Seroprevalence of Leptospirosis in Suspected High Risk Sudanese Patients; A Pilot Exploratory Study

BackgroundThe extent of leptospirosis is unknown in Sudan and it might be mistaken for other more common febrile infectious diseases. Leptospirosis might also be associated with renal diseases that are common in Sudan. We intended to explore the existence of human leptospirosis in suspected high risk patients in Khartoum, Sudan, via sero-screening random febrile patients and those undergoing renal dialysis.MethodsThis is a pilot exploratory study that was conducted in 6 months period from April to September of 2013. Hospitals were selected conveniently following a non-random sampling approach. A total of 119 febrile patients (with or without definitive diagnosis) and patients under renal dialysis were included and their serum specimens, clinical and demographic data were collected. Sera were screened qualitatively for the existence of anti-leptospiral IgM antibodies using rapid lateral flow immunosorbent assay. Ethical clearance and official permissions were obtained.ResultsOut of the total 119 patients, 57 (47.9%) had end stage renal disease and were under dialysis at Renal Dialysis Unit in Asbab Charity Hospital in Bahri, 47 (39.5%), were febrile with unknown origin attending the Tropical Medicine Hospital in Omdurman, and 15 (12.6%) were febrile and were diagnosed as having malaria or typhoid and attended Yastabshiron Medical Centre and Bashauer Teaching Hospital. The overall prevalence of anti-leptospiral IgM antibodies among all 119 screened patients was 7%. The prevalence among the 57 with end stage renal disease was 9%, and among the 47 with fever of unknown origin was 6%. The prevalence among the 15 with fever of known origin (diagnosed as malaria or typhoid) was 0%. Almost all positive patients had recurring episodes of fever, are in close contact with livestock, were farmers and have natural untreated source for drinking water.ConclusionLeptospirosis is probably a common febrile condition and can be easily considered as one of the major causes of chronic kidney disease affecting people in this country. A national sero-screening for leptospirosis among those living in high risk geographical areas and those at occupational risk is highly recommended.

The Screening of Rubella Virus, Cytomegalovirus, Hepatitis B Virus, and Toxoplasma gondii Antibodies in Prepregnancy and Reproductive-Age Women in Tabriz, Iran

Objectives. The organisms of Toxoplasma gondii, Rubella virus, Cytomegalovirus, and Herpes simplex virus as an acronym of TORCH are major pathogens in prepregnancy and reproductive-age women. These microorganisms are considered a serious problem and cause 2-3% of all birth defects in the fetus. Our study was aimed at screening the seroprevalence of TORCH antibodies among prepregnancy and reproductive-age women in Tabriz, Iran. Design and Setting. This study was carried out in 2726 prepregnancy and reproductive-age women, who were referred to the laboratory for prenatal TORCH screening. To detect the presence of IgG, IgM antibodies and Hepatitis B surface antigen against these microorganisms were carried out using a chemiluminescence immunoassay analyzer (CLIA). Results. In the current study, the rates of anti-Toxoplasma gondii IgG, anti-Rubella virus IgG, and anti-Cytomegalovirus IgG were found in 722 cases (26.5%), 2579 cases (94.6%0), and 2718 cases (99.7%), respectively. Moreover, the rates of anti-Toxoplasma gondii IgM, anti-Rubella virus IgM, and anti-Cytomegalovirus IgM were discovered in 10 cases (0.4%), 13 cases (0.5%), and 16 cases (0.6%), respectively. The Hepatitis B surface antigen was found in 32 cases (1.2%). The dissemination of positive TORCH in various ages was different ( P < 0.05 ). Conclusions. In our study, the seroprevalence of acute TORCH infections was relatively low. Due to the probability of vertical transmission to the fetus during pregnancy and the unpleasant complication of these pathogens, it is essential to be screened for detection of specific IgG and IgM antibodies in reproductive ages.

Persistent Anti- Borrelia IgM Antibodies without Lyme Borreliosis in the Clinical and Immunological Context

The reactivity of human IgM with the outer surface protein C (OspC) of Borrelia burgdorferi sensu lato is frequently used to detect Borrelia specific IgM in commercial immunoassays, and such antibodies usually occur in the early phase of the infection. We identified a group of individuals with persistent Borrelia IgM without symptoms of Lyme borreliosis.

Microarray-Based Detection of Antibodies against SARS-CoV-2 Proteins, Common Respiratory Viruses and Type I Interferons

A microarray-based assay to detect IgG and IgM antibodies against betacoronaviruses (SARS-CoV-2, SARS, MERS, OC43, and HKU1), other respiratory viruses and type I interferons (IFN-Is) was developed. This multiplex assay was applied to track antibody cross-reactivity due to previous contact with similar viruses and to identify antibodies against IFN-Is as the markers for severe COVID-19. In total, 278 serum samples from convalescent plasma donors, COVID-19 patients in the intensive care unit (ICU) and patients who recovered from mild/moderate COVID-19, vaccine recipients, prepandemic and pandemic patients with autoimmune endocrine disorders, and a heterogeneous prepandemic cohort including healthy individuals and chronically ill patients were analyzed. The anti-SARS-CoV-2 microarray results agreed well with the ELISA results. Regarding ICU patients, autoantibodies against IFN-Is were detected in 10.5% of samples, and 10.5% of samples were found to simultaneously contain IgM antibodies against more than two different viruses. Cross-reactivity between IgG against the SARS-CoV-2 nucleocapsid and IgG against the OC43 and HKU1 spike proteins was observed, resulting in positive signals for the SARS-CoV-2 nucleocapsid in prepandemic samples from patients with autoimmune endocrine disorders. The presence of IgG against the SARS-CoV-2 nucleocapsid in the absence of IgG against the SARS-CoV-2 spike RBD should be interpreted with caution.

Evaluation of in-house ELISA and 11 commercial ELISA kits in the serological diagnosis of COVID-19

Introduction: ELISA-Immunoassays can complement the molecular diagnostic methods, and can be one of the important tools of sero-surveillance and vaccine evaluation. The aim of the presented study was to develop in-house ELISA and evaluate 11 commercial ELISA tests for detection of anti-SARS-CoV-2 antibodies in serum samples collected from COVID patients. Methods: In total, 237 serum samples obtained from 165 people with COVID-19 with RT-PCR confirmed SARS-CoV-2 virus infection were used for the study. The specificity of the developed in-house ELISA kit was tested using 170 serum samples obtained from patients with various bacterial and viral infections. The study used an in-house ELISA and 11 commercial ELISA kits developed by various manufacturers. Results: The presented study showed high sensitivity (81.0%) and specificity (97.2%) of the developed in-house kit in relation to the RT-PCR method. The sensitivity of the inhouse test significantly increased (98.1%) when only convalescents - persons at least 3 weeks after COVID-19 were examined. Commercial ELISA kits most frequently detected IgG antibodies (from 44.9% to 89.4%), especially in samples obtained later in the disease, and the least frequent detection of IgM antibodies (from 4.2% to 42.4%). Conclusions: All the presented ELISA kits may be used in serodiagnosis of COVID-19 however the detection of antibodies in individual tests differed quite significantly and was dependent on the period of the disease, on the class of immunoglobulins and the type of antigen used. The sensitivity of serological tests in the IgG class is clearly higher when examining samples obtained at least 2-3 weeks from the onset of clinical symptoms. Searching for IgA antibodies may be useful mainly in the early phase of the disease while IgM antibodies does not provide significant additional information. In the case of asymptomatic or mild infection, the level of antibodies is low which may be the cause problems with the correct interpretation of epidemiological surveys

Microarray-based detection of antibodies against SARS-CoV-2 proteins, common respiratory viruses and type I interferons

A microarray-based assay to detect IgG and IgM antibodies against betacoronaviruses (SARS-CoV-2, SARS, MERS, OC43, and HKU1), other respiratory viruses and type I interferons (IFN-Is) was developed. This multiplex assay was applied to track antibody cross-reactivity due to previous contact with similar viruses and to identify antibodies against IFN-Is as the markers for severe COVID-19. In total, 278 serum samples from convalescent plasma donors, COVID-19 pa-tients in the intensive care unit (ICU) and patients who recovered from mild/moderate COVID-19, vaccine recipients, prepandemic and pandemic patients with autoimmune endocrine disorders, and a heterogeneous prepandemic cohort including healthy individuals and chronically ill patients were analyzed. The anti-SARS-CoV-2 microarray results agreed well with the ELISA results. Regarding ICU patients, autoantibodies against IFN-Is were detected in 10.5% of samples, and 10.5% of samples were found to simultaneously contain IgM antibodies against more than two different viruses. Cross-reactivity between IgG against the SARS-CoV-2 nucleocapsid and IgG against the OC43 and HKU1 spike proteins was observed, resulting in positive signals for the SARS-CoV-2 nucleocapsid in prepandemic samples from patients with autoimmune endocrine disorders. The presence of IgG against the SARS-CoV-2 nucleocapsid in the absence of IgG against the SARS-CoV-2 spike RBD should be interpreted with caution.

Prospective Risk Factors of Toxoplasmosis Seropositivity in Pregnant Women: The Fundamental Role of Community Healthcare Education

Background: The present study conducted a survey on awareness of toxoplasmosis infection, with an emphasis on risk factors, and an assessment of toxoplasmosis prevalence in pregnant women in Al-Kharj province of KSA. Methods and Results: A cross-sectional study with a qualitative approach was carried out from August 2018 to February 2019. The study recruited all pregnant women who attended maternity and children’s outpatient clinics. The non-probability sampling approach was used to select 345 blood samples from study subjects. T. gondii-specific IgG and IgM antibodies were identified using ELISA. Each participant enrolled in the study was provided with a validated questionnaire to fill out by an assistant of the laboratory technician or an antenatal care nurse. In addition to socio-demographic data, simple closed-ended questions about established risk factors for T. gondii exposure were included in the questionnaire items, and answers were listed in a three-point Likert scale (agree, disagree, I am not sure). The overall prevalence of T. gondii-specific antibodies among study subjects was 12.75%; 29(8.40%) women were positive for IgG only, 9(2.6%) - for IgM, and 6(1.7%) - for both IgG and IgM antibodies. About 41.4% of participants were in the first trimester of pregnancy; among them 31(9%) were positive for T. gondii antibodies. 82.8% of pregnant women had chronic infection in the first trimester, while 44.4% of those women also had an acute infection. The number of respondents to the questionnaire was 345 participants with a response rate of about 100%. It is important to note that 81.5% of women were unaware that toxoplasmosis is dangerous, and two-thirds of them didn't know the dangerous complications for the fetus and newborn. Conclusion: The current study concludes that there is a low prevalence of toxoplasmosis among Saudi pregnant women in Al-Kharj province. A general program must be implemented to increase population awareness, especially among the at-risk populations.

Seroprevalence of Brucella antibodies among vaccine manufacturing workers in contact with the Brucella melitensis Rev.1 vaccine strain

ABSTRACTBackgroundCattle vaccination remains an essential measure for the control of brucellosis. Strict preventive measures are applied to protect vaccine manufacturing workers (VMW) employed in processing these live attenuated vaccines. We analyzed the serological responses of VMW in contact with the Brucella melitensis Rev.1 strain.MethodsWe conducted an observational study of a cohort of VMW in a Spanish biopharmaceutical company, a leader in manufacturing veterinary products. The results of the Brucella serological tests carried out on these workers between 2012 and 2019 were reviewed, as well as demographic data, length of time in the company (seniority), and level of exposure. Multivariate analysis was performed with the logistic regression test.ResultsOf the 115 VMW studied, 47 (41%) showed positive Rose Bengal tests during company check-ups. Exposure levels were correlated with seropositivity, with an adjusted OR of 6.6 (95% CI: 2.1-20.3) for the high exposure and 2.0 (95% CI: 0.6-6.7) for the medium exposure groups. Sixteen (34%) seropositive VMW demonstrated an acute serologic pattern of IgG and IgM antibodies seropositivization, while 31 (66%) manifested a chronic serologic pattern of constant or intermittent positive IgG antibodies with persistently negative IgM antibodies. Seniority was inversely associated with the acute pattern: adjusted OR of 0.88 (95% CI: 0.79-0.97) for each year added. No seropositive VMW showed evidence of active brucellosis during follow up.ConclusionDespite strict safety measures, a percentage of VMW were exposed to the Rev.1 strain. Exposure levels were correlated with seropositivity. None of them developed symptomatic infection during follow-up. Two different serological patterns were observed: an acute IgM-positive pattern or a chronic IgM-negative pattern. Seniority was associated with the chronic pattern.