Prevalence of Anti-leptospiral IgM and Detection of Pathogenic Leptospira Species DNA in Neonates Presenting With Clinical Sepsis in Southwestern Uganda

BackgroundLeptospirosis is an emerging neglected zoonotic disease that presents with nonspecific signs/symptoms and it can be mistaken for other diseases. Due to limited diagnostic capacity and unawareness, data on human leptospirosis particularly in neonates is scarce in many sub-Saharan countries. It has been underreported hindering preventive and control measures in place. The study aimed at determining prevalence of leptospirosis as a cause of febrile illness in neonates using a commercially available IgM ELISA and a quantitative real-time PCR (qPCR). MethodsThis was a descriptive cross-sectional study that included 103 neonatal sepsis cases whose parents/legal guardians gave informed consent. Data on demographic and clinical characteristics was collected using structured data collection form. EDTA whole blood sample was collected from the neonates by trained study nurses. From the samples, IgM ELISA was done using automated analyzers, DNA extracted and qPCR was performed using primers for LipL32, specific for the pathogenic leptospires. ResultsThe prevalence of anti-leptospiral IgM among the neonates as determined by ELISA was 4.3%, where all of them presented with lethargy and poor feeding. No pathogenic Leptospira species DNA was amplified by qPCR.ConclusionsEvidence of leptospirosis was demonstrated in neonatal sepsis cases in this study. The findings suggest considerations of leptospirosis in the differential diagnosis of neonates with sepsis. More data is needed on the real epidemiology, clinical features and burden of leptospirosis in neonates. There is need to include intermediate pathogenic species of Leptospira in the diagnostic qPCR assays.

Development of Monoclonal Antibody Based IgG and IgM ELISA for Diagnosis of Severe Fever with Thrombocytopenia Syndrome Virus Infection

Background: Severe fever with thrombocytopenia syndrome virus (SFTSV) is a newly emerged virus that possesses a great threat to human health because of the high fatality rate. Method: To develop sensitive and specific sero-diagnosis systems for SFTSV infections, monoclonal antibodies (MAbs) against recombinant SFTSV nucleocapsid (rSFTSV-N) protein were developed by immunizing BALB/C mice with rSFTSV-N protein and fusing the spleen cells with SP2/0 myeloma cells. Three hybridoma cell lines secreting MAbs against rSFTSV-N were obtained. MAb based IgG sandwich enzyme linked immunosorbent assay (ELISA) and IgM capture ELISA systems were established by using the newly developed MAbs. One hundred fifteen clinical suspected SFTS patient serum samples were used to evaluate the newly established systems by comparing with the total antibody detecting sandwich ELISA system and indirect ELISA systems. Results: The MAb based sandwich IgG ELISA was perfectly matched with that of the total antibody sandwich ELISA and the indirect IgG ELISA with a sensitivity and specificity of 100%. IgM capture ELISA results perfectly matched with that of the total antibody sandwich ELISA while was more sensitive comparing with the indirect IgM ELISA. Conclusions: The MAbs against rSFTSV-N protein offer new tools for SFTSV studies and our newly developed MAb-based IgG and IgM capture ELISA systems would offer safe and useful tools for diagnosis of SFTS virus infections and epidemiological investigations.

Acute cerebellar ataxia: a rare presentation of scrub typhus in pediatric age group

Scrub typhus is known to cause local and systemic vasculitic response in almost all the systems of the body. Scrub typhus very rarely presents itself with CNS manifestations. In central nervous system it most commonly causes meningitis and encephalitis although several other atypical presentations have been documented. Cerebellar ataxia, which is the lack of coordination, has a number of causes none of which are as uncommon or unheard of as Scrub Typhus. We report a case of a 15 years old child presenting with fever and isolated acute cerebellitis. Scrub Typhus was diagnosed by serum IgM ELISA. Patient showed rapid response to doxycycline therapy.

Evidence of Chikungunya virus seroprevalence in Myanmar among dengue-suspected patients and healthy volunteers in 2013, 2015, and 2018

Introduction Chikungunya virus (CHIKV) is a mosquito-borne virus known to cause acute febrile illness associated with debilitating polyarthritis. In 2019, several institutions in Myanmar reported a CHIKV outbreak. There are no official reports of CHIKV cases between 2011 and 2018. Therefore, this study sought to determine the seroprevalence of CHIKV infection before the 2019 outbreak. Methods A total of 1,544 serum samples were collected from healthy volunteers and patients with febrile illnesses in Yangon, Mandalay, and the Myeik district in 2013, 2015, and 2018. Participants ranged from one month to 65 years of age. Antibody screening was performed with in-house anti-CHIKV IgG and IgM ELISA. A neutralization assay was used as a confirmatory test. Results The seroprevalence of anti-CHIKV IgM and anti-CHIKV IgG was 8.9% and 28.6%, respectively, with an overall seropositivity rate of 34.5%. A focus reduction neutralization assay confirmed 32.5% seroprevalence of CHIKV in the study population. Age, health status, and region were significantly associated with neutralizing antibodies (NAbs) and CHIKV seropositivity (p < 0.05), while gender was not (p = 0.9). Seroprevalence in 2013, 2015, and 2018 was 32.1%, 28.8%, and 37.3%, respectively. Of the clinical symptoms observed in participants with fevers, arthralgia was mainly noted in CHIKV-seropositive patients. Conclusion The findings in this study reveal the circulation of CHIKV in Myanmar’s Mandalay, Yangon, and Myeik regions before the 2019 CHIKV outbreak. As no treatment or vaccine for CHIKV exists, the virus must be monitored through systematic surveillance in Myanmar.

Chất lượng bộ sinh phẩm Polyvac - SARS-CoV-2 IgG/M ELISA chẩn đoán phát hiện kháng thể SARS - COV-2 trên các mẫu lâm sàng

Nghiên cứu này nhằm mục tiêu đánh giá bộ sinh phẩm phát hiện kháng thể IgG/M kháng SARS-CoV-2 bằng ELISA do POLYVAC sản xuất (Polyvac SARS-CoV-2 IgG/M ELISA). Nghiên cứu được tiến hành trên 633 mẫu huyết thanh gồm 302 mẫu dương tính và 331 mẫu âm tính lấy từ bệnh nhân (2020) đã được khẳng định bằng RT-PCR. Có 200 mẫu dương tính và 200 mẫu âm tính được thực hiện so sánh với Elecsys Anti-SARS-CoV-2 của Roche Diagnostics. Kết quả cho thấy Polyvac SARS-CoV-2 IgG ELISA có độ nhạy 86,42%, độ đặc hiệu 100%; Polyvac SARS-CoV-2 IgM ELISA có độ nhạy 85,43% và độ đặc hiệu 95,77% so với RT-PCR trên các mẫu lâm sàng. Ở thời điểm sau khi có triệu chứng 0 - 7 ngày, 8 - 14 ngày, >14 ngày độ nhạy của bộ sinh phẩm tương ứng trung bình là 34,15 % ( 21,56% - 44,45%), 92,05% (84,49% - 96,17%), 97,97% (94,21% - 99,31) với IgG và 70,73% (55,22% - 82,39%), 78,41% (68,72% - 85,72%), 92,57% (87,18% - 95,80%) với IgM. Độ tương đồng giữa Polyvac SARS-CoV-2 IgG/M ELISA và Elecsys Anti-SARS-CoV-2 với mẫu âm tính là 81% (76,49 - 86,09 %), mẫu dương tính là 98,04% (94,40 - 99,33%), độ tương đồng giữa 2 bộ sinh phẩm là 88,04% (84,45-90,83%). Polyvac SARS-CoV-2 IgG/M ELISA có thể sử dụng trong giám sát dịch tễ huyết thanh học để xác định tiền sử có phơi nhiễm với SARS-CoV-2 và hỗ trợ chẩn đoán ở giai đoạn sau 7 ngày phát hiện có triệu chứng.

Leptospirosis infections among hospital patients, Sarawak, Malaysia

Background Leptospirosis diagnoses have increased in Sarawak, Malaysia in recent years. Methods To better understand the burden of disease and associated risk factors, we evaluated 147 patients presenting with clinical leptospirosis to local hospitals in Sarawak, Malaysia for the presence of Leptospira and associated antibodies. Sera and urine specimens collected during the acute illness phase were assessed via a commercially available rapid diagnostic test (Leptorapide, Linnodee Ltd., Antrim, Northern Ireland), an ELISA IgM assay (Leptospira IgM ELISA, PanBio, Queensland, Australia) and a pan-Leptospira real-time PCR (qPCR) assay to estimate disease prevalence and diagnostic accuracy of each method. Microagglutination testing was performed on a subset of samples. Results Overall, 45 out of 147 patients (30.6%) showed evidence of leptospires through qPCR in either one or both sera (20 patients) or urine (33 patients), and an additional ten (6.8%) were considered positive through serological testing, for an overall prevalence of 37.4% within the study population. However, each diagnostic method individually yielded disparate prevalence estimates: rapid test 42.2% for sera and 30.5% for urine, ELISA 15.0% for sera, qPCR 13.8% for sera and 23.4% for urine. Molecular characterization of a subset of positive samples by conventional PCR identified the bacterial species as Leptospira interrogans in 4 specimens. A multivariate risk factor analysis for the outcome of leptospirosis identified having completed primary school (OR = 2.5; 95 CI% 1.0–6.4) and weekly clothes-washing in local rivers (OR = 10.6; 95 CI% 1.4–214.8) with increased likelihood of leptospirosis when compared with those who had not. Conclusion Overall, the data suggest a relatively high prevalence of leptospirosis in the study population. The low sensitivities of the rapid diagnostic test and ELISA assay against qPCR highlight a need for better screening tools.

A study on serodiagnosis of scrub typhus in a Teaching Hospital of South India

Background: crub typhus is caused by Orientia tsutsugamushi (rickettsial disease) commonly transmitted by the bite of larval chiggers of trombiculid mites. It has been one of the important causes of febrile illness, especially in south India. The clinical diagnosis is difficult owing to the non-specific presentation. We in the current study tried to evaluate the serodiagnosis of scrub typhus with the Weil Felix test and IgM ELISA. Methods: This study was conducted in the Department of Microbiology, Prathima Institute of Medical Sciences, Naganoor, Karimnagar. All the sera samples were subjected to the Weil Felix test using Proteus OX2, OX19, OX-K strain agglutination test, and subsequently, Scrub typhus IgM ELISA test. Results: All the samples were subjected to the Weil Felix test n=4(6.06%) were positive for scrub typhus (OXK antigen) n=11(16.67%) were positive for the spotted group of fever (OX2 antigen) and n=10 (15.15%) were positive of typhus group (OX19 antigen). N=5 sera samples were positive for more than one type of antigens. All the n=66 serum samples were subjected to IgM ELISA for scrub typhus. Out of n=66, only two serum samples (3.03%) were positive by IgM ELISA. Conclusion: Scrub typhus is emerging as an important public health issue. It is one of the important causes of acute febrile illness. Although it is difficult to distinguish scrub typhus based on the clinical symptoms alone a simple test such as Weil Felix was found to be promising in the diagnosis of scrub typhus. ELISA IgM test may be performed additionally in laboratories with adequate facilities. Hence for clinicians, any case with a fever of unknown origin should arouse suspicion of scrub typhus

Evaluation of a genus-specific rGroEL1-524 IgM-ELISA and commercial ELISA kits during the course of leptospirosis in Thailand

In the present study, we developed a genus-specific rGroEL1-524 IgM-ELISA assay for use in screening diagnosis of suspected leptospirosis among acute undifferentiated febrile illness patients during acute fever. The diagnostic accuracies of the rGroEL1–524 IgM-ELISA, commercial Panbio IgM-ELISA, and Virion-Serion Classic IgG-ELISA were evaluated using 133 Thai leptospirosis sera and 210 controls. Sensitivities were 91.7%, 59.6%, and 17.7% for acute infection, and the specificities were 92.6%, 90.2%, and 88.3% for the non-leptospirosis control, respectively. The rGroEL1-524 IgM-ELISA had high sensitivity, at 92.3% and 91.7%, among culture-positive and MAT-negative cases at 1–3 days post-onset of symptoms (DPO1–3), respectively. Impaired specificity on scrub typhus was found, possibly from antibody cross-reaction to ortholog GroEL. Commercial Panbio IgM-ELISA had sensitivities at DPO1–3 of 30.8% and 41.7% for culture-positive and MAT-negative cases whereas Virion-Serion IgG-ELISA showed sensitivities of 5.9% and 13.3%, respectively. The rGroEL1-524 IgM-ELISA could be useful as a screening test for early diagnosis. The performance of the commercial ELISA suggests the applicability of IgM-ELISA for diagnosis, while IgG-ELISA is useful for seroprevalence surveys. However, confirmation by reference tests is recommended.

A systematic evaluation of IgM and IgG antibody assay accuracy in diagnosing acute Zika Virus infection in Brazil; lessons relevant to emerging infections

Accurate diagnostics underpin effective public health responses to emerging viruses. For viruses, such as Zika virus (ZIKV), where the viremia clears quickly, antibody-based (IgM or IgG) diagnostics are recommended for patients who present seven days after symptom onset. However, cross-reactive antibody responses can complicate test interpretation among populations where closely related viruses circulate. We examined the accuracy (proportion of samples correctly categorized as Zika-positive or negative) for antibody-based diagnostics among Brazilian residents (Rio de Janeiro) during the ZIKV outbreak. Four ZIKV ELISAs (IgM and IgG Euroimmun, IgM Novagnost and CDC MAC), two dengue ELISAs (IgM and IgG Panbio), and the ZIKV plaque reduction neutralization test (PRNT) were evaluated. Positive samples were ZIKV PCR confirmed clinical cases collected in 2015-2016 (n=169); Negative samples (n=236) were collected before ZIKV was present in Brazil (≤2013). Among serum samples collected ≥7 days from symptom onset, PRNT exhibited the highest accuracy (93.7%), followed by the Euroimmun IgG ELISA (77.9%). All IgM assays exhibited lower accuracy (<75%). IgG was detected more consistently than IgM among ZIKV cases using Euroimmun ELISAs (68% versus 22%). Anti-DENV IgM ELISA was positive in 41.1% of confirmed ZIKV samples tested. The Euroimmun IgG assay, although misdiagnosing 22% of samples, provided the most accurate ELISA. Anti-ZIKV IgG was detected more reliably than IgM among ZIKV patients, suggesting a secondary antibody response to assay antigens following ZIKV infection. Antibody ELISAs need careful evaluation in their target population to optimise use and minimise misdiagnosis, prior to widespread deployment, particularly where related viruses co-circulate.