007. We developed a stochastic spatiotemporal model of Aedes albopictus-borne chikungunya transmission based on our recently developed environmentally-driven vector population dynamics model. We designed an integrated modelling framework incorporating large-scale gridded climate datasets to investigate disease outbreaks on Reunion Island and in Italy. We performed Bayesian parameter inference on the surveillance data, and investigated the validity and applicability of the underlying biological assumptions. The model successfully represents the outbreak and measures of containment in Italy, suggesting wider applicability in Europe. In its current configuration, the model implies two different viral strains, thus two different outbreaks, for the two-stage Reunion Island epidemic. Characterisation of the posterior distributions indicates a possible relationship between the second larger outbreak on Reunion Island and the Italian outbreak. The model suggests that vector control measures, with different modes of operation, are most effective when applied in combination: adult vector intervention has a high impact but is short-lived, larval intervention has a low impact but is long-lasting, and quarantining infected territories, if applied strictly, is effective in preventing large epidemics. We present a novel approach in analysing chikungunya outbreaks globally using a single environmentally-driven mathematical model. Our study represents a significant step towards developing a globally applicable Ae. albopictus-borne chikungunya transmission model, and introduces a guideline for extending such models to other vector-borne diseases.

An Outbreak of Dengue in Patna, Bihar: A study of 60 cases and review of literature

Background : Dengue virus belongs to family Flaviviridae , having four serotypes that spread by the bite of infected Aedes mosquitoes. Materials and methods : Dengue positive cases from June to December of two constitutive years, 2015-2016 were obtained, total number of cases were 60. Result: Male and female were 36(60%) and 24(40%) respectively. It denotes almost all cases were primary dengue infection. They were negative for IgM and IgG. Out of total cases 28(46.6%) patients had initial presentation with thrombocytopenia, below 150,000/ul, minimum 20,000/. In first weak leucopenia with relative lymphocytosis, neutropenia, raised ALT and AST are important laboratory findings. From first weak onwards, petechial rashes due thrombocytopenia and erythematous skin patches due to increased vascular permeability are important features. The erythematous patches due to vasculopathy give a hot touch feeling. Rapid ELISA for NS1, IgM, and IgG could be false negative in 10% cases. For those dengue suspected cases ELISA, hemagglutination or PCR based investigations are warranted for diagnosis. Conclusion: The study results are relevant in the characterization of biological markers in the evolution of the disease and can be used as markers for the most severe forms thereby enabling health professionals in taking early help with the adaption of therapeutic conduct for specific patients. It could be useful for making policy regarding control and prevention of dengue fever in state like Bihar where such type study is not till now published.