Seropositivity Rate Research Articles

Epidemiological Survey of Canine Distemper Virus Infection: Exploring the Link Between Virus Spread and Invasive Raccoon (Procyon lotor) Population Growth in Hokkaido, Japan

ABSTRACTInvasive raccoons (Procyon lotor) naturalized in Hokkaido, Japan, potentially spreading infectious diseases. Canine distemper virus infection is a serious epizootic disease, for which the raccoon is one of the hosts. We investigated the virus's prevalence in Hokkaido's wild raccoons, using 611 serum samples collected from captured raccoons in 2007–2012, 2021, and 2022. Higher seropositivity rates were confirmed in 2007 (32.7%), 2021 (46.4%), and 2022 (46.8%) than in 2008–2012 (0.00%–6.06%), suggesting the occurrence of an epidemic in 2007, 2021, and 2022 and its disappearance in 2008–2012. However, the infection status has recently changed, with high seropositivity rates consecutively confirmed in 2021 and 2022. Logistic regression analysis was performed to investigate the relationships among the catch per unit effort (an index of animal population density), host and environmental factors, and antibody status. The catch per unit effort correlated with seropositivity in 2007. As for environmental factors, the forest area ratio had a weak influence on seroprevalence in 2007; however, the residential area ratio had a clear influence on seroprevalence in 2021 and 2022. The epidemic occurred in forested areas in 2007; nonetheless, recent raccoon population growth and habitat expansion may have caused widespread infections even around residential areas in 2021 and 2022. Continuous monitoring of the infection and reinforcement of raccoon control programs are necessary to avoid serious damage through disease transmission to sympatric native raccoon dog (Nyctereutes procyonoides) and fox (Vulpes vulpes) populations, as well as health consequences for domestic dogs (Canis familiaris).

Toxoplasma gondii Prevalence and Risk Factors among Female Students at Al-Yemenia University, Sana'a City, Yemen

Abstract Background: Toxoplasmosis is one of the most common human infections worldwide. It is caused by the intracellular protozoan Toxoplasma gondii. Therefore, this study aimed to determine the prevalence of Toxoplasma gondii infection among female students at Al-Yemenia University in Yemen. Methods: Two hundred female students were selected for this study and screened for Toxoplasma gondii antibodies using an immunochromatographic technique (ICT). Demographic, socioeconomic, risk factors, and behavioral data were collected using a pre-tested questionnaire via face-to-face interviews. Results: The seropositivity rate for T. gondii was (6.0%). The majority were from age groups of 18–20 and 21–24 years (41.7%), who lived in the urban area (83.3%), unmarried individuals (83.8%), and middle-income participants (66.7%), with a non-significant difference (P < 0.05). Female students who washed vegetables before eating had a high risk of T. gondii infection (OR = 4.810), followed by raising cats in the house (OR = 3.812), and had a history of blood transfusion (OR = 1.618). Conclusion: This study reported low seroprevalence among female students at Al-Yemenia University, Yemen. Environmental sanitation, personal hygiene, and health education are all required for promotion to prevent Toxoplasma gondii infection among female students.

A comprehensive seroepidemiology of dengue and chikungunya arboviruses in Iran, 2020–2023

AimDengue virus (DENV) and Chikungunya virus (CHIKV) are the most common arthropod-borne viruses (Arboviruses) globally. So far, no autochthonous cases of DENV and CHIKV infections have been reported in Iran. Nevertheless, due to the recent identification of Aedes aegypti in the south and Aedes albopictus in the north of Iran, the country is at a serious risk of local outbreaks of these infections.MethodsBetween 2020 and 2023, a comprehensive cross-sectional study was conducted to explore the anti-DENV and CHIKV IgG antibodies in the general populations of both southern and northern regions of Iran using ELISA.ResultsA total of 11,192 participants were included, of whom 2.3% (256 individuals) and 0.1% (11 cases) were DENV seropositive and CHIK seropositive, respectively. Across the eight examined provinces, Sistan and Baluchestan province displayed the highest prevalence of dengue seropositive cases (6.80%) (P < 0.001). Samples collected in 2022 demonstrated a notably higher seropositive rate of 5.5% (P < 0.001). Interestingly, all 11 CHIKV seropositive cases were from Sistan and Baluchestan province.ConclusionThe seroprevalence of DENV was notably higher in southern regions, particularly in Sistan and Baluchestan province and CHIKV seropositive cases were exclusively found in Sistan and Baluchestan province. This study furnishes crucial insights into the seroepidemiology of DENV and CHIKV in Iran, which in conjunction with the presence of Ae. aegypti in the south and Ae. albopictus in the north of Iran, emphasizes the requirement of improving integrated surveillance and control systems in the whole of the country, especially in the south of Iran.

Avian raptors are indicator species and victims of high pathogenicity avian influenza virus HPAIV H5N1 (clade 2.3.4.4b) in Germany

Transition of highly pathogenic clade 2.3.4.4b H5 avian influenza virus (HPAIV) from epizootic to enzootic status in Northern European countries was associated with severe losses and even mass mortalities among various wild bird species. Both avian and mammalian raptors hunting infected debilitated birds or scavenging on virus-contaminated avian carcasses contracted HPAIV infection. This precarious pathogen-prey-predator relation further worsened when in 2021 and 2022 outbreaks in Germany overlapped with the hatching season of avian raptor species. Retro- and prospective surveillance revealed avian raptors as important indicators of HPAIV and its genetic diversity on the one hand. On the other hand, their role as victims of HPAIV is stipulated. The first case of an HPAIV H5N1-related death of a white-tailed sea eagle (Haliaeetus albicilla; WTSE) hatch in Germany, 2021, followed by several such cases in 2022, and a low overall seropositivity rate of 5.0–7.9% among WTSE nestlings, raised fears of a serious negative impact on reproduction rates of WTSEs and other birds of prey when HPAIV becomes enzootic in an ecosystem. However, comparably stable breeding success of WTSE in the study area in 2022 and a potentially evolving natural immunity raises hope for a less severe long-term impact.

Seroepidemiology of pertussis immunity in five provinces of China: A population-based, cross-sectional study

ABSTRACT This study aimed to evaluate the seroprevalence of Bordetella pertussis and persistence of antibodies following vaccination. We recruited 6060 healthy subjects from five provinces of China during 2017–2018. Serum IgG antibodies against pertussis toxin (anti-PT IgG) and filamentous hemagglutinin (anti-FHA IgG), and serum IgA antibodies against pertussis toxin (anti-PT IgA) were measured by ELISA. Geometric mean concentration (GMC), seropositivity rate, and recent infection rate were calculated. Among 0–6 years-olds, the anti-PT IgG, anti-PT IgA, and anti-FHA IgG GMCs were 6.4 IU/ml (95% CI 6.1–6.8), 2.8 IU/ml (95% CI 2.7–2.8), and 13.3 IU/ml (95% CI 12.4–14.2), respectively. The anti-PT IgG GMC increased in accordance with the primary vaccination series (4–6 months) and the toddler booster (18–24 months), but declined thereafter through to age 5 years [4.7 IU/ml (95% CI 4.2–5.4)]. The seropositivity rate of pertussis in >6 year-olds was 9.0% (95% CI 8.1–9.9) and the recent infection rate was 3.3% (95% CI, 2.7–3.8). Recent infection rate began to increase from 6 years of age, with peaks at 9, 20, 40, and ≥60 years of age. The anti-PT IgG GMCs of children aged 0–6 years who were vaccinated with DTaP, DTaP-IPV//PRP～T, and DTaP-Hib were 5.9 IU/ml (95% CI 5.6–6.3), 20.7 IU/ml (95% CI 15.6–27.8), and 11.7 IU/ml (95% CI 7.5–18.1) (p < .001), respectively (p < .001). Pertussis vaccination improves anti-PT IgG levels, however these wane soon after vaccination. Sero-estimated recent infection rates appear to increase from school age into adolescence and adulthood. Pertussis vaccine boosters should be considered in these age groups.

Toxoplasma gondii seroprevalence and risk factors of cats in the Budapest area.

This study aimed to survey the current distribution of Toxoplasma gondii (T. gondii) seropositivity within the cat population in Budapest area. Therefore, blood samples of 123 cats aged 0.5-18 years were collected. The measurements were performed by the commercial ID Screen® Toxoplasmosis Indirect Multi-species ELISA kit. The results indicate an overall 31.7% of seropositivity, which was significantly increasing with age. A correlation was also detected between the outdoor lifestyle and T. gondii infection. A significantly higher proportion of cats living outdoors were seropositive (38.8%) compared to those living indoor (18.6%) (P = 0.022). Finally, our study indicates a lower T. gondii seropositivity rate in cats compared to previous studies from Hungary, as well as from other European regions.

Seroprevalence of Toxoplasma gondii and Associated Risk Factors in Pregnant Women in Araçatuba, São Paulo, Brazil: A Multi-Level Analysis.

This study assessed the seroprevalence of Toxoplasma gondii and risk factors among 428 pregnant women attending Basic Health Units (BHUs) in Araçatuba, São Paulo, Brazil. The seroprevalence was 55.14%, indicating high exposure to the parasite in this population. Using a multi-level logistic regression model, this study analyzed these predictors to determine their association with a higher seropositivity rate, with BHUs included as a random factor. Predictors associated with higher seropositivity included older age (36-45 years), with a 71.64% prevalence in this group, and multiparity (61.65%). Women with lower educational levels were also more likely to be infected, with 59.46% seropositivity recorded among those who had only completed elementary school. Despite identifying several risk factors, no significant correlation was found between undercooked meat consumption or contact with soil and infection. These findings highlight the need for targeted public health interventions, particularly for educating high-risk groups about toxoplasmosis prevention, such as safe food handling and avoiding raw dairy products. Additionally, BHUs play a critical role in early detection and prevention. These units are important for providing healthcare access and preventive education for vulnerable populations. Given the high seroprevalence, this study underscores the urgency of implementing prenatal screening and educational programs to reduce the risks of congenital toxoplasmosis in this region.

Autoantibodies in type 1 diabetes: Prevalence and clinical profiles

Type 1 diabetes mellitus (T1D) is one of the most common chronic diseases in children and is associated with acute and serious chronic complications. T1D is characterized by the destruction of insulin-producing beta cells in the pancreas, with the emergence of circulating autoantibodies (a-Abs) targeting β cell antigens. Identifying autoantibodies can help predict the onset of T1D and associated autoimmune disorders, enhancing patient management strategies.We aimed to determine the prevalence of T1D autoantibodies and their clinical significance in the pediatric and adult populations. A multicenter cross-sectional study was carried out on 276 patient-first with T1D, including 167 pediatric (60.5 %) and 109 adult (39.5 %) cases, of which 144 were female and 132 were male (sex ratio= 0.91),with an average age of 14.1 ± 8.0 years. The immunological investigation was based on the detection of T1D related a-Abs, including anti-insulin, anti-glutamic acid decarboxylase (GAD65), anti-insulinoma-associated antigen 2 (IA2), and anti-zinc transporter 8 (ZnT8) specificities. The results revealed an overall autoantibody seropositivity rate of 75.36 % (n= 208). Among the positive cases, GAD65 antibodies were the most prevalent at 37.31 %, followed by anti-insulin and anti-ZnT8 antibodies, each at 36.59 %, and anti-IA2 at 28.62 %. Additionally, 45,67 % of patients had one a-Abs, 28.36 % had a two, 21.15 % had three, and 4.8 % had all four a-Abs.A statistically significant difference was observed between the seropositive and seronegative groups regarding the presence of associated autoimmune diseases (p = 0.005). These findings align with the existing literature, highlighting the importance and scientific value of detecting a-Abs in patients with T1D.

Heterologous Versus Homologous COVID-19 Boosters: Immune Response Outcomes in Renal Transplant Recipients.

We aimed to investigate the immune responses to homologous and heterologous COVID-19 booster vaccinations in renal transplant recipients (RTRs) and to identify factors affecting these responses. In this prospective multicenter observational study, we measured the antibody kinetics of 90 RTRs using the chemiluminescent microparticle immunoassay method. The mean age of participants was 45.2 ± 11.4 years, with 35.6% being female. On the 42nd day after the first vaccine dose, the median antibody level was 16.7 (IQR 2.5-249.5) AU/mL, and the seropositivity rate was 60% (n = 36). Mycophenolic acid (MFA) (OR: 0.087, 95% CI: 0.024-0.311) and ACE inhibitor use (OR: 0.203, 95% CI: 0.052-0.794) were identified as independent factors affecting seropositivity. Patients who received the Pfizer/BioNTech booster had significantly higher antibody levels compared to those who received the CoronaVac/Sinovac booster (p = 0.021). Additionally, a significantly higher rate of COVID-19 positivity was observed among patients who received the CoronaVac/Sinovac booster (p = 0.031). Heterologous COVID-19 booster vaccination is significantly more effective than homologous inactivated booster vaccination in enhancing immune responses and preventing new infections in RTRs. MFA and ACE inhibitor usage were independent factors affecting seropositivity. Additional COVID-19 vaccine doses are needed in this patient group.

Prevalence and Genetic Variation Investigation of the Pseudorabies Virus in Southwest China.

In 2022, a significant PRV outbreak in a southwestern China pig farm led to a high incidence of sow abortion. A serological analysis using gE antigen-based ELISA revealed a high prevalence (69.30%) of PRV gE antibodies among the affected pigs, with a significant variation across different pig populations (1.11-76.12%). We collected additional 5552 pig serum samples and 580 pig cerebrospinal fluid (CSF) samples from various pig farms in Southwest China between 2022 and 2024. The seropositive rates for PRV gE antibodies ranged from 2.36% and 8.65% in the serum samples, while the positive detection rates for the PRV gE gene in the cerebrospinal fluid samples, as determined by PCR, were between 1.06% and 2.36%. The PCR analysis and sequencing of the PRV gB, gC, gE, and TK genes from eight randomly selected samples identified two distinct strains, CQ1 and CQ2. CQ1's gC gene showed similarity to the vaccine strain Bartha, while the other genes aligned with Chinese classical strains, suggesting its potential genetic recombination. CQ2 aligned with the Chinese classical strain SC. Although the overall PRV infection in Southwest China's pig farms is relatively low, occasional outbreaks with high positivity rates are observed. These findings highlight the necessity for increased surveillance and stringent control measures to safeguard the swine industry.

Adenovirus-5 and adenovirus-37 seropositivity in obese patients.

Obesity is a major health issue linked to conditions like diabetes, hypertension, and hyperlipidemia. Infectobesity suggests that certain microorganisms may contribute to obesity. Human adenovirus serotypes, particularly Human adenovirus type-36 (HAdV-36), Human adenovirus type-5 (HAdV-5), and Human adenovirus type-37 (HAdV-37), are thought to influence body fat regulation. This study investigates the relationship between Immunoglobulin G (IgG) positivity for HAdV-5 and HAdV-37 and obesity, aiming to provide data on the infectious etiology of obesity. Blood samples separated into serums from obese (BMI ≥30) and non-obese (BMI 18.5-25) individuals were tested for HAdV-5 and HAdV-37 seropositivity using ELISA kits and seropositivity rates between the groups were compared. HAdV-37 antibody positivity was significantly higher in obese patients (39/48) compared to the control group (24/42) (p=0.011). For HAdV-5, antibody positivity was similar in both groups (26 individuals each) with no significant difference (p=0.461). No significant gender-related differences were found for either serotype. The study suggests HAdV-37 may be associated with obesity, while no such relationship was found for HAdV-5. There was no gender association for either serotype. These results align with existing literature on HAdV-37, but further research is needed to confirm the link between adenoviruses and obesity and explore potential treatment options.

Seroprevalence of antibodies against diphtheria, tetanus, and pertussis across various age groups during the post-COVID-19 pandemic period in Chonburi Province, Thailand

BackgroundLimited data exists regarding population immunity against diphtheria, tetanus, and pertussis in Thailand during the post-COVID-19 pandemic period. This study aimed to evaluate the age-specific seroprevalence of anti-diphtheria toxoid (anti-DT) IgG, anti-tetanus toxoid (anti-TT) IgG, and anti-pertussis toxin (anti-PT) IgG in individuals across diverse age groups in Chonburi province, Thailand following the COVID-19 pandemic. MethodsBetween October 2022 and January 2023, a total of 657 participants from Chonburi Province, Thailand, were included in this study. The participants were categorized into 9 age groups: <5, 5–10, 11–20, 21–30, 31–40, 41–50, 51–60, 61–70, and >70 years. Analysis of anti-DT, anti-TT, and anti-PT IgG levels was conducted using commercial ELISA kits (EUROIMMUN, Lübeck, Germany). ResultsOverall, 65.4 % of the population had seroprotection against diphtheria (antibody level ≥0.1 IU/mL), while 95.1 % had seroprotection against tetanus (antibody level ≥0.1 IU/mL). The 31–40 years age group exhibited the lowest seroprotection for diphtheria (48.9 %), and the >70 years age group had the lowest seroprotection for tetanus (73.3 %). The <5 years age group showed the highest seropositive rate and highest geometric mean titers for anti-PT IgG. On the contrary, the majority of individuals over 11 years of age displayed anti-PT IgG levels below 40 IU/mL. ConclusionsTo prevent diphtheria and pertussis outbreaks in Chonburi province, implementing catch-up vaccination is necessary. Targeted interventions should be deployed to enhance vaccination coverage among the susceptible population.

Seroprevalence of strongyloidiasis and toxocariasis among hypereosinophilic patients seeking care at diagnostic centers in Tehran, Iran

BackgroundHypereosinophilia is characterized by an increase in eosinophil levels above the normal range. Secondary hypereosinophilia is frequently seen in helminth infections and allergic conditions. If not diagnosed and managed promptly, eosinophilia can result in various complications impacting health. The aim of this study was to explore the seroprevalence of Strongyloides stercoralis and Toxocara spp. among hypereosinophilic patients undergoing evaluation at selected diagnostic centers in Tehran. MethodsA comprehensive questionnaire was completed, and a blood sample was collected from each participant. The seropositivity of helminth infections was ascertained through indirect enzyme-linked immunosorbent assay (ELISA) employing commercially procured kits for discerning anti-S. stercoralis and anti-Toxocara spp. IgG antibodies. Statistical analysis was conducted using SPSS 21 software. ResultsOf the 135 participants in this study, 61 (45.2 %) were male and 74 (54.8 %) were female. The seropositivity rates for strongyloidiasis and toxocariasis were found to be 9.6 % and 0.74 %, respectively. Among the various underlying medical conditions observed in the participants, Type 2 Diabetes (T2D) was the most prevalent, and it showed a significant association with seropositivity for strongyloidiasis (p < 0.05). ConclusionThe seropositivity for S. stercoralis was higher than that for Toxocara spp.. The significant association between seropositivity for S. stercoralis and diabetes underscores the importance of conducting community-based studies and implementing screening initiatives targeting high-risk populations to assess the seroprevalence of strongyloidiasis.

Influencing factors of antibody response after 2 doses of inactivated COVID-19 vaccine among adults aged ≥18 years in Chongqing, China: A cross-sectional serological study.

The study aimed to explore the influencing factors after 2 doses of inactivated COVID-19 vaccines (Sinopharm/BBIBP-CorV) in the real world. We conducted a cross-sectional serological study involving 316 volunteers aged ≧ 18 years from 7 vaccination hospitals in the Yubei districts, Yuzhong districts, and Jiulongpo districts of Chongqing. Serum samples were obtained about 1 month after 2 dose vaccination, and Nabs were tested using the pseudovirus-based neutralizing assay. Chi-square or Fisher exact tests were used to analyze the seropositive rates, while the Kruskal-Wallis H or Mann-Whitney U tests were used to analyze differences in Nabs level among stratified groups. Logistic regression analyses were conducted to identify the influencing factors. The results showed that seropositive rates was 76.27% and the GMT was 26.13 (95% CI: 23.03-29.66) after 2 doses of COVID-19 inactivated vaccination. The risk of being seropositive in 18 to 29, 30 to 39, 40 to 49, 50 to 59, and 60 to 69 years were 12.808-fold, 8.041-fold, 7.818-fold, 6.275-fold, 1.429-fold compared with the people aged ≥ 70 years (P < .05), and the risk of being seropositive of intervals 15 to 21 and 22 to 28 days were 0.273-fold and 0.286-fold compared with >28 days (P < .05), respectively. In conclusion, age may be a risk factor for reduced antibody production, and longer vaccination intervals-may be a protective factor that increases antibody production. These findings contribute to informing future vaccination strategies.

Long term T cell response and safety of a tetravalent dengue vaccine in healthy children

As robust cellular responses are important for protection against dengue, this phase 2 study evaluated the kinetics and phenotype of T cell responses induced by TAK-003, a live-attenuated tetravalent dengue vaccine, in 4–16-year-old living in dengue-endemic countries (NCT02948829). Two hundred participants received TAK-003 on Days 1 and 90. Interferon-gamma (IFN-γ) enzyme-linked immunospot assay [ELISPOT] and intracellular cytokine staining were used to analyze T cell response and functionality, using peptide pools representing non-structural (NS) proteins NS3 and NS5 matching DENV-1, -2, -3, and -4 and DENV-2 NS1. One month after the second TAK-003 dose (Day 120), IFN-γ ELISPOT T cell response rates against any peptide pool were 97.1% (95% CI: 93.4% to 99.1%), and similar for baseline dengue seropositive (96.0%) and seronegative (98.6%) participants. IFN-γ ELISPOT T cell response rates at Day 120 were 79.8%, 90.2%, 77.3%, and 74.0%, against DENV-1, -2, -3, and -4, respectively, and remained elevated through 3 years post-vaccination. Multifunctional CD4 and CD8 T cell responses against DENV-2 NS peptides were observed, independent of baseline serostatus: CD8 T cells typically secreted IFN-γ and TNF-α whereas CD4 T cells secreted ≥ 2 of IFN-γ, IL-2 and TNF-α cytokines. NAb titers and seropositivity rates remained substantially elevated through 3 years post-vaccination. Overall, TAK-003 was well tolerated and elicited durable T cell responses against all four DENV serotypes irrespective of baseline serostatus in children and adolescents aged 4–16 years living in dengue-endemic countries. TAK-003-elicited CD4 and CD8 T cells were multifunctional and persisted up to 3 years post-vaccination.

Analysis of antibody dynamics in Chinese children aged 1-3 years after single-dose varicella vaccination: A 42 months prospective study

ABSTRACT In China, children aged 12 months receive only a single dose of the varicella vaccine and the incidence of varicella remains high. This study aims to evaluate the changes in immunity among children aged 1–3 years following a single dose of the varicella vaccine, providing a scientific basis for determining the optimal age for a second vaccination. This prospective cohort study employed glycoprotein enzyme-linked immunosorbent assay (gpELISA) for antibody detection. The changes in IgG antibody levels over time post-vaccination were analyzed using a restricted cubic spline (RCS) fitted binary logistic regression model. Varicella surveillance data were collected from the National Notifiable Disease Reporting System (NNDRS). Following a peak in varicella incidence in 2019, the incidence shifted toward older age groups. The cohort study results revealed a seropositivity rate of 100% in children during the 18 months post-vaccination, which subsequently declined to 71.6% by the 42 months. The geometric mean concentration (GMC) decreased from 307.6mIU/mL to 115.2mIU/mL. Additionally, 14 children contracted varicella during the follow-up period, resulting in a breakthrough rate of 2.85%. RCS analysis indicated that antibody levels fell below the protective threshold 18.69 months post-vaccination, with a non-linear decline in the odds ratio(OR) of maintaining antibody concentrations ≥ 50mIU/mL(p < .001, Pnonlinear ≤ 0.001). This study demonstrates that the long-term protective efficacy of a single dose of the varicella vaccine diminishes over time in children, underscoring the necessity of implementing a two-dose vaccination strategy. The findings provide scientific evidence for determining the optimal timing for administering the second dose of the vaccine.

The 13-year long-term follow-up on the effectiveness and immunogenicity of the quadrivalent human papillomavirus vaccine in Chinese females vaccinated at 20–45 years of age

ABSTRACT The quadrivalent human papillomavirus (qHPV) vaccine demonstrated high efficacy against vaccine-type-related precancers in Chinese females through a 6.6-year double-blind, randomized control trial (V501–041, NCT00834106). We present results for its long-term follow-up (LTFU) phase, evaluating vaccine effectiveness and immunogenicity throughout 13 years post Dose 1. Participants receiving qHPV vaccines at ages 20–45 in the V501–041 study constituted the early vaccination group (EVG). Those who received the placebo in V501–041 but were vaccinated during 2018–2020 formed the catch-up vaccination group (CVG), while the control group (CG) comprised those remaining unvaccinated throughout V501–041 and LTFU. The primary endpoint was histopathologically-confirmed cervical intraepithelial neoplasia (CIN) 2+ tested PCR-positive for HPV-16/18. Antibodies against HPV-6, 11, 16, and 18 were assessed using an immunoglobulin G (IgG) Luminex immunoassay at year 13. A total of 1100 participants from V501–041, of whom 978 were followed in LTFU, were included with a median follow-up of 152.2 months. No cases of the primary endpoint were observed in the EVG during 5513.6 person-years of follow-up, while one case was observed in the CG over 2951.4 person-years of follow-up, indicating a 100% risk reduction in the EVG compared to the CG. In the CVG, no cases were detected from vaccination to the latest follow-up (0.0 per 10 000 person-years), contrasting with an incidence of 22.3 per 10 000 person-years prior to vaccination. Seropositivity rates at year 13 remained >92% (for HPV-6/11/16) and 84% (HPV-18). These findings demonstrated continued vaccine protection against cervical precancers and sustained immunogenicity through 13 years post-vaccination. Trial Registration The LTFU study was registered at the Chinese Clinical Trial Registry, ChiCTR2100052313.

Prevalence of Toscana Virus Antibodies in Residents of Bulgaria: A Nationwide Study Following the Pandemic of COVID-19.

Introduction: Toscana virus (TOSV) is an arthropod-borne virus transmitted by sandflies and is mainly found in countries around the Mediterranean basin. In this article, we present the findings of a seroprevalence study on TOSV in Bulgaria. We aim to assess the current epidemiological situation regarding TOSV in the country and raise clinical awareness. Methods: Serum samples (n = 1892) were collected in December 2023. Serological tests were performed using a commercial anti-TOSV ELISA kit. Results: Specific immunoglobulin G (IgG) antibodies were detected in 6.4% (121/1892) of the participants. A significantly higher seropositivity rate was found in the age group over 65 years compared with the age groups 18-29 and 40-64 (11.8% vs. 3.9% vs. 3.4%), as well as in males compared with females (8.0% vs. 5.3%). The seroprevalence rates in districts ranged from 0% to 18.5%. Higher seropositivity was found in the southern and northern regions. Conclusions: The seroprevalence rate of TOSV in Bulgaria, found in this study, is a significant decrease compared with the seropositivity rate of 24.5% reported in the country in 2018. The reasons for this are unknown and could possibly be related to the COVID-19 pandemic and the constantly changing environmental conditions. There is also a possibility that the higher seropositivity detected in 2018 together with the rise in clinical cases reported from endemic countries around that time might have been due to an unrecognized TOSV outbreak taking place in this period. Continued clinical awareness and surveillance are necessary for recognition and management of potential cases of TOSV neuroinfection, especially during summer.

Investigation of Seropositivity of Anti-Toxoplasma gondii Antibodies and Possible Risk Factors in Pregnant Women with Diabetes at Risk.

Toxoplasmosis is a parasitic infection caused by Toxoplasma gondii. Immunocompromised individuals and pregnant women are at risk, with the latter group being susceptible to miscarriages. This study aimed to determine the seropositivity of T. gondii antibodies and potential risk factors in pregnant women diagnosed with diabetes mellitus. The research was conducted at the Ankara City Hospital Perinatology Clinic between October 2021 and June 2022. The study included 277 pregnant women diagnosed with diabetes mellitus and 277 healthy pregnant women who had given birth. Retrospective analysis of anti-T. gondii immunoglobulin (Ig)G and IgM levels was performed for patients between January 2020 and February 2022. Participants were administered an informed consent form and a questionnaire. Data were analysed using SPSS 22. Among pregnant women with diabetes, IgG seropositivity was 18.4%, IgM was 0.0%, and IgG+IgM was 0.0%. In healthy pregnant women, IgG seropositivity was 12.3%, IgM was 0.4%, and IgG+IgM was 0.4%. Overall, seropositivity rates were 15.3% for IgG, 0.2% for IgM, and 0.2% for IgG+IgM. The difference between the two groups was statistically significant (p<0.05). Among pregnant women with diabetes, there was a significant statistical difference (p<0.05) in anti-T. gondii IgG seropositivity related to education, employment status, number of pregnancies and live births, history of toxoplasmosis diagnosis in children, previous toxoplasmosis diagnosis, hygiene, nutrition, and social habits. Among healthy pregnant women, significant statistical differences were found (p<0.05) in IgG seropositivity related to age, income, education level, number of pregnancies and live births, previous toxoplasmosis diagnosis, hygiene, nutrition, and social habits. No invasive interventions were performed on infants born to seropositive mothers, and perinatal data were not available. The seroprevalence of toxoplasmosis in Ankara appears to be decreasing, but T. gondii infections continue to pose a public health concern and are significant in pregnant women with diabetes mellitus.

Sero-epidemiological Study of Japanese Encephalitis in Some Selected Hospitals of Nepal

Japanese encephalitis is a major public health problem in Nepal, about 1000-3000 cases and 200-300 deaths reported annually, mainly in endemic areas and sporadic cases have also been reported from non-endemic areas such as Kathmandu. The diagnosis of JE is based on clinical signs and symptoms. This study was conducted in some hospitals of Nepal to find the epidemiological trend of the disease. Serological surveys have revealed that about 10 % of people living in JE endemic areas are infected with the virus, most of whom are infected before age 15. This type of study is essential to be carried out in our country to know the seroepidemiology of the JE virus. A descriptive cross-sectional study was conducted, and 267 serum samples from suspected Acute Encephalitis Syndrome and viral fever cases were collected from three different hospitals in Nepal. The results were confirmed by an IgM capture enzyme-linked immunosorbent assay. Of 267 serum samples, 242(90.6%) were clinical suspects of Acute Encephalitis Syndrome, and 25(9.4%) were clinical suspects of viral fever. Of 267 cases, 84(34.7%) Acute Encephalitis Syndrome cases and nine (36.0%) viral fever cases were positive for anti-Japanese encephalitis virus IgM antibodies. The seropositivity was higher in males 60(39.9%) than in females 33 (29.2%). Out of the total positive cases, the highest seropositivity (40.2%) was observed in the age group 15-50, and the least (25.0%) was observed in the age group above 50. Tribhuvan University Teaching Hospital accounts for highest seropositivity (36.6%) and the least (32.2%) in Bheri Zonal Hospital. The overall seropositivity rate was found to be 34.8% which was higher than the national data (21.6%). This study reports that the seropositivity was higher than national figure and the seroepidemiology pattern of JE has changed, indicating a need for urgent intervention. Diagnostic facilities should be expanded in every hospital in the endemic region of Japanese Encephalitis for better surveillance.