scholarly journals Increasing number of secondary dengue cases: a concern

Author(s):  
Kumar S. Abhishek ◽  
Oves Siddiqui ◽  
Anita Chakravarti

ackground: Dengue fever is caused by mosquito borne arbovirus of family Flaviviridae, Aedes agypti as the principle vector. In the recent past Delhi has witnessed several outbreaks affecting thousands of individuals and many of them get re-infected during subsequent years forming a bulk of secondary dengue cases putting them at risk of developing severe dengue.Methods: A total of 150 serum samples from suspected dengue cases were tested for dengue fever by NS-1 antigen and IgM antibody enzyme-linked immunosorbent assay (ELISA) followed by categorization into primary and secondary dengue using IgG avidity ELISA.Results: Out of total 150 clinically suspected dengue cases, 56 were positive either by Dengue NS-1 antigen or dengue IgM antibody or both. On the basis of dengue IgG avidity ELISA among 56 diagnosed dengue cases, 30 (53.57%) were found to be of secondary dengue.Conclusions: There is increasing trend of dengue cases in Delhi since past one decade. Being hyper-endemic area for dengue, more than 25% population have been reported to have past infection of dengue. Due to increased prevalence and simultaneous circulation of more than one serotypes, number of secondary dengue cases is also increasing. Since majority of severe dengue cases are associated with secondary dengue, early diagnosis and treatment can significantly reduce the fatal outcome. Thus, avidity testing for IgG antibody becomes an important tool.

Author(s):  
Dr. Tanajee Zade ◽  
Dr. K. Srinivas ◽  
Dr. Akshay Berad

Dengue fever is an acute febrile arboviral disease affecting tropical & subtropical regions of the world. Dengue infection produces a spectrum of clinical illness, ranging from an asymptomatic to its most severe form like dengue haemorrhagic fever and dengue shock syndrome. In view of high morbidity and mortality, it is imperative to have a rapid and sensitive laboratory assay for early detection of the dengue infection. The newer parameter NS1 antigen has gained a lot of interest for early diagnosis of the disease. Detection of non-structural antigen (NS1 Ag), IgM and IgG antibody may help in the early diagnosis. The present study was conducted in a RIMS Adilabad, tertiary care hospital & medical college in the Department of  General Medicine. A total of 100 serum samples were processed from suspected cases of dengue fever by using dengue test for detection of NS1 antigen and IgG antibodies. Platelet counts of all these cases were noted. . Of these 100 subjects 85 were serologically proved to have dengue illness, 57 patients were NS1 antigen positive, 28 patients were IgM antibody positive patients. As the NS1 antigen is detectable in blood from day one after onset of fever, its assay is an effective tool for early diagnosis of dengue infection so as to avoid complications. Key words:  Dengue, NS1 Antigen, IgM antibody, Platelet


2020 ◽  
Vol 14 (1) ◽  
pp. 47-52
Author(s):  
Md Shariful Alam Jilani ◽  
Tang Thean Hock ◽  
Sraboni Mazumder ◽  
Fahmida Rahman ◽  
Md Mohiuddin ◽  
...  

Background and objectives: Several types of Burkholderia pseudomallei antigens have been used to determine the antibody response in acute and asymptomatic cases. In the present study, we have detected immunoglobulin G (IgG) antibody to recombinant truncated flagellin antigen (RTFA) of B. pseudomallei in the sera of acute melioidosis cases and healthy individuals from melioidosis endemic areas of Bangladesh by indirect enzyme-linked immunosorbent assay (ELISA). In parallel, IgG antibody to sonicated whole cell antigen (SWCA) of B. pseudomallei was determined to compare with anti-RTFA antibody. Methodology: Serum samples from culture confirmed melioidosis cases and from healthy individuals aged 21 years and above residing in melioidosis endemic rural areas were included in the study. Serum IgG antibody to RTFA and SWCA of B. pseudomallei was determined by indirect ELISA. Results: Out of 8 culture confirmed acute melioidosis cases, 7 (87.5%) and 8 (100%) were positive for anti-B. pseudomallei IgG antibodies by RTFA and SWCA methods respectively. Among 361 healthy individuals, the rate of seropositivity by RTFA-ELISA was significantly less than that of SWCA-ELISA (16.1% versus 26.8%; p = 0.001). The mean optical density (OD) of RTFA-ELISA of positive cases was significantly less than that of SWCA-ELISA in both melioidosis and healthy individuals (0.79±0.11 versus 2.4±0.08, p = 0.0001; 0.67±0.01 versus 1.27±0.02, p = 0.0001). The sensitivity and specificity of RTFA-ELISA were 88.9% and 100% respectively. Conclusion: Findings of the study suggest that multiple or combination of antigens should be used to study the seroprevalence of B. pseudomallei infection in a community. Also, prospective study is necessary to find out the duration of persistence of antibodies to different antigenic components of B. pseudomallei after exposure. Ibrahim Med. Coll. J. 2020; 14(1): 47-52


Author(s):  
Qilin Wu ◽  
Qinlong Jing ◽  
Xiujuan Wang ◽  
Lili Yang ◽  
Yilan Li ◽  
...  

Guangzhou is believed to be the most important epicenter of dengue outbreaks in southern China. In this study, a longitudinal serological investigation of previous cases of dengue fever in Guangzhou was conducted to explore the persistence of IgG antibodies and related factors affecting the changes of antibody level. We recruited 70 dengue virus type 1 (DENV-1) primary infection cases at two years post infection for serological investigation and conducted a second follow-up in the 5th year of prognosis. An enzyme-linked immunosorbent assay (ELISA) for DENV IgG antibody was examined in all study subjects. Potential factors associated with the concentration of serum total IgG antibody were determined by the generalized estimation equation (GEE). No significant difference in serum total IgG antibody positive rate between two follow-ups was observed (χ2 = 3.066, p = 0.080). However, there was a significant difference in the concentration of serum total IgG antibody between the two follow-ups (Z = 7.154, p < 0.001). The GEE showed that the antibody level in the five-year prognosis was mainly affected by the antibody level in the two-year prognosis (OR: 1.007, 95%CI: 1.005–1.009). In conclusion, the serum IgG antibodies of previous dengue fever cases can persist for a long time.


2020 ◽  
Vol 5 (2) ◽  
pp. 68
Author(s):  
Kirk Osmond Douglas ◽  
Sudip Kumar Dutta ◽  
Byron Martina ◽  
Fatih Anfasa ◽  
T. Alafia Samuels ◽  
...  

Analysis of the temporal, seasonal and demographic distribution of dengue virus (DENV) infections in Barbados was conducted using national surveillance data from a total of 3994 confirmed dengue cases. Diagnosis was confirmed either by DENV–specific real time reverse transcriptase polymerase chain reaction (rRT–PCR), or non–structural protein 1 (NS1) antigen or enzyme linked immunosorbent assay (ELISA) tests; a case fatality rate of 0.4% (10/3994) was observed. The dengue fever (DF) prevalence varied from 27.5 to 453.9 cases per 100,000 population among febrile patients who sought medical attention annually. DF cases occurred throughout the year with low level of transmission observed during the dry season (December to June), then increased transmission during rainy season (July to November) peaking in October. Three major dengue epidemics occurred in Barbados during 2010, 2013 and possibly 2016 with an emerging three–year interval. DF prevalence among febrile patients who sought medical attention overall was highest among the 10–19 years old age group. The highest DF hospitalisation prevalence was observed in 2013. Multiple serotypes circulated during the study period and Dengue virus serotype 2 (DENV–2) was the most prevalent serotype during 2010, whilst DENV–1 was the most prevalent serotype in 2013. Two DENV–1 strains from the 2013 DENV epidemic were genetically more closely related to South East Asian strains, than Caribbean or South American strains, and represent the first ever sequencing of DENV strains in Barbados. However, the small sample size (n = 2) limits any meaningful conclusions. DF prevalence was not significantly different between females and males. Public health planning should consider DENV inter–epidemic periodicity, the current COVID–19 pandemic and similar clinical symptomology between DF and COVID–19. The implementation of routine sequencing of DENV strains to obtain critical data can aid in battling DENV epidemics in Barbados.


Blood ◽  
1997 ◽  
Vol 89 (6) ◽  
pp. 2155-2158 ◽  
Author(s):  
Peter A. Noronha ◽  
Loyda N. Vida ◽  
C. Lucy Park ◽  
George R. Honig

Abstract Human hemoglobins (Hbs) are known to be immunogenic, and both normal and variant forms of Hb have been shown to stimulate antibody formation in a variety of animal species. In patients who are homozygous for the sickle Hb (HbS) mutation, transfusion of normal, HbA-containing erythrocytes provides a potential stimulus for HbA alloimmunization. We tested serum samples for the presence of anti-Hb antibody by a solid-phase enzyme-linked immunosorbent assay (ELISA) using Hb-coated polystyrene microtiter plates. Hb-bound antibody was identified using an antihuman IgG antibody. Serum samples from 89 patients with sickle cell disease were initially tested for evidence of Hb antibody. The serum from three individuals exhibited antibody activity against HbA with little or no activity against HbS. Only one of them, a multiply transfused adult with HbSS, was available for further study. When this patient's antibody was tested against a variety of normal and mutant Hbs using antibody either to human IgG or to κ chains, the anti-Hb antibody demonstrated specificity for the region of the Hb β chain corresponding to the site of the amino acid substitution of HbS. The level of activity of the patient's anti-HbA showed no significant change over 1.5 years of observation. The transfusion of erythrocytes containing Hb structurally different from that of the recipient appeared to be capable of stimulating the production of Hb-specific alloimmune antibody.


2011 ◽  
Vol 18 (12) ◽  
pp. 2095-2101 ◽  
Author(s):  
Stuart D. Blacksell ◽  
Richard G. Jarman ◽  
Mark S. Bailey ◽  
Ampai Tanganuchitcharnchai ◽  
Kemajittra Jenjaroen ◽  
...  

ABSTRACTSix assays were evaluated in this study to determine their suitability for the diagnosis of acute dengue infection using samples from 259 Sri Lankan patients with acute fevers (99 confirmed dengue cases and 160 patients with other confirmed acute febrile illnesses): (i) the Merlin dengue fever IgG & IgM combo device (Merlin), (ii) the Standard Diagnostics Dengue Duo nonstructural 1 (NS1) antigen and IgG/IgM combo device (Standard Diagnostics, South Korea), (iii) the Biosynex Immunoquick dengue fever IgG and IgM (Biosynex, France) assay, (iv) the Bio-Rad NS1 antigen strip (Bio-Rad, France), (v) the Panbio Dengue Duo IgG/IgM Cassette (Inverness, Australia), and (vi) the Panbio dengue NS1 antigen strip (Inverness, Australia). The median number of days of fever prior to admission sample collection was 5 days (interquartile range, 3 to 7 days). Sensitivity and specificity of the NS1 antigen tests ranged from 49 to 59% and from 93 to 99%, respectively, and sensitivity and sensitivity of the IgM antibody test ranged from 71 to 80% and from 46 to 90%, respectively. Combining the NS1 antigen and IgM antibody results from the Standard Diagnostics Dengue Duo test gave the best compromise of sensitivity and specificity (93% and 89%, respectively) and provided the best sensitivity in patients presenting at different times after fever onset. The Merlin IgM/IgG antibody tests correctly classified 64% and 86% of the primary and secondary dengue infection cases, respectively, and the Standard Diagnostics IgM/IgG antibody tests correctly classified 71% and 83% of the primary and secondary dengue infection cases, respectively. This study provides strong evidence of the value of combining dengue antigen- and antibody-based test results in the rapid diagnostic test (RDT) format for the acute diagnosis of dengue.


2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Chukiat Sirivichayakul ◽  
Kriengsak Limkittikul ◽  
Pornthep Chanthavanich ◽  
Sutee Yoksan ◽  
Anuttarasakdi Ratchatatat ◽  
...  

Abstract Background Dengue is an important mosquito-borne disease. There is currently only one licensed vaccine for dengue prevention. The vaccine provides higher efficacy in pre-vaccination dengue-seropositive persons but a higher risk of subsequent more severe dengue in dengue-seronegative persons. It is recommended that the dengue vaccine may be given in dengue-seropositive individuals or as mass vaccination without individual pre-vaccination screening in areas where the dengue seroprevalence is > 80% in children aged 9 years. We evaluated a dengue specific immunoglobulin G monoclonal antibody-based capture enzyme-linked immunosorbent assay (MAb-ELISA) in the diagnosis of previous dengue infection using serum samples from the cohort study in Ratchaburi Province, Thailand. Methods The MAb-ELISA was compared to 70% plaque reduction neutralization test (PRNT70) in 453 serum samples from children aged 3–11 years in Ratchaburi Province, Thailand. Results The sensitivity and specificity of MAb-ELISA at the positive to negative (P/N) ratio cut-off level of > 3 were both 0.91 in the diagnosis of previous dengue infection, compared to PRNT70. The false positivity was mainly in Japanese encephalitis (JE) seropositive subjects. Conclusions This research provides evidence that MAb-ELISA is useful for dengue seroprevalence study and dengue pre-vaccination screening. JE seropositivity was the major cause of false positive result in the study population.


2012 ◽  
Vol 6 (04) ◽  
pp. 369-372 ◽  
Author(s):  
Emmanuel Bhaskar ◽  
Swathy Moorthy

A 26-year-old male presented with fever for five days and abdominal pain for 24 hours. System examination identified a soft abdomen with diffuse tenderness. CT-abdomen findings were consistent with splenic rupture with intra and peri-splenic hematoma. Laboratory investigations showed a platelet count of 40,000 per mm3. In due course he developed hypotension and underwent splenectomy. Non-structural protein 1 (NS1) dengue antigen was positive in the admission sample and IgM dengue antibodies were detected in the follow-up sample. Histopathology of the spleen showed normal architecture with no evidence of hyperplasia, cellular infiltrates or haematological malignancy. Splenic rupture is a rare, but potentially fatal complication of dengue fever and severe dengue which should be suspected when a patient presents with abdominal pain and hypotension. Our case highlights the occurrence of splenic rupture in the viremic phase of dengue illness before the development of IgM antibodies. 


1998 ◽  
Vol 36 (12) ◽  
pp. 3474-3479 ◽  
Author(s):  
Marianne J. Mathiesen ◽  
Michael Christiansen ◽  
Klaus Hansen ◽  
Arne Holm ◽  
Eva Åsbrink ◽  
...  

Sera from 210 patients with Lyme borreliosis (LB) were studied by an enzyme-linked immunosorbent assay (ELISA) based on a synthetic peptide (pepC10) comprising the C-terminal 10-amino-acid residues of OspC of Borrelia burgdorferi. We found that 36.3 and 45.0% of the serum samples from patients with erythema migrans (EM) and neuroborreliosis (NB), respectively, displayed immunoglobulin M (IgM) anti-pepC10 reactivities, while these samples rarely (≤8%) displayed IgG antibody reactivities. Sera from patients with acrodermatitis chronica atrophicans did not contain anti-pepC10 antibodies. The diagnostic performance of this newly developed peptide ELISA was compared with those of an ELISA based on the full-length recombinant OspC protein (rOspC) and a commercially available ELISA based on theB. burgdorferi flagellum (Fla). The sensitivity of the IgM pepC10 ELISA was slightly lower (P < 0.04) than that of the rOspC ELISA for EM patients (36.3 versus 43.8%), while there was no difference for NB patients (45.0 versus 48.0%). However, the optical density values obtained by the pepC10 ELISA were generally higher than those obtained by the rOspC ELISA, leading to a significantly better quantitative discrimination between seropositive patients with NB and controls (P < 0.008). The specificity of the pepC10 ELISA was similar to those of the rOspC ELISA and the Fla ELISA for relevant controls including patients with syphilis and mononucleosis. Although the overall diagnostic sensitivity of the Fla ELISA was superior, 8.8 and 12.0% of the EM and NB patients, respectively, were antibody positive only by the pepC10 ELISA. Thus, use of a diagnostic test for LB based on the detection of IgM antibodies to pepC10 and Fla has increased sensitivity for the diagnosis of early LB.


2020 ◽  
Vol 148 ◽  
Author(s):  
Forough Tavakoli ◽  
Farhad Rezaei ◽  
Nazanin Zahra Shafiei-Jandaghi ◽  
Azadeh Shadab ◽  
Talat Mokhtari-Azad

Abstract After the mass campaign of Measles and Rubella vaccination in 2003 in Iran, the cases of measles and rubella infection decreased but still, the cases of rash and fever were reported. It is worth noting that some other viral infections show signs similar to measles and rubella such as some arboviruses. Considering the epidemic outbreak of arbovirus infections in countries neighbouring Iran, we performed this study to estimate the possibility of chikungunya and dengue fever among measles and rubella IgM negative patients presenting with rash and fever from December 2016 to November 2017 in the National Measles Laboratory at Tehran University of Medical Sciences. Serum samples were selected at random from patients from eight provinces. The presence of DENV IgM and CHIKV IgM was examined by enzyme-linked immunosorbent assay. Of the 1306 sera tested, 210 were CHIKV seropositive and 82 were dengue seropositive. Statistical analysis demonstrated a significant increase in the CHIKV IgM antibody seropositivity rate in Kerman (OR = 2.07, 95% CI: 1.10–3.92; P = 0.024) and Fars (OR = 1.77, 95% CI: 1.06–2.93; P = 0.027). The DENV and CHIKV seropositivity rate in summer is higher than in other seasons (P < 0.01). Our seropositive samples suggest possible CHIKV and DENV infection in Iran. It is likely that these viruses are circulating in Iran and there is a need to study vector carriage of these two viruses.


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