Primary Dengue Research Articles

Multiple insecticide resistance mechanisms in primary dengue vector, Aedes aegypti (Linn.) from dengue endemic districts of sub-Himalayan West Bengal, India.

BackgroundMosquitoes belonging to genus Aedes are the prime vectors of several arboviral diseases such as Dengue, Zika and Chikungunya worldwide. Every year numerous cases of dengue infections occur throughout the world, proper control of which depends on efficient vector control. However the onset of insecticide resistance has resulted in failure of vector control approaches.Principal findingsThis study was carried out to unveil the degree of prevailing insecticide resistance along with its underlying mechanisms among the primary dengue vector in dengue endemic districts of West Bengal, India through standard WHO protocol. It was observed that, the majority of the tested populations were found to possess resistance to more than one insecticide. In adult bioassay, the toxicity levels of the six tested insecticides was found to decrease in the following order: deltamethrin > lambdacyhalothrin > malathion > propoxur > permethrin > DDT. In larval bioassay, one of the tested populations was found to possess moderate resistance against temephos, mortality percentage 92.5% and 79.8% for WHO (0.0200 ppm) and National Vector Borne disease Programme, India recommended dose (0.0125 ppm) respectively. Carboxylesterases were found to be involved in conferring resistance as revealed in synergistic and quantitative assay against temephos in North Dinajpur (NDP) population and malathion in Alipurduar (APD) and Darjeeling (DAR) populations. Similar correlations were also observed in the majority of the tested populations between reduced susceptibilities against pyrethroid insecticides and Cytochrome P450s activity.ConclusionEfficient disease management in this region can only be achieved through proper integrated vector management along with tools to minimize insecticide resistance. This study may help the concerned authorities in the formulation of an effective vector control strategy throughout this region incorporating the knowledge gained through this study.

Correlaton of Primary Dengue Viral Infection With Body Mass Index (BMI)

The objective of this study is to assess the correlation of body mass index (BMI) with primary dengue viral infection in urban and rural population of district Rawalpindi. Descriptive Cross Sectional Comparative Study. Microbiology Department, Benazir Bhutto Hospital, Affiliated with Rawalpindi Medical College (RMC), Rawalpindi. It was carried out from 1st March 2010 to 30th September 2011. A Stratified random sampling was adopted for 240 (N) subjects residents of urban and rural areas of District Rawalpindi. Urban residents were 144(n) while rural ones were 96(n). The height in meter square and weight in kilogram (kg) were the parameters used to calculate BMI. A 3ml venous blood sample was drawn from each participant for the detection of IgG antibodies against dengue virus by 3rd generation ELISA (Enzyme linked Immunosorbant Assay). The prevalence of primary Dengue viral infection (DVI) for urban residents according to the current study is 34.7% (n=50 out of the total 144 subjects). While 19.7% prevalence of primary DVI (n=19 out of the total 96 subjects) was noted for the residents of Rural strata. The correlation of primary DVI with five categories of BMI amongst urban and rural residents is evaluated by applying chi square test. The p-Value was not found to be significant for any of the five categories of BMI either an urban or rural resident. There is no significant association of primary dengue viral infection with BMI of an individual.

Assessment of insecticide resistance in primary dengue vector, Aedes aegypti (Linn.) from Northern Districts of West Bengal, India

Aedes mosquitoes are the major vectors transmitting several arboviral diseases such as dengue, zika and chikungunya worldwide. Northern districts of West Bengal is home to several epidemics vectored by mosquito including dengue infections, proper control of which depends on efficient vector control. However the onset of insecticide resistance has resulted in failure of vector control approaches. This study was carried out to unveil the level of insecticide resistance prevailing among the primary dengue vector in this dengue endemic region of India. It was observed that, field caught populations of Ae. aegypti were moderately to severely resistant to majority of the insecticide classes tested, i.e. Organochlorine (DDT), Organophosphates (temephos, malathion), Synthetic Pyrethroids (deltamethrin, lambdacyhalothrin and permethrin) and carbamate (propoxur). In majority of the populations, metabolic detoxification seemed to play the underlying role behind the development of insecticide resistance. This study seems to be the first report revealing the pattern of insecticide resistance in Ae. aegypti from Northern West Bengal. Efficient disease management in this region can only be achieved through proper insecticide resistance management. This study may help the concerned authorities in the formulation of an effective vector control strategy throughout this region incorporating the knowledge gained through this study.

Diagnostic performance of commercial IgM and IgG enzyme-linked immunoassays (ELISAs) for diagnosis of Zika virus infection

BackgroundSerologic detection of Zika virus (ZIKV) infections is challenging because of antigenic similarities among flaviviruses.ObjectiveTo evaluate the sensitivity and specificity of commercial ZIKV IgM and IgG enzyme-linked immunoassay (ELISA) kits.MethodsWe used sera from febrile patients with RT-PCR-confirmed ZIKV infection to determine sensitivity and sera from RT-PCR-confirmed dengue cases and blood donors, both of which were collected before ZIKV epidemics in Brazil (2009–2011 and 2013, respectively) to determine specificity.ResultsThe ZIKV IgM-ELISA positivity among RT-PCR ZIKV confirmed cases was 0.0% (0/14) and 12.5% (1/8) for acute- and convalescent-phase sera, respectively, while its specificity was 100.0% (58/58) and 98.3% (58/59) for acute- and convalescent-phase sera of dengue patients, and 100.0% (23/23) for blood donors. The ZIKV IgG-ELISA sensitivity was 100.0% (6/6) on convalescent-phase sera from RT-PCR confirmed ZIKV patients, while its specificity was 27.3% (15/55) on convalescent-phase sera from dengue patients and 45.0% (9/20) on blood donors’ sera. The ZIKV IgG-ELISA specificity among dengue confirmed cases was much greater among patients with primary dengue (92.3%; 12/13), compared to secondary dengue (7.1%; 3/42).ConclusionsIn a setting of endemic dengue transmission, the ZIKV IgM-ELISA had high specificity, but poor sensitivity. In contrast, the ZIKV IgG-ELISA showed low specificity, particularly for patients previously exposed to dengue infections. This suggests that this ZIKV IgM-ELISA is not useful in confirming a diagnosis of ZIKV infection in suspected patients, whereas the IgG-ELISA is more suitable for ZIKV diagnosis among travelers, who reside in areas free of flavivirus transmission, rather than for serosurveys in dengue-endemic areas.

FCγII (CD32) MONOSIT DI INFEKSI DENGUE PRIMER DAN SEKUNDER {FcγRII (CD32) Monocytes in Primary and Secondary Dengue Infection}

Dengue infection is a major health problem in the world, including Indonesia. Clinical manifestations of dengue infection varywidely, from asymptomatic until dengue shock syndrome (DSS). Antibody Dependent Enhancement (ADE) hypothesis that states thatnon-neutralizing antibodies in secondary dengue infection may enhance dengue infection via Fcγ receptors is still controversial. Clinicalresearch shows that not all secondary infections manifest as DHF/DSS, but nearly all DHF/DSS cases are caused by secondary infection.Allegedly, the expression of Fcγ has an effect on this incident. This study is an observational analytical study with a cross sectional designto determine the expression of FcγRII (CD32) monocytes in patients with primary and secondary dengue infection. CD32 of monocyteswas measured using FACS Calibur with lyse no wash technique. Primary and secondary dengue infection were determined by IgM/IgGoptical density ratio using ELISA capture method. The ratio of IgM/IgG ≥1.2 was considered as primary infection, while the ratio <1.2was considered as secondary infection. Twenty primary and 32 secondary dengue infection patients in acute phase of dengue infectionpartisipated in this study. Expressions of Fcγ RII (CD32) monocytes were significantly lower in primary than secondary dengue infection(187.825±31.584 vs 218.598±43.414 MFI; p=0.008). CD32 expressions were higher in day 3 compared to day 4 of fever.

SD DENGUE DUO® (NS1, IgG, IgM) RAPID TEST DALAM MENUNJANG DIAGNOSIS INFEKSI VIRUS DENGUE

Dengue virus infection can cause dengue hemorrhagic fever (DHF) which is still a major health problem in Indonesia. Thediagnosis of DHF is established based on WHO criteria and IgM/IgG antidengue serologic markers. A rapid method is needed for thedetecting or screening the disease. Antigen detection (NS1) can be performed by immunochromatography (rapid test) or enzyme -linkedimmunosorbent assay (ELISA). Recently, a rapid test to detect NS1 as an antigen and IgM/IgG antidengue to differentiate primary andsecondary dengue virus infection is available in one cassette. This study evaluated the new commercial dengue rapid test, SD DengueDuo for the detection of both antigen and antibodies to dengue virus. Serum samples used in this study were collected from 33 denguevirus infection patients according to WHO criteria and admitted in the Tropical Ward, Dr. Soetomo Hospital. Samples were taken twice,during acute and convalescent phase. SD Dengue Duo (NS1, IgG, IgM) rapid test was used and confirmed by ELISA as the gold standard.To determine the diagnostic specificity 20 samples of non dengue virus infection (typhoid fever and malaria) confirmed by laboratorytests were used. In the acute phase, SD Dengue Duo (NS1, IgG, IgM) rapid test showed IgG sensitivity 94.7% (18/19), specificity 92.9%(13/14), IgM sensitivity 85% (17/20), specificity 100% (13/13), NS1 sensitivity 50% (10/20), specificity 100% (13/13). In theconvalescent phase, SD Dengue Duo (NS1, IgG, IgM) rapid test showed antidengue IgG sensitivity 96.3% (26/27), specificity 66.7%(4/6), IgM sensitivity 95% (22/23), specificity 80% (8/10), NS1 sensitivity 42.9% (3/7), specificity 100% (26/26). To establish thediagnosis of dengue virus infection, not only NS1, but also antidengue IgM/IgG is needed. SD Dengue Duo containing dengue NS1 antigencombined with IgG/IgM test in one cassette is a rapid, practical and has a high validity diagnostic result.

PENINGKATAN AMINOTRANSFERASE SEBAGAI PENANDA CEDERA HATI PADA PENDERITA DEMAM DENGUE

Dengue infection can give unusual manifestation such as acute liver failure. The increased frequency of this complication in dengueinfection have been reported and have a high mortality. Elevated serum transaminase levels of dengue patients indicate the possibleimpact of dengue virus infection on liver function. The aim of this study was to know the frequency of the increased of aminotransferasein patient with dengue fever. An analysis was made of 67 serologically confirmed dengue cases at Hasan Sadikin Hospital. Thegrade of hepatic aggression was establish according to the alteration in the aminotransferase levels: grade A, have a normal levelsof aminotransferase, grade B have elevated aminotransferase, with increased levels of at least one of the enzymes, grade C elevatedaminotransferase, with the level of at least one of the enzymes increased more than three times the reference value. Among the 67serologically confirmed dengue cases, 7% (n = 5) have a primary dengue infection, 49% (n = 33) have secondary dengue infection,43.3% (n = 29) have a mix infection (secondary and primary infection). 88% (n = 59) have elevated levels of serum aspartataminotransferase (AST) and 68% (n = 46) have elevated level of serum ALT. 67.2% (n = 45) have elevated both AST and ALT. 1.7%(n = 1) presented a normal level of amiotransferase (grade A), 31.3% (n = 21) presented alterations in the aminotransferase (gradeB), 56% (n = 38 ) have elevated aminotransferase more than three times the reference value (grade C). As a conclusion, liver damagewith elevation of aminotransferase was common complication of dengue virus infection.

Enterobacter cloacae co-infection in a child with primary dengue fever

Enterobacter cloacae co-infection in a child with primary dengue fever

Langmuir-Blodgett Nanoassemblies of the MoS2-Au Composite at the Air-Water Interface for Dengue Detection.

We report Langmuir-Blodgett (LB) films of molybdenum disulphide (MoS2) and gold nanoparticles (AuNP) composite being utilized as a biosensing platform for dengue detection. The LB films of the MoS2-AuNP composite have been transferred from the air-water interface to the indium tin oxide-coated glass substrate under optimized conditions. Further, antibodies specific to dengue NS1 antigen were immobilized onto these LB films. The fabricated immunosensor has been explored for NS1 antigen detection in standard samples as well as in spiked sera samples using electrochemical impedance spectroscopy. The NS1 antigen is present in the blood of infected persons from day one of the onset of clinical symptoms in primary dengue infection. The limit of detection for the standard and the spiked samples is found to be 1.67 and 1.19 ng mL-1, respectively, which is suitable for clinical applications, as NS1 antigen levels in patient's sera range from 0.04 to 2 μg mL-1 in primary infection and from 0.01 to 2 μg mL-1 in secondary infection.

Role of NS1 Antigen in the Diagnosis of Dengue Viral Infection

Background: Dengue is widely distributed in subtropical and tropical areas of the world; it affects all agegroups and is classified as a major global health threat by the World Health Organization. Detection of dengue virus-specific antibodies is commonly used for routine diagnosis. Methodology: 81 consecutive serum samples were tested for dengue NS1 antigen in addition to dengue IgM and IgG antibodies and the results were analyzed with other parameters. Results: Out of 81 samples tested for both antigen and antibody, 53 were positive for dengue infection. NS1 antigen was detected in 12 patients. In five of these cases, neither IgM nor IgG was detected. Discussion: Viral isolation and RT-PCR are time consuming and expensive. Therefore, their use in routine labs is not feasible. In our study, there were more number of secondary dengue infections than primary dengue cases. Among the 13 cases of primary dengue infection, NS1 antigen was the only marker detected in five cases. Conclusion: Dengue NS1 Ag detection test is highly appropriate for field-testing conditions, particularly for early acute-phase samples, as its sensitivity and specificity far exceeds those of the MAC-ELISA for such samples

English

For several decades, applications of organophosphates and pyrethroids insecticides have been extensively used to control Aedes aegypti as the primary dengue vector. Hence it is important to study dengue vector resistance status and its mechanisms in relation to long term use of insecticides. This study aimed to determine the resistance status and to characterize mechanisms of Ae. aegypti to organophosphates and pyrethroids using biological, biochemical and molecular assays. Larvae and puppae of Ae. aegypti were collected in the field of Plosokuning, Minomartani, Sleman, Yogyakarta, Indonesia. The biological assay was carried out using CDC Bottle Bioassay to test the resistant status to malation and cypermetrin. The biochemical assay was conducted using microplate assay with substrate α-naphthyl acetate to test the presence of esterase elevated activity, and the molecular assay was done using PCR with AaSCF7 and AaSCR7 primer to detect of point mutation at 1534 site, that located in the area of segment 6 of domain III. The biological assay showed Ae. aegypti suggests the possibility of resistance to malathion (mortality 82%) that needs to be confirmed further and already resistant to cypermetrin (mortality 76%). The biochemical assay of Ae. aegypti showed the presence of non-specific esterase elevated activity. The PCR method showed specific DNA bands were formed with the size of 748bp, and with sequencing showed there has been F1354C point mutation of voltage gated sodium chanel gene in the area of segment 6 of domain III. Long term use of insecticides did not successfully eliminate the targeted dengue vector, because Ae. aegypti mosquitoes were resistant to both insecticides. The results demonstrate the importance of designing better health policies regarding insecticide usage

Serum Cytokine Profiles in Patients with Dengue Fever at the Acute Infection Phase.

Background Dengue virus (DENV) is transmitted by mosquito and has been circulating in Guangdong, China, for over 30 years. Dengue infection causes mild to severe disease symptoms in human. Cytokine profiles were suggested to be crucial especially during the acute stage in the dengue infection. Aim To determine the cytokine profiles at the acute stage in patients with primary or secondary dengue infection in Guangzhou city in the 2014 outbreak. Methods We investigated 23 inflammatory cytokines in serum collected from dengue-infected patients and analyzed their correlations with their clinical indexes. Results The concentrations of CXCL9, IP-10, CXCL11, IL-8, IL-10, and CCL2 in serum were significantly higher in the groups of DENV-infected patients during the first two weeks than those of control group while CCL17 and CXCL5 showed lower expression level in the patients. Among these cytokines, CXCL9, CCL17, and CXCL5 showed statistical difference between the groups of primary and secondary infections. The platelet count and lactate dehydrogenase were correlated with the level of CCL17 and MIP-1α/CXCL5, respectively, in the group of secondary infection. Conclusions We determined the cytokine profiles in serum of the patients during the 2014 dengue outbreak. The expression of specific cytokines was associated with the secondary infection.

Seroprevalence of Dengue from a Tertiary Care Hospital in South India

Dengue is a mosquito borne viral fever transmitted by Aedes aegypti and albopictus mosquito. The globally estimated burden of symptomatic cases ranges to 96 million and 58.4 million cases/year). The estimated mortality amounts 2.5% and the endemicity is spread around 128 countries of the world. The aim of our study is to identify the prevalence of dengue to the patients reporting to our tertiary care hospital in Puducherry. A prospective crosssectional study was conducted at our tertiary care hospital in Puducherry. The study was conducted over a period of 4 years from January 2013 to December 2016. The serum samples were tested by Rapid immunochromatography test. Around 272 (12.3%) cases of both primary and secondary dengue were identified. The age wise distribution of cases showed more cases in 21 to 30 age group (38.6%). The seasonal distribution shows more cases were present from September to January. There was a gradual increase in the positive cases from 2013 onwards with a peak during 2016. Being a persistent viral infection a proper vector control measure, concomitant monitoring on the Seroprevalence of dengue among the population is needed.

Several Dengue: About 2 Cases with Pulmonary Disease

The most widespread arbovirus in the world, dengue fever has been rampant since the 18th century. Since then, several epidemics have been documented in Asia, the Caribbean, South America and Africa. The authors report two cases of dengue fever in children aged six (6) and twelve (12) years respectively. The diagnosis of several dengue pulmonary was retained in these children, clinico-radiological and biological arguments. In addition to the hemorrhagic syndrome, the pulmonary symptomatology associated cough, dyspnea. Chest X-ray revealed bilateral and extensive alveolar interstitial radiological lesions. From a biological point of view, the positivity of dengue-specific IgM has confirmed arboviruses. From the diagnostic peculiarities of the cases observed, the authors suggest the search for factors associated with a primary dengue infection from several onsets to pulmonary manifestation in children. Indeed, this fringe of the population is no longer concerned with acute respiratory infections. In addition, the socio-cultural context of poverty, of pre-hospital therapeutic itinerary favoring traditional medicine, delays hospital care.

Profile of serum transaminases in patients with dengue infection in a tertiary care hospital

Background: Although dengue virus is a non hepatotropic virus, liver injury due to dengue infection is not uncommon. Atypical manifestations with liver involvement have frequently been reported, ranging from mild elevations of aminotransferase levels to fulminant hepatitis. The aim of the present study is to study the serum transaminases level in various forms of dengue infection and correlate with severity.Methods: An analysis of 151 serologically confirmed cases (0-14 yrs) of dengue from June 2017 to July 2017 at a tertiary care hospital, Dharwad was made to assess the frequency and degree of hepatic dysfunction in children with dengue infection by analyzing serum transaminase levels. Patients were classified according to WHO as dengue without warning signs, with warning signs and severe dengue. Patients were divided into primary and secondary dengue based on serology and serum transaminases levels were assessed in each of the above groups. Patients with normal aminotransferase levels were categorized into Grade A, those with atleast one of the enzymes raised to less than 3 times the reference range as Grade B, those with atleast one of the enzymes elevated more than 3 times but less than 10 times as Grade C and those with elevations more than 10 times as Grade D. χ2 test was applied to check statistical significance.Results: During the study period, the total number of serologically confirmed cases of dengue were 151 among which dengue fever without warning signs were 38, with warning signs were 91 and severe dengue were 22. Serum transaminase levels were significantly raised in severe dengue (χ2=14.228, df=6, p=0.027).It was also found that transaminases were significantly higher in secondary dengue infection than primary dengue ( χ2=10.155, df=3, p=0.017). Transaminases were significantly elevated in non-survivors (χ2=16.958, df=3, p<0.001).Conclusions: Hepatic dysfunction was common in all forms of dengue infection, with AST rising significantly more than ALT. Transaminases were significantly elevated in severe dengue and secondary dengue infections. Patients with significantly high transaminases had a poor outcome.

It is Time for Action: Consuming Evidence: Critical Appraisal: Part II

Dengue is a major public health problem in tropical regions around the world. Viral and immune host factors determine the clinical courses of the infection. We analyzed the dynamics of viremia (by real-time polymerase chain reactions), antigenemia (through detection of the viral non-structural protein [NS]-1 by enzyme-linked immunosorbent assays) and the frequency of virus-infected peripheral blood mononuclear cells (PBMCs) (by multiparametric flow cytometry) in children with primary or secondary dengue virus (DENV) infection in mild to severe cases. Additionally, we evaluated the association of these factors with clinical severity and laboratory parameters. The levels of viremia and antigenemia peaked during the early days of illness and these viral parameters were correlated (rho = 0.37, P = 0.003). Circulating monocytes were the most naturally infected subset within the PBMCs population, with kinetics similar to those of viremia and antigenemia. The levels of viremia and antigenemia were higher in children with primary infections than in those with secondary infections (P ≤ 0.04). Although there were no associations between the three evaluated factors and clinical severity, the levels of plasma NS1 and the frequency of dengue virus-infected monocytes correlated with prolonged coagulation times. In short, the viremia, antigenemia and infected monocytes were detected early and were not related to clinical severity. The magnitude of antigenemia and infected circulating monocytes was associated with coagulation disorders.

TLR2/MyD88 pathway-dependent regulation of dendritic cells by dengue virus promotes antibody-dependent enhancement via Th2-biased immunity.

Possible risk mediators in primary dengue virus (DenV) infection that favor secondary DenV infection to life-threatening dengue hemorrhagic fever (DHF) and shock syndrome (DSS) via antibody-dependent enhancement (ADE) have not yet been described. Here, DenV infection enhanced the expression of inflammatory mediators and activation molecules in dendritic cells (DCs) through TLR2/MyD88 pathway. TLR2 appeared to facilitate DenV infection in DCs that were less permissive than macrophages for viral replication. In experiments using separate evaluations of DenV-infected and uninfected bystander DCs, infected DCs showed impaired maturation accompanied with TLR2-dependent production of inflammatory cytokines, by which uninfected bystander DCs showed increased expression of co-stimulatory molecules. Differential phosphorylation of MAPK and STAT3 was also detected between DenV-infected and uninfected DCs. Furthermore, DenV infection stimulated Th2-polarized humoral and cellular immunity against foreign and DenV Ag via TLR2/MyD88 pathway, and DenV-infected DCs were revealed to facilitate Th2-biased immune responses in TLR2-dependent manner. TLR2/MyD88-mediated Th2-biased Ab responses to primary DenV infection increased the infectivity of secondary homotypic or heterotypic DenV via ADE. Collectively, these results indicate that TLR2/MyD88 pathway in DC-priming receptors can drive Th2-biased immune responses during primary DenV infection, which could favor secondary DenV infection to DHF/DSS via ADE.

Outcomes of lupus and rheumatoid arthritis patients with primary dengue infection: A seven-year report from Brazil.

We described the clinical profile and outcomes of patients with SLE and RA diseases reported to the Brazilian Health Information System with primary dengue infection. Databases from the Brazilian Public Health Informatics System (SUS) were linked as the source of information. Three databases comprising different longitudinal information of lupus or rheumatoid arthritis (RA) patients under treatment and care through the Brazilian Health System were linked. Patients who had lupus ICD-9 code or RA ICD-9 code and their treatment approved by SUS were included in the study. In Study 1, we described the clinical characteristics of RA/lupus patients who had dengue infection. In Study 2, we compared RA/lupus patients with or without dengue for hospitalization rates after index dengue diagnosis for dengue-exposed or matching date for dengue-unexposed. We included 69 SLE and 301 RA patients with dengue. In the RA/lupus with dengue case series, hospitalization was found in 24.6% of lupus subjects and of 11.2% of RA subjects. It differed by geographic region (p = 0.03), gender (p = 0.05) and the use of azathioprine (p = 0.02). Dengue was the most frequent reason for hospitalization reported (43.0%). Hospitalization due to dengue was noted in 12 (42.9%) dengue-exposed patients (p = 0.02), while rheumatoid arthritis was reported as the cause of hospitalization in 22.2% of dengue-unexposed (p = 0.005). Five deaths were reported among the dengue-exposed and none among dengue-unexposed. Bacterial infection was the most frequent cause of death. We found that the dengue exposure was associated with an increased risk of hospitalization outcome in RA and lupus patients (RR = 6.2; 95% CI: 2.99-12.94). We found that when comparing RA/lupus patients with or without dengue, dengue-exposed patients had an increased rates of hospitalization and death.

Wolbachia and dengue virus infection in the mosquito Aedes fluviatilis (Diptera: Culicidae)

Dengue represents a serious threat to human health, with billions of people living at risk of the disease. Wolbachia pipientis is a bacterial endosymbiont common to many insect species. Wolbachia transinfections in mosquito disease vectors have great value for disease control given the bacterium’s ability to spread into wild mosquito populations, and to interfere with infections of pathogens, such as dengue virus. Aedes fluviatilis is a mosquito with a widespread distribution in Latin America, but its status as a dengue vector has not been clarified. Ae. fluviatilis is also naturally infected by the wFlu Wolbachia strain, which has been demonstrated to enhance infection with the avian malarial parasite Plasmodium gallinaceum. We performed experimental infections of Ae. fluviatilis with DENV-2 and DENV-3 isolates from Brazil via injection or oral feeding to provide insight into its competence for the virus. We also examined the effect of the native Wolbachia infection on the virus using a mosquito line where the wFlu infection had been cleared by antibiotic treatment. Through RT-qPCR, we observed that Ae. fluviatilis could become infected with both viruses via either method of infection, although at a lower rate than Aedes aegypti, the primary dengue vector. We then detected DENV-2 and DENV-3 in the saliva of injected mosquitoes, and observed that injection of DENV-3-infected saliva produced subsequent infections in naïve Ae. aegypti. However, across our data we observed no difference in prevalence of infection and viral load between Wolbachia-infected and -uninfected mosquitoes, suggesting that there is no effect of wFlu on dengue virus. Our results highlight that Ae. fluviatilis could potentially serve as a dengue vector under the right circumstances, although further testing is required to determine if this occurs in the field.

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.