Seroprevalence Levels Research Articles

P0632 Analysis of serological responses to SARS-Cov-2 vaccination in patients with Inflammatory Bowel Disease in India identifies low BMI as an independent determinant of vaccine non-response

Abstract Background Studies of patients with inflammatory bowel diseases (IBD) from Western countries have demonstrated that serological responses to mRNA and vector-based vaccines are differentially impacted by IBD therapies. Little is known regarding antibody responses in patients with IBD residing in low- and middle-income countries (1). In this study, we investigate the factors which may influence the inhibitory and total antibody responses to SARS-CoV-2 in two centers in Northern India. Methods We studied 180 IBD patients in Chandigarh and New Delhi, India, who received two doses of a COVID-19 vaccine. All patients received Oxford-AstraZeneca equivalent Covishield (n=149) or inactivated virus vaccine Covaxin (n=31) between January 2021 and December 2022. We measured anti-S and anti-N antibody levels and performed inhibition assays to measure the inhibition of ACE2 on SARS-CoV-2 binding against alpha, delta, and omicron variants after first and second vaccine doses. Univariate and multivariate analyses were performed to identify determinants of vaccine response. Results On univariate analysis, IBD patients taking steroids (p= 0.019), immunomodulators (p= 0.047), or infliximab (p= 0.0057) had lower responses after dose 2 for any vaccine compared to those not on these medications or receiving 5-ASAs. Low BMI was associated with reduced rates of seroconversion in univariate analysis. For every fall in BMI by 1, the average ACOV2S V2 anti-Spike level was reduced by 8.2 (Figure 1). Additionally, 97% (28/29) of vaccinated IBD patients with a BMI greater than or equal to 25 reached the maximum anti-Spike value after their second dose of a COVID-19 vaccine. Multivariate analysis comparing gender, IBD type, smoking status, comorbidities, IBD medications, and a history of COVID-19 diagnosis revealed that low BMI (dose 1: OR: 1.12 [CI: 0.084, 0.136]; dose 2: 1.11 [0.076, 0.128]), infliximab (dose 1: 1.67 [-.92, 1.94]), and patients on steroids (dose 1: 1.50 [-1.384, 2.195]; dose 2: 0.200 [-3.76 0.54]) were each independent determinants of lower seroprevalence levels after receiving a dose of Covishield or Covaxin. Conclusion Immunosuppressive drug therapy and reduced BMI emerge as determinants of sub-optimal seroconversion rate in this patient population. The association with low BMI represents a unique finding in this population, and directly contrast with studies reported in Europe & North America. These data are useful for future pandemic vaccine considerations in patients with IBD. References (1)Wong SY, Wellens J, Helmus D, et al. Geography Influences Susceptibility to SARS-CoV-2 Serological Response in Patients With Inflammatory Bowel Disease: Multinational Analysis From the ICARUS-IBD Consortium. Inflamm Bowel Dis. 2023;29(11):1693-1705. doi:10.1093/ibd/izad097

High seroprevalence to SARS-CoV-2 among healthcare and non-healthcare workers of the ophthalmology center

Background. The pandemic of COVID-19 raised safety concerns for healthcare workers while non-medical personnel were left unattended. Comparing the levels of seroprevalence to SARS-CoV-2 and vaccination in different employee groups will allows us to assess the risk of infection and develop a strategy to minimize the spread of infections in medical institutions in future.The aim. To identify the level of seroprevalence to SARS-CoV-2 for seven groups of medical center workers. Methods. The seroprevalence to SARS-CoV-2 was analyzed in 361 employees of the ophthalmology center in mid-2021. Data on the level of specific IgM and IgG antibodies were compared with questionnaire, including occupation data.Results. Depending on occupation, workers were divided into seven groups. The average seroprevalence rate for all employees was 82.3 %, and the percentage of vaccinated employees was 27.4 %. The lowest level of seroprevalence was found in the group of maintenance staff (55.0 %) which is significantly lower (p ˂ 0.05) than in the groups of doctors (84.4 %), nurses (85.6 %), administrative stuff (82.6 %) and cafeteria stuff (77.7 %). The seroprevalence rate for cleaning staff was 84.6 % and for pharmacy workers it was 80 %. The highest vaccination coverage was among doctors – 50.0 %, the lowest was among cafeteria and kitchen staff – 7.4 %.Discussion. We believe the high seroprevalence is associated with asymptomatic spread of SARS-CoV-2.Conclusions. High seroprevalence was among doctors and nurses, pharmacy workers, canteen workers, cleaners, as well as administration workers. Anti-epidemic measures for these groups will reduce the spread of infectious diseases and help retain staff during the seasonal increase in incidence.

Screening of Antibodies Against Leptospiral Hardjo Among Bovine Species of Nawalpur, Tanahun and Gorkha Districts of Nepal

Introduction: Leptospirosis, a bacterial zoonosis, can affect livestock species with considerable losses especially cattle and buffalo. Leptospira interrogans serovar hardjo is known to be associated with reproductive disorders in bovines. Information on the seroprevalence of antibodies against this serogroup in this territory is important in managing risks and instituting control measures for the area, such as Nepal since these diseases could be overlooked due to the absence of some surveillance practices. The aim of the study was to investigate the seroprevalence of Leptospira interrogans serovar hardjo antibodies among cattle and buffalo from Nawalpur, Tanahun and Gorkha districts of Nepal in order to evaluate the extent of the disease and its effect on cattle. Methods: A total of blood samples were collected aseptically using purposive sampling from cattle and buffalo in the study area 174. These samples were analyzed serologically using PrioCHECK®L.hardjo Ab ELISA kit for antibodies to Leptospira interrogans serovar hardjo. Results: The serological analysis indicated that the seroprevalence was 1.149% which points out the existence of a natural infection in cattle and buffalo reared without any immunization against leptospirosis. Geographical factors, especially region, combined with other factors like low immunogenicity of their vaccines offered to the animals, might explain the low level seroprevalence of the disease. Conclusion: This current study has highlighted the natural occurrence of the leptospires in the hardjo serovar in cattle and buffalo within the study region. The above studies bring out the necessity for active programs for control and preventative measures to restraints leptospirosis disease among the cattle as the disease prevalence designates low seroprevalence rate.

Herd and animal level seroprevalence and associated risk factors of Leptospira interrogans sensu lato serovar Hardjo in cattle in southwest Ethiopia

Leptospirosis is a significant zoonotic disease that causes high economic losses in cattle production due to its association with abortions, stillbirths, infertility, and reduced milk yields. However, the epidemiology of bovine leptospirosis in Ethiopia is poorly understood. From October 2020 to October 2021, a cross-sectional study was conducted to investigate the seroprevalence of serovar Hardjo in cattle in southwest Ethiopia, as well as the associated risk factors. To test for the existence of L. Hardjo antibodies, blood samples were taken from 461 cattle. Indirect ELISA was used to identify the presence of antibodies against L. Hardjo in sera samples. We conducted a multivariable random-effect logistic regression analysis to identify potential risk factors associated with L. Hardjo seropositivity. An overall L. Hardjo seroprevalence of 24.7% (95% CI: 20.2–48.8) and 53.5% (95% CI: 45.7–90.5) was recorded at the animal level and the herd level, respectively, in the study areas. This study revealed six factors influencing L. Hardjo seropositivity in cattle herds. Large herds had twice the odds of seropositivity (OR = 2.0, 95% CI: 1.1–3.8) compared to small herds. Co-grazing cattle exhibited higher odds (OR = 2.2, 95% CI: 1.2–4.1) of seropositivity. Extensive management systems significantly increased the odds (OR = 10.3, 95% CI: 1.7–61.8) compared to semi-intensive systems. Highland cattle had higher odds (OR = 3.7, 95% CI: 1.4–10.3) than lowland cattle. Older cattle (OR = 4.6, 95% CI: 2.4–8.9) were more likely to be seropositive. At the herd level, extensive management (OR = 2.8, 95% CI: 1.3–5.8) and large herds (OR = 2.5, 95% CI: 1.3–4.7) increased the risk of seropositivity. Herds with sheep/goats (OR = 2.3, 95% CI: 1.3–4.1) were also at higher risk, highlighting significant L. Hardjo seropositivity risk factors in cattle herds. The study findings showed that leptospirosis was highly prevalent across the study areas. As a result, use proper management, raise zoonotic awareness for leptospirosis, and conduct molecular bovine leptospirosis research in study areas were recommended.

Silent reactivation of Varicella Zoster virus in hemodialysis patients.: A management dilemma.

To determine the seroprevalence of Varicella Zoster virus (VZV) immunoglobulin (Ig)G and IgM antibodies among hemodialysis patients (HDP). Additionally, the presence of VZV viral DNA has been investigated for possible reactivation status. Sera from 265 individuals were collected and tested. The study was carried out from November 2023 to February 2024. Enzyme linked immunosorbent assay was accomplished to determine the VZV IgG and IgM antibody levels. The viral DNA was tested by qPCR. We found a significantly higher proportion of Host defense peptides (HDP) have positive antibody levels compared to healthy controls (HC) (92.0% of HDP have positive immune responses compared to 79.1% of HC, p=0.005). Patients with both hypertension and diabetes showed lower VZV seropositivity (25.6%) than those without (74.4%). Only 3 HDP had positive IgG and IgM levels (1.9%, n=3), while 14 patients (100%) had negative IgG and IgM levels. Additionally, all IgM-positive patients appeared to have detectable viral DNA of the VZV. In conclusion, significantly higher VZV seroprevalence and antibody levels in HDP indicate greater viral exposure than HC. Screening of hemodialysis (HD) to VZV serologically or at the molecular level is most important to avoid the consequences of viral reactivation, especially in those with asymptomatic HDP.

SARS-CoV-2 cross-sectional serosurvey across three HIV-1 therapeutic clinical trials in Africa.

Data on the impact of COVID-19 in people living with HIV (PWH) are lacking in resource-constrained settings. We utilised existingrandomised clinical trials (RCTs) on antiretroviral therapies (ART) in HIV-1 infection to conduct a SARS-CoV-2 serosurvey, between January and March 2021, while characterising participants' features. Cross-sectional serosurvey. Demographic characteristics, medical history and a serum sample were collected from consenting PWH. Samples were analysed centrally for immunoglobulin G antibodies to recombinant nucleocapsid and spike proteins derived from SARS-CoV-2 using a Luminex based assay. The 549participants recruited in 9 sites across Africa had a median age of 40 years (IQR [34-45]); 63.0% (346) were female. All were on ART; 81.8% (449) had an HIV-1 viral load <50 copies/mL, with CD4 count median at 478/mm3 (IQR [320-677]). None had received vaccination against SARS-CoV-2. Forty participants (7.3%) had a prior SARS-CoV-2 PCR testing, of whom 10 were positive (1.8%). Crude SARS-CoV-2 seroprevalence was 36.2% (; 95%CI [32.2-40.4]). In the explorative multivariable analysis, comparison of the characteristics of PWH with a positive SARS-CoV-2 serology with those with a negative or indeterminate serology: PWH with a body mass index (BMI)≥30 kg/m2 were more likely to have a positive serology than those with a BMI≤25 (aOR = 2.39 [1.48-3.86], p < 0.001); and PWH living in Cameroon were less likely to have a positive serology. This study demonstrates a substantial seroprevalence level of SARS-CoV-2 in PWH in the first quarter of 2021, with a marked disparity with the number of COVID-19 PCR tests reported positive.

HERD IMMUNITY TO VACCINE PREVENTABLE INFECTIONS IN SAINT PETERSBURG AND THE LENINGRAD REGION: SEROLOGICAL STATUS OF MEASLES, MUMPS, AND RUBELLA

Abstract Specific measles, mumps, and rubella prevention has been the main prerequisite for a striking decline in the incidence of such infections in Russia. An increase in the percentage of seronegative individuals observed in recent years resulted in higher measles incidence being directly related to low herd immunity that accounts for a population protection solely under conditions of a high density of immunized individuals and their uniform distribution in the population. The number of immunized individuals may be estimated only while conducting seroepidemiological monitoring of herd immunity. Objective of the study: to assess a level of herd immunity in the St. Petersburg and Leningrad Region population against measles, mumps, and rubella viruses. Materials and methods. There were enrolled 6,774 residents into the study: volunteers aged from 1 to 70+ years. The representativeness of the surveyed cohort was ensured by using the Web application "Monitoring of herd immunity against socially significant infections", used at the stage of volunteer enrollment, by randomization and regulation of the sample size in age groups. Participants filled out a questionnaire and agreed to provide venous blood samples to assess IgG antibody levels against measles, mumps, and rubella viruses by using ELISA. Results. In September 2023, in St. Petersburg and the Leningrad Region, herd immunity met the criterion for epidemiological well-being only with respect to rubella. In all age groups, the proportion of seronegative individuals did not exceed 15%, and most volunteers had high Ab levels, both after illness and vaccination. For measles and mumps, the criterion for epidemiological well-being is considered not to exceed more than 7% seronegative individuals. A sufficient level of measles seroprevalence was detected only in older age groups (≥60 years old). Sufficient mumps seroprevalence was not detected in any age group. The average population (St. Petersburg, Leningrad Region) seroprevalence magnitude for measles, rubella, and mumps viruses were 81.4%, 95.5%, and 78.4%, respectively. The problematic age groups with low measles seroprevalence (62.4–74.3%) were adolescents (12-17 yrs) and young adults (18-39 yrs). Most seropositive individuals vaccinated against measles had low Ab levels; high levels were noted mainly in older measles convalescent individuals. Low mumps seroprevalence (~70%) was more often observed among adults aged 18 to 49 years. The distribution of seroprevalence in various occupational group was relatively uniform, with some predominance of seropositivity among pensioners and schoolchildren. Conclusion. The system of specific prophylaxis for vaccine-preventable viral infections used in Russia has shown high efficacy and contributed to the formation of herd immunity, which for many years allowed to lower a risk of both sporadic and group infections to minimal levels. Currently, measles and mumps seroprevalence in the local population is maintained at insufficient level to ensure epidemiological well-being. This necessitates making appropriate management decisions and conducting additional preventive measures aimed at enhancing relevant herd immunity.

Seroprevalence and associated risk factors of bovine herpesvirus 1 in smallholder dairy farms in two districts of Gondar zones, North-West Ethiopia

Bovine herpesvirus 1 (BoHV-1) is the infectious agent that causes infectious bovine rhinotracheitis (IBR), a disease affecting the reproductive and respiratory systems of cattle. Significant economic losses result from infectious bovine rhinotracheitis because of metritis, abortions, placenta retention, recurrent breeding, animal deaths, and losses from trade restrictions. Reports of the diseases have been made in southern, southwestern and in major cities that kept improved breed of dairy cows in Ethiopia with prevalence ranging from 28.5–67 %. However, there is insufficient information available regarding the frequency and spread of IBR in the northwest part of the nation. In northwest Ethiopia, a cross-sectional study was carried out to estimate seroprevalence of BoHV-1 and identify associated risk factors. Dairy farms and farm owners were chosen using a multistage cluster sampling technique, while dairy cattle were chosen using a simple random sample technique. Four hundred and thirty-one dairy cattle from 177 herds in the Debark and Lay-Armachiho districts in the North and Central Gondar zones, respectively, both in Northwestern Ethiopia, were selected to provide serum samples. Owners of dairy animals provided information via questionnaires. Using a competitive enzyme-linked immunosorbent assay (c-ELISA), anti-BoHV-1 antibodies were detected in serum samples. To identify risk factors, univariable and multivariable mixed effect logistic regression models were used. We calculated animal level and herd level seroprevalence of 72 % (95 % CI: 64.9–78.4 %) and 85.7 % (95 % CI: 79.8–90 %), respectively. Parity was associated with seroprevalence of BoHV-1; cows with higher parity had increased seroprevalence of BoHV-1. Bull mating [OR=3.13, (95 % CI: 1.74–5.64)] compared to AI and Debark district [OR=2.73 (95 % CI: 1.63–4.57)] compared to Lay-Armachiho district, were associated with seroprevalence of BoHV-1. The study had shown that BoHV-1 is circulating out of the major cities and also on dairy farms keeping local breeds of dairy cows in Gondar zones, North-West Ethiopia. This suggests need of attention in prevention and control of BoHV-1.

Risk factors associated with increased Toxoplasma gondii seroprevalence in South Australian Sheep

Toxoplasma gondii (T. gondii) is a protozoan parasite of substantial impact to small ruminants, with reproductive failure a possible outcome of exposure. This observational study assessed T. gondii prevalence within the South Australian sheep population and investigated on-farm risk factors to T. gondii exposure via a cross-sectional survey. 1433 individual animals, consisting of 1282 mixed-age ewes and 151 mixed-age rams were blood sampled and serologically screened for T. gondii-specific antibodies. A risk-analysis questionnaire was conducted for each participating property. Of the 1433 animals sampled, 530 tested positive, with seroprevalence observed to be 39 % (95 % CI 28.7–49.3 %) after accounting for clustering within properties. All properties returned at least one positive result, indicating a flock level seroprevalence of 100 %. T. gondii seroprevalence was found to be higher in sheep on Kangaroo Island (46.6 %; 95 % CI 32.1–61.1 %) compared to the South Australian mainland (31.3 %; 95 % CI 18.4–44.2 %), however this difference was not statistically significant (P=0.125). A significant association was observed between T. gondii seroprevalence and age, with seroprevalence increasing from 30.2 % (95 % CI 17.7–42.6 %) in one year old sheep, to 69.7 % (95 % CI 47.0–92.5 %) in sheep older than six years (P=0.001). T. gondii seroprevalence was significantly higher in animals drinking water from surface water sources (55.9 %; 95 % CI 35.2–76.6 %), compared to those exclusively sourcing reticulated mains water (19.1 %; 95 % CI 0 %-39.0 %) (P=0.028). An individual animal exposed to a surface water source was found to be more than ten times as likely to be exposed to T. gondii, than an animal sourcing only reticulated mains water (odds ratio:10.68; 95 % CI 1.30–87.88). Water source is important in the transmission of T. gondii to South Australian sheep. Mitigation strategies should be developed and targeted at reducing contact between oocysts and water sources and reducing interaction between livestock and contaminated water.

Anti-HBs Seroprevalence in Blood Donors from Tyrol, Austria.

Background/Objectives: Antibodies against the hepatitis B surface antigen (anti-HBs) are a marker of immunity against hepatitis B virus (HBV) infections. There is uncertainty about the anti-HBs seroprevalence in the general population of Austria. Methods: We conducted a cross-sectional analysis in blood donors from the Federal State of Tyrol in Austria (August-September 2023) to estimate anti-HBs seroprevalence and median antibody levels. Results: We enrolled 3935 blood donors (median age 47.6 years [25th-75th percentile: 33.3-56.6]; 40.7% female), who were hepatitis B surface antigen negative and had no detectable HBV-DNA. Overall seroprevalence was 51.4% (95% CI: 49.8-52.9%). Anti-HBs seropositivity decreased with higher age (p < 0.001), with 70.3% (66.1-74.3%) being seropositive among participants < 25 years of age and 30.2% (24.2-36.9%) in those aged ≥ 65 years. More females than males were seropositive (54.3% [51.8-56.7%] vs. 49.4% [47.4-51.4%]; p = 0.003). Seroprevalence was significantly higher in urban than in rural areas in participants aged 40 to <55 (p = 0.045) and ≥55 years (p = 0.001). Among 2022 seropositive participants, the overall median anti-HBs antibody level was 539.3 IU/L (25th-75th percentile: 116.3-5417.0). Furthermore, 5% of the participants had an anti-HBs antibody level between 10 and <20 IU/L, 18% between 20 and <100 IU/L, and 77% ≥100 IU/L. Conclusions: Anti-HBs seroprevalence in blood donors from Tyrol, Austria, was 51.4% between August and September 2023 and differed across age, sex, and residence area. Catch-up vaccination programs, especially targeting the elderly living in rural areas, are needed to close HBV immunity gaps.

SARS-CoV-2 serosurvey across multiple waves of the COVID-19 pandemic in New York City between 2020–2023

Sero-monitoring provides context to the epidemiology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and changes in population immunity following vaccine introduction. Here, we describe results of a cross-sectional hospital-based study of anti-spike seroprevalence in New York City (NYC) from February 2020 to July 2022, and a follow-up period from August 2023 to October 2023. Samples from 55,092 individuals, spanning five epidemiological waves were analyzed. Prevalence ratios (PR) were obtained using Poisson regression. Anti-spike antibody levels increased gradually over the first two waves, with a sharp increase during the 3rd wave coinciding with SARS-CoV-2 vaccination in NYC resulting in seroprevalence levels >90% by July 2022. Our data provide insights into the dynamic changes in immunity occurring in a large and diverse metropolitan community faced with a new viral pathogen and reflects the patterns of antibody responses as the pandemic transitions into an endemic stage.

Serological and Community Awareness Study of Lumpy Skin Disease in Different Agro-Ecological Zones of Sidama Regional State, Southern Ethiopia.

The lumpy skin disease (LSD) vaccination status and epidemiological distribution remain unknown in some parts of Ethiopia, including the Sidama regional state. In this study, a serological survey of LSD was performed using a specific virus neutralization assay in selected districts of the Sidama regional state representing three agroecological zones from September 2021 to June 2022. Moreover, an assessment of community awareness and LSD vaccine-related problems was conducted using a questionnaire. Our results showed an overall animal and herd level seroprevalence of 40.8% (95%CI = 35.8, 45.8) and 81% (95%CI = 77, 85), respectively. High and low seroprevalence were observed in lowland (48%) and highland (28%) areas, although they were not statistically significant. However, risk factors such as management systems and breeds showed substantial differences in their LSD prevalence. The results obtained through the questionnaire showed that a small portion of respondents (29.2%) know about LSD and vaccinate their cattle (23.3%) against this disease. Only 20.8% of the respondents stated that there was LSD occurrence in their vaccinated cattle. In conclusion, both qualitative and quantitative study results showed the need for intervention in terms of community-based awareness creation about LSD clinical signs and vaccination advantages together with the frequently updated information on LSD prevalence.

Sero-epidemiological study of brucellosis in cattle under pastoral/agro-pastoral and mixed crop-livestock systems in South Omo, southern Ethiopia

BackgroundIn the pastoral/agro-pastoral communities in Ethiopia, like in South Omo, brucellosis constitutes a serious health threat for livestock and the public. The public health risk is especially high in these communities, as their way of life is highly linked with their herds. ObjectiveThe study was conducted to estimate the seroprevalence and identify potential risk factors of cattle brucellosis in South Omo zone in southern Ethiopia. MethodsA total of 614 traditionally managed local zebu female cattle, above six months old, were bled and data on hypothesized risk factors were collected using a semi-structured questionnaire. The preliminary screening of the sera for Brucella antibodies was done using Rose Bengal Plate Test (RBPT) and positive sera were further subjected to complement fixation test (CFT). ResultsThe overall animal level seroprevalence of brucellosis was 2.8 % (95 % CI: 1.72–4.41) while herd level prevalence was 11.3 % (95 % CI: 6.5–19.0). Among the risk factors considered, seroprevalence was associated with herd size, new animal introduction, district, history of occurrence of abortion, and retained fetal membranes (RFM), at both individual- and herd-level (p < 0.05). Higher seroprevalence of brucellosis was observed in cows than heifers and in animals older than 4 years (p < 0.05). Brucella seroprevalence was higher in herds in lowland areas than those in mid-altitude and highlands (p < 0.05). ConclusionThe individual and herd level prevalence observed in our study indicates endemicity of brucellosis and the potential public health threat it poses in pastoral and agro-pastoral areas of southern Ethiopia. The results of the study also suggest that the disease might be responsible for significant losses in cattle productivity due to impaired reproductive performance.

Correlation between toxoplasmosis and schizophrenia in Egyptian patients and its impact on dopamine serum levels

Toxoplasma gondii, a parasite infecting around one-third of the global population, has been linked to neurological disorders like schizophrenia. Abnormal dopamine levels are linked to the pathophysiology of schizophrenia, but their association remains unclear. This study aimed to investigate the relationship between T. gondii seroprevalence and dopamine serum levels in schizophrenic patients in Egypt. This case-control study included 93 patients diagnosed with schizophrenia and 93 individuals as controls. T. gondii seroprevalence was determined using an enzyme-linked immunosorbent assay (ELISA). Dopamine serum levels were measured using ELISA. Sociodemographic and clinical characteristics were also collected. The study found a higher prevalence of T. gondii IgG antibodies in patients with schizophrenia (68 %) compared to controls (46.2 %). Contact with cats, sausage consumption, and undercooked meat were identified as possible risk factors associated with T. gondii infection. The mean level of serum dopamine was significantly (P < 0.001) higher in patients with schizophrenia (115.3 Pg/ml ±31.8) compared to the control group (75.02 Pg/ml ±26.5). The study found that schizophrenic patients with T. gondii seropositivity had significantly higher dopamine serum levels (mean=145.2 ± 32.1 pg/ml) than those without T. gondii seropositivity (mean=122.5 ± 29.7 pg/ml) (p = 0.001). Logistic regression analysis revealed that T. gondii seropositivity was a significant predictor of increased dopamine serum levels in schizophrenic patients (odds ratio=3.4, 95 % confidence interval=1.8–6.4, p < 0.001). The study suggests that T. gondii seroprevalence may increase dopamine serum levels in Egyptian schizophrenic patients, potentially contributing to dopamine dysregulation in schizophrenia, but further research is needed to confirm these findings and investigate the underlying mechanisms.

The first evidence of bovine viral diarrhea virus circulation in Libya.

Bovine viral diarrhea (BVD) is endemic in North Africa and the Mediterranean Basin with high socioeconomic impacts. However, there are no data on this disease in Libya. One of the aims of this study was to provide data on BVD in Libya, to fill in the gap in the region and to investigate the level of seroprevalence of BVD virus (BVDV) in Libya and associated risk factors. A total of 1599 serum samples were collected from cattle herds belonging to seven Libyan regions. All sera were assayed using a screening enzyme-linked immunosorbent assay for the detection of antibodies against BVDV. The overall seroprevalence of BVDV was estimated to be 48.6% (95% confidence interval, 46.08%-50.98%). A seroprevalence rate of 36.8% was detected in cattle aged <1 year, 41.0% in cattle aged between 1 and 2 years, and 49.7% in cattle aged >2 years. Statistically significant differences (p = 0.001) were observed between age groups. BVDV seroprevalence was significantly associated with geographical region (p = 0.033). To the best of our knowledge, this is the first study on BVD in Libya, and the results suggest that BVD is endemic in Libya. Further studies are required to isolate and characterize the circulated BVDV in Libya.

Preoperative Hepatitis B seroprevalence and AntiHbs Levels in Children Consulted for Dental Procedures Under Anaesthesia

Background/Aims: Hepatitis B virus infection continues to be a major global and national public health concern. The aim of this study was to examine the seroprevalence of hepatitis B virus in children who were consulted to child health and diseases before dental intervention and to share our findings with the healthcare personnel involved on this subject. Methods: A total of 932 children were enrolled in the study, of which 533 (57.2%) were boys and 399 (42.8%) were girls. In the blood samples taken; hepatitis B virus tests were studied with the Enzyme Linked Immuno Sorbent Assay method. The results of blood samples and demographic data of the patients were evaluated. Results: HBsAg positivity was not found in any of the patients (0%). AntiHbs seropositivity was found in 73.8% of the whole patient population. No statistically significant difference was detected when comparing the anti-HBs levels based on gender. The average age of children with antiHbs seropositive was found to be statistically significant lower than that of those with antiHBs negative. The median anti-HBS antibody levels were significantly higher in the group of children under 5 years old than in the other two age groups older than five years old in our study. When investigating the association between the level of antiHBs and age, a weak negative correlation was found. Conclusions: Our study showed that the antiHbs seropositivity is higher in Konya compared to previous studies. It suggests that the national vaccination program has a positive impact on antiHbs seroprevalence. Our study revealed that children under the age of five displayed the highest levels of anti-HBs seropositivity, while the anti-HBs levels diminished with advancing age.

Tick-borne infections in the Leningrad oblast: incidence and seroprevalence

The study’s objective was to reveal trends in infections transmitted by ixodes ticks epidemic processes and the level of seroprevalence of the population to the tick-borne encephalitis virus, Borrelia burgdorferi sensu lato, Coxiella burnetii, Anaplasma phagocytophilum and Ehrlichia chaffeensis/ E. muris in the Leningrad Oblast.Materials and methods. A retrospective epidemiological analysis of the tick-bite incidence rate, the ixodic tick-borne borreliosis, tick-borne encephalitis, Q fever, human granulocytic anaplasmosis and human monocytic ehrlichiosis incidence rates, as well as vaccination against tick-borne encephalitis of the population of the Leningrad Oblast in 20112020. The official data of the tick-bite incidence rate, infections transmitted by ixodes ticks incidence rates and vaccination of the population was taken from the forms of federal statistical observation No. 2 and No. 5. Blood was sampled in 2019-2020 from randomly selected donors. Blood serum samples were examined by enzyme-linked immunosorbent assay for the presence of IgG antibodies to the pathogens of the studied infections using commercial test systems according to the manufacturer’s instructions.Results. In the Leningrad Oblast, in 2011-2020, there was a downward trend in the tick-bite incidence rate, as well as in the incidence rates of infections transmitted by ixodic ticks. The long-term average tick bite incidence rate was 369.0. The long-term average incidence rate of ixodic tick–borne borreliosis was 4.1; tick–borne encephalitis was 1.4; Q fever was 0.02. During the analyzed period, no cases of human granulocytic anaplasmosis and human monocytic ehrlichiosis were reported. The seroprevalence to tick-borne encephalitis virus was 1.7%; to B. burgdorferi s. l. – 3.7%; to C. burnetii – 1.8%; to A. phagocytophilum – 1.0%; to E. chaffeensis/ E.muris – 3.2%.Conclusion. The results obtained indicate the existence of active natural foci of infections transmitted by ixodes ticks, fairly frequent contact of the residents with these foci, and possible significant hypodiagnosis of these infections in the Leningrad Oblast.

Seroprevalence of bovine viral diarrhea virus and detection of persistently infected (PI) animals in dairy farms of Holeta, central Ethiopia

Bovine viral diarrhea virus (BVDV) is one of the most important pathogens of the reproductive systems that have a significant socio economic impact on the dairy industry. A cross-sectional study was conducted on 17 randomly selected farms out of 133 registered dairy farms in Holeta, a town in the Walmera district of Ethiopia. The study aimed to detect BVDV antigen-positive animals and investigate the seroprevalence of BVDV infection. A total of 337 serum samples were collected from selected farms with no history of BVDV vaccination. The indirect enzyme-linked immunosorbent assay (I-ELISA) test was the screening test used to detect antibodies against BVDV. In contrast, antigencapture ELISA was used for the detection of BVDV antigens in seronegative animals. A logistic regression model was used to assess the association between potential predictors and BVDV exposure. The overall animal level seroprevalence was 15.4%, and 64.7% of the herds had at least one seropositive animal. From 285 seronegative animals, one animal (0.4%) was found positive for BVDV antigen. The same animal was found positive in a double check 21 days later. In this study, cows with a history of abortion (OR = 6.3; 95% CI: 1.61 -13.1), history of repeated breeding (OR = 7; 95% CI: 2.5 - 14.3), animals managed intensively (OR = 4.6; 95% CI: 1.6 - 13.0) and multiparous cows (OR = 3.6; 95% CI: 1.5 - 8.9) had higher proportion of seroreactors in their respective comparison category (p&lt;0.05). Besides, cows with a history of congenital defective calve birth (OR = 15.2; 95% CI: 3.2 - 73.6), adult age groups (OR = 2.9; 95% CI: 1.0-7.9), and cows bred both artificially and natural mating (OR = 4.6; 95% CI: 1.7 - 12.6) were statistically associated with BVDV seropositivity (p&lt;0.05). In conclusion, this report demonstrated the presence of persistently infected (PI) dairy cattle in Ethiopia. Thus, the findings warrant the need for immediate control intervention that involves both screening and culling of PI animals and vaccination.

Age-specific case data reveal varying dengue transmission intensity in US states and territories.

Dengue viruses (DENV) are endemic in the US territories of Puerto Rico, American Samoa, and the US Virgin Islands, with focal outbreaks also reported in the states of Florida and Hawaii. However, little is known about the intensity of dengue virus transmission over time and how dengue viruses have shaped the level of immunity in these populations, despite the importance of understanding how and why levels of immunity against dengue may change over time. These changes need to be considered when responding to future outbreaks and enacting dengue management strategies, such as guiding vaccine deployment. We used catalytic models fitted to case surveillance data stratified by age from the ArboNET national arboviral surveillance system to reconstruct the history of recent dengue virus transmission in Puerto Rico, American Samoa, US Virgin Islands, Florida, Hawaii, and Guam. We estimated average annual transmission intensity (i.e., force of infection) of DENV between 2010 and 2019 and the level of seroprevalence by age group in each population. We compared models and found that assuming all reported cases are secondary infections generally fit the surveillance data better than assuming all cases are primary infections. Using the secondary case model, we found that force of infection was highly heterogeneous between jurisdictions and over time within jurisdictions, ranging from 0.00008 (95% CrI: 0.00002-0.0004) in Florida to 0.08 (95% CrI: 0.044-0.14) in American Samoa during the 2010-2019 period. For early 2020, we estimated that seropositivity in 10 year-olds ranged from 0.09% (0.02%-0.54%) in Florida to 56.3% (43.7%-69.3%) in American Samoa. In the absence of serological data, age-specific case notification data collected through routine surveillance combined with mathematical modeling are powerful tools to monitor arbovirus circulation, estimate the level of population immunity, and design dengue management strategies.

Seroprevalence of small ruminant brucellosis in the state of Qatar

AbstractBackgroundBrucellosis is one of the most important zoonotic diseases worldwide, with a significant economic and health burden. The disease is endemic in many regions around the world. Data regarding the disease in the Arabic Gulf region is scarce, and a limited number of studies have been conducted in Qatar. This study is the first to investigate the seroprevalence of small ruminant brucellosis in the state of Qatar.MethodsThe country was divided into three zones based on animal population (high, medium and low). A total of 494 blood samples from 57 small ruminant flocks were randomly collected from the three zones. Rose Bengal and competitive enzyme‐linked immunosorbent assay were used to investigate the apparent and true seroprevalence at both the animal and flock levels. A regression model was used to investigate the potential risk factors, including geographic zone, sex and age.ResultsAt the animal level, the overall (sheep and goat) apparent and true seroprevalence were 9.6% (95% confidence interval [95% CI]: 7.3–12.5) and 8.4% (95% CI: 5.9–11.5), respectively. In sheep, the apparent seroprevalence was 16.7% (95% CI: 12.5–21.8), and the true seroprevalence was 16.1% (95% CI: 11.6–21.7), whereas in goats, the apparent seroprevalence was 2.4% (95% CI: 1.1–5.2), and the true seroprevalence was 0.7% (95% CI: −0.7 to 3.7). At the flock level, overall, apparent sheep and goat seroprevalence were 19.3% (95% CI: 11.1–31.3), 30.0% (95% CI: 16.1–49.8) and 7.4% (95% CI: 2.1–23.4) and true seroprevalence was 18.9% (95% CI: 10.1–31.9), 30.5% (95% CI: 16.1–49.8) and 6.1% (95% CI: 0.3–23.3) respectively. Univariable regression analysis revealed age as the only significant risk factor in the sampled population.ConclusionsBrucella appears to be endemic to small ruminants in Qatar. The findings of this study provide baseline data regarding small ruminant brucellosis in Qatar and will aid in plans to control and eradicate the disease.