Sero-epidemiology of hepatitis E virus (HEV) in urban and rural children of North India

OBJECTIVE: To estimate the prevalence of anti-HEV IgG and IgM antibodies to ORF3 peptide of Hepatitis E virus genome in an age stratified urban and rural population of children. DESIGN: Cross sectional survey. SETTING: Pediatric out-patient clinics in a tertiary hospital and a rural dispensary. METHODS: Study subjects between 6 months and 10 years with minor, non-hepatic illnesses were recruited for the study from March to December 1996. Baseline demographic details, drinking water source, sewage disposal methods, reasons for attending the hospital, histories of parenteral exposure in the past 12 months and acute hepatitis in the subjects and the family in the previous six months were obtained. Serum anti-HEV IgG antibodies were screened in all subjects, and in those who were positive, anti-HEV IgM antibodies were assayed as an indicator of recent infection. Serum aminotransferase (ALT) was estimated in those who were anti-HEV IgM antibody positive. RESULT: Out of 2160 subjects recruited, 2070 samples could be screened for anti-HEV IgG antibodies. In the urban population (n = 1065) anti-HEV IgG antibodies were detected in 306 subjects (28.7%; 95% CI 26.0-31.6) and of these 131 (42.8%; 95%CI 37.2-48.6) were anti-HEV IgM antibody positive. Amongst 1005 rural children, anti-HEV IgG antibodies were present in 239 (23.8%; 95% CI 21.1-26.4) and IgM antibodies in 113 (47.3%; 95% CI 40.9-53.7) children. The antibodies were present since the first year of age till 10 years of age and, increased with advancing age. Serum transaminases were raised in 7.5% (9/120) and 5.5% (5/88) of subjects with anti-HEV IgM antibodies in urban and rural centers respectively. Overall the seroprevalence of IgG antibodies against HEV were significantly more in urban as compared to that in rural subjects (p = 0.011). However, proportion of children with anti-HEV IgG carrying IgM antibodies was similar in the two study groups (p = 0.298). A model for estimating expected prevalence of anti-HEV IgG antibodies was developed. The observed antibody prevalence in both urban and rural subjects at each age interval after 48 months was less as compared to the expected levels and this gap increased with advancing age categories. It appeared that there was a decay of HEV antibodies with time. CONCLUSIONS: Children are susceptible to HEV infection since early infancy. The probability of exposure to HEV during childhood was higher in urban than rural population. Seropositivity to HEV antibodies increased by over 2 times beyond 4 years of age as compared to younger age. Anti-HEV IgG antibodies appear to wean off with increasing age.     

喘息性疾病患儿非细菌性病原体感染分析

目的：探讨呼吸道非细菌性病原体与婴幼儿喘息性疾病的相关性,以及血清总IgE水平和外周血中嗜酸性粒细胞计数在其感染中的临床意义。方法：对2010年9月至2011年9月住院治疗的490例喘息性疾病患儿,采用间接免疫荧光法检测血清中9种呼吸道感染非细菌性病原体IgM抗体并进行病原学分析,并同时检测血清中总IgE水平和外周血中嗜酸性粒细胞计数。结果：490例喘息性疾病患儿中, 检测出非细菌性病原体IgM抗体阳性233例,阳性率为47.6%,其中肺炎支原体（MP）的阳性率最高(25.3%),其次为腺病毒（ADV） （8.9%）和乙型流感病毒（FluB）（8.8%）。 36例患儿同时检测出两种以上非细菌性病原体,且主要为MP与其他病原体的混合感染（94%）。各年龄组（0 d~、1个月～、6个月～、1岁～、3~8.9岁）IgM抗体的总检出率分别为50.0%、67.3%、33.1%、57.3%、61.7%,各组间差异有统计学意义（P<0.05）。支气管哮喘的呼吸道感染病原体IgM抗体检出率最高,其次为喘息性支气管炎,最低为毛细支气管炎。病原体检出阳性的患儿,血中嗜酸性粒细胞的数目明显减少,而血清总IgE水平显著升高。结论：喘息性疾病患儿的非细菌性病原体主要是MP、ADV和FluB;MP和其他非细菌性病原体的混合感染比较普遍;1～6个月婴幼儿感染率较高;监测总IgE水平及嗜酸性粒细胞计数的变化对于婴幼儿喘息性疾病临床诊断和治疗有重大意义。     

Antibodies to endotoxin core in sudden infant death syndrome.

To assess the possible role of endotoxaemia in the pathogenesis of sudden infant death syndrome (SIDS), antibodies to endotoxin core (EndoCAb), which have previously been shown to be depressed by systemic endotoxaemia, were measured. IgG and IgM EndoCAb and total serum IgG and IgM were measured in serum samples from 25 children who had died from SIDS and 164 control children under 1 year of age. Twelve (48%) of the 25 children who had died from SIDS had no detectable IgG EndoCAb compared with 28 (17%) of the 164 control children, and this difference was concentrated in children aged less than 3 months. There was no significant difference between the two groups in the percentage of children with no IgM EndoCAb, nor in the total IgG and IgM concentrations. For IgM EndoCAb, the younger children who had died from SIDS had higher concentrations than the controls. These results suggest that, in children who have died from SIDS, due to either unusually early or severe exposure to endotoxin, maternal IgG EndoCAb have been depleted and early IgM EndoCAb triggered.     

Antibodies to endotoxin core in sudden infant death syndrome

To assess the possible role of endotoxaemia in the pathogenesis of sudden infant death syndrome (SIDS), antibodies to endotoxin core (EndoCAb), which have previously been shown to be depressed by systemic endotoxaemia, were measured. IgG and IgM EndoCAb and total serum IgG and IgM were measured in serum samples from 25 children who had died from SIDS and 164 control children under 1 year of age. Twelve (48%) of the 25 children who had died from SIDS had no detectable IgG EndoCAb compared with 28 (17%) of the 164 control children, and this difference was concentrated in children aged less than 3 months. There was no significant difference between the two groups in the percentage of children with no IgM EndoCAb, nor in the total IgG and IgM concentrations. For IgM EndoCAb, the younger children who had died from SIDS had higher concentrations than the controls. These results suggest that, in children who have died from SIDS, due to either unusually early or severe exposure to endotoxin, maternal IgG EndoCAb have been depleted and early IgM EndoCAb triggered.     

Increased frequency of IgM antibodies to cow's milk proteins in Hungarian children with newly diagnosed insulin-dependent diabetes mellitus

We investigated the association between serum antibodies to cow’s milk proteins and insulin-dependent diabetes mellitus (IDDM) in Hungarian children. Forty-eight children 1.0–17.1 years of age with newly diagnosed IDDM and 74 control children 1.0–16.0 years of age were studied for serum IgG, IgA and IgM antibodies to cow’s milk, β-lactoglobulin, bovine serum albumin and ovalbumin by enzyme-linked immunosorbent assays. The specificity of IgM antibodies to β-lactoglobulin and bovine serum albumin was controlled by Western blot. The levels of IgG and IgA antibodies to cow’s milk proteins were similar in children with and without IDDM, with the exception of slightly increased levels of IgA antibodies to β-lactoglobulin in diabetic children (P = 0.05). The levels of IgM antibodies to cow’s milk were significantly higher in IDDM patients than in control children (P = 0.0002). Children with IDDM more often had IgM antibodies to β-lactoglobulin (46.3% vs 18.8%; P = 0.002) and bovine serum albumin (87.8% vs 49.3%, P < 0.0001) than control children. Neither the levels of IgG or IgA antibodies to ovalbumin nor the frequency of IgM antibodies to ovalbumin differed between diabetic and control children. Conclusion In Hungarian children, clinical manifestation of IDDM is often associated with IgM antibody response to cow’s milk protein and its fractions, β-lactoglobulin and bovine serum albumin, indicating a loss of immunological tolerance to these proteins. IgG and IgA antibodies to cow’s milk proteins, associated with an early introduction of cow’s milk in diet, seem to play a minor role in the development of childhood IDDM in Hungary. Received: 14 November 1995 Accepted: 3 March 1996     

Antibodies to group B streptococci in neonates and infants

Invasive group B streptococcal (GBS) infections are common in neonates but are rare after the 1st month of life. It is not known why GBS infections have this age distribution which differs from that of invasive infections caused by other encapsulated bacteria. The aim of this study was to test the possibility that serum antibodies against the GBS capsular polysaccharides (CPS) are acquired during the first months of life thereby preventing infections after the neonatal period. Cord sera were collected from 321 healthy term newborns. A second blood sample was collected at 2, 4, 8, 13 or 26 weeks of age. IgG CPS antibodies (measured by ELISA) against serotypes Ia, II and III were present in 98%–100% of all cord sera and decreased continuously during the first 6 months of life. No IgM antibodies against serotype III CPS were present in cord sera. Only 16%–17% of the children acquired IgM antibodies against serotype III CPS at 3 and 6 months of age. Conclusion Early acquisition of IgG or IgM antibodies against CPS of the most common GBS serotypes was not demonstrated and cannot explain the rare occurrence of invasive GBS infections in children after the 1st month of life. Received: 8 April 1997 and in revised form: 16 September 1997 / Accepted 16 September 1997     

Long term follow up of serostatus after maternofetal parvovirus B19 infection.

BACKGROUND: Maternofetal parvovirus B19 infection may result in fetal hydrops or abortion. Chronic infection has been associated with long term complications (polyarthritis, persistent aplastic anaemia, hepatitis). In pregnancy maternal immunosuppression caused by a TH2 dominant response to viral antigens has been observed. There is little information on long term reactivity to intrauterine infection. AIMS: To assess the serological status in children and their mothers after maternofetal parvovirus B19 infection and development of fetal hydrops. METHODS: A total of 18 children and their mothers, and 54 age matched control infants were studied. Main outcome measures were parvovirus B19 DNA, specific IgM and IgG against the virus proteins VP1/VP2, and NS-1 in venous blood. RESULTS: Parvovirus B19 DNA and antiparvovirus B19 (IgM) were undetectable in all sera. A significant larger proportion of maternal sera compared to study children's sera contained IgG against the non-structural protein NS-1. Mean levels of VP1/VP2 IgG antibodies were significantly lower in the children than in their mothers (48 (36) v 197 (95) IU/ml). There was no history of chronic arthritis in mothers and children. Five women had subsequent acute but transient arthritis postpartum, which was not correlated with antibodies against NS-1. CONCLUSIONS: Serological evidence of persistent infection after maternofetal parvovirus B19 disease could not be detected. Increased maternal prevalence of anti NS-1 (IgG) and increased levels of antiparvovirus B19 (IgG) may reflect prolonged viraemia compared to fetal disease.     

Long term follow up of serostatus after maternofetal parvovirus B19 infection

Background: Maternofetal parvovirus B19 infection may result in fetal hydrops or abortion. Chronic infection has been associated with long term complications (polyarthritis, persistent aplastic anaemia, hepatitis). In pregnancy maternal immunosuppression caused by a TH2 dominant response to viral antigens has been observed. There is little information on long term reactivity to intrauterine infection. Aims: To assess the serological status in children and their mothers after maternofetal parvovirus B19 infection and development of fetal hydrops. Methods: A total of 18 children and their mothers, and 54 age matched control infants were studied. Main outcome measures were parvovirus B19 DNA, specific IgM and IgG against the virus proteins VP1/VP2, and NS-1 in venous blood. Results: Parvovirus B19 DNA and antiparvovirus B19 (IgM) were undetectable in all sera. A significant larger proportion of maternal sera compared to study children''s sera contained IgG against the non-structural protein NS-1. Mean levels of VP1/VP2 IgG antibodies were significantly lower in the children than in their mothers (48 (36) v 197 (95) IU/ml). There was no history of chronic arthritis in mothers and children. Five women had subsequent acute but transient arthritis postpartum, which was not correlated with antibodies against NS-1. Conclusions: Serological evidence of persistent infection after maternofetal parvovirus B19 disease could not be detected. Increased maternal prevalence of anti NS-1 (IgG) and increased levels of antiparvovirus B19 (IgG) may reflect prolonged viraemia compared to fetal disease.     

武汉地区住院患儿EB病毒感染状况

目的：分析武汉地区住院患儿EB病毒（EBV）感染的情况及临床特点,为明确诊断、合理治疗提供帮助。方法：采用ELISA法检测住院患儿EBV衣壳抗原(VCA)抗体IgM、IgG,并按年龄将患儿分为＜6个月、6个月～、1岁～、3岁～、7～15岁5个组,对结果进行统计分析。结果：14 840例住院患儿EBV抗体阳性7 899例,感染率为53.23%;VCA IgM阳性率为4.05%(601/14 840);VCA IgG阳性率为49.18%(7 298/14 840)。VCA IgM阳性率以＜6月组最低(0.11%);VCA IgG阳性率以7～15岁组最高(79.83%)。601例VCA IgM阳性的患儿中,以呼吸道感染最多（429例,71.4%）。结论：武汉地区住院患儿EBV感染率较高,EBV感染的相关疾病以呼吸道感染为主;不同年龄组患儿间EBV感染率不同。     

Role of mycoplasma pneumoniae infection in aetiopathogenesis of juvenile idiopatic arthritis

Although more and more is known about chronic autoimmune diseases, attempts to establish one trigger factor have been unsuccessful. The role of endogenic factors is beyond doubt. But it is emphasized that environmental factors are necessary to cause the disease. Infections are taken under consideration as trigger mechanism in the development of autoimmune diseases including chronic arthritis. Both numerous viruses and bacteria are among the microorganism mentioned. We considered it sensible to conduct research on Mycoplasma pneumoniae infections in a group of patients with juvenile idiopathic arthritis (JIA). MATERIALS: 19 patients diagnosed with JIA aged between 6-17 were investigated for Mycoplasma pneumoniae infection whose blood was examined for antibodies against Mycoplasma pneumoniae in class IgG and IgM. The control group comprised 20 children of similar age admitted to hospital with digestive tract complaints. Methods: Serologic tests were made in serum. Marking of antigens of class IgM and IgG were made by Elisa method using commercial kits produced by Scientific Point. Quantitative calculations of a level of antigens were done using appropriate standards, positive and negative serum of reference standard and calibration curve. RESULTS: In 11 patients positive reaction for Mycoplasma pneumoniae in class IgG was observed and only in 2 in class IgM with low titer. In the control group positive reaction was observed in 3 children (15%). The fact that 58% of patients were infected (contact either with Mycoplasma pneumoniae) indicates that in the group of our patients with JIA, infections with these bacteria might have had a role in triggering the disease.     

Relevance of vesico-ureteric reflux in development of lipid a antibodies in recurrent urinary tract infections in children — a preliminary study

The serum titres of IgG and IgM antibodies to lipid A were measured in 24 children with chronic pyelonephritis (PN), 55 with recurrent lower urinary tract infections (LUTI), 13 with gram-negative sepsis (S), and in 50 control children using an enzyme-linked immunosorbent assay (ELISA). Children ranged in age from 1 month-17 years. Patients with PN were differentiated by the presence or absence of an acute infectious episode and/or vesico-ureteric reflux (VUR). During an acute episode in PN and LUTI, IgG titres were significantly higher than in controls, but only PN patients with an acute infectious episode also had significantly elevated IgM titres. Overall, children with LUTI showed a significantly lower frequency of detectable IgG lipid A antibodies (27%) than in PN (63%). In PN children with VUR not accompanied by an infectious episode, lipid A antibody was found at relatively low titres, while an episode not accompanied by VUR displayed significantly elevated IgG titres, and an episode accompanied by VUR showed elevation of both IgG and IgM anti-lipid A antibody titres.Abbreviations UTI urinary tract infections - LUTI lower UTI - LUTI₁ LUTI with acute infectious episode - LUTI₂ LUTI without acute infectious epsisode - PN pyelonephritis - PN₁ PN with VUR but no acute infectious episode - PN₂ PN with acute infectious episode but no VUR - PN₃ PN with VUR and acute infectious episode - VUR vesico-ureteric reflux - S sepsis - ELISA enzyme-linked immunosorvent assay - LPS lipopolysaccharide     

Seroprevalence of Bordetella pertussis immunoglobulin G antibodies among children in Samsun, Turkey

In this study, we aimed to investigate anti-pertussis immunoglobulin (Ig) G antibodies in the serum of children in our region vaccinated against pertussis with four doses. Between August 2008-2009, antibody levels to Bordetella pertussis (B. pertussis) antigens were studied in 385 serum samples from healthy children aged 1.5-18 years (y) vaccinated against pertussis in Samsun, Turkey. The study population was divided into six groups according to ages: 1.5-3 y; 4-5 y; 6-8 y; 10-12 y; 13-15 y; and 16-18 y. IgG antibodies to B. pertussis antigens were measured with a commercial ELISA kit. Mean age of the children was 9.6 +/- 5.3 y. Anti-pertussis IgG titers were positive in 48.3% of the cases. The lowest positivity rate was determined in the 4-5 y age group (28.1%) and the highest rate in the 16-18 y age group (64.2%). Geometric mean titer of anti-pertussis antibodies was 39.2 IU/ml, and again the lowest value was obtained in the 4-5 y age group (23.3 IU/ml) and the highest in the 16-18 y age group (51.4 IU/ml). The antibody levels to B. pertussis antigens significantly decrease 4-6 years after vaccination and again increase in school children, possibly due to natural infection.     

Long term enhancement of the IgG2 antibody response to Haemophilus influenzae type b by breast-feeding

SUBJECTS: Sets of sera were obtained from 30 children <6 years of age with invasive type b (Hib) infection and their mothers. Duration and mode of breast-feeding were monitored. Titers of IgG1, IgG2, IgA and IgM antibodies against Hib capsular polysaccharide were determined in sera taken during the acute illness and during early and late convalescence. RESULTS: Children 18 months or older with longer durations of exclusive breast-feeding (13 weeks or more; mean, 19.3 weeks) had higher Hib antibody concentrations of the IgG1, IgG2, IgA and IgM isotypes than those with a shorter duration of exclusive breast-feeding (<13 weeks; mean, 5.4 weeks). The difference was greatest for the IgG2 isotype. In regression analyses the association between the duration of exclusive breast-feeding and the anti-Hib IgG2 concentration was significant when breast-feeding, type of Hib infection, maternal Hib antibody titer and age were used as explanatory factors. In the group of 14 children <18 months of age no significant differences were noted. DISCUSSION: This study indicates the presence of a long lasting enhancing effect of breast-feeding on the antibody response to Hib in children, in particular on IgG2 Hib antibody production. This may result from the content in the milk of IFN-gamma and IFN-gamma-producing cells and possibly other factors, which can support IgG2 antibody production.     

Serologic response to a secreted and a cytosolic antigen of Mycobacterium tuberculosis in childhood tuberculosis.

BACKGROUND AND AIM: Bacteriologic diagnosis of childhood tuberculosis is difficult, and alternate methods are needed. The utility of a serologic test for major secretory antigen (30 kDa) and a cytosolic antigen (16 kDa) of Mycobacterium tuberculosis was evaluated for the diagnosis of tuberculosis in children. METHODS: Enzyme-linked immunosorbent assay was used. Specific IgG, IgA and IgM antibodies were measured in the sera from 26 clinically and/or bacteriologically diagnosed cases of childhood tuberculosis and 61 normal children. RESULTS: Anti-IgG antibodies alone, against both 30- and 16-kDa antigens, were detected in 65.4% of patients. However, by combination of all three isotypes, increased sensitivities of 84.6 and 73%, with a specificity of 96.7% each, were obtained for 30- and 16-kDa antigens, respectively. CONCLUSIONS: We found good specificity and reasonably good sensitivity for detection of antibodies by enzyme-linked immunosorbent assay to 30-kDa antigen alone. The 16-kDa antigen did not perform as well.     

EB-virus-specific IgM and IgG antibodies in first-degree relatives of children with acute lymphoblastic leukaemia.

EB-virus-specific IgM and IgG antibodies (to virus capsid and soluble complement fixing antigens) were estimated in sera from mothers and sibs of children with acute lymphoblastic leukaemia, from patients with infectious mononucleosis, and from control induviduals. IgM antibodies were present in 12 of 16 mothers and 3 of 4 sibs of children with acute lymphoblastic leukaemia. They were also present in 14 of 16 patients with infectious mononucleosis, but in only 1 of 12 control individuals.     

Value of the comparative enzyme-linked immunofiltration assay for early neonatal diagnosis of congenital Toxoplasma infection

BACKGROUND: The transplacental transfer of specific maternal IgG antibodies makes the diagnosis of congenital Toxoplasma infection quite difficult in the neonate. The enzyme-linked immunofiltration assay (ELIFA), comparing at delivery the immunologic profile of the mother's antibody response and that of her child, allows discrimination between IgG antibodies of maternal origin and IgGs synthesized by the fetus. OBJECTIVE: To evaluate the diagnostic reliability of the comparative ELIFA for diagnosing congenital Toxoplasma infection as well as the reliability of testing for IgM- and IgA-specific antibodies in cord blood. METHODS: From November, 1991, to December, 1995, an ELIFA was prospectively performed at delivery on blood samples obtained from 227 women with primary Toxoplasma infection during pregnancy and from their infants. For each child the ELIFA result was evaluated in relation to the serologic follow-up: disappearance of specific anti-Toxoplasma gondii IgG antibodies in the absence of treatment before 12 months of age indicating an uninfected child, as opposed to persistence beyond 12 months of age indicative of a congenital infection. RESULTS: Of 227 children 139 were lost to follow-up. Among the 88 children available for follow up, the ELIFA was negative in 70 infants, 69 of whom were confirmed to be uninfected. Thirteen of these 69 cord blood ELIFA-negative samples were positive for anti-T. gondii IgM and/or IgA detected by means of a conventional immunosorbent agglutination assay. Of the remaining 18 children (representing 75% of all new cases of congenital toxoplasmosis diagnosed during the study period at our institution), the ELIFA was positive in 16, negative in 1 and inconclusive in 1. CONCLUSIONS: The ELIFA test is a valuable tool for diagnosing congenital T. gondii infection and in differentiating between true neonatal infection and cord blood contamination. In our experience the diagnostic sensitivity of the ELIFA test was 94.1% and the specificity was 98.6%. The cord blood was contaminated by specific maternal anti-T. gondii IgA and/or IgM in as many as 20% of the cases.     

Antibodies against some bacterial antigens in children

The prevalence of bacterial antibodies was determined in 173 children aged 0–15 years. The prevalence of IgG Borrelia burgdorferi antibodies in titres > 500 in children less than 8 years of age was 6% while none of the older children had these antibodies in titres > 400. IgG Helicobacter pylori antibodies were detected only in children older than 6 years of age, with a prevalence of 6.5%, as were IgA H. pylori antibodies, with a prevalence of 3.7%. The prevalence of high-titre IgG Campylobacter jejuni antibodies was 1.2%, that of IgA 1.8% and IgM 1.2%. The prevalence of high-titre (> 500 IU/ml) antistreptolysin O was 3%, that of antistaphylolysin-alpha (≥ 4 IU/ml) 2% and that of antiteichoic acid antibodies (titre 2) 2%. Low-titre Yersinia antibodies were detected in 2%. High-titre Bordetella pertussis antibodies were detected in 6% of recently vaccinated children and in 8% of children in their first years of school. In the latter, high-titre antibodies were mainly of the IgM and IgA classes. Altogether 35 children tested positive for bacterial antibodies other than Bordetella pertussis antibodies. Clinical evaluation revealed a possible infection, suggested by the antibody, in 5 (3%) of the children. Two (vaccinated) children had evidence of whooping cough. Eight of the 35 children with high-titre bacterial antibodies (23%) also had elevated levels of autoantibodies (but not autoimmune diseases).     

Congenital pernicious anemia: report of seven patients, with studies of the extended family

Unstimulated whole saliva was collected from 203 uninfected individuals at various ages from birth until adulthood. Levels of specific antibodies against Escherichia coli O antigens of secretory IgA, secretory IgM and IgG, as well as total amounts of SIgA, were determined using ELISA. Levels of SIgA antibodies found in adults were approached by the age of 12 months, but high levels could be attained earlier, presumably in response to antigenic exposure at the mucosal level. During the first few months of life, secretory IgM antibodies appeared in the saliva, possibly compensating for the relative lack of IgA.     

Three children with congenital toxoplasmosis: early report from a Swedish prospective screening study

The aim of this prospective study was to define the incidence of congenital toxoplasmosis in Sweden. Blood eluates collected on filter papers, Guthrie cards, from 40978 newborn babies were analysed for specific immunoglobulin M (IgM) and IgG antitoxoplasma antibodies. This is a preliminary report of three children with congenital toxoplasmosis, defined by the occurrence of antitoxoplasma-specific IgM antibodies. Two children were asymptomatic at birth. They were both normally developed at the age of 12 and 15 months, respectively. The third child had unidentified but uncomplicated symptoms of infection in the neonatal period. As a result of the screening congenital toxoplasmosis was confirmed and treatment instituted. Microphthalmus and peripheral chorioretinitis were detected in one eye. In spite of the chemotherapeutic treatment he developed hydrocephalus needing neurosurgical intervention at the age of 3 months. His development at 14 months was normal. The incidence in Sweden of congenital toxoplasmosis detected by specific IgM antitoxoplasma antibodies in blood from filter papers is less than 1:10000.     

Helicobacter pylori colonization in early life

Helicobacter pylori infection is a major cause of upper gastrointestinal disease throughout the world. Colonization begins in childhood, although little is known about its age of onset, rate, or mode of colonization. Our aim was to identify the age of acquisition of H. pylori colonization in Gambian children. A cohort of 248 Gambian children aged 3 to 45 months was studied at intervals of 3 months for 2 years, using the 13C-urea breath test, specific IgM and specific IgG serology. The prevalence of positive breath tests rose from 19% at 3 months of age to 84% by age 30 months. Elevated specific IgG and IgM antibody levels were associated with positive breath tests, although there was discrepancy between breath test results and serology, particularly IgG serology, during the 1st year of life. Neither IgG nor IgM serology could be validated as reliable diagnostic tools for infant H. pylori colonization compared with the 13C-urea breath test. Reversion to negative breath test, in association with declining specific antibody levels, occurred in 48/248 (20%) of children. On the assumption that the 13C-urea breath test is a reliable index of H. pylori colonization, we conclude that the infection is extremely common from an early age in Gambian children. Transient colonization may occur. Previous studies relying on serodiagnosis may have significantly underestimated the true early prevalence of colonization in the developing world, where the target age for intervention studies is probably early infancy.