IgM Enzyme-linked Immunosorbent Assay Research Articles

Anti-SARS-CoV-2 IgM Antibody Levels Measured by an In-House ELISA in a Convalescent Latin Population Persist over Time and Exhibit Neutralizing Capacity to Several Variants of Concern.

The coronavirus, SARS-CoV-2, is the causative agent for COVID-19, first registered in Wuhan, China and responsible for more than 6 million deaths worldwide. Currently, RT-PCR is the gold-standard method for diagnosing COVID-19. However, serological tests are needed for screening acute disease diagnosis and screening large populations during the COVID-19 outbreak. Herein, we described the development and validation of an in-house enzyme-linked immunosorbent assay (ELISA) for detecting the levels of anti-spike-1-RBD IgM antibody (CovIgM-ELISA) in well-defined serum/plasma panel for screening and identifying subjects infected with SARS-CoV-2 in a Latin population. In-house CovIgM-ELISA has the format of an indirect ELISA. It was optimized by checkerboard titration using recombinant SARS-CoV-2 spike-S1-RBD protein as an antigen. We found that, compared to the RT-PCR as the standard method, the in-house CovIgM-ELISA displayed sensitivities of 96.15% and 93.22% for samples collected up to 30 or 60 days after infection, respectively, as well as 95.59% specificity with 97.3% accuracy. The agreement kappa value (κ) of our CovIgM-ELISA was substantial when compared to RT-PCR (κ = 0.873) and the anti-SARS-CoV-2 IgM ELISA (InBios Int) (κ = 0.684). The IgM levels detected in the population positively correlated with the neutralizing activity against the wild-type, Alpha and Delta variants of concern, but failed to neutralize Omicron. These data indicate that our in-house CovIgM-ELISA is a compatible performing assay for the detection of SARS-CoV-2 infection.

Reproducibility Assessment of Enzyme-Linked Immunosorbent Assays to Detect Anti-HPV16 L1-Specific IgG1, IgG3, IgA, and IgM Antibodies.

Enzyme-linked immunosorbent assays (ELISAs) have been used to measure anti-human-papillomavirus (HPV) immunoglobulin IgG. The goal of this study was to evaluate the reproducibility of ELISAs measuring different HPV immunoglobulin isotypes, IgG1, 2, 3, and 4, IgA, and IgM, against HPV16. Seventy-two serum samples collected from participants in the Costa Rica HPV Vaccine Trial (CVT) and immunized with bivalent HPV vaccine (2vHPV) were used for reproducibility assessment. IgG2 and IgG4 levels were too low to be detected. Levels of IgG1, IgG3, IgA, and IgM were measured, and the data were used to calculate intraclass correlation coefficients (ICCs) and coefficients of variation (CVs). CVs were assessed between technicians (12.8-22.7%) and across days (6.2-30.6%). The overall CVs ranged from 7.7-31.1%. IgM ELISA showed higher CVs (15.8-31.1%) than IgG1, IgG3, and IgA (6.2-22.7%). All ICC values were >98.7%. IgG3 was detected in all samples, while IgG1 and IgA had >86.3% detectability and IgM had 62.1% detectability. Pearson correlational analyses between different antibodies all showed significant correlations (p ≤ 0.001), except when comparing IgGs or IgA to IgM (p = 0.29-0.53). Our data showed that these ELISAs are reproducible and detect isotype antibodies to HPV16 L1 across a range of concentrations in 2vHPV-vaccinated participants.

Clinical profile, complications, outcome and predictors of intensive care for paediatric scrub typhus: a tertiary hospital-based study from Southern Rajasthan, India

Background: Scrub typhus is an endemic acute febrile zoonotic disease and one of the most neglected tropical illnesses. In 2019, its outbreak was reported from Mewar region of Rajasthan, India. It is caused by Orientia tsutsugamushi which is intra cellular gram-negative coccobacilli. Methods: It is retrospective descriptive study conducted on children diagnosed positive for scrub typhus by IgM enzyme-linked immunosorbent assay (ELISA) admitted in ward and paediatric intensive care unit at tertiary care centre during 1 year of study period from April 2023 to March 2024. Clinical profile, laboratory parameters, course of illness and outcome data were collected in predesigned case records proforma for analysis. Results: Mean age of presentation was 10.5±3.2 years with female preponderance (F:M 1.21:1). 78.5% belong to rural areas. Environmental exposure was living close to forests, bushes in 38%, crop fields in 26% and cattle shed with pets in 30%. All cases had fever (100%, n=42) followed by vomiting (62%), cough-cold (42.8%), myalgia (40.4%), altered sensorium (35.7%), breathlessness (31%), oliguria (16.6%), conjunctival redness (11.9%). Most common signs were temperature >101’F (90.4%), hepatomegaly (62%), hypotension (21.4%), edema (23.8%), meningeal signs (14.2%). Tachypnoea (n=14) (p value <0.0001), CRT>3 seconds (n=13) (p value <0.0003), altered sensorium (n=15) (p value=0.0003) and SpO2 <90% (n=7) (p value=0.004) were found significant predictors of pediatric intensive care unit (PICU) admission. Eschar and rash seen in 3 cases (7.1%). 16 (38%) children requiring intensive care unit admission had statistically significant anaemia (85.7%) (p=0.013), thrombocytopenia (78.5%) (p=0.042) and raised C-reactive protein (CRP) (50%) (p<0.0001). Conclusions: Scrub typhus is common in Rajasthan and should be suspected in any child with acute febrile encephalopathy, signs of shock, breathlessness, hepatomegaly, anaemia and thrombocytopenia in the monsoon season with the history of exposure. Early diagnosis and prompt treatment with doxycycline can prevent mortality.

Seroprevalence and Clinical Profile of Leptospirosis and Scrub Typhus in Clinically Suspected Patients at a Tertiary Care Center: A Retrospective Study from Theni, Tamil Nadu

Abstract Background: Leptospirosis and Scrub typhus are zoonotic illnesses that are found worldwide. Scrub typhus is a rickettsial infection caused by Orientia tsutsugamushi and spread through the biting of a mite’s chigger. Leptospirosis is an anthropozoonotic illness that can be found anywhere but is most common in tropical and subtropical areas. In this study, we report the seroprevalence of Scrub typhus and Leptospirosis with relation to demographic factors in clinically suspected patients attending a tertiary care hospital in Theni, Tamil Nadu. Methods: This is a retrospective study in which 9574 serum samples from clinically suspected cases were collected from January 2018 to December 2023 and tested for immunoglobulin M (IgM) antibodies for Scrub typhus using the enzyme-linked immunosorbent assay (ELISA) and rapid test. A blood sample was taken from each patient, and an IgM ELISA was performed to make the diagnosis. The ELISA cut-off was determined. Results: In this study, 9574 probable cases, 4306 were examined for Leptospira IgM ELISA and 5268 for Scrub typhus IgM ELISA. Out of 4306 suspected Leptospira cases, 167 (3.8%) were positive and 485 (9.2%) were positive in 5268 suspected Scrub typhus cases. The bulk of Leptospirosis and Scrub typhus cases were in the 21–40 years’ age range, followed by the 0–20 years’ age range. Males were found to have higher seroprevalence (57.1%) than females (42.9%). Conclusions: Scrub typhus and leptospirosis are developing infections, and prompt treatment can save many lives. It is strongly advised to take a programmatic approach to the prevention, control, and management of these developing diseases.

Challenging Neurological Presentation: Scrub Typhus with Meningoencephalitis and Multiple Cranial Nerve Involvement.

A 40-year-old male farmer from rural West Bengal, India, presented with fever, headaches, seizure, eschar, and palsy of left cranial nerves VII, VIII, IX, and X as a rare clinical manifestation of scrub typhus. Positive IgM enzyme-linked immunosorbent assay tests in serum and cerebrospinal fluid confirmed the diagnosis, with brain magnetic resonance imaging showing meningoencephalitis findings. Treatment with steroids and doxycycline led to neurological improvement. This case highlights the need for heightened clinician awareness towards early detection of scrub typhus's atypical presentations to ensure timely and effective treatment.

Seroprevalence and Risk Factors Associated with Leptospirosis in High-Risk Occupational Groups in the State of Gujarat as Determined by IgM ELISA and MAT Test: A Cross-Sectional Study.

Leptospirosis is a reemerging zoonosis affecting humans and animals worldwide in tropical and subtropical countries. The study was conducted to estimate the seroprevalence of leptospirosis in high-risk occupational groups (cattle farm workers, poultry farm workers, and slaughterhouse workers) in the state of Gujarat and to determine related risk factors for leptospirosis. Using an interview-guided questionnaire, a cross-sectional study was conducted involving 123 people in high-risk occupational groups (namely, cattle farm workers, poultry farm workers, and slaughterhouse workers) from five districts of the state of Gujarat, India. The participants' serum samples were screened for antileptospiral antibodies by using Immunoglobulin G (IgG) and Immunoglobulin M (IgM) enzyme-linked immunosorbent assays (ELISAs) followed by a microscopic agglutination test (MAT). The Chi-square (χ2) test and odds ratio were calculated using IBM SPSS Statistics for Windows, version 22 (IBM Corp., Armonk, N.Y., USA) to ascertain the associated risk factors. Regarding demographic information, this study included 104 men and 19 women in high-risk occupational groups. The overall seroprevalence of antileptospiral antibodies in these high-risk workers was 46.3%. The seroprevalence was the highest among poultry farm workers (56.6%), followed by cattle farm workers (54.5%) and slaughterhouse workers (25.6%). The MAT in combination with IgM is adequate for the serological diagnosis of leptospirosis, but we have also employed IgG ELISA to understand the chronic infection in these high-risk occupational groups as exposure was both past and present. Tests were conducted for antibodies against various Leptospira serovars in the major serogroups; frequent serovars included Hurstbridge, Panama, Javanica, Tarassovi, Copenhageni, Pomona, and Weaveri, among others. The significant (P < 0.05) risk factors associated with leptospirosis in these high-risk occupations reported to be living in field areas, the presence of livestock in the neighborhood, working in slaughterhouses, drinking water from natural water resources, contact with animals such as dogs or livestock, and wounds during occupational practice. Considering the high seroprevalence of leptospirosis, high-risk occupational groups should be regularly screened for potential development of the fatal disease. Hurstbridge was found to be the most prevalent serovar in the studied population, followed by Panama, Javanica, and Tarassovi.

Comparison of an Enzyme Linked-Immunosorbent Assay and a Chemiluminescent Immunoassay with an Immunofluorescence Assay for Detection of Phase II IgM and IgG Antibodies to Coxiella burnetii.

In this study, we have compared the detection of IgM and IgG against C. burnetii phase II of an enzyme-linked immunosorbent assay (ELISA) (Euroimmun) and a chemiluminescent immunoassay (CLIA) (VIRCLIA, Vircell). In addition, an indirect immunofluorescence assay (IFA) was used as a reference test. One hundred forty-eight sera were used for IgG evaluation, and eighty-eight for IgM. The sensitivity of ELISA and CLIA in detecting phase II IgM was excellent. On the other hand, the CLIA IgM showed better specificity than the ELISA IgM. As for phase II IgG, the specificity of ELISA and CLIA was similar, while the ELISA technique showed a higher sensitivity. In conclusion, the best system to detect phase II IgM antibodies against C. burnetii is the CLIA from Vircell, which is characterized by high sensitivity and specificity. For the detection of phase II IgG, the Euroimmun ELISA and Vircell CLIA assays are suitable for the determination of this marker in the laboratory, although the IgG ELISA has greater sensitivity.

Accuracy of commercial ELISA and ICT for screening schistosomiasis infections at a low endemicity area in Brazil.

Control interventions recommended by the World Health Organization have successfully resulted in low-intensity schistosomiasis transmission areas. To achieve elimination of transmission, new diagnostic screening tools are needed to overcome less than adequate sensitivity of the currently used Kato-Katz faecal thick smear method. Ideally, in-house serological tests should be avoided due to not having a continuous supply of kits as would be necessary for large population studies. Quality assurance provided by manufacturers and proper performance evaluations are also needed. We evaluated the accuracy of two commercially available serology tests as screening methods for detecting light schistosomiasis infections. Serum samples were collected in 2015 from individuals living in a low-endemicity locality in northeastern Brazil and deposited in a biorepository. We evaluated immunoglobulin G (IgG) and IgM enzyme-linked immunosorbent assays (ELISAs) and an immunochromatographic test (ICT). The Helmintex method was used to define true-positive samples. Overall sensitivity was close to 90% for both the IgG ELISA and ICT, yet specificity was 28% and 18%, respectively. For the IgM ELISA, the values were estimated to be 55% and 43%, respectively. Poor specificity and positive predictive values prevent these tests from being recommended for screening populations in low-intensity schistosomiasis-endemic areas.

Scrub typhus in Indonesia: A cross-sectional analysis of archived fever studies samples.

Scrub typhus is an understudied vector-borne bacterial infection. We tested archived fever samples for scrub typhus seropositivity to begin charting its geographic distribution in Indonesia. We analysed 1033 serum samples from three sites. IgM and IgG enzyme-linked immunosorbent assay (ELISA) against Orientia tsutsugamushi was performed using Karp, Kato, Gilliam, TA 716 antigens. To determine the cutoff in the absence of a presumed unexposed population and gold standard tests, we identified the visual inflection point, performed change point analysis, and used finite mixture models. The optical density cutoff values used for IgM and IgG were 0.49 and 0.13, respectively. Across all sites, IgM seropositivity was 4.6% (95% CI: 3.4 to 6.0%) while IgG seropositivity was 4.4% (95% CI: 3.3 to 5.8%). The overall seropositivity across sites was 8.8% (95% CI: 8.1 to 11.7%). The overall seropositivity for Jambi, Denpasar, Tabanan were 9.7% (95% CI: 7.0 to 13.3%), 8.0% (95% CI: 5.7 to 11.0%), 9.0% (95% CI: 6.1 to 13.0%), respectively. We conclude that O. tsutsugamushi exposure in humans occurred at all sites analysed and could be the cause of illness in some cases. Though it was not the main cause of acute fever in these locations, it is still important to consider scrub typhus in cases not responding to beta-lactam antibiotics. Future seroprevalence surveys and testing for scrub typhus in acute febrile illness studies will be essential to understand its distribution and burden in Indonesia.

Comparative seropositivity of Listeria monocytogenes in the serum of pregnant women with and without a history of abortion by serological and culture methods.

Listeria monocytogenes is a major cause of miscarriage and postpartum infections in infant. Determining antibody levels against listeriolysin O can be valuable for diagnosing both invasive listeriosis and febrile gastroenteritis. However, serological methods that detect antibodies against incomplete forms of listeriolysin O can be more specific. The objective of this study was to identify (Listeria monocytogenes) in the serum of pregnant women using serological and culture methods. Clinical samples (120 cases) were collected from pregnant women with a gestational age of less than 20 weeks. Diagnosis of Listeria monocytogenes was conducted using culture methods to identify anti-Listeria antibodies. Statistical analysis of the results was conducted using IBM SPSS Statistics version 23.0 (New York, USA), Pearson's Chi Square and fisher tests. The number of positive samples by culture and ELISA was 24.16% (29) and 28.3% (34), respectively. Out of the 29 positive sample by the culture method, 10 individuals had no abortion history, 16 and 3 individuals had 1 and 2 abortions and no sample had 3 abortions. Maybe, the more abortions a person has had, the less likely they are to be infected. In the Enzyme Linked Immuno-Sorbent Assay (ELISA) method, 13 individuals tested positive for both IgG and IgM antibodies and 38 individuals tested negative. Additionally, among the positive individuals with 1, 2, and 3 miscarriages, 0, 17, and 3 people were positive for the IgG antibody and 0, 18, and 3 individuals were positive for the IgM antibody. The analysis results indicated that there was no significant relationship between culture and abortion history (p = 0.316), IgG ELISA and history of miscarriage (p = 0.672) and IgM ELISA and history of miscarriage (p = 0.552). There was no significant relationship between infection with Listeria monocytogenes and abortion (p ⩾ 0.05) in our samples. These results should be interpreted with caution due to the limitation of our small sample size.

The Rate of Anti-measles Immunoglobulin M Positivity among Children with Skin Rash and Fever in Diyala Province

Abstract Background: Measles is an extremely contagious disease characterized by generalized maculopapular rash, fever, cough, coryza, and conjunctivitis. It is caused by the measles virus. Objective: The objective of this study was to explore the anti-measles immunoglobulin (Ig) M positivity rate among children with clinical suspicion of having measles. Subjects and Methods: This is a cross-sectional study carried out in Diyala Province, Iraq, from November/2020 to October/2021. A total of 425 blood samples were collected from children (≤14 years of age): 90 from patients who were clinically suspected as having measles (18 were vaccinated with measles vaccine and 72 were not); 270 from measles-vaccinated children, including those children who received all recommended vaccines in the Iraqi Expanded Program of Immunization (IEPI); and 65 from nonvaccinated children, including those children who received none of the vaccines in the IEPI. Enzyme-linked immunosorbent assay (ELISA) kits for the detection of anti-measles IgM were used. Results: The results found that 14 (15.6%) of clinically suspected children were positive for anti-measles IgM antibody versus 76 (84.4%) who were negative. Whereas, only one (1.5%) of the unvaccinated children was positive, and all vaccinated children were negative. Thus, clinically suspected patients had a significantly higher positivity rate compared to other study groups (P = 0.0001). Similarly, the mean ± standard deviation of anti-measles IgM concentration was significantly higher compared to other study groups (P = 0.0001). Conclusion: About one-sixth of patients clinically comparable to measles in Diyala Province actually had measles, most of them were unvaccinated, and the anti-measles IgM ELISA technique was a good marker for exploring measles cases.

Rapid immunochromatographic test: An evolving tool for diagnosis of scrub typhus

Background: Scrub typhus is prevalent in many districts of South Bengal throughout the year where an average temperature of 20–35°C, which contributes to the spread of Leptotrombidium deliense. However, its diagnosis remains complicated by the lack of readily available and validated assays, the non-specificity of clinical symptoms on admission, and even non-availability of the pathognomonic eschar in most of the cases. Aims and Objectives: This study was carried out to evaluate the rapid immunochromatographic test (RICT) for early detection of scrub typhus for using it as an early diagnostic tool at the field level. Materials and Methods: This cross-sectional study in which 181 serum samples from clinically suspected cases (after excluding dengue, malaria, Japanese encephalitis, and typhoid fever) collected over 13 months were processed for the detection of immunoglobulin M (IgM) antibodies for scrub typhus by enzyme-linked immunosorbent assay (ELISA) and rapid test. Results: Considering IgM ELISA for scrub typhus as the gold standard, the sensitivity, specificity, positive predictive value, and negative predictive value for RICT were found to be 100%, 86.87%, 50%, and 100%, respectively. Conclusion: RICT is a simple, rapid, and reliable assay for diagnosis of scrub typhus, capable of providing accurate results quickly and is highly suitable for field deployment in remote areas with limited medical support.

NS1-Specific Antibody Response Facilitates the Identification of Children With Dengue and Zika in Hyperendemic Areas.

Infections by dengue virus (DENV) and Zika virus (ZIKV) have some similar symptoms and a cross-reactive immune response, although with different risk populations and outcomes. Here, we evaluated the virologic characteristics and the nonstructural protein 1 (NS1)-specific antibody responses to DENV and ZIKV in children suspected of dengue in different epidemiologic moments in Colombia. Viral RNA, circulating NS1 and IgM/IgG specific for DENV and ZIKV were performed by reverse transcription-quantitative polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) in 301 children suspected of dengue enrolled in a hospital setting during the ZIKV epidemic and a primary healthcare setting during a DENV epidemic. For the detection of DENV and ZIKV-specific IgM, an NS1-based ELISA was validated using characterized pediatric samples. Clinical and laboratory parameters were also evaluated. DENV RNA or NS1 antigen was detected in the plasma of 62% of children, and in none, the ZIKV RNA was found. NS1-based ELISA for DENV and ZIKV IgM showed a sensitivity/specificity of 90/84% and 73/98%, respectively. Of 114 children without detectable viremia or antigenemia, 30.7%, 17.5%, 22% and 30% were IgM-DENV + , IgM-ZIKV + , IgM-DENV + ZIKV + and IgM-DENV - ZIKV - , respectively. The ZIKV/DENV IgM-NS1 ratio allows the identification of the infecting orthoflavivirus in 88% of the children with IgM-DENV + ZIKV + , confirming a high predominance of DENV infections in the 2 pediatric settings. Overall, 88% of the children with clinical suspicion of dengue had an identifiable orthoflaviviral infection, with 80% caused by DENV, 7% by ZIKV and 0.7% classified as recent infections or coinfection, demonstrating active viral cocirculation in the pediatric population of southern Colombia. The IgM-NS1 detection improved the identification of orthoflaviviral infections in children without viremia or antigenemia, suggesting it is a helpful complementary tool for medical personnel in tropical regions with high viral cocirculation and different clinical scenes.

Serological profile of patients suspected with non-scrub typhus rickettsioses

BackgroundRickettsial pathogens are Gram-negative, obligate intracellular bacteria. They are transmitted by arthropods and are responsible for a wide variety of disease, from minor to life-threatening, which have a global effect on human health. Limited data are available on the prevalence of rickettsial diseases from India, and the disease epidemiology is not fully described. This study aimed to diagnose non-scrub typhus rickettsioses including spotted fever and typhus group of Rickettsia in clinically suspected patients by using standard serological tests and recognition of common epidemiological conditions and clinical manifestations. MethodsDuring the study period, a total of 700 patients of all ages with acute febrile illness were enrolled. Patients were screened for rickettsial infection using IgM Enzyme-linked immunosorbent assay (ELISA) and Immunofluorescence assay (IFA) was performed to confirm the ELISA positive results. The relevant demographic, clinical, and laboratory details of patients were documented and analyzed. ResultsOf 700 samples tested, 141 (20.2%) were found to be positive for IgM antibodies against rickettsioses using ELISA and IFA. SFGR was positive in 15 (2.2%), TGR was positive in 112 (16%) and 14 (2%) samples were positive for both groups. 20 (14.2%) patients required admission to the intensive care unit (ICU), and 24 (17%) in-hospital deaths occurred. ConclusionsThe prevalence of rickettsioses in India appears to be underestimated; therefore, increased awareness and improved diagnostic testing could facilitate early detection of cases, pathogen-targeted appropriate treatment, and improved outcomes for patients. Despite the fact that Rickettsiae can be isolated or detected using molecular techniques in clinical specimens, serology still remains the most commonly used diagnostic method for rickettsioses around the world. Our study helps bridge the gap of limited data on Rickettsia in north India and could be useful for future epidemiological investigation of rickettsial diseases and outbreaks.

Human Brucellosis: An Observational Study From a Tertiary Care Centre in North India.

The main aim/objective of this study was to detect and characterize theBrucella speciesfrompatients having complaints of joint pain and also to know thepotential causes of human brucellosis. In our study, we focused on joint pain symptoms that may be due to arthralgia or arthritis. Introduction: Brucellosis is a neglected zoonotic disease that affects both humans and animals.In humans, brucellosis begins with chronic illness leading to greatfinanciallosses fromnot being able to work welland continued treatment costs, butfew such studies have come from northern India.Joint pain is the common presentation of brucellosis and there are several risk factors associated with brucellosis. A total of 200 blood samples were collected from the participants having joints pain from September 2019 to September 2021 at Gandhi Memorial & Associated Hospitals ofKing George's Medical University, Lucknow, India, and tested by serology for anti-BrucellaIgM and IgG enzyme-linked immunosorbent assay (ELISA),moleculartests byreverse transcriptase-polymerase chain reaction (RT-PCR),conventional polymerase chain reaction (PCR), and automated blood culture system.The anti-Brucella IgM and IgG ELISA were performed using the kit from NovaTec Immundiagnostica GmbH (Dietzenbach, Germany). Isolation of DNAwas carried out using the QIAamp DNA Mini kit (QIAGEN,Hilden, Germany), and the primers and probes specific for targeted regions (BCSP31 and IS711 gene)in theBrucellagenome were procured from Eurofins Scientific SE (Luxembourg, France), and for internal control from CDC. The study showed 19(9.5%) and 23 (11.5%) positive results by anti-BrucellaIgM ELISA and anti-BrucellaIgG, respectively, andof these, one (0.5%) was positive for both anti-BrucellaIgM and anti-BrucellaIgG ELISA.Out of 19 anti-Brucella IgM ELISA positive, eight (4%) samples were positive forPCR/RT-PCRandthat was negative for anti-Brucella IgG ELISA. All blood culture reports of all patients were negative. Conclusion: Anti-Brucella IgM ELISA was more accurate than anti-Brucella IgG ELISA in detecting human brucellosis. Consumption of animal products(i.e. milk, a dairy product of cow, buffalo, goat, and meat of goat)and contact with animals were themain risk factors that were identifiedfor Brucelladisease.

Seroprevalence and incidence of primary dengue infection and its correlation with fetomaternal prognosis in Western Rajasthan.

Viral hemorrhagic fevers are becoming increasingly common in the tropics and subtropics. Dengue fever is currently the most important arthropod-borne viral disease because of its widespread distribution in more than 100 countries and its potential for extensive outbreaks of life-threatening disease. This study was a hospital-based cross-sectional study conducted in the Microbiology Laboratory of Maternal and Child Tertiary Care Hospital in Western Rajasthan, India, between January 2021 and December 2021. Institutional Ethical Committee permission was obtained. All patients with clinical suspicion of dengue-like illness (DLI), attending outpatient department (OPD) or inpatient department (IPD), were included in the study after obtaining their written consent. A blood sample was collected, and the Dengue Duo rapid card test was conducted for the detection of nonstructural protein 1 (NS1) antigen and immunoglobulin (Ig) M or IgG antibody estimation. All positive samples were tested for IgM enzyme-linked immunosorbent assay (ELISA) test using MAC-ELISA. Of 250 positive sample, the distribution of cases as per clinical features was as follows: all cases presented with fever (100%) followed by myalgia (24.5%), headache (16.06%), hemorrhagic manifestation (13.25%), rash (8.84%), and bleeding gums (2.01%). Thrombocytopenia was seen in 30.40% (76/250) of dengue fever cases. NS1 antigen was detected in 157 cases (62.80%) followed by IgG in 84 cases (33.60%), IgM in 77 cases (30.80%), NS1+IgG in 27 cases (10.80%), NS1 + IgM in 16 cases (6.40%), and NS1 + IgM + IgG in five cases (2%). Of 250 samples, 77 cases were IgM positive and 173 were IgM negative by the Dengue Duo card test. Among the 173 Dengue Duo IgM card negative, 131 cases (79.39%) were also detected negative by IgM ELISA and 42 cases (49.41%) were detected positive by IgM ELISA. The sensitivity was 50.59%, the specificity was 79.39%, the positive predictive value (PPV) was 55.84%, the negative predictive value (NPV) was 75.72%, and the diagnostic accuracy was 69.90%. The case fatality of the cases was 2.35%. Early diagnosis and treatment can prevent mortality in pediatric and pregnant females suffering from dengue and dengue-like illness. Facility and availability of ELISA kits should be adequate for early confirmation of suspected dengue patients by ELISA test.

Seroprevalence of Dengue, Chikungunya and Zika at the epicenter of the congenital microcephaly epidemic in Northeast Brazil: A population-based survey.

The four Dengue viruses (DENV) serotypes were re-introduced in Brazil's Northeast region in a couple of decades, between 1980's and 2010's, where the DENV1 was the first detected serotype and DENV4 the latest. Zika (ZIKV) and Chikungunya (CHIKV) viruses were introduced in Recife around 2014 and led to large outbreaks in 2015 and 2016, respectively. However, the true extent of the ZIKV and CHIKV outbreaks, as well as the risk factors associated with exposure to these viruses remain vague. We conducted a stratified multistage household serosurvey among residents aged between 5 and 65 years in the city of Recife, Northeast Brazil, from August 2018 to February 2019. The city neighborhoods were stratified and divided into high, intermediate, and low socioeconomic strata (SES). Previous ZIKV, DENV and CHIKV infections were detected by IgG-based enzyme linked immunosorbent assays (ELISA). Recent ZIKV and CHIKV infections were assessed through IgG3 and IgM ELISA, respectively. Design-adjusted seroprevalence were estimated by age group, sex, and SES. The ZIKV seroprevalence was adjusted to account for the cross-reactivity with dengue. Individual and household-related risk factors were analyzed through regression models to calculate the force of infection. Odds Ratio (OR) were estimated as measure of effect. A total of 2,070 residents' samples were collected and analyzed. The force of viral infection for high SES were lower as compared to low and intermediate SES. DENV seroprevalence was 88.7% (CI95%:87.0-90.4), and ranged from 81.2% (CI95%:76.9-85.6) in the high SES to 90.7% (CI95%:88.3-93.2) in the low SES. The overall adjusted ZIKV seroprevalence was 34.6% (CI95%:20.0-50.9), and ranged from 47.4% (CI95%:31.8-61.5) in the low SES to 23.4% (CI95%:12.2-33.8) in the high SES. The overall CHIKV seroprevalence was 35.7% (CI95%:32.6-38.9), and ranged from 38.6% (CI95%:33.6-43.6) in the low SES to 22.3% (CI95%:15.8-28.8) in the high SES. Surprisingly, ZIKV seroprevalence rapidly increased with age in the low and intermediate SES, while exhibited only a small increase with age in high SES. CHIKV seroprevalence according to age was stable in all SES. The prevalence of serological markers of ZIKV and CHIKV recent infections were 1.5% (CI95%:0.1-3.7) and 3.5% (CI95%:2.7-4.2), respectively. Our results confirmed continued DENV transmission and intense ZIKV and CHIKV transmission during the 2015/2016 epidemics followed by ongoing low-level transmission. The study also highlights that a significant proportion of the population is still susceptible to be infected by ZIKV and CHIKV. The reasons underlying a ceasing of the ZIKV epidemic in 2017/18 and the impact of antibody decay in susceptibility to future DENV and ZIKV infections may be related to the interplay between disease transmission mechanism and actual exposure in the different SES.

Diagnostic value of PCR analysis of synovial fluid for the diagnosis of Lyme borreliosis in dogs

Lyme borreliosis, also known as Lyme disease, is a chronic multiorgan disease of humans and animals transmitted by ticks of the Ixodidae family and caused by a group of spirochetes Borrelia burgdorferi sensu lato. Dogs are one of the most susceptible animal species to Lyme disease. Symptoms of the disease in dogs can range from mild lameness and fever to more severe and potentially life-threatening conditions, such as kidney damage and neurological disorders. Due to the variety of clinical manifestations and the lack of a universal diagnostic approach, veterinarians often face difficulties in accurately diagnosing the disease. Therefore, improving the algorithms for diagnosing Lyme borreliosis in dogs remains an urgent issue for practical veterinary medicine. The article describes and analyzes data on two cases of dogs from Kyiv (Ukraine) that presented with musculoskeletal disorders, including lameness, swelling of the knee joints, and tenderness, which raised suspicion of Lyme borreliosis. The diagnostic tests used to confirm the diagnosis of Lyme borreliosis included clinical blood test, C-reactive protein test, cerebrospinal fluid cytology, enzyme-linked immunosorbent assay for IgM and IgG antigens to Borrelia burgdorferi sensu lato, computed tomography and PCR analysis of synovial fluid for the presence of Borrelia burgdorferi sensu lato DNA. As a result, the clinical blood test, C-reactive protein test, and cerebrospinal fluid cytology were not diagnostically important for the diagnosis of Lyme borreliosis. In both cases, serological tests for antibodies to Borrelia burgdorferi sensu lato were not positive. Computed tomography showed the development of an inflammatory process in the knee joints with the formation of osteophytes, enthesophytes, sclerosis of the articular surfaces, and an increase in the volume of synovial bursa. The final diagnosis of Lyme arthritis in both dogs was established by PCR analysis of synovial fluid from the affected joints for the presence of Borrelia burgdorferi sensu lato DNA. This study emphasizes the importance of considering Lyme borreliosis as a potential cause of musculoskeletal disorders in dogs. We also propose an expanded algorithm for the diagnosis of Lyme borreliosis in dogs with a pronounced symptom complex of Lyme arthritis using the method of PCR analysis of synovial fluid to detect the DNA of Borrelia burgdorferi sensu lato spirochetes. Key words: Lyme borreliosis in dogs, clinical cases, diagnosis, polymerase chain reaction, Borrelia burgdorferi sensu lato.

Granulomatous reaction as a postherpetic isotopic response after primary varicella infection in a healthy adult

We report the first case of post-herpetic isotopic reaction (PHIR) after primary varicella infection in a healthy adult. PHIR refers to the development of new skin lesions at sites where prior herpetic skin lesions have been resolved. Herpes zoster is the most common cause of PHIR; however, only a few cases of PHIR due to primary varicella infections have been reported. Postherpetic isotopic reaction (PHIR) refers to the development of new skin lesions at sites where prior herpetic skin lesions have been resolved. Herpes zoster (HZ) is the most common cause of PHIR; however, only a few cases of PHIR due to primary varicella infections have been reported. A 22-year-old Japanese man with no relevant medical history presented with multiple vesicles throughout the body. The patient was diagnosed with primary varicella infection based on a positive Tzanck test. Three weeks after onset, new skin eruptions appeared in the regions affected by the primary rash. He had multiple nodules of 5–8 mm size and hues ranging from red to normal skin on his face, trunk, and limbs (Figure 1A,B). He had been vaccinated against varicella during childhood. No abnormal findings were observed except for slightly low immunoglobulin (Ig) A and IgG (IgM: 37 mg/dL, IgA: 63 mg/dL, IgG: 734 mg/dL) in blood tests. Viral antibody examination revealed varicella-zoster virus (VZV)-IgM enzyme-linked immunosorbent assay (EIA) and VZV-IgG EIA titers of 0.03 and 6.8, respectively (both tests are positive at ≥4.0), indicating a previous infection. Histological findings showed epithelioid cells and granulomatous foreign body giant cells within the upper dermis, surrounded by marked neutrophilic and lymphocytic infiltration. No caseous necrosis, inclusion bodies, or residual viral particles were observed (Figure 1C,D). The patient was diagnosed with granulomatous reaction as PHIR after primary varicella infection. The nodules gradually improved with topical steroid, and no recurrence was noted. Postherpetic isotopic reaction is a type of Wolf's isotope reaction (WIR), and some argue that WIRs are Koebner reactions.1 However, Koebner reactions generally indicate the appearance of the same preexisting dermatosis on the injured skin. In the present case, a completely different eruption appeared after the primary rash. Thus, it was appropriate to describe it as a PHIR. Various skin manifestations have been reported in PHIR, with granulomatous dermatitis being the most common. According to Wang et al., the pathogenesis of granulomatous reaction as PHIR possibly encompasses post-infection nerve damage and residual virus particles, which may induce secretion of interleukin-4 and other chemokines, promote infiltration of inflammatory cells, and locally modulate immune and angiogenic responses.2 Less nerve damage associated with primary varicella compared to that associated with HZ may be a reason for the infrequent PHIR phenomenon following primary varicella infection. Several pediatric cases of granulomatous reactions as PHIR after primary varicella have been reported previously.3-6 Two PHIR cases in adults were previously reported, but the patients were immunosuppressed hosts with myelogenous leukemia. Immunocompromised patients are susceptible to greater nerve damage by VZV.7 This is the first case of PHIR after varicella infection in a healthy adult. Histological findings supported the possibility of a hyperimmune response to residual viral particles, resulting in granulomatous dermatitis. Blood samples showed a slightly low level of immunoglobulins, but no other abnormalities were observed. Although the cause is unclear, the patient should be followed carefully for the future development of immune system diseases. Further studies are required to understand the mechanisms underlying PHIR after varicella infection. The authors declare no conflict of interest. Informed consent: Informed consent was provided by the patient, and approval was received. Approval of the research protocol: N/A. Registration No. of the study/trial: N/A. Animal studies: N/A. The data that support the findings of this study are available from the corresponding author, Y. W., upon reasonable request.

Epidemiology of scrub typhus in a tertiary care hospital of Southern Odisha: a cross sectional study.

Scrub typhus, is a mite-borne disease caused by bacteria named Orientia tsutsugamushi. In recent years the incidence of scrub typhus is increasing day by day. The disease is easily missed because of low sensitization among clinicians and non-specific clinical manifestation. The disease can be fatal in untreated cases. With the availability of testing methods, it can be easily diagnosed and treated. This study aims to depict the epidemiology of scrub typhus in southern Odisha. A total of 170 blood samples were collected from clinically suspected acute undifferentiated febrile illness (AUFI) cases. Samples were tested serologically for antibodies against Orientia tsutsugamushi by commercially available Immunochromatography test (ICT) and enzyme-linked immunosorbent assay (ELISA) kit as per the manufacturer's instruction. Molecular diagnosis was done by nested polymerase chain reaction (N-PCR) and Sanger sequencing was done to know the circulating strains. Out of 170 cases of AUFI, 74 cases were diagnosed scrub typhus by IgM ELISA and 67 were positive by ICT. Males were affected more and cases were more clustered in the Ganjam district. The disease followed a typical seasonal i.e. more cases were seen in cooler months of the year. Sequencing revealed the strains were Gilliam and Karp like. The burden of scrub typhus was 43.5% among the study population. Determining the serotypes in endemic areas is important for basic research on the classification of Orientia tsutsugamushi, the development of vaccines, and the definitive diagnosis of scrub typhus. Expanding the panel of antigens used to test scrub typhus and to take into account of local antigenic diversity would improve the sensitivity of serological diagnosis.