IgM ELISA Research Articles

Etiology of Acute Encephalitis Syndrome in Adults in a Tertiary Care Center in Eastern Uttar Pradesh

Seasonal outbreaks of acute encephalitis syndrome (AES) with high case fatality rates have been commonly reported among adults in India. With an increase in Japanese encephalitis virus (JEV) vaccination, the etiology of AES is also changing. However, most studies on AES in India have focused only on children and on JEV. This study was conducted in the Department of Medicine, Institute of Medical Sciences, Banaras Hindu University between 2020 and 2022 to determine the etiology of AES in adults. Blood and cerebrospinal fluid (CSF) were collected from patients 18 years or older with fever and altered sensorium for ≤15 days. We did IgM ELISA for dengue, chikungunya, West Nile virus, scrub typhus, leptospirosis from serum, CSF-IgM for JEV, and CSF–polymerase chain reaction for herpes simplex virus 1 and 2, varicella-zoster virus, enterovirus, and cartridge-based nucleic acid amplification test (CBNAAT) for tuberculous meningitis (TBM). The most common cause of AES identified in our study was TBM (16.7%), followed by leptospirosis (15.1%) and scrub typhus (11.9%). The high occurrence of TBM in our study highlights the importance of CSF-CBNAAT for all AES patients. As leptospirosis and scrub typhus are easily treatable, early detection and treatment of these infections should be recommended.

Molecular Diagnosis and Antibodies Tests for Brucellosis Detected in Aborted and Apparently Healthy Sheep and Goats in and around Al Bayda City, Libya

The goal of the current research was to evaluate antigen and antibody reaction’s method in comparison with real time PCR for detection of brucella agent in sheep and goat. Therefore, seven hundreds and twenty-eight blood and milk samples were isolated from sheep and goats apparently healthy and suspected brucellosis brought to the Veterinary Clinical Complex from areas in and around Al Bayda, Libya. Blood samples were subjected to serological tests including Rose Bengal Plate Technique (RBPT), Enzyme-linked immunosorbent test (ELISA) for detection of IgA, IgM and also milk ring test to detect the antibodies of brucella agent. Also, the samples subjected by Real Time PCR to determine the presence of bcsp31 gene (Brucella gen). Out of the total examined samples (133) 18.26%, (139) 19.09%, (3) 0.41% and (126) 17.3% were tested positive by RBPT, ELISA IgG, IgM and Real Time PCR respectively. specificity and Sensitivity of RBPT compared with real- time PCR were 98.9% and 79.59% respectively. While, sensitivity and specificity of ELISA for IgG with Real Time PCR were 79.59% and 100% respectively, while, for ELISA IgM were 6.12% and 100% respectively. In conclusion, we suggest using Real Time PCR as a supplementary test in the diagnosis of brucella disease and as a confirmatory test in suspicious cases.

Seroprevalence and risk factors of Toxoplasmosis in HIV positive and negative patients attending the Bamenda Regional Hospital, North West Region, Cameroon

Background: Toxoplasmosis, caused by Toxoplasma gondii, can infect almost all warm-blooded animals including humans. T. gondii is regarded as an important opportunistic pathogen that can cause infection in HIV/AIDS patients associated with high mortality. The objective of this study is to determine the prevalence and risk factors of T. gondii infection in HIV-positive and negative patients and establish the relationship between HIV viral load and active toxoplasmosis in the Bamenda Regional Hospital Cameroon. Methodology: Three hundred and three (201 HIV-positive and 102 HIV-negative) participants attending the Bamenda Regional Hospital, Cameroon, were randomly recruited into the study. Well-structured questionnaires were used to obtain information on demographic characteristics and potential risk factors from each participant. Venous blood samples were collected for serological detection of toxoplasmosis using One-Step Toxo IgG/IgM rapid diagnostic test (RDT) kits, followed by confirmation of all positive samples by Toxoplasma IgM ELISA test. Data were analysed on SPSS version 23.0. Association of potential risk factors with seroprevalence of toxoplasmosis was done using Chi square test, and comparison of means HIV loads between participant categories was done using Mann-Whitney U-test and Kruskal-Wallis as applicable, with p<0.05 considered as significant level. Results: Of the 303 participants, 93 were positive for Toxoplasma IgG, giving latent toxoplasmosis seroprevalence rate of 30.7%, while 2 of the 303 participants were seropositive for Toxoplasma IgM, indicating active toxoplasmosis in 0.7%. The seroprevalence of latent toxoplasmosis was 28.9% (n=58/201) in HIV-positive compared to 34.3% (n=35/102) in HIV-negative participants (χ2=0.948, OR=0.775, p=0.330), while the seroprevalence of active toxoplasmosis was 1.0% (n=2/201) in HIV-positive compared to 0% (n=0/102) in HIV-negative participants (χ2=0.068, OR=2.568, p=0.552). Viral load was detectable (≥ 42 viral copies/ml) in 54 of the 201 HIV-positive participants, giving an overall detectable viral load rate of 26.9%. The sero-prevalence of latent toxoplasmosis was higher in HIV-positive participants with detectable viral load than those with non-detectable viral load, and the two HIV-positive patients with active toxoplasmosis had detectable viral loads. The risk factors significantly associated (p<0.05) with the latent toxoplasmosis were owning a cat, presence of stray cats, playing with cats, and eating soya. Conclusion: Latent toxoplasmosis is prevalent among HIV-positive and negative patients attending the Bamenda Regional Hospital in Cameroon, with active infection only among HIV-infected patients.

Persistence of West Nile Virus circulation in North-East region of India: A prospective facility-based study spanning over a decade.

To understand the distribution and presence of West Nile (WN) among the acute encephalitis syndrome (AES) patients, a prospective facility-based study was conducted over 13 years (2007-2019). During the period, 8957 patients hospitalized with AES in northeastern India were tested for the evidence of WN virus infection by IgM ELISA followed by Plaque reduction neutralization test (PRNT). Of the samples tested 324 (3.62%) were found positive for WN IgM antibodies and 73 paired sera showed a fourfold rise in neutralizing antibody titre by PRNT. The study establishes WN as a noteworthy cause of encephalitis in an erstwhile endemic area for Japanese encephalitis (JE). Therefore, it is important that WN is recognized as an important acute encephalitis syndrome (AES) causing aetiology in this region and the National centre for vector borne disease control (NCVBDC) guidelines for detection of AES may be modified accordingly. Thus, inclusion of WN in routine diagnosis, along with establishment of an integrative surveillance network with one-health approach will be important.

EXTRAHEPATIC MANIFESTATIONS IN PATIENTS WITH ACUTE HEPATITIS E – PAZARDZHIK, BULGARIA 2014 – 2022

BACKGROUND: Hepatitis E is a global health issue, only partially understood. Bulgarian record started in 2019 and data is not sufficient. AIM: This research aims to analyze extrahepatic manifestation of acute hepatitis E in patients with hepatitis E from Pazardzhik region, between 2014 – 2022. MATERIALS AND METHODS: The analysis includes 247 patients with acute hepatitis E, treated at the Department of Infectious Diseases of Pazardzhik Multiprofile Hospital for Active Treatment, Bulgaria between 2014 – 2022. The methodology includes clinical observation, laboratory tests and medical imaging. The diagnosis was established by serological /ELISA for anti-HEV IgM, IgG detection/and molecular-biological tests /RT-PCR for HEV RNA detection/. RESULTS: We observed extrahepatic manifestations in 19% (47/247) of the cases. In 60% (28/47) comorbidities were present, and 9% (4/47) were with underlying acute/chronic coinfection with another hepatotropic virus. Thrombocytopenia was found in 83% (39/47) of the patients; asymptomatic creatine kinase elevation – in 13% (6/47), acute pancreatitis – in 9% (4/47), transitory renal impairent – in 6% (3/47); 2% (1/47) had Guillain-Barré syndrome (GBS), 2% (1/47) – arrhythmia and 13% (6/47) – multiorgan involvement. While 91% (43/47) of the patients recovered, in 9% (4/47) the outcome was fatal. CONCLUSION: Extrahepatic manifestations might prevail, potentially delaying diagnosis of HEV-infection. Symptoms associated with comorbidities might also impede the final diagnosis. A diagnostic algorithm is needed to enhance the accurate diagnosis of HEV in patients with dubious symptoms.

Serologic evidence of dengue and chikungunya among patients with acute febrile illness in Ghana, 2016 – 2018

ObjectiveThis study aimed to describe the exposure levels to Dengue and Chikungunya viruses among individuals presenting with febrile illnesses in Ghana between January 2016 to June 2018. MethodsThe study was conducted in health facilities in seven selected regions in Ghana; namely, Ashanti, Greater Accra, Northern, Upper West, Volta, and Western regions. Patients who met the case definition were enrolled in the study. A total of 1105 blood samples were collected from patients from 2016 to 2018 and serological analysis of Dengue and Chikungunya viruses were performed with ELISA IgM and IgG commercial kits (Abcam, Cambridge, UK). ResultsAnalysed results indicated that Dengue and Chikungunya viruses showed seropositivity of 62.0% and 40.0% respectively. All processed samples tested negative for Dengue and Chikungunya using the Polymerase Chain Reaction (PCR) assay. Greater Accra and Ashanti regions recorded the highest positivity for Chikungunya and Dengue fever viruses respectively. ConclusionThough no detection of Dengue and Chikungunya using molecular tools, the seropositivity suggests the need for an established surveillance for arboviruses to monitor transmission of these pathogens for epidemic preparedness and response.

Diagnostic Dilemma between Scrub Typhus Meningoencephalitis and Dengue Encephalopathy Resolved! - A Novel Prediction Score.

Scrub typhus and dengue, common etiologies of acute encephalitis syndrome, present with similar clinico-laboratory profiles but differ in management protocol. We aimed to devise a score differentiating between scrub typhus meningoencephalitis (STM) and dengue encephalopathy (DE). A prospective cohort of 204 children, (aged 6 months to 14 years) presenting with acute encephalitis syndrome in a public teaching hospital in northern India was subjected to standardized workup including serum IgM against Orientia tsutsugamushi and Dengue virus. Clinico-laboratory features were compared between STM and DE using univariate and multivariate analysis. Area under the receiver operating characteristic (ROC) curve (AUROC) for the score derived from independent predictors and its sensitivity, specificity, predictive values was calculated at cutoffs. STM and DE IgM ELISA were positive in 38 (18.6%) and 41 (20.1%) children, respectively. Longer duration of fever, prodromal stage, respiratory complaints and pneumonia were significantly frequent in STM; however, swelling, petechiae and myalgia were significantly prevalent in DE. STM had higher blood total leukocyte count (TLC), higher CSF protein and lower CSF sugar compared to DE. At admission, TLC >10,000/mm3, pneumonia, absence of myalgia and petechiae were independent predictors for differentiating STM from DE. AUROC of novel score (range: -5 to 5) was 0.879 (95% CI: 0.805-0.952). Score at cutoff ≥5 had 100% specificity and 100% PPV for differentiating STM from DE. Prediction score may benefit physicians to differentiate between these two infections and treat them accordingly.

Measles immunity status in Iranian infants and children and outbreak concerns: Time for reconsidering the vaccination schedule?

Introduction: Measles vaccination has greatly reduced the disease burden worldwide, but challenges remain due to variations in vaccine effectiveness across age groups. This study aimed to assess the serological profile of measles antibodies across different age groups, evaluate the impact of maternal immunity on antibody levels in infants under 12 months, and assess measles immunity in vaccinated individuals. Material and methods: This cross-sectional study was conducted from June 2022 to January 2023 at the Children’s Medical Center, a referral hospital in Iran. Serum samples were tested for measles-specific IgG and IgM antibodies using a commercial enzyme-linked immunosorbent assay (ELSA). An avidity assay was performed to assess measles virus-specific IgG antibodies on the samples that were positive and borderline for the measles IgG ELISA. Results: The study included 969 participants across various age groups. Among them, 23% (221 out of 953) tested positive for measles IgM ELISA, and 52% (504 out of 969) for measles IgG ELISA. Regarding the avidity assay for measles virus-specific IgG, the majority (418 out of 573, 73%) showed high-avidity antibodies. Measles-specific IgG levels varied significantly across different age groups, with infants below 6 months old showing a mean IgG level of 477 mIU/mL, declining to 230 mIU/mL between 6 and 12 months, and increasing significantly to 683 mIU/mL in the 12 to 18 month age group, reaching a peak at 938 mIU/mL among children aged 18–72 months. Conclusion: The increasing IgM positivity among young Iranians suggests a rising risk of measles outbreaks, possibly due to vaccination gaps. Inadequate antibody levels in infants raise concerns about vaccination effectiveness. Considering declining maternal antibodies, vaccinating infants at 6–9 months could be beneficial. Boosters for adolescents and women may further mitigate outbreak risks.

A case-control study of the association of toxoplasmosis with antirheumatic therapy in rheumatoid arthritis

Background & Objective: Toxoplasmosis is a globally prevalent opportunistic zoonotic infection. Rheumatoid arthritis (RA) is an autoimmune disease which is manifested as joint inflammation, pain, stiffness, and swelling. The patients may contract toxoplasmosis, especially when receiving antirheumatic immunosuppressive therapy. However conflicting results have been reported on toxoplasmosis in RA patients. We aimed to evaluate Toxoplasma gondii positivity and associated risk factors in patients with RA in Duhok province, Iraq, and to assess the role of antirheumatic therapy in toxoplasmosis and the possibility of its reactivation. Methodology: This case-control study was carried out in Duhok, Kurdistan Region, Iraq, from February 2022 to June 2023. A total of 88 RA patients, with and without concurrent antirheumatic therapy, were recruited. The diagnosis of RA was according to the 2010 American College of Rheumatology/European League. RA-patients were categorized into three groups: Group 1 - no-therapy (n = 14); Group 2 - conventional therapy (n = 49) and Group 3 - biologics in combination with conventional medications (n = 25). Healthy subjects (n = 61) were also selected as controls. Plasma samples obtained from the participants were screened for T. gondii infection using Human anti-Toxoplasma gondii antibody IgG. IgG positive samples were tested utilizing human anti-Toxoplasma gondii antibody IgM ELISA Kit and the avidity T. gondii IgG ELISA kit was used to determine the state of infection. Results: Of the 88 RA patients, with or without antirheumatic therapy, 76 (86.36%) were females and 12 (13.64%) were males. Patients on therapy (n = 74) received several conventional antirheumatic drugs of which methotrexate was the most frequently used one (86.36%). Among biological therapies, etanercept, a TNF-alpha inhibitor, was mostly used (13.51%). The toxoplasmosis was significantly less in the older age group (> 50 y) compared to individuals under 30 y. Gender had no significant effect. Toxoplasma IgG positivity was found to be significantly higher in the three groups of RA patients in comparison with healthy controls. Further assessment of anti-Toxoplasma IgM positivity and Toxoplasma IgG avidity results to identify the state of T. gondii infection in anti-Toxoplasma IgG positive subjects revealed that the frequency of reactivation of toxoplasmosis in RA patient groups was not significantly different from that of the control counterparts. Conclusion: The study showed higher seroprevalence of anti-Toxoplasma antibodies in patients with RA irrespective of therapy; therefore, we could consider toxoplasmosis interaction with RA in the pathogenesis of both diseases. This seroprevalence was higher in younger age groups, but with no significant role of gender, duration of disease, duration of therapy and its type. No significant difference was noted in rates of reactivation of latent T. gondii infection among RA patients and healthy controls. Abbreviations: CI - Confidence interval; O - Odds ratio; RA - Rheumatoid arthritis; SD - Standard deviation; T. gondii - Toxoplasma gondii; TNF - Tumor necrosis factor. Keywords: Autoimmune disease; Rheumatoid arthritis; Antirheumatic drugs; Toxoplasma gondii; Toxoplasma seroprevalence; Toxoplasma IgG avidity. Citation: Abdullah RG, Eassa SH, Mohammad FK. A case-control study of the association of toxoplasmosis with antirheumatic therapy in rheumatoid arthritis. Anaesth, pain intensive care 2024;28(4):674−680; DOI: 10.35975/apic.v28i4.2510 Received: May 14, 2024; Reviewed: June 28, 2024; Accepted: June 28, 2024

Performance evaluation of microfluidic microplate-based fluorescent ELISA for qualitative detection of SARS-CoV-2–specific IgG and IgM

We evaluated the diagnostic performance of newly developed microfluidic microplate-based fluorescent ELISA for anti-SARS-CoV-2 antibody detection: the Veri-Q opti COVID-19 IgG and IgM ELISAs (hereafter, “Opti IgG/M”; MiCo BioMed, Gyeonggi-do, Republic of Korea), in comparison with conventional ELISAs. A total of 270 serum samples were analyzed, among which 90 samples were serially obtained from 25 COVID-19 patients. Another 180 samples were collected from 180 SARS-CoV-2–negative individuals. As comparative assays, we used SCoV-2 Detect IgG/M ELISA (hereafter, “InBios IgG/M”; InBios, Seattle, WA, USA) and Veri-Q COVID-19 IgG/IgM ELISA (hereafter, “Veri-Q IgG/M”; MiCo BioMed). Compared with conventional ELISAs, the Opti IgG yielded 97.1–100.0% positive percent agreement, 95.2–98.0% negative percent agreement, 96.3–97.8% total percent agreement, and kappa values of 0.90–0.94. Between the Opti IgM and the InBios IgM, the values were 93.7%, 96.6%, 95.9%, and 0.89, respectively. For the Opti IgG, sensitivities for the samples collected from 0–7, 8–14, 15–21, and ≥ 22 days after symptom onset were 40.0, 58.3, 94.1, and 100.0%, respectively. The values for the Opti IgM were 30.0, 54.2, 88.2, and 80%, respectively. The diagnostic specificities of the Opti IgG and IgM were 99.4 and 97.2%, respectively. The microfluidic microplate-based fluorescent ELISAs showed comparable diagnostic performance to conventional ELISAs for detecting anti-SARS-CoV-2 antibodies. With the combination of high throughput, a simplified workflow, and the ability to analyze reduced volumes, this new technology has great potential for improving SARS-CoV-2 serologic testing.

Epidemiological analysis of leptospirosis, dengue, and Co-infection rates among febrile illness cases in Dakshina Kannada, Karnataka

IntroductionLeptospirosis and dengue are two significant public health concerns in tropical and subtropical regions, often resulting in severe forms of disease and fatality. This study addresses the pressing public health issues of leptospirosis and dengue in the Dakshina Kannada district of Karnataka, India. Both diseases pose significant health risks and are relatively understudied in this region, making it essential to investigate their prevalence and clinical presentations for targeted healthcare planning. AimThe primary aim is to determine the frequency of leptospirosis and dengue among febrile illness cases to understand the epidemiological patterns and assess co-infection rates in Dakshina Kannada. MethodBetween 2020 and 2021, serum samples suspected of leptospirosis were tested using IgM ELISA (n = 1629) and the Microscopic Agglutination Test (MAT) (n = 92) for leptospirosis, while dengue was tested using NS1Ag and IgM antibodies ELISA (n = 1415). Data were collected through medical records and patient interviews. Seasonal trends, gender, and age distributions were analyzed. ResultThe study found a significant prevalence of leptospirosis (21 %) and dengue (10 %) among febrile illness cases in the study area, with a 1.3 % co-infection rate. Clinically, fever was common to both diseases, but leptospirosis also frequently exhibited symptoms such as abdominal pain, myalgia, and jaundice. MAT screening revealed a predominance of anti-leptospiral antibodies against the Djasiman, Pyrogenes, Hurstbridge, Hebdomadis, and Grippotyphosa serogroups in Dakshina Kannada. ConclusionThe study highlights the urgent need for focused public health interventions, improved diagnostic tools, and targeted epidemiological studies to manage these diseases. The findings underscore the necessity of enhancing diagnostic capabilities and public health awareness, particularly considering the significant health risks posed by leptospirosis and dengue in the region.

Comparison of the Accuracy of HSV1 and HSV2 Antibody Tests with PCR in the Diagnosis of Recurrent Genital Herpes.

To assess the accuracy of HSV1and HSV2 antibody testing in identifying genital herpes infection. A cohort of 299 patients previously diagnosed with recurrent genital herpes, confirmed via PCR, were tested using ELISA for HSV1 and HSV2 IgM and IgG antibodies. The study compared the accuracy of HSV1 and HSV2 antibody tests in diagnosing genital herpes. Among 299 patients, 14 tested positives for HSV1 DNA. Of these, 9 had HSV1 IgG antibodies, but none had HSV2 IgG antibody. Among 278 patients with HSV2 DNA, 149 had HSV1 IgG, 9 had HSV2 IgG, and 97 had both. Seven patients had both HSV1 and HSV2 DNA; 3 had HSV1 IgG, 1 had HSV2 IgG, and 3 had both. The accuracy of HSV1 IgG for HSV1 infection was 64.2%, and for HSV1 and HSV2 co-infection, 85.7%. The accuracy of HSV2 IgG for HSV2 infection was 38.1%, and for HSV1 and HSV2 co-infection, 57.1%. The combined antibody positivity accuracy was 34.9%. Genital herpes is primarily caused by HSV2 (92.98%). A smaller percentage is HSV1 (4.67%) or co-infection (2.34%). Despite relatively low diagnostic accuracy (34.9-85.7%) for antibody detection, combined antibody testing is necessary. Herpes DNA testing is recommended for accurate diagnosis. Absence of antibodies does not rule out genital herpes and clinical assessment is essential.

Detection of IgM antibodies against bovine viral diarrhea virus using IgM capture ELISA on farms with persistently infected cattle

Bovine viral diarrhea (BVD) is a serious disease in cattle and causes economic losses in the livestock industry. Bovine viral diarrhea virus (BVDV) is the causative agent of BVD and spreads among herds via persistently infected (PI) animals that shed large amounts of the virus throughout their lives. Hence, identifying, and culling PI animals and assessing the immune status against BVDV on farms are important strategies for controlling BVD. Additionally, estimating the time when individuals around PI animals were infected with the virus could also be supportive information to interpret a farm status. We herein constructed a BVDV-specific IgM capture ELISA using recombinant E2 antigen and applied it to detecting BVDV-specific IgM antibodies on farms with identified PI cattle. The IgM ELISA detected anti-BVDV IgM antibodies during approximately 2–3 weeks post infection and identified IgM-positive cattle on two farms with recognized PI cattle. Virus neutralization tests showed that almost all adult cattle had high virus neutralization antibodies against BVDV, and sero-positive and -negative cattle coexisted in young herds. In this situation, most of the IgM-positive cattle were in relatively young animals, implying that BVDV had been recently spreading in these young herds. Thus, our findings demonstrated that detecting IgM antibodies could be useful to know recent BVDV infection on farm on which PI cattle were identified.

Investigation of atypical serological profiles for Epstein-Barr virus (EBV)

BackgroundCommercial immunoassays that detect IgG and IgM directed toward VCA and IgG EBNA are used in combination to assess EBV immune status. However, this strategy does not always confirm/exclude recent/past EBV infection or absence of immunity. ObjectivesThe aim of our study was to perform complementary investigations on samples with atypical EBV serological profiles, in order to identify the clinical situation they correspond to. Study designEBV serology was performed using EBV VCA IgM/IgG and EBNA IgG LXL® DiaSorin assay. Complementary investigations included ELISA IgM VCA, immunoblots, CMV IgM/IgG and CMV IgG avidity, and EBV PCR. ResultsIn our study, 12810 EBV serological results were analyzed, and 3580 atypical profiles were detected (28 %). Among these latter, isolated VCA IgG represented 42.9 %, the three positive markers accounted for 29.1 %, isolated EBNA IgG represented 18.5 %, isolated VCA IgM accounted for 6.4 % and positive VCA IgM & positive EBNA IgG represented 3.1 %. VCA IgG detected alone were specific in 100 % cases and EBNA IgG detected alone were specific in 91.7 % cases. VCA IgM detected alone were false positive or due to a cross reaction with CMV in 52.8 % cases. The pattern positive VCA IgM and positive EBNA IgG correspond to a false positive in VCA IgM, EBNA IgG or both in 83.4 % cases. Positive EBV VCA IgM/IgG and EBNA IgG were unreliable to detect active EBV infection in 66.7 % cases. DiscussionAtypical EBV serological profiles may correspond to several clinical situations and complementary investigations allow to determine the immune status in more than 98.5 % cases.

Epidemiological Features of Leptospirosis and Identification of Leptospira wolffii as a Persistently Prevailing Species in North-Central Bangladesh.

Leptospirosis is considered to be the most widespread, yet neglected, re-emerging zoonotic disease caused by infection with a pathogenic species of the genus Leptospira. Although this disease is prevalent in Bangladesh, the recent epidemiological status has not yet been well documented. In this study, we aimed to determine the prevalence of leptospirosis among febrile patients using different diagnostic methods and to characterize the epidemiological features and species of Leptospira in Mymensingh, north-central Bangladesh. Among the blood samples of 186 patients with suspected leptospirosis who met the inclusion criteria, including having a fever for more than 5 days (November 2021-June 2022), 88 samples (47%) were Leptospira-positive according to IgM LAT, IgM ELISA, or nested PCR (positivity rates: 38%, 37%, and 42%, respectively). Nested PCR showed a significantly higher positivity rate (54%) in patients with a short fever (5-10 day) than the other methods did, with lower rates among those with a longer fever. Leptospirosis cases were more common in males (68%), those 16-45 years of age (70%), residents of rural areas (81%), and farmers (41%). In addition to a fever, myalgia and jaundice were found in more than 70% of the patients, while variable symptoms were observed. The 16S rRNA sequencing analysis revealed that the Leptospira species in all the 22 samples tested were L. wolffii, belonging to the pathogenic subclade P2. This study showed the recent epidemiological features of leptospirosis in Bangladesh, indicating the presumptive predominance of L. wolffii since 2019.

Development and Evaluation of a Noninvasive Microfluidic-Based Paper Analytical Device for Leptospirosis Diagnosis.

Leptospirosis is a re-emerging infectious disease that presents a diagnostic enigma for clinicians with frequent misdiagnosis due to lack of rapid and accurate diagnostic tests, as the current methods are encumbered by inherent limitations. The development of a diagnostic sensor with a sample-in-result-out capability is pivotal for prompt diagnosis. Herein, we developed a microfluidic paper-based analytical device (spin-μPAD) featuring a sample-in-result-out fashion for the detection of Leptospira specific urinary biomarker, sph2 sphingomyelinase, crucial for noninvasive point-of-care testing. Fabrication of paper devices involved precise photolithography techniques, ensuring a high degree of reproducibility and replicability. By optimizing the device's configuration and protein components, a remarkable sensitivity and specificity was achieved for detecting leptospiral sph2 in urine, even at low concentrations down to 1.5 fg/mL, with an assay time of 15 min. Further, the spin-μPAD was validated with 20 clinical samples, suspected of leptospirosis including other febrile illnesses, and compared with gold standard microscopic agglutination test, culture, Lepto IgM ELISA, darkfield microscopy, and Leptocheck WB spot test. In contrast to commercial diagnostic tools, the spin-μPAD was noninvasive, rapid, easy to use, specific, sensitive, and cost-effective. The results highlight the potential of this innovative spin-μPAD for an efficient and dependable approach to noninvasive leptospirosis diagnosis, addressing critical needs in the realms of public health and clinical settings.

STUDY OF PREVALENCE OF SCRUB TYPHUS IN ACUTE FEBRILE ILLNESS IN A TERTIARY CARE HOSPITAL, VISAKHAPATNAM

Objective: Re-emergent cases of rickettsial disease, the scrub typhus is seen prevalent in cases of acute febrile illness. The objective of this study was to study the magnitude and prevalence of scrub typhus in a tertiary care hospital. Methods: This prospective study was carried on for a period of one year from February 2023 to February 2024. Inpatients between the age group of 16 to 25 y with a triad of fever for more than 5 d of onset with or without an eschar, headache, myalgia and abnormal haematological and biochemical parameters were included in the study. IgM ELISA for scrub typhus was performed. Results: Prevalence of scrub typhus in this study was 9.4% with higher male preponderance of 69.4% in 18 y age group 28.6%. Positive cases were recorded higher during post monsoon season of September 18.9%. Co-infection with dengue and malaria observed in 2 cases and ARDS was the complication in 3 cases. No mortality in this study. Conclusion: It is important to get familiar with the clinical and diagnostic laboratory findings of scrub typhus so as to differentiate it from other aetiologies of acute febrile illness.

Diagnosis of Dengue by Serology (NS-1 Antigen and IgM ELISA) and Identification of Serotypes by RT-PCR at a Tertiary Care Hospital, Jaipur, Rajasthan

Diagnosis of Dengue by Serology (NS-1 Antigen and IgM ELISA) and Identification of Serotypes by RT-PCR at a Tertiary Care Hospital, Jaipur, Rajasthan

Re-Emergence of Rift Valley Fever Virus Lineage H in Senegal in 2022: In Vitro Characterization and Impact on Its Global Emergence in West Africa.

Rift Valley fever (RVF) is a re-emerging vector-borne zoonosis with a high public health and veterinary impact. In West Africa, many lineages were previously detected, but since 2020, lineage H from South Africa has been the main cause of the outbreaks. In this study, clinical samples collected through national surveillance were screened for RVF virus (RVFV) acute infection by RT-PCR and IgM ELISA tests. Sequencing, genome mapping and in vitro phenotypic characterization in mammal cells were performed on RT-PCR positive samples in comparison with other epidemic lineages (G and C). Four RVFV human cases were detected in Senegal and the sequence analyses revealed that the strains belonged to lineage H. The in vitro kinetics and genome mapping showed different replication efficiency profiles for the tested RVFV lineages and non-conservative mutations, which were more common to lineage G or specific to lineage H. Our findings showed the re-emergence of lineage H in Senegal in 2022, its high viral replication efficiency in vitro and support the findings that genetic diversity affects viral replication. This study gives new insights into the biological properties of lineage H and calls for deeper studies to better assess its potential to cause a future threat in Senegal.

A Case Series on Spotted Fever and Typhus Fever Seropositivity at National Center for Disease Control and Epidemiological Perspective.

Background: The rickettsioses, except for typhus fever and scrub typhus (ST), were not really recognized as distinct clinical entities until the early 20th century. Only when specific rickettsial serologic testing was introduced in the 1940s could the precise etiologies of various rickettsial diseases (RDs) be determined with certainty. Although ST is a well- recognized zoonotic disease entity, but non-scrub typhus rickettsial infection like spotted fever group and typhus group are not well studied in India and are still underestimated. Methods: We report cases who had shown seropositivity of spotted fever and typhus fever RD in IgM and IgG ELISA whose samples were referred from various hospitals of Delhi/National Capital Region in which clinicians had strong suspicion of rickettsiosis other than ST or Weil-Felix test found positive for any of the OX2, 19, and K antigens. Results: We reported 18 cases of SFG and TGRD with mostly cases presented with fever followed by hepato-intestinal symptoms. Conclusion: The vast variability and nonspecific presentation of rickettsiosis in spotted and typhus fever at times have often made it difficult to diagnose clinically. Prompt antibiotic therapy shortens the course of the disease, lowers the risk of complications, and in turn, reduces morbidity and mortality owing to RDs. There is a distinct need for physicians and health care workers at all levels of care in India to be aware of the clinical features, available diagnostic tests and their interpretation, and the therapy for these infections.