Seropositivity of West Nile virus among acute febrile patients in Ilorin, Nigeria.

INTRODUCTION: West Nile Virus (WNV), a member of Flaviviridae family, is one of the most widely distributed arboviruses in the world. In developing countries like Nigeria, fever resulting from the WNV infection is often presumptively ascribed to malaria or typhoid due to misdiagnosis and low-level awareness of the viral infection. This study determined the prevalence of WNV IgM and IgG antibodies among febrile patients in the Ilorin metropolis. MATERIALS AND METHODS: A total of two hundred (200) blood samples were collected from consenting patients and each serum was screened for anti-WNV IgM and IgG antibodies using indirect enzyme-linked immunosorbent assay (ELISA). Statistical correlation and logistic regression analysis were conducted. RESULTS: Overall, 6% (12/200) anti-WNV IgM seropositivity rate was recorded amongst the acute febrile patients with higher prevalence (6.30%) in females than in males (5.45%). Anti-WNV IgG positivity rate of 52% (104/200) was recorded, with 50.67% positivity rate in males and 38.95% in female participants. The convalescence phase posited by the 5.4% (11/200) co-detection of anti-WNV IgG and IgM antibodies among the participants was recorded. A statistical correlation was noticed with the age and religion of respondents to WNV serological positivity while gender, occupation, use of mosquito nets and formal education had no positive correlation at p < 0.05. However, based on odd ratio at 95% CI and logistic regression coefficients, the evaluated risk factors such as blood transfusion, residency, malaria parasite, and proximity to stagnant water and bush were significant to anti-WNV IgG and IgM positivity. CONCLUSION: The findings of this study show the circulation of WNV in the study area. There is an urgent need for clinicians/physicians to include screening for the West Nile virus in cases of febrile patients before the commencement of treatment.

Sero-Positive Isolated Ocular Myasthenia Gravis.

Ocular myasthenia gravis (OMG) is a neuromuscular disease characterized by the production of autoantibodies against post-synaptic proteins at the neuromuscular junction (NMJ). An 18-year-old male who had symptoms of drooping eyelids and double vision was diagnosed with ocular myasthenia gravis on investigations and examinations. Treatment was initiated with a tablet of pyridostigmine 60 mg twice daily per oral for two weeks, followed by three times daily for four weeks. The patient demonstrated significant improvement in ptosis and diplopia. There are still a considerable number of challenges in the diagnosis and treatment of ocular myasthenia gravis, with the typical treatment involving acetylcholinesterase inhibitors and immunosuppressants.

Exposure to Arboviruses in Cattle: Seroprevalence of Rift Valley Fever, Bluetongue, and Epizootic Hemorrhagic Disease Viruses and Risk Factors in Baringo County, Kenya.

Rift Valley fever virus (RVFV) causes disease outbreaks in livestock and humans; however, its inter-epidemic circulation is poorly understood, similar to other arboviruses affecting cattle such as bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV). Serum samples were collected in Baringo County, Kenya from 400 cattle, accompanied by a risk factor questionnaire. Serological tests were then conducted to determine the exposure of cattle to RVFV, BTV, and EHDV. RVFV, BTV, and EHDV IgG seroprevalence rates were 15.5%, 91.5%, and 91%, respectively. Seropositivity for RVFV, BTV, and EHDV was significantly higher in adult cattle, as well as in females for RVFV. Cattle with herd owners aged between 30-39 years were less likely to be seropositive for RVFV compared to those with owners over the age of 60 years. High seroprevalence of BTV and EHDV in cattle indicates significant exposure and the subclinical circulation of these viruses, presenting a risk of outbreaks to sheep and naïve cattle. Moreover, the detection of RVFV-seropositive young cattle born after the last reported outbreak suggests inter-epidemic circulation of the virus. Overall, monitoring these arboviruses in cattle is crucial in understanding their distribution and seroprevalence during inter-epidemic periods.

Serological survey on Hepatitis E virus in Namibian dogs, cats, horses, and donkeys.

The present study investigated the seropositivity rate of Hepatitis E virus (HEV) in domestic and working animals in Namibia, which included dogs, cats, horses, and donkeys. HEV poses a growing threat as a significant cause of human hepatitis globally and has several genotypes of varying zoonotic potential. As epidemiological data on the seroprevalence of HEV in Namibia is scarce, a serosurvey was conducted on archived serum samples of 374 dogs, 238 cats, 98 horses, and 60 donkeys collected between 2018 and 2022 from different regions, to assess the potential of these animals as sources of HEV infection. The findings revealed that 10.43% (n = 39/374) canine and 5.88% (n = 14/238) feline samples tested positive for HEV antibodies, whereas no seropositivity was detected in horses and donkeys. The study further examined the risk factors associated with HEV seropositivity, including animal sex, age, and geographical region, and noted a higher prevalence in dogs living in areas with intensive pig farming. Although there is no direct evidence indicating that these animals served as major reservoirs for HEV transmission to humans, the study underscores the importance of preventive measures to minimize contact exposure with pets considering the potential zoonotic risk, especially for susceptible risk groups. Further research is needed to explore the zoonotic potential of domestic animals and the epidemiological links between animal and human HEV transmissions in Namibia.

Association between human herpesvirus 8 and lipid profile in northwest China: A cross-sectional study.

Human herpesvirus 8 (HHV-8) infection shows obvious regional and ethnic differences. Although studies have shown that these differences may be associated with lipid metabolism, to date, no large-scale studies have explored this. This study explored the seropositivity rate of HHV-8 among 2516 residents from 10 regions of northwest China and then the correlates of HHV-8 infection with lipid profile. The HHV-8 serological positivity rate was 15.6% among all residents. The HHV-8 seroprevalence ranged 11.2-27.6% among different ethnicities. Across different BMI levels, the positive rates of HHV-8 were 27.6%, 16.9%, and 13.6% for a BMI < 18.5, 18.5-24.9, and ≥25, respectively. HHV-8 seropositivity rate was lower for hypertensive people (12.6%) than for non-hypertensive people (16.7%). Univariate logistic regression analyses revealed that age, hypertension, systolic blood pressure, BMI, total cholesterol, and high-density lipoprotein cholesterol (HDL-C) significantly correlated with HHV-8 seropositivity (p < 0.05). Multivariate logistic regression analysis after adjusting for confounding factors showed that HDL-C (odds ratio [OR]: 0.132, 95% confidence interval [CI], 0.082-0.212; p < 0.001) and BMI (OR: 0.959, 95% CI 0.933-0.986; p = 0.003) were associated with HHV-8 seropositivity. Subgroup analyses concerning ethnicity, sex, or age demonstrated a consistent relationship with HDL-C. The results of HHV-8 seropositivity and BMI were inconsistent in the subgroups. However, Spearman's correlation analysis between HHV-8 serum antibody titer and HDL-C levels showed no linear relationship among HHV-8 seropositive individuals (ρ = -0.080, p = 0.058). HHV-8 serum antibody titers were also not significantly correlated with BMI (ρ = -0.015, p = 0.381). Low HDL-C levels may be an independent risk factor for HHV-8 infection, but there is no significant correlation between HDL-C levels and HHV-8 antibody titers.

Vaccine challenges in CLL: a comprehensive exploration of efficacy of SARS-CoV-2 immunization for patients with chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is characterized by disease- and treatment-related immunosuppression. Patients with CLL comprise a vulnerable population to coronavirus disease 2019 (COVID-19), while the protective effect of COVID-19 vaccination remains uncertain.We conducted a systematic review to evaluate published data reporting response to COVID-19 vaccination in patients with CLL. The primary outcome was the rate of seropositivity after full primary vaccination, while secondary outcomes were rates of positive neutralizing antibodies, cellular responses, and adverse events. Response after booster doses of vaccination was also evaluated.Twenty-three studies of full primary vaccination (12 CLL-specific with 1747 patients, 11 with mixed hematologic diseases including 1044 patients with CLL) with a total of 2791 patients, and eight studies on booster doses with 389 patients were included in the analysis. The serologic response varied between studies with a median of 55%. Where reported, the median neutralizing antibody response rate was 61.2% and the cellular response rate was 44.2%. Poor serologic response was noted in patients under active treatment with anti-CD20 monoclonal antibodies, BCL2, and BTK inhibitors.The present review highlights the substantially impaired humoral and cellular response to COVID-19 vaccination in patients with CLL with patients under active treatment being the most vulnerable.

SARS-CoV-2 seropositivity in African women living with HIV and their infants.

BACKGROUND: SARS-CoV-2 seropositivity data in women living with HIV (WLHIV), their infants and associated factors in this subpopulation remain limited. We retrospectively measured SARS-CoV-2 seropositivity from 07/2020-11/2021 among WLHIV and their children in the PROMOTE observational cohort in Uganda, Malawi, and Zimbabwe prior to widespread SARS-CoV-2 vaccination in those countries. METHODS: Plasma stored during 3 waves of the COVID-19 pandemic in East/Southern Africa were tested for SARS-CoV-2 specific IgG antibodies (Ab) using serological assays that detect adaptive immune responses to SARS-CoV-2 spike protein. (EUROIMMUN, Mountain Lakes, New Jersey and Roche Diagnostics, Indianapolis, IN). Modified-Poisson regression models were used to calculate prevalence rate ratios (PRR) and 95% confidence intervals (CI) to identify sociodemographic and clinical risk factors. RESULTS: PROMOTE samples from 918 mothers and 1237 children were analysed. Overall, maternal SARS-CoV-2 seropositivity was 60.1% (95% CI: 56.9 -63.3) and 41.5% (95%CI: 38.8 - 44.2) for children. Non-breastfeeding mothers had a 31% higher risk of SARS-CoV-2 seropositivity compared to breastfeeding mothers (aPRR=1.31, 95%CI: 1.08-1.59). WLHIV with undetectable viral load had a 10% increased risk of SARS-CoV-2 seropositivity (aPRR=1.10, 95%CI: 0.89-1.37). Moreover, those who were normotensive had 12% increased risk SARS-CoV-2 seropositivity (aPRR= 1.12, 95% CI: 0.68-1.85) compared to women with hypertension. Children between 2 and 5 years had a 19% reduced risk of SARS-CoV-2 seropositivity (aPRR=0.81, 95%CI: 0.64-1.02) when compared to younger children. Mother/infant SARS-CoV-2 serostatuses were discordant in 346/802 (43.1%) families tested: mothers+/children- in 72.3%; mothers-/children+ in 26.3%; child+/sibling+ concordance was 34.6%. CONCLUSIONS: These SARS-CoV-2 seropositivity data indicate that by late 2021, about 60% of mothers and about 40% of children in a cohort of HIV-affected families in eastern/southern Africa had been infected with SARS-CoV-2. More mothers than their infants tested SARS-CoV-2+, likely due to a greater external exposure for mothers linked to daily routines/employment, and school closures. Breastfeeding was protective for mothers, likely because of higher likelihood of staying home with young children, and thus less exposure. Discordant results between children within the same families underscores the need to further understand transmission dynamics within households.

Immunity Against Measles in Korean Autologous Hematopoietic Stem Cell Transplant Recipients.

The seropositivity of measles antibodies among 261 autologous stem cell transplant recipients (ASCTs) in Korea, assessed approximately 1-2 years after transplant (median, 11 months; interquartile range, 9-14), was significantly lower than age- and sex-matched control healthcare workers (83.1% [217/261] vs. 90.3% [539/597], P = 0.002). The findings underscore the vulnerability of adult ASCT recipients to measles. Clinicians should prioritize testing for measles IgG after ASCT and consider vaccination for ASCT recipients who remain seronegative 2 years after ASCT.

Post-discharge follow-up of pediatric COVID-19 patients: insights into serological dynamics.

Introduction: Limited data are available regarding SARS-CoV-2 serological response dynamics in pediatric patients with COVID-19, contributing to gaps in our understanding of the immune response in this population. This study aimed to investigate SARS-CoV-2 IgG seropositivity in patients diagnosed with COVID-19 during hospitalization and 2-4 weeks after discharge. Methods: A cohort of patients, consisting of 31 individuals with confirmed acute COVID-19 infection and 27 diagnosed with Multisystem Inflammatory Syndrome in Children (MIS-C), was enrolled in the study. Follow-up clinic appointments were scheduled for 2-4 weeks post-discharge. During admission and follow-up, blood samples were collected from each patient for laboratory analysis. Anti-nucleoprotein SARS-CoV-2 IgG levels were determined using the Enzyme-Linked Immunosorbent Assay (ELISA) method. Results: In this study, a cohort of 58 patients was examined. At admission, 52% (n = 14) of MIS-C patients and 10% (n = 3) of acute COVID-19 patients had positive SARS-CoV-2 IgG test. Only 48 cases were referred to the hospital, and follow-up data was available for 20 cases with MIS-C and 28 cases with acute COVID-19. All patients (n = 15) who initially tested positive for SARS-CoV-2 IgG at admission remained positive serology during follow-up (100%). Among the 33 patients who initially tested negative, 12 (37.5%) showed a positive serology result during follow-up, while 21 (62.5%) remained negative. Within this subgroup, 11 cases (44%) were diagnosed with acute COVID-19, and one patient (12.5%) presented with MIS-C. Fourteen cases with acute COVID-19 infection (56%) and seven cases with MIS-C (87.5%) consistently showed negative serology results throughout the study. During follow-up, the median lymphocyte count demonstrated a significant difference, with 0.96 × 109 cells per L (IQR: 0.75-3.0 × 109 cells per L) in the SARS-CoV-2 IgG-negative group and 2.9 × 109 cells per L (IQR = 1.33-7.22 × 109 cells per L) in the SARS-CoV-2 IgG-positive group (p-value = 0.03). Patients who demonstrated seropositivity during the follow-up were associated with a notably severe disease (p-value = 0.028). Conclusion: Our study highlights the dynamic nature of SARS-CoV-2 IgG antibody responses in pediatric patients with COVID-19 infection. We observed a notable increase in seropositivity rates during follow-up. Furthermore, patients who were seropositive at follow-up demonstrated a severe disease course and lower lymphocyte counts compared to those with persistently negative serology. Our findings underscore the importance of longitudinal serological monitoring in understanding disease progression and immune response dynamics in pediatric COVID-19 cases.

Laboratory diagnosis and epidemiological features of leptospirosis cases in a tribal region of Western Maharashtra, India: A retrospective study.

PURPOSE: Palghar district, located in the coastal region of the Konkan division of Maharashtra, has a predominantly tribal population. Leptospirosis is a major neglected public health problem and is highly underreported in Palghar district. The study aimed to evaluate the seropositivity of Leptospira infection and its associated epidemiological factors in tribal areas of the Palghar district of Maharashtra. METHODS: The present retrospective study included 94 samples of patients clinically suspected of leptospirosis during a period of one year (2021-2022) tested at Model Rural Health Research Unit (MRHRU) Dahanu. The serum sample testing was done for the presence of specific Leptospira IgM antibodies using the Panbio™ Leptospira IgM ELISA kit. Leptospirosis seropositivity was correlated with various epidemiological risk factors. RESULTS: A total of 12 samples of patients tested positive for specific IgM antibodies by ELISA method, indicating an overall positivity of 12.8%. Among those who tested positive, fever (83.3%), headache (58.3%), myalgia (50%), redness of the eyes (50%), and calf tenderness (16.7%) were the common symptoms observed. Subjects with redness of the eyes were significantly associated with leptospirosis (p = 0.018). The highest positivity (50%) was reported from the Ganjad area of Dahanu taluka. Farmers and animal handlers were most affected by leptospirosis. CONCLUSION: The high proportion of Leptospirosis cases reflects the endemic nature of the disease in the Palghar district. This study shows seasonal trends in leptospirosis incidence over the year. The clinical presentation of leptospirosis may vary from sub-clinical to mild illness to severe and potentially fatal. The findings of this study will be important for achieving the overarching goal of One Health.

Effectiveness of instant versus text messaging intervention on antiretroviral therapy adherence among men who have sex with men living with HIV.

Objective: This study aimed to compare the effectiveness of instant versus text messaging intervention (TMI) on antiretroviral therapy (ART) adherence among men who have sex with men (MSM) living with HIV. Methods: This study was conducted in an infectious disease hospital of Jinan, China from October 2020 to June 2021, using non-randomized concurrent controlled design to compare the effectiveness of instant messaging intervention (IMI) versus TMI. The intervention strategies (health messaging, medication reminder, and peer education) and contents were consistent between the two groups, and the difference was service delivery method and type of information. The primary outcome was the proportion of achieving optimal ART adherence, defined as never missing any doses and delayed any doses more than 1 hour. Results: A total of 217 participants (including 72 in TMI group and 145 in IMI group) were included in the study. The proportion of achieving optimal adherence was higher in IMI group than TMI group at the first follow-up (90.2% versus 77.6%, p = 0.021) and second follow-up (86.5% versus 76.6%, p = 0.083). The effect of IMI versus TMI on improving ART adherence was found not to be statistically significant (risk ratio (RR) = 1.93, 95% confidence interval (CI): 0.95-3.94) in complete-case analysis. However, when excluding participants who did not adhere to the interventions, a significant improvement was observed (RR = 2.77, 95%CI: 1.21-6.38). More participants in IMI group expressed highly rated satisfaction to the intervention services than those in TMI group (67.3% versus 50.0%). Conclusions: The IMI demonstrated superior efficacy over TMI in improving ART adherence and satisfaction with intervention services. It is suggested that future digital health interventions targeting ART adherence should prioritize instant messaging with multimedia information in areas with Internet access. Trial registration: The study was registered at the Chinese Clinical Trial Register (ChiCTR), with number [ChiCTR2000041282].

Prediction of Seropositivity in Suspected Autoimmune Encephalitis by Use of Radiomics: A Radiological Proof-of-Concept Study.

In this study, we sought to evaluate the capabilities of radiomics and machine learning in predicting seropositivity in patients with suspected autoimmune encephalitis (AE) from MR images obtained at symptom onset. In 83 patients diagnosed with AE between 2011 and 2022, manual bilateral segmentation of the amygdala was performed on pre-contrast T2 images using 3D Slicer open-source software. Our sample of 83 patients contained 43 seropositive and 40 seronegative AE cases. Images were obtained at our tertiary care center and at various secondary care centers in North Rhine-Westphalia, Germany. The sample was randomly split into training data and independent test data. A total of 107 radiomic features were extracted from bilateral regions of interest (ROIs). Automated machine learning (AutoML) was used to identify the most promising machine learning algorithms. Feature selection was performed using recursive feature elimination (RFE) and based on the determination of the most important features. Selected features were used to train various machine learning algorithms on 100 different data partitions. Performance was subsequently evaluated on independent test data. Our radiomics approach was able to predict the presence of autoantibodies in the independent test samples with a mean AUC of 0.90, a mean accuracy of 0.83, a mean sensitivity of 0.84 and a mean specificity of 0.82, with Lasso regression models yielding the most promising results. These results indicate that radiomics-based machine learning could be a promising tool in predicting the presence of autoantibodies in suspected AE patients. Given the implications of seropositivity for definitive diagnosis of suspected AE cases, this may expedite diagnostic workup even before results from specialized laboratory testing can be obtained. Furthermore, in conjunction with recent publications, our results indicate that characterization of AE subtypes by use of radiomics may become possible in the future, potentially allowing physicians to tailor treatment in the spirit of personalized medicine even before laboratory workup is completed.

IgG seroprevalence of Toxoplasma gondii and Leishmania infantum in leprosy patients: Implications for screening and management of co-infections.

Parasitic co-infections are common in developing countries and can interfere with leprosy treatment, leading to an increased risk of inflammatory leprosy reactions. This study assessed serum immunoglobulin G (IgG) levels against Toxoplasma gondii and Visceral Leishmaniasis (VL) antigens in 270 leprosy patients from Brazilian states. Regarding the respective cut-offs, the prevalence of IgG seropositivity for T. gondii and VL were 21.05 % and 47.36 % in the leprosy-negative group, and 77.7 % and 52.6 % in the leprosy-positive group. Of the 270 leprosy patients, 158 (58.5 %) presented with inflammatory leprosy reactions. Of those, 72 (59.5 %) had neuritis, 35 (48.6 %) had reverse reactions, and 28 (38.9 %) had ENL in both Brazilian states. Leprosy patients with anti-Leishmania IgG seropositivity were 3.25 times more likely to develop neuritis (95 % C.I.: 1.187 - 9.154; p = 0.019). These findings are particularly relevant for clinical settings where both leprosy and parasitic diseases are prevalent and could provide essential guidance for detecting and addressing complications arising from parasitic co-infections in leprosy patients, thereby improving clinical management strategies.

High SARS-CoV-2 infection rate in children unvaccinated with COVID-19 vaccine in Changzhou, China, shortly after lifting zero-COVID-19 policy in December 2022.

BACKGROUND: China experienced an overwhelming COVID-19 pandemic from middle December 2022 to middle January 2023 after lifting the zero-COVID-19 policy on December 7, 2022. However, the infection rate was less studied. We aimed to investigate the SARS-CoV-2 infection rate in children shortly after discontinuation of the zero-COVID-19 policy. METHODS: From February 20 to April 10, 2023, we included 393 children aged 8 months to less than 3 years who did not receive COVID-19 vaccination and 114 children aged 3 to 6 years who received inactivated COVID-19 vaccines based on the convenience sampling in this cross-sectional study. IgG and IgM antibodies against nucleocapsid (N) and subunit 1 of spike (S1) of SARS-CoV-2 (anti-N/S1) were measured with commercial kits (Shenzhen YHLO Biotech, China). RESULTS: Of the 393 unvaccinated children (1.5 ± 0.6 years; 52.2% boys), 369 (93.9%) were anti-N/S1 IgG positive. Of the 114 vaccinated children (5.3 ± 0.9 years; 48.2% boys), 112 (98.2%) were anti-N/S1 IgG positive. None of the unvaccinated or vaccinated children was anti-N/S1 IgM positive. The median IgG antibody titers in vaccinated children (344.91 AU/mL) were significantly higher than that in unvaccinated children (42.80 AU/mL) (P < 0.0001). The positive rates and titers of anti-N/S1 IgG had no significant difference between boys and girls respectively. CONCLUSION: Vast majority of children were infected with SARS-CoV-2 shortly after ending zero-COVID-19 policy in China. Whether these unvaccinated infected children should receive COVID-19 vaccine merits further investigation.

A first insight into seropositivity of Neospora caninum and associated risk factors in free-roaming dogs from Ecuador.

Neosporosis is a worldwide parasitic disease caused by the protozoan Neospora caninum. It can cause economic losses to farmers due to its relationship with abortions and neonatal mortality in cows. Dogs play a key role in its spread as they are considered definitive hosts. In this study, we determined for the first time the seropositivity of N. caninum infection in dogs from Ecuador and evaluated potential risk factors. A total number of 339 free-roaming dogs from the three main regions of Ecuador (Coastal, Andean, and Amazonian regions) were included in the study and classified either as urban or rural dogs. Serum samples were collected from November 2018 to May 2019, and analyzed with a commercial ELISA test. An overall seropositivity of 6.8 % (CI: 95 %, 2.8 % - 11.7 %) was found in N. caninum infection with no statistical differences among regions or urban/rural dogs. This is the first surveillance of N. caninum in Ecuador, confirming a country-wide distribution of this pathogen. Considering the large populations of free-roaming dogs in Ecuador, a One Health approach for surveillance and managing N. caninum in dogs is needed to protect either livestock or wildlife.

Raising Epidemiological Awareness: Assessment of Measles/MMR Susceptibility in Highly Vaccinated Clusters within the Hungarian and Croatian Population-A Sero-Surveillance Analysis.

Perceptions of the complete eradication of vaccine-preventable diseases such as measles, mumps, and rubella (MMR) may foster complacency and compromise vaccination efforts. Decreased measles vaccination rates during the COVID-19 pandemic have heightened the risk of outbreaks, even in adequately vaccinated populations. To address this, we have aligned with ECDC recommendations, leveraging previous cross-border sero-epidemiological assessments between Pécs, Hungary, and Osijek, Croatia, to identify latent risk groups and uncover potential parallels between our nations. Testing 2680 Hungarian and 1764 Croatian serum samples for anti-MMR IgG via ELISAs revealed anti-measles seropositivity ratios below expectations in Croatian cohorts aged ~20-30 (75.7%), ~30-40 (77.5%) and ~40-50 years (73.3%). Similarly, Hungarian samples also showed suboptimal seropositivity ratios in the ~30-40 (80.9%) and ~40-50 (87.3%) age groups. Considering mumps- and rubella-associated seropositivity trends, in both examined populations, individuals aged ~30-50 years exhibited the highest vulnerability. Additionally, we noted congruent seropositivity trends across both countries, despite distinct immunization and epidemiological contexts. Therefore, we propose expanding research to encompass the intricate dynamics of vaccination, including waning long-term immunity. This understanding could facilitate targeted interventions and bolster public awareness. Our findings underscore persistent challenges in attaining robust immunity against measles despite vaccination endeavors.

In the fight against HIV/AIDS: the arduous implementation of government-funded pre-exposure prophylaxis programme in Taiwan.

INTRODUCTION: The government-funded pre-exposure prophylaxis (PrEP) programme was targeted to those aged under 30 years or serodiscordant couples and implemented in September 2018-October 2020 in Taiwan. The study aimed to examine the effectiveness of the programme and the relationship between sexually transmitted disease (STD) and HIV seroconversion. METHODS: This study was a retrospective cohort analysis with questionnaires designed for participants who joined the aforementioned programme in the PrEP-designated hospitals. The questionnaires included sociodemographic factors, sexual risk behaviours, number and types of sexual partners, and usage of narcotics filled in at the beginning of the programme and every 3 months. The McNemar test was used for the paired questionnaire analysis. The HIV seroconversion status among STD-notified patients nationwide was confirmed by using the data linkage method, followed up until October 2021 with stratification of PrEP programme participation or not. RESULTS: The programme recruited 2155 people. 11 participants (0.5%) had seroconversion within the programme, while 26 (1.2%) had seroconversion after withdrawing from the programme. Overall, 1892 subjects with repeated questionnaires were included in the analysis for behaviour changes with median follow-up of 289 days. After joining the programme, 94.7% of them claimed that they had sexual behaviours: the rate of those who had condomless sex rose to 5.5% (p<0.001) and the rate of those who used narcotics decreased to 2% (p<0.001), compared with their response in the pre-questionnaire. Notably, the frequency of non-use of narcotics in recent 3 months increased from 16.9% to 38.4% in the pre-questionnaire and post-questionnaire responses, among the 177 who had claimed narcotics usage in recent 12 months (p=0.003). More HIV seroconversion was found among patients with STD who did not join the programme than those who joined the programme (8.7% vs 4.9%, p=0.031). CONCLUSIONS: The government-funded programme showed HIV case reduction and positive changes in health behaviours except for condomless sex which had increased prevalence. The reduction of HIV cases was also observed among people with STD. More resources should be allocated to the PrEP programme.

Seroprevalence of leptospirosis among stray dogs in Bosnia and Herzegovina.

Leptospirosis is a (re) emerging zoonosis that occurs worldwide. This study aimed to assess seroprevalence of leptospirosis and to identify the most common reactive serovars and risk factors for seropositivity in apparently healthy stray dogs of unknown vaccination status in the Sarajevo region of Bosnia and Herzegovina. Positive microscopic agglutination test titres (≥ 1:25) were detected in 3.87% (156/4028) of samples and most of the sera reacted against one serovar (85.9%). Dogs were most commonly reactive to Canicola (40.4%) and Hardjo (33.3%), followed by Pomona (15.4%) Tarassovi (14.7%), Icterohaemorrhagiae (8.3%), Grippotyphosa (5.8%), Bratislava (1.3%) and Saxkoebing (0.6%). Dogs older than one year had higher odds of seropositivity compared to younger dogs. The seropositivity was higher in spring and autumn than in summer. These results advocate for the need of a control strategy for this zoonosis in the country, which should include sero-surveillance, monitoring, and the inclusion of additional serovars in the testing.

The subdued post-boost spike-directed secondary IgG antibody response in Ugandan recipients of the Pfizer-BioNTech BNT162b2 vaccine has implications for local vaccination policies.

Introduction: This study aimed to delineate longitudinal antibody responses to the Pfizer-BioNTech BNT162b2 COVID-19 vaccine within the Ugandan subset of the Sub-Saharan African (SSA) demographic, filling a significant gap in global datasets. Methods: We enrolled 48 participants and collected 320 specimens over 12 months after the primary vaccination dose. A validated enzyme-linked immunosorbent assay (ELISA) was used to quantify SARS-CoV-2-specific IgG, IgM, and IgA antibody concentrations (ng/ml) and optical densities (ODs). Statistical analyses included box plots, diverging bar graphs, and the Wilcoxon test with Bonferroni correction. Results: We noted a robust S-IgG response within 14 days of the primary vaccine dose, which was consistent with global data. There was no significant surge in S-IgG levels after the booster dose, contrasting trends in other global populations. The S-IgM response was transient and predominantly below established thresholds for this population, which reflects its typical early emergence and rapid decline. S-IgA levels rose after the initial dose then decreased after six months, aligning with the temporal patterns of mucosal immunity. Eleven breakthrough infections were noted, and all were asymptomatic, regardless of the participants' initial S-IgG serostatus, which suggests a protective effect from vaccination. Discussion: The Pfizer-BioNTech BNT162b2 COVID-19 vaccine elicited strong S-IgG responses in the SSA demographic. The antibody dynamics distinctly differed from global data highlighting the significance of region-specific research and the necessity for customised vaccination strategies.