Anti-dengue IgM Antibodies Research Articles

IgG, IgM, and Nonstructural Protein 1 Response Profiles after Receipt of Tetravalent Dengue Vaccine TAK-003 in a Phase 2 Randomized Controlled Trial.

The profiles of vaccine-induced dengue antibodies may differ from those produced following natural infection and could potentially interfere with the interpretation of diagnostic tests. We assessed anti-dengue IgG and IgM antibodies, and nonstructural protein 1 antigen profiles in the serum of adults who received a single dose of the tetravalent dengue vaccine TAK-003 as either an initially developed high-dose formulation or the standard approved formulation in a phase 2 study in Singapore (#NCT02425098). Immunoglobulin G and IgM profiles during the first 30 days postvaccination varied by baseline serostatus (microneutralization assay). Nonstructural protein 1 antigen was not detected in the serum of any participants. Vaccine-induced IgG and IgM antibodies can affect serological confirmation of subsequent dengue infection in vaccinees. These results highlight the limitations of using serological tests for dengue diagnosis, particularly in a postvaccination setting, and emphasize the need for more sensitive antigen- and molecular-based testing for accurate dengue diagnosis.

Significance of Serological Markers in Diagnosis of Acute Dengue Infection: 2021 Outbreak

Objective: To highlight the significance of Dengue anti-IgM and Dengue NS1 antigen in diagnosing Acute Dengue infection. Study Design: Cross-sectional study. Place and Duration of Study: Virology Department, Armed Forces Institute of Pathology, Rawalpindi Pakistan, from Sep to Nov 2021. Methodology: One hundred and fifty Dengue NS1-positive patients of either gender with age≥5 years were included. ELISA tested patients for detection of Dengue anti-IgM antibody. A questionnaire was used to collect demographic and personal data of each patient. Results: Out of 150 dengue NS1 positive samples, 26(17%) were positive for dengue anti-IgM. In collected samples, Dengue serological markers (NS1 and anti-IgM) positivity was observed based on ‘the day of onset of symptoms. On days 1 and 2, 54 and 44 NS1 positive samples were collected, respectively, but no one was found positive for anti-IgM. Anti-IgM was detected on day-3 and onwards. 27% Dengue anti-IgM positivity was found on day-3, which increased gradually as the time of infection increased. On day four, it was 53%; on day 5, it was 55%; on day-6, it was 60%; on day 7, it was 75%; and on day 8, it was 100%. Conclusions: The findings of present study suggested that anti-Dengue IgM antibodies are less significant than the Dengue NS1 antigen in diagnosing acute dengue infection.

Hematological and Biochemical Profiles of Patients with Dengue Virus Infection in Lalitpur, Nepal

Dengue viral infection is a disease transmitted by mosquitoes of the Aedes genus, and it arises as a result of being bitten by mosquitoes that are carrying the virus. This infection induces a wide range of changes in the body’s immune system. Thus serological evaluation together with hematological and biochemical parameters in cases of dengue viral infection make an accurate clinical diagnosis. The main objective of this study was to study the serological, hematological, and biochemical parameters among patients infected with Dengue virus. A total of 102 blood samples were collected at Asrik Diagnostic Lab, Lalitpur during the period of August to October 2022. Samples were analyzed by following methods: hematological tests were done by coulter counter, Biochemical tests were done by fully automated analyzer and serological tests were done by ELISA. Of the 102 blood samples NS1 antigen was detected in 62 (60.9%) whereas anti-dengue IgM antibody was detected in 10 (9.8%). Leukopenia and thrombocytopenia were present in 33 (53.1%) and 32 (51.6%) of the 62 NS1 positive samples, respectively. Of the 62 cases, only 16 samples were tested for the alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Out of 16 samples, ALT and AST level were significantly higher in 11 (68.8%) and 14 (87.5%) positive cases, respectively. The statistical analysis showed that there was no significant association between NS1 and IgM. It can be concluded that the investigation of leukocytes, thrombocytes, ALT, and AST helps to diagnose the dengue efficiently.

Investigation of Dengue Infection in Asymptomatic Individuals during a Recent Outbreak in La Réunion.

The number of dengue cases has increased dramatically over the past 20 years and is an important concern, particularly as the trends toward urbanization continue. While the majority of dengue cases are thought to be asymptomatic, it is unknown to what extent these contribute to transmission. A better understanding of their importance would help to guide control efforts. In 2019, a dengue outbreak in La Reunion resulted in more than 18,000 confirmed cases. Between October 2019 and August 2020, 19 clusters were investigated in the south, west, and east of the island, enabling the recruitment of 605 participants from 368 households within a 200 m radius of the home of the index cases (ICs). No active asymptomatic infections confirmed by RT-PCR were detected. Only 15% were possible asymptomatic dengue infections detected by the presence of anti-dengue IgM antibodies. Only 5.3% of the participants had a recent dengue infection confirmed by RT-PCR. Although the resurgence of dengue in La Réunion is very recent (2016), the rate of anti-dengue IgG positivity, a marker of past infections, was already high at 43% in this study. Dengue transmission was focal in time and space, as most cases were detected within a 100-m radius of the ICs, and within a time interval of less than 7 days between infections detected in a same cluster. No particular demographic or socio-cultural characteristics were associated with dengue infections. On the other hand, environmental risk factors such as type of housing or presence of rubbish in the streets were associated with dengue infections.

Detection of dengue virus serotype 4 in Sudan.

Dengue virus infection is spreading globally and most parts of Sudan have witnessed repeated dengue outbreaks, with the detection of DENV-1, DENV-2 and DENV-3 serotypes. In this report we describe the dengue fever outbreaks that occurred in eastern Sudan (Kassala and Port Sudan cities) from August to November 2019. We enrolled 79 (29.8%) suspected cases from Kassala and 186 (70.2%) from Port Sudan who presented with fever. The participants were medically examined and their clinical signs recorded. Blood samples were collected for complete blood count, detection of anti-dengue virus IgM, detection of NS1 dengue antigen and identification of the virus serotype using RT-PCR. The main clinical presentations were fever, abdominal pain, joint pain and vomiting, and thrombocytopenia was the main laboratory finding. One hundred and twenty-five blood samples tested positive for the anti-dengue IgM antibody, and 145 were positive for the NS1 antigen. Using RT-PCR, we identified 35 (24%) infections with DENV-2, 100 (69%) with DENV-3 and 10 (7%) with DENV-4 serotypes. We identified multiple serotypes - DENV-2, DENV-3 and DENV-4 - as the causes of the outbreak. The presence of DENV-4 serotype was documented for the first time in Sudan.

Trends in dengue virus infection with seasonal variation at a tertiary care centre, Mangaluru: A retrospective study

: Dengue is currently the second most prevalent vector borne disease in the world. Dengue fever and its more serious forms, dengue hemorrhagic fever and dengue shock syndrome are becoming important public health problems. Since there is no immunoprophylaxis or specific antiviral therapy available, clinico-microbiological diagnosis plays a vital role in patient management and implementation of control measures. : To identify dengue seropositive patients by NS1 antigen and anti-dengue IgM antibody detection by ELISA and correlate the changes in epidemiology. A retrospective study was performed for a period of 5 years from January 2017 to December 2021 in A.J Institute of Medical Sciences & Research Centre, Mangaluru. 1871 seropositive cases of all age groups admitted in the medical wards were included. Rapid immunochromatography test and ELISA was performed to detect NS1 antigen and IgM antibodies. Platelet count and total leucocyte count were also analysed. : Out of 14656, 1871 samples (12.75%) were positive for dengue. Higher rate of cases were in males and the age group of 21 to 30 years were chiefly affected. 1158(61.89%) were positive for NS1 antigen and total positive cases for IgM antibody was 530(28.32%). About 183 (9.79%) cases were positive for both NS1 antigen and IgM antibody. An increase in the prevalence of dengue was recorded during the month of June to October. The present study indicates a decline in dengue infection from 2020 which may be attributable to preventive and control measures provided by the health care workers besides having increased awareness among people. The decline may also may be due to the outbreak of SARS –Cov-2 in December 2019, which led to under diagnosis of dengue cases.

An epidemiological prospective of focal outbreak of dengue infection in Kathmandu, Nepal

Background In 2019, highest number of dengue cases ever were reported in Nepal. This article highlights an epidemiological prospective of dengue infection incidence in Swyambhu, Kathmandu.Methods Retrospective data of 563 dengue suspected patients was collected from Council of Community Health Services (CCHS) Swyambhu, Kathmandu and analyzed. All samples were tested for complete blood count and NS1 antigen and 32 samples (NS1 antigen negative) for anti-dengue IgM & IgG antibody.Results Out of 563 suspected patients, 370 (65.7%) were positive for dengue infection, 365 (n = 563) NS1 antigen positive and 5 (n = 32) anti-dengue IgM antibody positive while none were anti-dengue IgG positive. Among positive cases, ratio of female and male was 1:1. In ethnicity-wise distribution of positive cases, Newar was 60.1%, Tamang 15.0%, Chhetri 13.1% and Brahmin 10.3%. Symptoms like high grade fever (95.5%), nausea (74.0%), headache (44.0%) and gum and nose bleeding (2.9%) were recorded. Mean white blood cells count was 4059.11 cells/cumm, mean platelet count was 169,454.30 cells/cumm and mean hematocrit was 44.0%. Age groups 16–30 years and 31–45 years were statistically significant for nausea compared to other age groups. NS1 antigen positivity was statistically significant in the age groups from 16 to 60 years. Symptoms like retino-orbital pain, head-ache, nose/gum bleeding, petechaie formation was found statistically significant (p < 0.005).Conclusion Higher number of NS1 antigen positive cases indicates active dengue infection circulating in the community. There is need for preparedness to prevent massive outbreaks in future and perform extensive epidemiological studies.

Comparative evaluation of dengue NS1 antigen rapid test and IgM ELISA in a tertiary care hospital in VIMS, Ballari

Dengue virus infection is becoming a major public health problem in recent decades because of the mortality and morbidity associated with it. Dengue is endemic in many parts of India and epidemics are frequently reported from various parts of India and abroad. The mortality rate in patients with dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) is as high as 44%. Hence early and rapid laboratory diagnosis of dengue is crucial. Appropriate clinical management can save the lives of DHF and DSS patients and mortality can be reduced to less than 1%. It is also worthwhile for planning appropriate control strategies. The present communication reports the seroprevalence of dengue infections occurred in Central India.To detect Dengue infection by NS1 Antigen Rapid detection and by IgM ELISA and compare Rapid NS1 Antigen detection test and IgM ELISA test.Blood samples from 5273 suspected cases were collected from January 2016 to December 2016. Sera were separated and subjected for NS1 antigen detection testing by the solid phase immunochromatographic assay, a commercial dengue virus rapid test kit. and antidengue IgM antibody ELISA in the Department of Microbiology, VIMS, Ballari. All samples were put for ELISA.3036 samples were tested for NS1 Antigen detection rapid method.2272 samples were tested for both rapid test and ELISA. Out of 5273 cases, 446 (8.46%) were found to be positive by IgM ELISA. 3036 samples WHICH were tested for NS1 Antigen detection by rapid method 208 (6.85%)samples were positive. The most affected age group was 5-10yrs with 284 cases, out of which 29 were positive, followed by the age group 0f 15yrs and above with 8.74%. Males were affected more than females with a percentage of 9.2 and 7.4 respectively. The highest number of suspected dengue patients admitted was in the month of November, i.e., 459 with 68 positive (14.81%) followed by August (12.16%) and September (11.03%), i.e., 28 with 7 (25%) positive. For the 2272 samples for which both tests were done, 153 cases were positive for rapid test and 137 cases were positive by ELISA. Dengue cases were more during September to November in the post monsoon season which is useful to plan special preventive strategies. The study draws attention toward the male, young and adult age group. To conclude, in countries lacking infrastructure for the diagnostic labs especially in the rural and remote areas, the rapid dengue ICT tests can play a major role in diagnosis and in patient management of acute dengue infection. The rapid ICTs are very simple, easy to perform, and can be used as point of care tests. We suggest that the rapid ICT for NS1 Ag detection may be used in patients presenting with fever less than 5 days

Evaluation of VIDAS® Diagnostic Assay Prototypes Detecting Dengue Virus NS1 Antigen and Anti-Dengue Virus IgM and IgG Antibodies.

Dengue is a serious tropical disease caused by the mosquito-borne dengue virus (DENV). Performant, rapid, and easy-to-use assays are needed for the accurate diagnosis of acute DENV infection. We evaluated the performance of three prototype assays developed for the VIDAS® automated platform to detect dengue NS1 antigen and anti-dengue IgM and IgG antibodies. Positive and negative agreement with competitor enzyme-linked immunosorbent assays (ELISA) and rapid diagnostic tests (RDT) was evaluated in 91 Lao patients (57 adults, 34 children) with acute DENV infection. The VIDAS® NS1 assay showed the best overall agreement (95.6%) with the competitor NS1 ELISA. Both VIDAS® NS1 and NS1 ELISA assays also demonstrated high sensitivity relative to DENV RNA RT-PCR set as gold standard (85.7% and 83.9%, respectively). In contrast, NS1 RDT was less sensitive relative to DENV RNA RT-PCR (72.7%). The overall agreement of VIDAS® IgM and IgG assays with the competitor assays was moderate (72.5% for IgM ELISA, 76.9% for IgG ELISA, and 68.7% for IgM and IgG RDT). In most analyses, test agreements of the VIDAS® assays were comparable in adults and children. Altogether, the VIDAS® dengue prototypes performed very well and appear to be suitable for routine detection of dengue NS1 antigen and anti-dengue IgM/IgG antibodies.

Clinical Profile, Haematological Changes and Outcomes of Dengue Patients in Dengue Outbreak-2019 in Jashore, Bangladesh- An Observational Study

Background: Bangladesh is an endemic zone for re-emerging dengue viral infection since 2000. For the last few years, dengue viral outbreak occurs in the rainy season mostly in Dhaka city and seldom sporadic case finds beyond the Dhaka city of Bangladesh. But this outbreak expands also outside the Dhaka city of Bangladesh in 2019. Therefore, with scarcity of data regarding this field in the peripheral part of Bangladesh, we have designed this study among dengue infected patients in Jashore, Bangladesh.&#x0D; Objectives: This observational study aims to assess the clinical presentations, laboratory findings especially hematological changes and outcomes of patients with dengue viral infection at Jashore district in dengue outbreak-2019 in Bangladesh.&#x0D; Methodology: This was an observational study, carried out from 25thApril 2019 to 5thSeptember 2019 during dengue outbreak season in Jashore, Bangladesh. Patients were selected from outpatient department and indoor of a local private hospital in Jashore, Bangladesh who had given informed written consent to participate in our study.&#x0D; Result: Total eligible 77 patients were included in this study. Out of which 70 patients (90.9%) were dengue NS1 antigen Positive on Immunochromatography (ICT) and the rest were anti-dengue IgM antibody positive on ICT method. Around 74 (96.1%) patients had fever as the most common feature in dengue infection. Eighty-seven percentages (87%) of patients had history of headache. Other striking complaints were body ache (66.2%), back pain (51.9%), nausea (55.8%), vomiting (31.2%), anorexia (27.3%), arthralgia (29.9%) and retro-orbital pain (26.0%). Sore throat being a common feature in flu-like illness also found in 18.2% cases. Mean total count of whole blood count (WBC) falls on day 5 (5.76 X 109/L) and then gradually increased. Mean platelet count of study patient was normal throughout the course of the disease process. But, in some cases minimum platelets was found 21 X 109/L at the time of presentation and on day 5 and day 6 which was dropped down to 17 X 109/L. Mean Haematocrit (%) was more or less in a steady state throughout the acute phage of the disease. But, in some cases throughout the hospital stay minimum haematocrit was less than 30% and initially in some cases maximum haematocrit was more than 50% among some dengue infected patients. Total 67 (87%) subjects with dengue viral infection required hospital admission and mean hospital stay was 4 days with a standard deviation (SD) was ±2 days. Blood transfusion was required in only one patient. Around 95% patient was recovered and only 4 cases were referred to the higher centre further better management. Regarding complications, we had found diarrhoea in 9(11.7%) and bleeding disorder in 14.3% patients.&#x0D; Conclusion: In our study, the most common clinical presentations were fever, headache, body-ache, back pain, and gastrointestinal upset. The mean hematological started dropping down from 4th day and gradually improved after 7th day. Some patients developed diarrhea, bleeding disorders and hepatitis as complications during their disease process. We observed a good clinical outcome evident by without having severity and death toll among our study participants. There was very seldom requirement of blood and blood product transfusion in our study.&#x0D; J MEDICINE JAN 2021; 22 (1) : 33-40

Frequency of dengue infection in febrile patients attended Dhaka Medical College Hospital during January to December, 2018

Introduction: Dengue is a major public health concern in our country. The alarming thing is that the seasonal trend of dengue infection is changing with time in Bangladesh due to climate change and unplanned urbanization. Our study was conducted to determine the frequency of dengue virus infection among the febrile patients in 2018 at Dhaka Medical College Hospital (DMCH) and to observe the seasonal trend.&#x0D; Materials and Methods: The study was carried out on 899 febrile patients attended in DMCH from January to December, 2018. Whole blood samples were collected and sera were tested for dengue NS1 antigen and anti-dengue IgM antibodies using commercial test kits (NS1 by OMC Healthcare (Pvt.) Ltd &amp; IgM antibody by Omega Diagnostics Ltd.), respectively. All negative dengue cases were tested for anti Chikungunya antibody to exclude chikungunya.&#x0D; Results: Of the total 899 febrile patients, 350(38.93%) were positive for Dengue infection. Out of them 264(75.43%) were positive for NS1, 82 (23.43%) were positive for IgM and 4 (1.14%) were positive for dengue NS1antigen + anti dengue IgM antibody. More than 50% patients belonged to age group 15-29 years. Males were predominant. More than 60% cases were detected in the post monsoon season.&#x0D; Conclusion: Highest dengue cases were detected in this year in comparison to the previous year’s probably due to re-emergence of DEN-3 serotype. Due to pattern of climate change, seasonal trend of dengue infection was not maintained. Moreover, unplanned urbanization and poor solid waste management have worsened the situation more.&#x0D; J Dhaka Medical College, Vol. 28, No.1, April, 2019, Page 105-111

Antibodies to Zika virus, Campylobacter jejuni, gangliosides in Guillain Barre syndrome. A prospective single centre study from southern India

The objective was to study the presence of antibodies against Zika virus, Camplyobacter jejuni and gangliosides in patients with Guillain Barre syndrome. Ninety consecutive patients (age more than 12 years) with GBS admitted to a tertiary care centre in southern India were included in this study. Data on the clinical manifestations, Nerve conduction studies and response to therapy were collected. The following tests were done in stored serum samples - Anti-Zika virus (IgM) antibodies, Anti-Campylobacter jejuni (IgG) antibodies and Anti-ganglioside antibodies (IgG). Those samples which were positive to Anti Zika antibodies were tested for conventional PCR for Zika virus, IgM antibodies against Dengue and Japanese encephalitis. Of the 90 patients, 3 died and 8 had persistent weakness. AIDP was the most common type of GBS (56.7%). Anti-ganglioside antibodies were present in 62.2% with GT1b being most common. Anti-C.jejuni antibodies were present in 46.6%. Anti-Zika antibodies (IgM) were present in 14 patients (15.5%). Four of these patients also had anti-Dengue antibody (IgM) positivity. This is one of the largest study on GBS from India and the first one to report on the presence of Zika antibodies form this geographical area. Our study had high prevalence of anti C.jejuni and anti ganglioside antibodies. Evidence of recent ZIKV infection as evidenced by anti IgM antibodies was present in 14 patients with 4 of them tested positive for anti-Dengue IgM antibody. Whether this represents cross reaction with Dengue or prior/co- infection with Dengue could not be addressed in this study.

Laser scanning optical investigations of dengue virus infection from antibody fluorescence of human blood

Dengue is the most important arthropod-borne viral disease of public health significance today, and the geographic distribution includes more than 100 countries worldwide. A definite diagnosis of dengue virus infection is based on clinical criteria supported by antibody tests of whole blood. In this study, we report on dengue infected whole blood diagnostics using laser scanning confocal microscopy (LSCM) over a laser excitation of 488, 543 and 633 nm wavelengths. Based on our findings, the system has potential applications in the detection and quantification of dengue virus infected cells, antigens and antibodies in blood in vitro. Analysis of about 100 infected patients shows that the primary organism (or pathogen), characteristic of dengue infection, causes a significant biochemical change in the nature of human blood in which it resides, and, due to which, fluorescence increases in dengue samples. Thus, the use of a reliable and sensitive rapid diagnostic test using LSCM can simultaneously detect the presence of anti-dengue IgG and IgM antibodies, which is a breakthrough in diagnosis and of great clinical use. The antibodies for dengue continue to be distinguishable for a couple of months after infection. This change in blood fluorescence may be a significant contribution from light scattering through antibodies produced against the dengue antigen.

Can rapid dengue diagnostic kits be trusted? A comparative study of commercially available rapid kits for serodiagnosis of dengue fever.

BACKGROUND:Dengue virus infection is an important emerging disease of the tropical and subtropical regions and is mainly diagnosed by serological detection of NS1 antigen and IgM antidengue antibodies. Since enzyme-linked immunosorbent assay (ELISA) facilities are not easily available at most diagnostic centers, so most of them use various commercially available rapid diagnostic tests (RDTs) kits.AIMS AND OBJECTIVES:This study was designed to access the diagnostic accuracy of four commercially available and widely used RDTs for serodiagnosis of dengue virus infection in Indian laboratories.SUBJECTS AND METHODS:The study was conducted at Department of Microbiology, G.S.V.M Medical College, Kanpur, India, to estimate the sensitivity and specificity of following RDTs: (1) Dengue Cassette (Panbio, Australia), (2) Bioline Dengue Duo (SD Diagnostics, Korea), (3) Dengue Day 1 test (J Mitra and Co., India), and (4) Dengucheck Duo (Tulip Diagnostics, India) on 72 confirmed dengue serum samples that were positive by dengue reverse transcription-polymerase chain reaction, dengue NS1, and IgM ELISA along with 80 serum samples from nondengue febrile illness patients.RESULTS:The majority of the RDTs demonstrated low sensitivity but good specificity for detecting NS1 antigen. Detection of antidengue IgM antibodies by RDTs demonstrated low sensitivity ranging from 27.8% to 77.7%. However, specificity was generally higher (50%–86.2%) and more consistent across the assays.CONCLUSION:The study results differed markedly from the RDTs manufacturers' claimed performance characteristics. Therefore, the RDT results should be interpreted cautiously and ELISA should be performed as far as possible for serodiagnosis of dengue virus infection.

Diagnosis of Dengue Infection Cases by Serum Lactate Dehydrogenase Profiling Compared to Dengue NS1 Antigen and Anti-dengue IgM Antibody Detection: A Retrospective Study

Diagnosis of Dengue Infection Cases by Serum Lactate Dehydrogenase Profiling Compared to Dengue NS1 Antigen and Anti-dengue IgM Antibody Detection: A Retrospective Study

Molecular Characterisation and Phylogenetic Analysis of Dengue Outbreak in Pasighat, Arunachal Pradesh, Northeast India

Background and Objectives: Dengue is one of the most prevalent arboviral diseases in the world with 390 million dengue infections per year. In this study, we report the molecular characterisation of dengue outbreak in Pasighat, Arunachal Pradesh, Northeast India during 2015. Subjects and Methods: A total of 613 dengue-suspected cases were screened for dengue virus by dengue NS1 Ag and anti-dengue IgM antibody depending on the duration of sample collection and onset of symptom. Further, molecular characterisation was done by amplifying the C-PrM region by real-time polymerase chain reaction followed by phylogenetic analysis. Results: Molecular characterisation revealed that the dengue outbreak was predominantly due to dengue virus serotype-1 (DENV-1) (90.9%) while DENV-2 was detected in 7.5% of samples. Co-infection of DENV-1 and DENV-2 was detected in one case. Phylogenetic analysis of the DENV-1 strains with the prototype revealed that the DENV-1 strains were grouped within genotype III. Similarly, DENV-2 strains were clustered within genotype IV. The study revealed a change in the predominant serotype in recent years with DENV-3 in 2012 to DENV-1, 2, 3 and 4 in 2014 to DENV-1 in 2015 in the study region. A unique L24M mutation was observed in the DENV-1 strains of Arunachal Pradesh which was absent in all the circulating strains in India except one strain from the state of Kerala in South India. Marked variation within the DENV-2 strains was observed at A102V and I163V in one strain similar to earlier circulating isolates in India. Conclusions: The present study reveals a shift in the serotype dominance in the study region. As serotype shifts and secondary infection with a heterologous DENV serotype are frequently associated with disease severity, there is an urgent need for sustained monitoring of the circulating serotypes and enhanced surveillance operations, especially in the monsoon and post-monsoon periods to prevent large-scale, severe dengue outbreaks in this region.

Antibodies to Zika virus, Campylobacter jejuni and gangliosides in Guillain-Barre syndrome: A prospective single-center study from southern India.

The objective of this article was to study the presence of antibodies against Zika virus (ZIKV), Campylobacter jejuni, and gangliosides in patients with Guillain-Barre syndrome (GBS). Ninety consecutive patients (age more than 12 years) with GBS admitted to a tertiary care center in southern India were included in this study. Data on clinical manifestations, nerve conduction studies, and response to therapy were collected. The following tests were done in stored serum samples - anti-ZIKV (IgM) antibodies, anti-C. jejuni (IgG) antibodies, and anti-ganglioside antibodies (IgG). Those samples which were positive to anti-Zika antibodies were tested for conventional polymerase chain reaction for ZIKV and IgM antibodies against dengue, and Japanese encephalitis virus. Of the 90 patients, 3 died and 8 had persistent weakness. Acute inflammatory demyelinating polyradiculoneuropathy was the most common type of GBS (56.7%). Anti-ganglioside antibodies were present in 62.2% patients with GT1b being the most common. Anti-C. jejuni antibodies were present in 46.6%. Anti-Zika antibodies (IgM) were present in 14 patients (15.5%). Four of these patients also had anti-dengue antibody (IgM) positivity. This is one of the largest studies on GBS from India and the first one to report on the presence of Zika virus antibodies from this geographical area. Our study had a high prevalence of anti-C. jejuni and anti-ganglioside antibodies. Evidence of recent ZIKV infection, as evidenced by anti-IgM antibodies, was present in 14 patients, with 4 of them being tested positive for anti-dengue IgM antibody. Whether this represents cross-reaction with dengue or prior/co-infection with dengue virus could not be addressed in this study.

Preliminary Seroepidemiological survey of dengue infections in Pakistan, 2009-2014

BackgroundDengue virus is the causative agent of dengue fever, a vector borne infection which causes self-limiting to life threatening disease in humans. A sero-epidemiological study was conducted to understand the current epidemiology of dengue virus in Pakistan which is now known as a dengue endemic country after its first reported outbreak in 1994.MethodsTo investigate the prevalence of dengue virus in Pakistan during 2009-2014, a total of 9,493 blood samples were screened for the detection of anti-dengue IgM antibodies using ELISA. Clinical and demographic features available with hospital records were reviewed to ascertain mortalities related to dengue hemorrhagic shock syndrome.ResultsOut of 9,493 samples tested, 37% (3,504) were found positive for anti-dengue IgM antibodies. Of the seropositive cases, 73.6% (2,578/3,504) were male and 26.4% (926/3,504) were female. The highest number (382/929; 41.1%) of sero-positive cases was observed among the individuals of age group 31-40 years. The highest number of symptomatic cases was reported in October (46%; 4,400/9,493), and the highest number of sero-positive cases among symptomatic cases was observed in November (45.7%; 806/1,764). Mean annual patient incidence (MAPI) during 2009-2014 in Pakistan remained 0.30 with the highest annual patient incidence (11.03) found in Islamabad. According to the available medical case record, 472 dengue related deaths were reported during 2009-2014.ConclusionThe data from earlier reports in Pakistan described the dengue virus incidence from limited areas of the country. Our findings are important considering the testing of clinical samples at a larger scale covering patients of vast geographical regions and warrants timely implementation of dengue vector surveillance and control programs.Trial registration numberIt is an epidemiological research study, so trial registration is not required.

Dengue virus exposure among blood donors in Ghana

Dengue is an urban arbovirus whose aetiologic agent is the flavivirus with four distinct antigen serotypes (DENV-1, DENV-2, DENV-3 and DENV-4) that is transmitted to humans through the bite of the mosquito Aedes aegypti. Ghana is endemic for Aedes aegypti mosquitoes and probably dengue viruses. Due to limited data on dengue virus exposure among Ghanaians, we surveyed 188 healthy adult blood donors for the presence of IgG and IgM antibodies to the four serotypes of dengue. Five milliliters of peripheral blood from the blood donors were collected in plain tubes. Serum was then obtained and ELISA tests were employed to detect both dengue virus total antibodies and IgM. The samples were further tested for dengue virus RNA using RT-PCR. Dengue virus IgG was positive for 43.6% of all the 188 blood donor samples tested but all donors were negative for anti-dengue IgM antibody and dengue virus RNA. The rate of dengue virus total antibody exposure did not differ statistically between urban and rural districts. This study shows for the first time that some regions of Ghana are hyperendemic for dengue virus infection but suggests blood for transfusion is invariably dengue virus free. This report has provided a baseline data that will inform wider discussions about the impact of this dengue fever and also guide policy makers to develop effective and affordable early warning and outbreak response systems for Ghana.Journal of Medical and Biomedical Sciences (2016) 5(2), 30-35

Detection of dengue cases by serological testing in a dengue vaccine efficacy trial: Utility for efficacy evaluation and impact of future vaccine introduction

BackgroundDengue diagnosis confirmation and surveillance are widely based on serological assays to detect anti-dengue IgM or IgG antibodies since such tests are affordable/user-friendly. The World Health Organization identified serological based diagnosis as a potential tool to define probable dengue cases in the context of vaccine trials, while acknowledging that this may have to be interpreted with caution. MethodsIn a phase IIb randomized, placebo-controlled trial assessing the efficacy of a tetravalent dengue vaccine (CYD-TDV) in Thai schoolchildren, case definition was based on virological confirmation by either serotype-specific RT-PCRs or by NS1-antigen ELISA (Clinicaltrials.gov NCT00842530). Here, we characterized suspected dengue cases using IgM and IgG ELISA to assess their utility in evaluating probable dengue cases in the context of vaccine efficacy trials, comparing virologically-confirmed and serologically diagnosed dengue in the vaccine and placebo groups. Serologically probable cases were defined as: (1) IgM positive acute- or convalescent-phase samples, or (2) IgG positive acute-phase sample and ≥4-fold IgG increase between acute and convalescent-phase samples. ResultsSerological diagnosis had good sensitivity (97.1%), but low specificity (85.1%) compared to virological confirmation. A high level of false positivity through serology diagnosis particularly in the 2 months post-vaccination was observed, and is most likely related to detection of the immune response to the dengue vaccine. This lack of specificity and bias with vaccination demonstrates the limitation of using IgM and IgG antibody responses to explore vaccine efficacy. ConclusionReliance on serological assessments would lead to a significant number of false positives during routine clinical practice and surveillance following the introduction of the dengue vaccine.