A modified quality control protocol for infectious disease serology based on the Westgard rules.

When traditional statistical quality control protocols, represented by the Westgard protocol were applied to infectious disease serology, the rejection limits were questioned because of the high rejection probability. We first define the probability of false rejection (Pfr) and error detection (Ped) for infectious disease serology. QC data in 6 months were collected and the Pfr of each rule in the Westgard protocol and Rilibak protocol was evaluated. Then, as improvements, we chose different rules for negative and positive QC data to constitute an asymmetric protocol, furthermore, while reagent lot changes, the mean value of QC protocol is reset with the first 15 QC results of new lot reagent. QC materials and Standard Reference Materials were tested synchronously in the next 6 months, to verify whether the Pfr and Ped of the asymmetric protocol could meet the requirement. Protocol 1 exhibited the higher level of rejection rate among the two protocols, especially after reagent lot changes; Pfr below the lower control limit (LCL) was 1.39-21.78 times higher than the upper control limit (UCL); false rejections were more likely to occur in negative QC data, with Pfr-total of 27-65%. The asymmetric protocol can significantly reduce the proportion of analytes with Pfr by over 20%. Systematic error due to reagent lot changes and random error due to routine QC data variation were considered potential factors for excessive Pfr. Asymmetric QC protocol that can reduce Pfr by different control limits for negative and positive QC data.

Discovery of new antigens for serodiagnosis of visceral leishmaniasis in humans and dogs adds valuable tools to our arsenal.

Surveillance and sustained control of visceral leishmaniasis (VL) require reliable serodiagnostic tools. rK39, the gold standard antigen for VL diagnosis, is limited by its documented poor sensitivity in certain endemic regions, such as East Africa, and by the longevity of its antibodies, making it difficult to distinguish active from cured infections. In a recent publication in mBio, Roberts et al. (A. J. Roberts, H.B. Ong, S. Clare, C. Brandt, et al., mBio 15:e00859-24, 2024, https://doi.org/10.1128/mbio.00859-24) identified new immunogenic Leishmania candidates in dogs and humans. In dogs, combined antigens LdBPK_290790.1 + LdBPK_362700.1 (D4 +D46) distinguished symptomatic from asymptomatic infections. For humans, LdBPK_323600.1 (D36) antigen produced short-lived antibodies and performed well in patient cohorts from Bangladesh and Ethiopia, but not Kenya. This study adds promising new candidates to our serodiagnostic toolbox but highlights the need for more antigen discovery studies that may have to be focused on regional performance.

Relative Contribution of Diagnostic Testing to the Diagnosis of Respiratory Syncytial Virus in Hospitalized Adults in the United States.

BACKGROUND: Respiratory syncytial virus (RSV) is a leading cause of acute respiratory illness (ARI) in older adults. Optimizing diagnosis could improve understanding of RSV burden. METHODS: We enrolled adults ≥50 years of age hospitalized with ARI and adults of any age hospitalized with congestive heart failure or chronic obstructive pulmonary disease exacerbations at two hospitals during two respiratory seasons (2018-2020). We collected nasopharyngeal (NP) and oropharyngeal (OP) swabs (n=1558), acute and convalescent sera (n=568), and expectorated sputum (n=153) from participants, and recorded standard-of-care (SOC) NP results (n=805). We measured RSV antibodies by two immunoassays and performed BioFire testing on respiratory specimens. RESULTS: Of 1,558 eligible participants, 92 (5.9%) tested positive for RSV by any diagnostic method. Combined NP/OP PCR yielded 58 positives, while separate NP and OP testing identified 11 additional positives (18.9% increase). Compared to Study NP/OP PCR alone, the addition of paired serology increased RSV detection by 42.9% (28 vs 40) among those with both specimen types, while the addition of SOC swab RT-PCR results increased RSV detection by 25.9% (47 vs 59). CONCLUSIONS: The addition of paired serology testing, SOC swab results, and separate testing of NP and OP swabs improved RSV diagnostic yield in hospitalized adults.

Performance of a point-of-care test for the detection of anti-Leishmania infantum antibodies is associated with immunofluorescent antibody titer and clinical stage of leishmaniosis in dogs from endemic regions.

Canine leishmaniosis (CanL) is caused by the protozoal parasite Leishmania infantum, which is transmitted by sand flies in warm climates across the world. Because dogs are considered a primary domestic reservoir for the parasite that causes leishmaniosis in humans, it is important from a One Health perspective that CanL be properly managed. In endemic regions, CanL is a common differential diagnosis in sick dogs because the clinical signs and clinicopathological disorders of the disease are non-specific, variable, and may overlap those of other common conditions. Diagnosis is based on the presence of compatible clinical signs, laboratory abnormalities, and confirmation by serological and parasitological evidence of infection. Here, we describe the performance of a point-of-care (POC) immunoassay that uses recombinant antigens to detect canine anti- L. infantum antibodies in a convenience sample set from a diagnostic laboratory, a group of canine patients with clinical staging, and in apparently healthy dogs from endemic areas. An immunofluorescence antibody test (IFAT) was used as the semiquantitative reference method. In the convenience sample set with high IFAT titers (≥ 1:800), the POC immunoassay demonstrated perfect agreement with IFAT (100%; 90/90). Using samples from dogs staged as either LeishVet Stage 2 or 3 or LeishVet Stage 1, positive agreement of the POC immunoassay with the IFAT was 98.8% (82/83) and 83.8% (31/37), respectively. The negative agreement with IFAT was 98.9% (272/275) in apparently healthy dogs from endemic areas of Greece and Italy. Since the performance of the POC immunoassay was associated with IFAT titer and clinical stage of CanL, the test may help veterinarians when determining if CanL is likely responsible for a patient's clinical picture or when evaluating an apparently healthy patient prior to vaccination.

Control of Coxiella burnetii shedding in a dairy goat herd by annual offspring vaccination.

A Coxiella burnetii vaccination program, targeting only doelings, was introduced on a German goat farm to curb bacterial shedding. In 2018, adults were vaccinated with a C. burnetii Phase I vaccine at three-weeks apart following pathogen diagnosis, with a booster administered six months later due to sustained high shedding. From 2018 to 2021, doelings received two vaccine doses without any further boosters. To assess the program's efficacy, vaginal swabs from up to 40 animals per age group were collected during kidding seasons from 2019 to 2022. Bulk tank milk (BTM) samples were gathered monthly from January 2018 to October 2022 to monitor herd-level shedding. Real-time PCR analysis determined genome equivalents in all three sample types. Serum samples were taken before the initial immunization and during the post-kidding season from up to 40 goats per age group annually from 2018 to 2022. Phase-specific ELISAs determined IgG Phase I and Phase II antibodies. Additionally, two serum samples per age group from 2022 were analyzed using a neutralization assay. A few goats continued shedding small quantities during subsequent kidding seasons. Although positive BTM samples decreased, they displayed an undulating trend. Most age groups exhibited robust IgG Phase I responses and lower IgG Phase II levels post immunization. Mean IgG levels remained elevated until the study ended compared to pre-vaccination levels in most age groups. Additionally, neutralizing antibodies were present regardless of IgG response. Overall, double vaccination induced lasting antibody levels, but did not entirely prevent C. burnetii shedding. The resilience of the observed humoral immune activity requires further investigation.

The prevalence and rate of undiagnosed celiac disease in an adult general population, the Trøndelag Health Study, Norway.

BACKGROUND & AIMS: This study aimed to determine the total prevalence of celiac disease (CeD), including undiagnosed cases, in a population-based study of adults screened for CeD. METHODS: The study utilized the fourth Trøndelag Health Study (HUNT4), conducted in 2017-2019, where 56,042 adult (aged >20 years) residents of Nord-Trøndelag County, Norway, participated. Serum samples from 54,505 participants were analysed for anti-transglutaminase 2 immunoglobulin A and G. Seropositive individuals were invited for a clinical assessment, including upper endoscopy with duodenal biopsies. Previously diagnosed and seronegative CeD cases were identified through linkage to hospital records and the Norwegian Patient Registry. RESULTS: The rate of CeD seropositivity was 2.0% (1107/54,505). Out of these, 724 individuals attended the clinical assessment. Additionally, the hospital records and registry identified individuals with a known CeD diagnosis, that were seronegative or without serology in HUNT4 or seropositive in HUNT4 but did not participate in the clinical assessment. In total, the study confirmed a new CeD diagnosis after participation in HUNT4 in 470 individuals and a known CeD diagnosis before participation in HUNT4 in 383 individuals. The total biopsy-confirmed prevalence of CeD was 1.5% (853/56,042), and the ratio of new, previously undiagnosed CeD cases (after HUNT4) to known, previously diagnosed CeD cases (before HUNT4) was 1.2:1 (470/383). CONCLUSION: The total prevalence of CeD in this population-based study of adults in Norway was high and many individuals were previously undiagnosed. Detection of CeD should be improved, as early diagnosis is crucial for effective management and prevention of complications.

Influence of bovine pestivirus heterogeneity on serological responses to 10 different commercial vaccine formulation.

Bovine Pestivirus typically involves one or more organ systems, with clinical manifestations ranging from mild to severe fatal systemic illness that lead to significant reproductive, productive, and economic losses. Vaccines face the challenge of addressing the significant variability of pestiviruses, which affects the interaction between viral antigens and the immune system's ability to provide protection. This study aimed to evaluate the serological responses against bovine viral diarrhea virus 1 (Pestivirus A) and Pestivirus B induced by 10 commercial vaccines, including one recombinant (vaccine E), two modified live (MLV multivalent, vaccine I, and MLV monovalent, vaccine J), and seven killed vaccines (KLV, vaccines A to H). Additionally, we evaluated the cross-reactivity between Pestivirus A and B from vaccines and HoBi-like pestivirus (Pestivirus H). In Phase 1, guinea pigs were used to screen for non-MLVs. They were divided into nine groups (n=6 each) and received two doses (⅕ of bovine dose) of eight different non-MLV on Days 0 and 21. Serum samples were collected on Days 0 and 30 for serological analyse. In Phase 2, Holstein × Gir heifers (n= 45) were divided into five groups, comprising 6-9 animals. They were vaccinated either once with MLVs or twice with the top non-MLVs screened in Phase 1. Serum samples were harvested on d0 (vaccination day) and d60 (60 days after the first dose) for MLV and non-MLV. Specific antibody titers were assessed virus neutralization (VN) and transformed in log2 for statistical analysis using PROC-MIXED. Significant effects were observed for vaccine groups, time points, and their interactions concerning neutralizing antibodies against Pestivirus A and B in both Guinea pigs and heifers. The Phase 1 study revealed serological responses against Pestivirus A exclusively in non-MLV D (85.33±13.49) and E (72.00±19.26). In the bovine study, the KLD vaccine D (72.00±15.10), recombinant vaccine E (90.66±25.85), and MLV I (170.66±28.22) resulted in an average of neutralizing antibodies against Pestivirus A that exceeded the protective threshold (≥ 60). However,individual analysis of heifers showed a higher frequency of animals presenting titers of Pestivirus A Ab surpassing 32 following vaccination with MLV I and J. None of the vaccine formulations in either study elicited a protective immune response against Pestivirus B or demonstrated cross-reactivity against Pestivirus H.

Seroprevalence of Toxoplasma gondii and Neospora spp. in horse population of Tehran, Iran.

Neospora spp. and Toxoplasma gondii are two closely related protozoan parasites that are widely distributed throughout the world. Horses can act as intermediate hosts for both parasites and can acquire disease. Blood samples were taken from 487 clinically healthy horses from 17 different mechanized stables in Tehran, the capital of Iran, during September and November of 2022. IFAT and ELISA were employed to detect antibodies directed against Neospora spp. and T. gondii. The anti-N. caninum antibodies were detected in 52 of the horses (10.67%) based on IFAT and in 86 of the 487 horses (17.65%) based on the ELISA test. Also, antibodies against T. gondii were detected in 41 horses (8.42%) based on IFAT and in 63 of 487 horses (12.94%) based on the ELISA test. Also, in 6 of the horses (1.23%) based on IFAT and in 13 of the 487 horses (2.67%) based on the ELISA test, double positivity suggested co-infection with both parasites. Gender, age groups, and the presence of dogs for neosporosis, and age groups and the presence of cats for toxoplasmosis, could be considered factors having an influence on the seroprevalences (P < 0.05). The results proved the importance of the urgent implementation of stringent regulatory measures to prevent and control the spread of these parasites.

Evaluation of the Veterinary IDEXX SNAP 4Dx Plus Test for the Diagnosis of Lyme Disease in Humans.

Background: Lyme disease, caused by infection with Borrelia burgdorferi, is the most common vector-borne disease in the United States. The standard two-tier testing (STTT) algorithm suffers from low sensitivity, misinterpretation, and long turnaround time, preventing timely detection and treatment. To address these challenges, we hypothesized that the canine point-of-care (PoC) SNAP 4Dx Plus test used to detect Borrelia burgdorferi antibodies could be employed for human diagnosis. Materials and Methods: The SNAP 4Dx Plus testing was conducted in accordance with the manufacturer's instructions, with results read by manual inspection. All analyses were conducted using R version 4.3.1, and agreement between the PoC assay and the STTT was assessed using kappa statistics with GraphPad software. Results: We included 102 previously-tested human serum samples, of which 19 samples (18.6%) were STTT positive. Compared to the STTT, the SNAP 4Dx Plus test demonstrated a low sensitivity of 0.16 (95% CI 0.03 to 0.40). Conclusion: Overall, our results do not support the use of the SNAP 4Dx Plus LD assay for the diagnosis of human Lyme disease. Differences in antibody concentrations between human and canine samples may partly explain our findings.

Chlamydia trachomatis Seroassays Used in Epidemiologic Research: A Narrative Review and Practical Considerations.

Chlamydia trachomatis (CT) is a sexually transmitted infection that can lead to adverse reproductive health outcomes. CT prevalence estimates are primarily derived from screening using nucleic acid amplification tests (NAATs). However, screening guidelines in the United States only include particular subpopulations, and NAATs only detect current infections. In contrast, seroassays identify past CT infections, which is important for understanding the public health impacts of CT, including pelvic inflammatory disease and tubal factor infertility. Older seroassays have been plagued by low sensitivity and specificity and have not been validated using a consistent reference measure, making it challenging to compare studies, define the epidemiology of CT, and determine the effectiveness of control programs. Newer seroassays have better performance characteristics. This narrative review summarizes the "state of the science" for CT seroassays that have been applied in epidemiologic studies and provides practical considerations for interpreting the literature and employing seroassays in future research.

Sigma metrics analysis of serology screening assays to enhance quality and efficiency in New Zealand blood services.

Sigma metric analysis was conducted across two New Zealand Blood Services (NZBS) laboratories (Auckland and Christchurch) to optimize quality control (QC) procedures. We evaluated five assays (anti-HCV, HIV Ag/Ab combo, HTLV-I/II, HBsAg, and Syphilis) using internal quality control (IQC) and third-party daily QC data extracted from four Architect i2000SR instruments during Jan 2 -31st, 2023. Mean, standard deviation (SD), and coefficient of variation (CV%) were calculated, assuming zero bias. Sigma metrics were determined using the Total Allowable Error (TEa %) based on difference between positive control mean and signal-to-cutoff (s/co) cut-off. Most assays exhibited CV% values ≤10 % except for HBsAg IQC (18.5 %) and anti-HCV third-party QC (13.4 %) at Christchurch. TEa % ranged from 38 % to 90 %. Overall, the assays demonstrated Six Sigma performance (σ > 6), except for HBsAg IQC (3.97) and anti-HCV third-party QC (5.46) at Christchurch. These high-quality serology assays can benefit from simplified QC design without compromising blood safety.

Performance assessment of a new serological diagnostic test for COVID-19 with candidate peptides from spike and nucleocapsid viral proteins.

Numerous commercial tests for the serological diagnosis of COVID-19 have been produced in recent years. However, it is important to note that these tests exhibit significant variability in their sensitivity, specificity, and accuracy of results. Therefore, the objective of this study was to utilize bioinformatics tools to map SARS-CoV-2 peptides, with the goal of developing a new serological diagnostic test for COVID-19. Two peptides from the S protein and one from the N protein were selected and characterized in silico, chemically synthesized, and used as a serological diagnostic tool to detect IgM, IgG, and IgA anti-SARS-CoV-2 antibodies through the ELISA technique, confirmed as positive and negative samples by RT-qPCR or serology by ELISA. The results showed a sensitivity, specificity, Positive Predictive Value and Negative Predictive Value of 100% (p < 00001, 95% CI) for the proposed test. Although preliminary, this study brings proof-of-concept results that are consistent with the high-performance rates of the ELISA test when compared to other well-established methods for diagnosing COVID-19.

Varicella-Zoster Virus Pretransplant Vaccination and Posttransplant Infections Among Pediatric Solid Organ Recipients in the Two-Dose Varicella Era: A Single-Center, Multi-Organ Retrospective Study.

BACKGROUND: Varicella-zoster virus (VZV) pretransplant immunization rates, exposures, and posttransplant disease are poorly characterized among pediatric solid organ transplant (SOT) recipients in the two-dose varicella vaccine era. METHODS: A retrospective analysis of the electronic health records among children <18 years old who received SOT from January 1, 2011 through December 31, 2021, was performed at a single center to assess for missed pretransplant varicella vaccination opportunities, characterize VZV exposures, and describe posttransplant disease. RESULTS: Among 525 children, 444 were ≥6 months old (m.o.) at SOT with a documented VZV vaccine status. Eighty-five (19%) did not receive VZV Dose One; 30 out of 85 (35%) could have been immunized. Infants 6-11 m.o. accounted for 14 out of 30 (47%) missed opportunities. Among children ≥12 m.o. with documented Dose Two status (n = 383), 72 had missed vaccination opportunities; 57 out of 72 (79%) were children 1-4 years old. Most children had unclassifiable pre-SOT serostatus as varicella serology was either not obtained/documented (n = 171) or the possibility of passive antibodies was not excluded (n = 137). Of those with classified serology (n = 188), 69 were seroimmune. Forty-seven of 525 (9%) children had recorded VZV exposures; two developed varicella-neither had documented pre-SOT seroimmunity nor had received post-exposure prophylaxis. Nine additional children had medically attended disease: four primary varicella and five zoster. Of the 11 cases, 10 had cutaneous lesions without invasive disease; one had multi-dermatomal zoster with transaminitis. Seven (64%) received treatment exclusively outpatient. CONCLUSIONS: VZV exposure and disease still occur. Optimizing immunization among eligible candidates and ensuring patients have a defined VZV serostatus pretransplantation remain goals of care.

Interleukin-2-mediated CD4 T-cell activation correlates highly with effective serological and T-cell responses to SARS-CoV-2 vaccination in people living with HIV.

People living with HIV (PLWH) despite having an appreciable depletion of CD4+ T-cells show a good severe acute respiratory syndrome coronavirus 2 vaccination response. The underlying mechanism(s) are currently not understood. We studied serological and polyfunctional T-cell responses in PLWH receiving anti-retroviral therapy stratified on CD4+ counts as PLWH-high (CD4 ≥ 500 cells/mm3) and PLWH-low (<500 cells/mm3). Responses were assessed longitudinally before the first vaccination (T0), 1-month after the first dose (T1), 3-months (T2), and 6-months (T3) after the second dose. Expectedly, both PLWH-high and -low groups developed similar serological responses after T2, which were also non-significantly different from age and vaccination-matched HIV-negative controls at T3. The immunoglobulin G titers were also protective showing a good correlation with angiotensin-converting enzyme 2-neutralizations (R = 0.628, p = 0.005). While surface and intracellular activation analysis showed no significant difference at T3 between PLWH and controls in activated CD4+CD154+ and CD4+ memory T-cells, spike-specific CD4+ polyfunctional cytokine expression analysis showed that PLWH preferentially express interleukin (IL)-2 (p < 0.001) and controls, interferon-γ (p = 0.017). CD4+ T-cell counts negatively correlated with IL-2-expressing CD4+ T-cells including CD4+ memory T-cells (Spearman ρ: -0.85 and -0.80, respectively; p < 0.001). Our results suggest that the durable serological and CD4+ T-cell responses developing in vaccinated PLWH are associated with IL-2-mediated CD4+ T-cell activation that likely compensates for CD4+ T-cell depletion in PLWH.

Three novel Er blood group system alleles and insights from protein modeling.

BACKGROUND: The Er blood group system was recently shown to be defined by PIEZO1. The system consists of high prevalence antigens Era, Er3, ERSA, and ERAMA; and low prevalence antigen Erb. Era/Erb are antithetical with Er(a-b+) defined by the ER*B allele [c.7180G>A p.(Gly2394Ser)]. A nonsense variant c.5289C>G p.(Tyr1763*) is associated with a predicted Ernull phenotype, and a missense variant c.7174G>A p.(Glu2392Lys) in close proximity to p.2394 causes loss of both Era and Erb expression. STUDY DESIGN AND METHODS: We investigated PIEZO1 in four Er(a-) individuals who presented with anti-Era. Whole genome sequencing (WGS) and Sanger sequencing were performed. The location and structural differences of predicted protein changes were visualized using the predicted 3-D structure of Piezo1 created using AlphaFold2. RESULTS: One individual was homozygous for the reported ER*B. A second had a novel heterozygous nonsense variant c.3331C>T p.(Gln1111*), but a second allelic variant was not found. In the remaining two individuals, two different heterozygous novel missense variants, c.7184C>T p.(Ala2395Val) or c.7195G>A p.(Gly2399Ser), were in trans to the reported c.7180G>A variant, ER*B. AlphaFold2 protein modeling showed that each of the missense variants is predicted to encode an altered structural conformation near Era and Erb. CONCLUSIONS: Investigation of archived samples resulted in the identification of three novel PIEZO1 alleles including a predicted Ernull and two missense variants. Structural modeling suggests that the missense changes potentially alter Era/Erb epitope expression with p.2399Ser resulting in a small increase in the negative electrostatic potential.

Detection and Serological Evidence of European Bat Lyssavirus 1 in Belgian Bats between 2016 and 2018.

Lyssaviruses are neurotropic viruses capable of inducing fatal encephalitis. While rabies virus has been successfully eradicated in Belgium, the prevalence of other lyssaviruses remains uncertain. In this study, we conducted a survey on live animals and passive surveillance to investigate the presence of lyssaviruses in Belgium. In 2018, a total of 113 saliva samples and 87 blood samples were collected from bats. Saliva was subjected to RT-qPCR to identify lyssavirus infections. Additionally, an adapted lyssavirus neutralisation assay was set up for the detection of antibodies neutralising EBLV-1 in blood samples. Furthermore, we examined 124 brain tissue samples obtained from deceased bats during passive surveillance between 2016 and 2018. All saliva samples tested negative for lyssaviruses. Analysis of the blood samples uncovered the presence of lyssavirus-neutralising antibodies in five bat species and 32% of samples with a wide range depending on bat species, suggesting past exposure to a lyssavirus. Notably, EBLV-1 was detected in brain tissue samples from two Eptesicus serotinus specimens collected in 2016 near Bertrix and 2017 near Étalle, confirming for the first time the presence of EBLV-1 in Belgium and raising awareness of the potential risks associated with this species of bats as reservoirs of the virus.

Does the ultrasensitive HBsAg Next assay enhance Hepatitis B diagnosis? An evaluation of analytical performances.

BACKGROUND: Accurate laboratory confirmation for Hepatitis B diagnosis and monitoring are crucial. Recently an ultrasensitive immunoassay test, the HBsAg Next (HBsAgNx), has been reported approximately eight times more sensitive than current HBsAg assays. The aim of our study was to assess the analytical performances of this new test. METHODOLOGY: 253 clinical samples from Saint Louis University Hospital were analyzed, splitted into four panels: (1) routine prospectively screening serums (n = 196), (2) retrospective serum samples before HBV reactivation (HBV-R) (n = 18), (3) occult HBV infection (OBI) (n = 10) and (4) a selection of wild type HBV genotypes (n = 29) RESULTS: Panel 1, showed robust agreement with the HBsAg Qualitative II (HBsAgQII) assay (Cohen's kappa = 0.83). Despite this agreement, 7 false positive with the HBsAgQII assay were found negative with HBsAgNx. One OBI was detected only with HBsAgNx. Panel 2 showed potential time savings in diagnosing HBV-R using HBsAgNx among 4/18 HBsAg positives samples. Panel 3 highlighted the ability of HBsAgNx to detect HBsAg in OBI patients defined by negative for HBsAg with HBsAgQII assay and positive for HBV DNA. Furthermore, the HBsAgNx assay detected all different genotypes. CONCLUSION: The study highlights the effectiveness of the HBsAgNx assay, showing its performance. It excels in detecting weakly positive samples and addressing challenging cases. HBsAgNx assay demonstrates promising analytical performances, with improved sensitivity and specificity compared to standard HBsAgQII assay, able to detect all genotypes. Its potential impact on early detecting and monitoring reactivations, and occult infections could be very useful in clinical practice.

Molecular and serological prevalence of Leptospira spp. among slaughtered cattle and associated risk factors in the Bahr El Ghazal region of South Sudan.

INTRODUCTION: Leptospirosis is a neglected emerging and zoonotic disease reported worldwide. This study sought to determine the molecular and serological prevalence of Leptospira spp. and the associated risk factors in slaughtered cattle from the Bahr El Ghazal region of South Sudan. MATERIALS AND METHODS: Between January 16th and February 25th, 2023, blood and urine samples were collected from 402 cattle at the Lokoloko Municipal Slaughterhouse in Western Bahr El-Ghazal State. Serum samples were tested using the microscopic agglutination test (MAT), with a panel of 12 serovars (sv) from 12 serogroups (sg) and 4 species (spp) of Leptospira spp. These serovars had been previously identified in Sudan and the East African region. Simultaneously, 400 corresponding urine samples were screened using qualitative real-time polymerase chain reaction (PCR) to detect the shedding of Leptospira spp. in urine. To identify the associated risk factors, the age, sex, breed and body condition score of each sampled cattle was noted at the time of sampling and subsequently analysed using logistic regression models. RESULTS: Among the 402 serum samples screened, a substantial 81.8% (329/402, 95% CI 77.9-85.3) displayed seropositivity for Leptospira spp. with a MAT titre ≥ 100. The prevalence of urine shedding determined by PCR was 6% (23/400, 95% CI 3.8-8.4), while probable recent leptospirosis with a MAT ≥ 1:800 was observed in 33.1% (133/402, 95% CI 28.6-37.8) of the cattle. Multiple reactions were detected in 34.8% (140/402, 95% CI 30.6-39.5) serum samples. The seropositivity was against L. borgpetersenii sg. Tarassovi (78.6%; 316/402, 95% CI 74.4-82.3), followed by L. borgpetersenii sg. Ballum at 20.4% (82/402, 95% CI, 16.7-24.4%), L. kirschneri sg. Autumnalis At 8.7% (35/402, 95% CI 5.7-11.7), L. interrogans sg. of Pomona at 7.0% (28/402, 95% CI 4.5-9.5), and L. interrogans sg. Hebdomadis was 5.0% (20/402, 95% CI 2.8-7.2). Several risk factors are associated with seropositivity. Older animals (≥ 2 years) had 2.0 times greater odds (95% CI 1.14-3.5) of being seropositive than younger animals (< 2 years), P-value = 0.016. Female animals demonstrated 2.1 times greater odds (95% CI 1.2-3.6) of seropositivity than males did (P-value = 0.008). Additionally, Felata/Mbororo cattle exhibited 2.4 times greater odds (95% CI 1.3-4.5) of being seropositive than did local Nilotic cattle (P-value = 0.005). The agreement between the MAT and PCR results was poor, as indicated by a kappa statistic value of 0.001 and a P-value of 0.913. But there was a moderate agreement between MAT high titres ≥ 800 and PCR positivity with a kappa statistic value = 0.501 and a P-value < 0.001. CONCLUSION: In addition to the high seroprevalence, Leptospira spp. were found in the urine of slaughtered cattle, suggesting that leptospirosis is endemic to the study area. This finding underscores the significance of cattle as potential sources of infection for slaughterhouse workers, the general public, and other animal species. To address this issue effectively in the Bahr El Ghazal Region and South Sudan, a comprehensive strategy involving a multidisciplinary approach is essential to minimize disease among animals, hence reducing potential zoonotic risks to humans.

Treponematosis in critically endangered Western chimpanzees (Pan troglodytes verus) in Senegal.

Treponematoses encompass a group of chronic and debilitating bacterial diseases transmitted sexually or by direct contact and attributed to Treponema pallidum. Despite being documented since as far back as 1963, the epidemiology of treponematoses in wild primates has remained an uninvestigated territory due to the inherent challenges associated with conducting examinations and obtaining invasive biological samples from wild animals. The primary aim of this study was to investigate the presence of treponemal infections in the critically endangered Western chimpanzees in Senegal, utilizing an innovative non-invasive stool serology method. We provide compelling evidence of the existence of anti-Treponema-specific antibodies in 13 out of 29 individual chimpanzees. Our study also underscores the significant potential of stool serology as a valuable non-invasive tool for monitoring and surveilling crucial emerging diseases in wild animals. We recognize two major implications: (1) the imperative need to assess the risks of treponematosis in Western chimpanzee populations and (2) the necessity to monitor and manage this disease following a holistic One Health approach.