Seropositivity In Children Research Articles

COVID-19 and SARS-CoV-2 Seropositivity in Children of Healthcare Workers in London

Background: The COVID-19 pandemic in the UK began in late January 2020 and peaked in mid-April before declining. Children typically develop only very mild symptoms and it remains unclear what role children play in the spread of COVID-19. The aim of this study was to report the prevalence of SARS-CoV-2 antibodies in healthy children of healthcare workers. Methods: Healthy children of healthcare workers, were recruited in London during May 2020. Participants had nose and throat swabs tested for SARS-CoV-2 infection via RT-qPCR and blood serums samples for SARS-CoV-2 immunoglobulin G (IgG) antibodies. Findings: A total of 215 children from 126 families took part and 25(12%) were seropositive for SARS-CoV-2. Children of clinical healthcare workers were significantly more likely to be seropositive 23/133(17%) than those of non-clinical healthcare workers 2/83(2%); p=0.001.In children of parents with confirmed COVID-19, seropositivity was 19/47(40%) compared to 3/44(7%) in children of parents with suspected COVID-19 and 3/124(2%) in children of asymptomatic parents (pInterpretation: The secondary attack rate in children of healthcare workers with confirmed COVID-19 was 40% compared to 2% of children in families with no reported symptoms. One in three seropositive children were asymptomatic.Trial Registration: NCT0434740Funding Statement: This study was funded by the Public Health Agency [COM/5596/20].Declaration of Interests: None disclosed.Ethics Approval Statement: The London (Chelsea) research ethics committee reviewed the study protocol and provided a favourable outcome (Project ID 282617, OREC ID 20/HRA/1731).

Association between Body Mass Index and Hepatitis B antibody seropositivity in children.

BackgroundThe seropositivity rate of hepatitis B surface antigen (anti-HBs) antibodies is known to be ≥95% after hepatitis B virus vaccination during infancy. However, a low level or absence of anti-HBs in healthy children is discovered in many cases. Recent studies in adults reported that a reduced anti-HBs production rate is related to obesity.PurposeTo investigate whether body mass index (BMI) affects anti-HBs levels in healthy children following 3 serial dose vaccinations in infancy.MethodsWe recruited 1,200 healthy volunteers aged 3, 5, 7, or 10 years from 4-day care centers and 4 elementary schools. All subjects completed a questionnaire including body weight, height, and vaccine type received. Levels of serum hepatitis B surface antigen (HBsAg) and anti-HBs in all subjects were analyzed using electrochemiluminescence immunoassay. The standardized scores (z score) for each sex and age were obtained using the lambda-mu-sigma method in the 2017 Korean National Growth Charts for children and adolescents.ResultsOur subjects (n=1,200) comprised 750 males (62.5%) and 450 females (37.5%). The overall anti-HBs seropositivity rate was 57.9% (695 of 1,200). We identified significant differences in mean BMI values between seronegative and seropositive groups (17.45 vs. 16.62, respectively; P<0.001). The anti-HBs titer was significantly decreased as the BMI z score increased adjusting for age and sex (B=-15.725; standard error=5.494; P=0.004). The probability of anti-HBs seropositivity based on BMI z score was decreased to an OR of 0.820 after the control for confounding variables (95% confidence interval, 0.728–0.923; P=0.001).ConclusionThere was a significant association between anti-HBs titer and BMI z score after adjustment for age and sex. Our results indicate that BMI is a potential factor affecting anti-HBs titer in healthy children.

The clinical spectrum and incidence of anti-MOG-associated acquired demyelinating syndromes in children and adults

Objectives: The aim of this study was to assess the Dutch nationwide incidence of myelin oligodendrocyte glycoprotein (MOG)-IgG-associated acquired demyelinating syndromes (ADS) and to describe the clinical and serological characteristics of these patients. Methods: All serum samples for routine diagnostics from February 2014 to December 2017 were sent to the single central reference laboratory for the full-length MOG-IgG cell-based assay (CBA) in the Netherlands. Clinical data from patients known in our National ADS centre were available. Results: A total of 1414 samples of 1277 patients were received; of these, 92 patients (7%) were MOG-IgG-seropositive. The mean incidence was 0.16/100,000 people, with higher seropositivity in children (0.31/100,000) than in adults (0.13/100,000). In MOG-IgG-positive patients at the National ADS centre (61/92, 66%), the most common presenting phenotype is acute disseminated encephalomyelitis (ADEM, 56%) in children and optic neuritis (ON, 44%) in adults. Relapsing disease occurred in 9/34 (26%) children and 11/27 (41%) adults during median follow-up of 27.5 months. Patients were tested MOG-IgG-positive >200 months after the initial attack, suggesting an extended time to first relapse (TTFR). Longitudinal analysis of MOG-IgG (25/61, 41%) showed that 67% of the monophasic patients remain seropositive and 60% in relapsing patients. Majority of seronegative patients had no relapses (89%). Conclusion: This nationwide study shows that the overall incidence of MOG-IgG-seropositive disorders is 0.16 per 100,000 people. The distribution over the clinical phenotypes differs between adults and children. Seropositivity can be maintained over years even without clinical activity, while seronegative patients generally had no relapses.

Epidemiology of onchocerciasis-associated epilepsy in the Mbam and Sanaga river valleys of Cameroon: impact of more than 13\xa0years of ivermectin

BackgroundA high epilepsy prevalence has been reported in several onchocerciasis-endemic villages along the Mbam and Sanaga river valleys in Cameroon, including Bilomo and Kelleng. We sought to determine the prevalence of epilepsy in these two villages following more than 13 years of community-directed treatment with ivermectin (CDTI).MethodsDoor-to-door surveys were performed on the entire resident population in the villages in August 2017 and January 2018. Epilepsy was diagnosed using a 2-step approach: administration of a standardized 5-item questionnaire followed by confirmation by a neurologist. Previously published diagnostic criteria for onchocerciasis-associated epilepsy (OAE) were used. Ov16 serology was done for children aged 7–10 years to assess onchocerciasis transmission. Findings were compared with previous data from these two villages.ResultsA total of 1525 individuals (1321 in Bilomo and 204 in Kelleng) in 233 households were surveyed in both villages. The crude prevalence of epilepsy was 4.6% in Bilomo (2017) and 7.8% in Kelleng (2018), including 12 (15.6% of cases) persons with epilepsy (PWE) with nodding seizures. The age and sex-standardized prevalence in Kelleng decreased from 13.5% in 2004 to 9.3% in 2018 (P < 0.001). The median age of PWE shifted from 17 (IQR: 12–22) years to 24 (IQR: 20–30) years in Bilomo (P < 0.001); and slightly from 24 (IQR: 14–34) years to 28 (IQR: 21.25–36.75) years in Kelleng (P = 0.112). Furthermore, 47.6% of all tested children between 7 and 10 years had Ov16 antibodies.ConclusionsThere is a decrease in epilepsy prevalence after 13 years and more of CDTI in both villages. The age-shift observed in PWE suggests that ivermectin may prevent OAE in younger residents. Ov16 seropositivity in children indicates ongoing onchocerciasis transmission possibly due to suboptimal control measures. Our findings support the existence of OAE in Cameroon and highlight the need to strengthen onchocerciasis elimination programs.

On-going transmission of human onchocerciasis in the Massangam health district in the West Region of Cameroon: Better understanding transmission dynamics to inform changes in programmatic interventions.

BackgroundMassangam health district (HD), in the West Region of Cameroon, has received ivermectin mass drug administration (MDA) for 20 years, however there is evidence of continued high transmission of Onchocerca volvulus. In order to better understand the transmission dynamics in the HD and inform intervention strategies there is a need to delineate the boundaries of the suspected area of high transmission within the wider transmission zone.Methodology/Principal findingsParasitological and entomological surveys were conducted to map out the breeding sites of Simulium damnosum and evaluate the prevalence of onchocerciasis in neighbouring communities, including Makouopsap sentinel community. Potential rapids were prospected for identification of S. damnosum larvae and black flies collected to determine infectivity rates. Adults were assessed for the presence of O. volvulus microfilariae through a skin snip biopsy and examined for the presence of nodules. Anti Ov-16 antibodies were tested for in children. Four perennial breeding sites were identified on the Rivers Mbam and Nja. Large number of flies were collected along the River Mbam, especially in the rainy season, with up to 955 flies per day, suggesting this river is a perennial source of black flies. A total of 0.8% of parous flies were infective across the study area. Parasitological studies provided evidence of high rates of infection in the sentinel community and three neighbouring communities, with 37.1% of adults microfilariae positive in Makouopsap. High Ov-16 seropositivity in children also provided evidence of recent on-going transmission. In comparison, communities sampled further away from the sentinel community and neighbouring breeding sites were much closer to reaching onchocerciasis elimination targets.Conclusions/SignificanceThis study provides evidence of a particular geographic area of high transmission in an approximate 12 km range around the sentinel community of Makouopsap and the neighbouring breeding sites on the River Nja. To eliminate onchocerciasis by 2025, there is a need to explore alternative intervention strategies in this area of high transmission.

Helicobacter pylori Seropositivity in Children in Duhok City, Iraq

Introduction: Helicobacter pylori(H. pylori) is a gram negative bacteria that causes gastritis and peptic ulcer disease (PUD). It is widely accepted that the infection may occur early in life and may persist for decades before causing diseases. The aim of this paper was to determine the prevalence of H. pyloriseropositivity in pediatric age group and to examine the associated risk factors. Patients and methods: Blood samples were collected from 100 subjects attending Hevi Pediatric Teaching Hospital over a period of 6 months and IgG positivity was determined. A questionnaire sheet was prepared and used for each study subject. Data were collected by a face-to-face interview.Results: It was found that 28/100 (28%) of the recruited sample was positive for H. pyloriseropositivity. A significant association was found between the number of siblings and H. pyloripositivity (P=0.01, OR=1.3). No significant relationships were found between other factors and H. pyloripositivity. Conclusions: The prevalence of H. pyloriinfection was less than that reported in the city previously and less than that reported in neighboring countries. A significant positive association was found between number siblings and H. pyloriinfection rate. Further studies are needed recruiting larger sample size to explore H. pyloriprevalence and its associated risk factors.

Seropositivity of Hepatitis A in Children Aged 7-14 Years in Diyarbakir Province Center.

BackgroundHepatitis A virus (HAV) is a common morbidity in society, and mortality is more common in older ages. It is important to identify the prevalence in the population, the development of primary protection methods, and vaccination policies. This study aimed to identify anti-HAV seropositivity in children in 3 different schools in Diyarbakır, Turkey, to evaluate the risk factors influencing prevalence, and thus to develop strategies to prevent infection.Material/MethodsThe study was a prospective investigation of 600 children with a mean age of 10.5 years (range, 7–14), including 291 males and 309 females.ResultsThe seropositivity was 45.7% (41.2% in males and 49.8% females) with a statistically significant difference by sex (p=0.042). It was also significantly correlated with age. Factors significantly associated with seropositivity were educational level and income of parents, number of rooms in the house, type of toilet, number of siblings, and source of drinking water. Hence, older age, more siblings, crowded household, and low socioeconomic level are risk factors for seropositivity.ConclusionsProtection strategies for the disease include improving socioeconomic level, increasing the level of education, disseminating appropriate drinking water, improving infrastructure and sewage disposal, and public health education on hygiene and the importance of vaccination. We also believe that active immunization against HAV in Turkey in general and in our province in particular can prevent infection in children and related complications in older people.

Assessment of Toxoplasma Seropositivity in Children Suffering from Anxiety Disorders.

This study aimed to assess the seroprevalence of Toxoplasma gondii in children with anxiety disorders. This cross-sectional study was conducted between Sep 2012 and May 2013 in Pediatrics Clinic of Baqiyatallah Hospital, Tehran, Iran. Children were assessed clinically. Diagnosis of patients with anxiety disorders was based on DSM-4 system, performed by child psychiatrist. Then their anti-Toxoplasma antibodies were measured. A questionnaire was verbally administered to all individuals' parents including demographic information and questions about life style, family history, medical history, economic situation, residence, nutritional patterns and contact with animals. Ninety-six male and female cases with a mean age of 8.56±2.5 and 8.42±1.9 yr underwent analysis. Anti- T. gondii IgG antibody was found in one case of each group. There was no significant difference between case and control groups for serum Toxoplasma IgG antibody (P=0.14). No case individuals had Anti- T. gondii IgM antibody, while it was found in one control individual. No significant difference was seen between case and control groups for Toxoplasma IgM antibody (P=0.27). Toxoplasmosis has no direct effect on the incidence of anxiety disorders. More studies are needed with a larger volume of individuals in future.

Assessment of Toxoplasma Seropositivity in Children Suffering from Attention Deficit Hyperactivity Disorder

Background: Toxoplasmosis, a protozoan infection caused by Toxoplasma gondii, is suggested to be a risk factor for many psychological disorders such as schizophrenia and depression. Attention deficit hyperactivity disorder (ADHD) is one of the most common psychiatric disorders among children. Previous studies have assessed the correlation between ADHD and infectious diseases like toxoplasmosis. So we aimed to investigate the possible correlation between Toxoplasma seropositivity and ADHD in children. Materials and Methods: In this cross-sectional study children with signs of ADHD were regarded as patients and underwent clinical assessments. Diagnosis of these patients was based on DSM-IV-TR system which was performed by a pediatric psychiatrist. Forty-eight Children without signs of ADHD or other psychic disorders were considered as control, and 48 patients were considered as case group. Parents were asked to answer a questionnaire including demographic, pregnancy and habitual questions. Blood samples were taken from all individuals and assessed for anti-Toxoplasma IgM and IgG antibodies. Results: Ninety-six male and female patients with a mean age of 8.12 years underwent analysis. Seropositivity rate for anti-T.gondii IgG antibody was 4.2% in the case and 2.1% in control individuals (P=0.92). Anti-T.gondii IgM antibodies were not found in control individuals while it was found in 2.1% of case individuals (P=0.74). There was no statistically significant association between seroprevalence of IgM (P=0.74) and IgG (P=0.92) antibodies and ADHD in study individuals. Conclusion: Our findings showed that the toxoplasmosis seropositivity has no significant difference between children with and without ADHD. Further studies are needed with a larger amount of individuals. [GMJ. 2016;5(4):188-93]

Helicobacter pylori Seropositivity in Children With Asthma

Background: Some studies have reported an association between Helicobacter pylori (H. pylori) colonization and the occurrence of asthma or other allergies. However, data are inconsistent, and few studies have been performed in children. Objectives: The current study aimed to investigate H. pylori seropositivity in children with and without asthma. Patients and Methods: This cross-sectional study was performed with 208 children aged 5- to 12-years-old (104 asthmatic subjects in the case group and 104 healthy individuals in the control group) who had been referred to the pediatric clinic of Amir Kabir hospital in Arak, Iran. H. pylori seropositivity was compared between the two groups according to the serum level of immunoglobulin G (IgG) antibody against the H. pylori cytotoxin-associated gene A (CagA) protein, which was measured using the enzyme-linked immunosorbent assay (ELISA). Results: The H. pylori serology test was positive in 13 (12.5%) asthmatic subjects and 18 (17.3%) healthy subjects. This difference was not significant (P = 0.54). Duration of asthma in the serology-positive children (3.61 ± 1.5 years) was significantly higher than that of the serology-negative children (2.16 ± 1.33 years) (P = 0.0001). No significant correlations were found between H. pylori seropositivity and age (P = 0.95), gender (P = 0.7), severity of asthma (P = 0.54), control of the asthma (P = 0.23), or pulmonary function test (PFT) results (P = 0.23). Conclusions: The results showed no association between childhood asthma and H. pylori seropositivity. However, due to the lack of studies, especially in children, and controversial results of the clinical studies, further studies are recommended.

Frequency of HLA-DQB1*0201/02 and DQB1*0302 alleles and tissue transglutaminase antibody seropositivity in children with type 1 diabetes mellitus.

Patients with type 1 diabetes mellitus (T1DM) have an increased risk of celiac disease (CD). Both diseases have a common genetic susceptibility locus in the human leukocyte antigen (HLA) class II alleles. Testing for tissue transglutaminase antibodies (anti-tTG) is highly accurate for a CD diagnosis. To determine the frequency of HLA-DQB1*0201/02 and DQB1*0302 alleles and anti-tTG seropositivity in children with T1DM. Forty-six children with T1DM (male:female=24:22; mean age 12±3.7 years) without significant digestive symptoms were enrolled. The mean duration of diabetes was 5±3.5 years. Serum anti-tTG IgA and IgG as well as HLA-DQ2 (DQB1*0201/02) and -DQ8 (DQB1*0302) alleles were analyzed. The allele frequencies were compared with those in controls, which included 124 normal Thai individuals, as reported in our previous study. All subjects were negative for anti-tTG IgG. Only one patient (2.2%) was positive for anti-tTG IgA (38.5 U/mL; cut-off 15 U/mL). Although this patient was also heterozygous for HLA-DQ2 and was asymptomatic for CD, he declined endoscopic confirmation. Twenty-nine of 46 patients carried HLA-DQ2 and/or -DQ8 heterodimers. HLA-DQB1*0201/02 and HLA-DQB1*0302 allele frequencies were significantly higher (27% and 14%) in T1DM patients compared with normal controls (13.3% and 7.3%; P<0.001 and P=0.002, respectively). A significantly greater frequency of DQB1*0201/02 and DQB1*0302 alleles were present in children with T1DM compared with the control group. This indicates a potentially important role of these alleles in the development of T1DM. The prevalence of CD screening by serologic testing is negligible in Thai children with T1DM.

Seroprevalence of Epstein-Barr Virus, Cytomegalovirus, and Polyomaviruses in Children with Inflammatory Bowel Disease.

Young age and thiopurine therapy are risk factors for lymphoproliferative disease among patients with inflammatory bowel disease (IBD). The aims of this study were to evaluate the prevalence of seropositivity for the Epstein-Barr virus (EBV) and human cytomegalovirus (CMV) among children and adolescents with IBD, to assess the viral load of EBV, CMV, and BK and JC polyomaviruses (BKV, JCV) in these patients, and to assess the influence of different therapeutic regimens on seroprevalence and viral load. Children who had been followed in our center were tested for EBV, CMV, BKV, and JCV in a cross-sectional study. One hundred and six children were included who had Crohn's disease (68%), ulcerative colitis (29%), and unclassified IBD (3%). We found that 64% of patients were EBV seropositive. The proportion of EBV seropositive patients increased during childhood. Azathioprine therapy (p = 0.003) was associated with EBV seropositivity in a multiple logistic regression model, after adjusting for gender, age, and disease activity at determination. We found a significant association between the number of polymerase chain reaction copies and infliximab dose (p = 0.023). We did not find any significant association between CMV serology and CMV, BKV, or JCV viral load, or any other therapeutic regimen or clinical characteristics. Treatment with azathioprine appears to be a risk factor for early EBV seropositivity in children with IBD, and the infliximab dose was associated with a higher EBV viral load.

The Impact of Helicobacter pylori on Atopic Disorders in Childhood

The prevalence of Helicobacter pylori in Western populations has steadily decreased. This has been suggested as one of the factors involved in the recent increase of asthma and allergy. Some studies have reported a negative association between H. pylori and asthma and allergy, but data are inconsistent and there are a few studies in children. We investigated whether the prevalence of H. pylori was associated with asthma symptoms, allergic rhinitis, and atopic dermatitis in childhood. We determined IgG anti-H. pylori and CagA antibodies in serum of Dutch children, who took part in the PIAMA birth cohort study. Serum was collected from 545 children, aged 7-9 years (Dutch ethnicity 91.5%). Symptoms of asthma and atopy were assessed by yearly questionnaires. Chi-square tests and logistic regression were used. We found 9%H. pylori and 0.9% CagA seropositivity. Twelve (5.9%) children with reported wheezing ever were H. pylori positive, compared to 37 (10.9%) of the non-wheezers (p = .05). No significant differences in H. pylori prevalence were found between children with or without allergic rhinitis (8.5% vs 9.5%), atopic dermatitis (8.7% vs 9.2%), and physician-diagnosed asthma (7.1% vs 9.4%). Multivariate analysis showed no significant associations between H. pylori seropositivity and wheezing (OR 0.52; 95% CI 0.25-1.06), allergic rhinitis (OR 0.96; 95% CI 0.51-1.81), atopic dermatitis (OR 1.05; 95% CI 0.56-1.98) or physician-diagnosed asthma (OR 0.87; 95% CI 0.37-2.08). We found a borderline significantly lower H. pylori seropositivity in children with wheezing compared to non-wheezers, but no association between H. pylori serum-antibody status and allergic rhinitis, atopic dermatitis, or asthma.

Association between contamination of public squares and seropositivity for Toxocara spp. in children

A concomitant study was carried out, of the association of positive serology for Toxocara spp. in 90 children who played in public squares used for leisure, with the frequency with which each child used these areas, and the presence of eggs of Toxocara spp. in the sand or grass in these locations. The sand and grass of their peridomiciles and school playgrounds, as well as the feces of their dogs were also analyzed for Toxocara. Serum samples were tested for IgG antibodies to Toxocara canis excreted–secreted larval antigens by ELISA, and blood samples for eosinophilia. The water-sedimentation technique was used to evaluate the presence of parasite eggs in the sand and grass turfs, and in feces of the dogs that also frequented these locations. 16/90 (17.8%) of the children were seropositive for Toxocara spp. There was a positive association between seropositivity in children who played in the public squares six or seven times a week, with a parasite load above 1.1eggs/g of sand, as well as with contamination of the peridomicile, even at less than 1.0egg/g of sand. Eosinophilia, the habit of geophagy, age from one to four years, and the presence of parasitized pet dogs were also positively correlated with seropositivity in the children. Eggs were found in 15/15 (100%) of the public squares, 17/90 (18.9%) of the peridomiciles, 3/13 (23.1%) of the schools, and 12/41 (29.3%) of the dogs living in the peridomiciles investigated.

Helicobacter pylori Seropositivity in Institutionalized Children With Down Syndrome

To the Editors: Helicobacter pylori is usually acquired in early infancy and probably persists throughout the life.1 Host genetic background, environment, and bacterial determinants contribute to the development of H. pylori-associated diseases.2 Poor living and socioeconomic conditions as well as overcrowding are among the main risk factors for infection during childhood.3 Children with Down syndrome (DS) have multiple immunologic defects.4 It remains controversial whether abnormality of immune responses in such children increases the propensity to infections. We undertook a study to find H. pylori seropositivity among children with DS compared with age- and gender-matched children having other intellectual disabilities with similar nutritional regimen and living and hygienic environment. Peripheral blood samples were collected from 24 children with DS and 24 children with other intellectual disabilities who were residents of 3 institutes for intellectually disabled children in Tehran. The paired match of each DS case was selected from other intellectual disabilities cases of the same institute, so the matched cases had similar living conditions. Serum H. pylori-specific immunoglobulin G (IgG) antibody was measured using ELISA (enzyme-linked immunosorbent assay) method, according to manufacturer's instructions (IMMUNOLAB GmbH, Germany). The results were considered positive if H. pylori IgG titer were >0.1 U/mL. For statistical analysis, χ2 test and nonparametric tests (Mann-Whitney and Kruskal–Wallis tests) were used. A P value of ≤0.05 was considered statistically significant. The DS and other intellectual disabilities groups each consisted of 13 females and 11 males, ranging in age from 1 to 15 years, and the mean age ± SD was 5.75 ± 4.35. H. pylori-specific IgG was detected in 17 of 24 (70.8%) DS children with a median titer of 30.09 U/mL. Among other intellectual disabilities children, 15 of 24 (62.5%) were seropositive with a median IgG of 34.34 U/mL. The seroprevalence of H. pylori infection in children with DS did not significantly differ from that in children suffering from other intellectual disabilities (odds ratio: 1.45; 95% confidence interval: 0.43–4.87). In the current small groups, seropositivity rates were similar in DS and other intellectual disabilities children in relation to age. More than half of seropositive children in DS (52.9%) and other intellectual disabilities (60%) groups were younger than 6 years, and this difference was not statistically significant. The median duration of institutionalization was 30 months (range, 6–96 months) for DS group and 24 months (range, 7–96 months) for other intellectual disabilities group. The antibody response against H. pylori was not associated with gender and duration of institutionalization. The current study demonstrated high seropositivity for H. pylori in DS children. The high seropositivity may be attributed to the fact that overcrowding, sanitary conditions, and dietary regimen in childhood affect the route of H. pylori transmission and infection.3 No significant difference was found in the risk of H. pylori seropositivity between children with DS and those with other intellectual disabilities. Two studies have reported H. pylori seropositivity in children with DS with lower rates. Jaber5 assessed 24 children with DS in Saudi Arabia and found a 29.2% seropositivity rate. A study of 46 children with DS by Failla et al6 showed that 19.5% of cases were seropositive. Both studies were of noninstitutionalized children with DS, whereas we examined children reside permanently in the institutes. Hence, the higher seropositivity of H. pylori infection might be explained by institutionalization and sanitary conditions as major risk factors. On the other hand, children with DS did not show a significantly higher susceptibility to H. pylori infection than children with other intellectual disabilities. It seems that host response against H. pylori infection is similarly influenced by environmental conditions in DS versus other intellectually disabled cases. Masoumeh Douraghi, PhD Department of Microbiology Shahid Beheshti University of Medical Sciences Division of Microbiology Department of Pathobiology School of Public Health Tehran University of Medical Sciences Tehran, Iran Hossein Goudarzi, MD, PhD Department of Microbiology Shahid Beheshti University of Medical Sciences [email protected] Mahmoud Nateghi Rostami, PhD Department of Public Health Qom University of Medical Sciences Qom, Iran Elnaz Sadat Mirsamadi, MSc Department of Microbiology Shahid Beheshti University of Medical Sciences Tehran, Iran

Q fever seroprevalence in metropolitan samples is similar to rural/remote samples in Queensland, Australia

Q fever is a vaccine preventable disease; however, despite this, high notification numbers are still recorded annually in Australia. We investigated the seroprevalence of Coxiella burnetii, the Q fever agent, in a Queensland sample population. Notification data (N = 6425) from 1984-2008 were collated, identifying high risk areas of Q fever exposure. Of these 177 were recorded in children. Serum samples were collected from Queensland and screened using both an immunoflourescence assay at 1:10 dilution and a commercially available ELISA kit. Results were collated based on age, geographical location and sex. From 1988 Queensland samples screened, 103 were identified as Q fever IgG-positive, giving a seroprevalence of 5.2% (95% CI 4.3-6.2%). Seroprevalence in the rural/remote population was 5.3% (95% CI 4.6-6.6%), and the metropolitan Brisbane population, which is considered not at risk, was 5.0% (95% CI 3.7-6.7%). Sixty-three seropositive males and 40 females were identified, along with an increase in seropositivity with increasing age. The seropositivity of children was 1.3% (95% CI 0.7-2.3%) from 844 samples. We have shown that both metropolitan and paediatric populations which are considered low risk of Coxiella exposure have surprisingly high seropositivity. These emerging groups require further investigation and consideration for the introduction of preventive measures.

Human Herpesvirus 8 Infection in Children and Adults in a Population-based Study in Rural Uganda

Human herpesvirus 8 (HHV-8) infection is endemic in sub-Saharan Africa. We examined sociodemographic, behavioral, and biological factors associated with HHV-8 infection in children and adults to determine HHV-8 seroprevalence and potential routes of transmission. Participants were 1383 children and 1477 adults from a population-based sample in a rural community in Uganda. Serum samples were tested for HHV-8 antibodies with use of an enzyme immunoassay against K8.1. HHV-8 seroprevalence increased from 16% among children aged 1.5-2 years to 32% among children aged 10-13 years (P <.001) and from 37% among participants aged 14-19 years to 49% among adults aged ≥ 50 years (P <.05). HHV-8 seropositivity in children was independently associated with residing with a seropositive parent (P < .001) and residing with ≥ 1 other seropositive child aged <14 years (P < .001). History of sharing food and/or sauce plates was marginally associated with HHV-8 infection in children (P = .05). Among 1404 participants aged ≥ 15 years , there was no association between correlates of sexual behavior (eg, number of lifetime sex partners and HIV infection) and HHV-8 seropositivity (P > .10). Our data suggest that HHV-8 is acquired primarily through horizontal transmission in childhood from intrafamilial contacts and that transmission continues into adulthood potentially through nonsexual routes.

Toxocara seropositivity in Sri Lankan children with asthma

Toxocariasis occurs in humans due to infection with Toxocara canis or T. cati, the nematode parasites of dogs and cats, respectively. The relationship between toxocariasis and asthma is complex, with some studies demonstrating that children with asthma were more likely to be Toxocara seropositive as compared to non-asthmatic children, and other studies indicating no such significant relationship. The aim of the present study was to investigate Toxocara seropositivity and its association with asthma in a selected group of Sri Lankan children. Two groups of children were studied: group 1 included 100 children with confirmed bronchial asthma who were on regular inhaler steroid treatment for asthma; group 2 included 96 children who did not have physician-diagnosed asthma or upper respiratory tract infections, attending the same hospital. Diagnosis of Toxocara seropositivity was based on IgG Toxocara Microwell Serum Elisa Kits. Enzyme-linked immunosorbent assay was regarded as positive for a reading of 0.3 optical density units. Stool samples were examined for helminth ova. Toxocara seropositivity in children with asthma was 29% and this was significantly more than Toxocara seropositivity among non-asthmatic children (P < 0.001). Toxocara seropositivity was identified as a significant risk factor of asthma in a univariate model. Eosinophilia was seen in a significantly higher proportion of non-asthmatic and asthmatic children who were Toxocara seropositive. Toxocara seropositivity, however, was not identified as a significant risk factor in a multivariate model. The analysis confirmed previously identified risk factors for asthma but there was no association between the helminth parasitic infection, toxocariasis and bronchial asthma in children.

Seroprevalence of hepatitis A among children of different socioeconomic status in Cairo

To determine seroprevalence of anti-hepatitis A virus (HAV) antibodies and potential risk factors for and age of contracting symptomatic hepatitis A infection among children of different socioeconomic status (SES) in Cairo, we carried out a cross-sectional study on 426 children aged 3-18 years from low SES areas and 142 from high SES areas. Seroprevalence was significantly higher with age. Seropositivity to anti-HAV antibodies was significantly higher among children of low and very low SES, 90%, compared to children of high SES, 50%. Water supply and sewage disposal were the most significant risk factors for HAV seropositivity in children of low SES. Children of high SES were more likely to be vulnerable to infection in adolescence than those of low SES.

Helicobacter pylori seropositivity in children with chronic disease in Jeddah, Saudi Arabia

Helicobacter pylori (H. pylori) is an important pathogen in gastrointestinal disorders. Seroprevalence among asymptomatic and chronically diseased children in Jeddah, Saudi Arabia was determined to gain insight into its prevalence. Serum samples obtained from 1432 children; 543 asymptomatic and 889 chronically diseased children (diabetes, chronic asthma, chronic hemolytic anemia, neurological impairment and Down's syndrome); were tested by ELIZA for H. pylori IgG antibodies. Demographic data obtained including nationality, gender, age and disease status. One hundred and twenty eight (23.6%) of 543 asympatomatic children were seropositive with no significant difference in seroprevalence of infection between Saudi and non-Saudi (p<0.09) and between boys and girls (p<0.67), but significant rise was notice with increasing age (p<0.001). An increase in risk of H. pylori among chronically diseased children was observed (diabetes: 34.4%, chronic asthma 20.4%, chronic hemolytic anemia: 31.7%, neurological impairment: 32.1%, and Down's syndrome: 29.2%) which increased significantly in chronic anemia and neurological impairment (p<0.01 and p<0.05) compared to controls. The prevalence did not differ according to nationality and gender but significantly increased with age in chronic asthma, chronic anemia and neurological impairment (p<0.01 for all) and also increased significantly with duration of illness, number of blood transfusions, number of hospital admission and mode of feeding. Infection with H. pylori seems to occur early in life and its prevalence increased with age in Jeddah, Saudi Arabia. The risk of H. pylori infection was significantly increased within children suffering from chronic hemolytic anemia; neurological impairment compared to controls and was significantly related to severity of the chronic disease.