Asymptomatic Infected Children Research Articles

Spectrum of COVID-19 infection in children in Southern Nigeria

Background: Corona virus disease 2019 (COVID-19) is a global pandemic that affects all age groups. Infected asymptomatic children can transmit the disease to vulnerable adults with co-morbidities resulting in severe disease in the latter. There are few reports of COVID-19 in children in Sub-Saharan Africa in general and in Nigeria in particular.Aim: To determine the prevalence, symptoms and risk factors for COVID-19 in Southern Nigerian children.Methods: This was a one-year retrospective cross-sectional study between April 2020 and March 2021. Data of all children tested for COVID-19 was extracted from the Epidemiology unit of Akwa Ibom state ministry of health. All patient identifiers were omitted and data was analyzed using STATA version 13.Results: Two hundred and fifty five children (2.25%) out of a total of 11,289 people were tested for COVID-19. Fifty -four children (0.47%) of the total number of persons tested for COVID-19 were positive. Twenty one percent of the 255 children tested were positive for COVID-19. Two hundred and fifty- four (99.6%) of children that were tested had a positive history of contact with a confirmed COVID-19 case. Five (9.3%) of COVID-19 positive children were symptomatic. The commonest symptoms seen were Fever (90.9%), Anosmia (63.6%) and Aguesia (36.4%). Increasing age (15 years and above) was significantly associated with COVID-19 positivity (p=0.000). In addition, the presence of symptoms was significantly associated with COVID-19 positivity (p=0.04).Conclusion/Recommendation: The prevalence of COVID-19 in Southern Nigerian children is low. Majority of the children have asymptomatic disease. Increasing age is significantly associated with COVID-19 positivity. We recommend increased COVID-19 testing in the general children population.

Inflammatory cytokine responses in children with asymptomatic malaria infection living in rural, semi-urban and urban areas in south-eastern Gabon.

Cytokines are soluble mediators of the immune response, and their evolution influences the disease outcome. Gaining knowledge on cytokines has become important, as they can constitute biomarkers allowing the diagnosis of malaria and preventing severe forms of the disease. Here, we investigated 10cytokines and their circulating levels in asymptomatic Gabonese children with Plasmodium falciparum infection living in urban, semi-urban and rural areas. Blood samples were collected from 273 schoolchildren (153 uninfected and 120 infected) aged 6 to 192months. Hematological parameters were determined and P. falciparum diagnosis was performed using a rapid diagnosis test, microscopy and nested polymerase chain reaction (PCR). Plasma pro- [interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-12p70, IL-17A and IL-22] and anti-inflammatory [IL-10, IL-4, IL-13 and transforming growth factor (TGF)-β] cytokine levels were measured by enzyme-linked immunosorbent assay (ELISA) and compared between asymptomatic-infected and uninfected children. Results revealed that without distinction of area, IL-10 and IL-6 levels were higher in infected compared to uninfected children; however, the pro- and anti-inflammatory ratios (IL-6/IL-10 and TNF-α/IL-10) were similar. Furthermore, with area distinction significantly elevated levels of IL-10 in these asymptomatic children were always accompanied by either significantly low or high levels of a proinflammatory cytokine. Also, comparison between asymptomatic-infected children from the three areas showed significantly lower IL-17A, IL-22 and TGF-β levels in urban area compared to semi-urban and rural areas. These results suggest that asymptomatic malaria infections induce significantly high inflammatory cytokine levels without modifying the balanced between pro- and anti-inflammatory cytokines and underline the higher exposure to infections of children in rural areas.

Comparison of Reverse-Transcription Polymerase Chain Reaction Cycle Threshold Values From Respiratory Specimens in Symptomatic and Asymptomatic Children With Severe Acute Respiratory Syndrome Coronavirus 2 Infection.

Background Understanding viral kinetics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is important to assess risk of transmission, manage treatment, and determine the need for isolation and protective equipment. The impact of viral load in asymptomatic infected children is important to understand transmission potential. We sought to determine whether children deemed to be asymptomatic had a difference in the polymerase chain reaction (PCR) cycle threshold (Ct) value of respiratory samples from symptomatic children with SARS-CoV-2 infection.MethodsThis was a retrospective cross-sectional study to compare PCR Ct values of children who tested positive for SARS-CoV-2 by respiratory samples collected over a 4-month period at a large tertiary care children’s hospital.ResultsWe analyzed 728 children who tested positive for SARS-CoV-2 by reverse-transcription PCR (RT-PCR) from a respiratory sample over a 4-month period and for whom data were available in the electronic medical record. Overall, 71.2% of infected children were symptomatic. The mean Ct value for symptomatic patients (Ct mean, 19.9 [standard deviation, 6.3]) was significantly lower than for asymptomatic patients (Ct mean, 23.5 [standard deviation, 6.9]) (P < .001; 95% confidence interval, 2.6–4.6). The mean PCR Ct value was lowest in children <5 years of age.ConclusionsIn this retrospective review of children who tested positive by RT-PCR for SARS-CoV-2, the mean Ct was significantly lower in symptomatic children and was lowest in children <5 years of age, indicating that symptomatic children and younger children infected with SARS-CoV-2 may have a higher viral load in the nasopharynx compared to asymptomatic children. Further studies are needed to assess the transmission potential from asymptomatic children.

Gametocyte carriage after seasonal malaria chemoprevention in Plasmodium falciparum infected asymptomatic children

BackgroundTreatment of clinical Plasmodium falciparum malaria with sulfadoxine-pyrimethamine (SP) and amodiaquine (AQ) is associated with increased post-treatment gametocyte carriage. The effect of seasonal malaria chemoprevention (SMC) with SP and AQ on gametocyte carriage was assessed in asymptomatic P. falciparum infected children.MethodsThe study was carried out in eastern Gambia. Asymptomatic P. falciparum malaria infected children aged 24–59 months old who were eligible to receive SMC (SMC group) and children 5–8 years that were not eligible to receive SMC (comparison group) were recruited. Gametocytaemia was determined by molecular methods before and after SMC administration. Gametocyte carriage between the groups was compared using the chi-squared test and within-person using conditional logistic regression.ResultsDuring the 2017 and 2018 malaria transmission seasons, 65 and 75 children were recruited in the SMC and comparison groups, respectively. Before SMC administration, gametocyte prevalence was 10.7% (7/65) in the SMC group and 13.3% (10/75) in the comparison group (p = 0.64). At day 13 (IQR 12, 13) after SMC administration, this was 9.4% (5/53) in children who received at least the first dose of SMC treatment and 12.7% (9/71) for those in the comparison group (p = 0.57). Similarly, there was no difference in prevalence of gametocytes between children that adhered to all 3-day doses of SMC treatment 15.6% (5/32) and those in the comparison group (p = 0.68). In the SMC group, within-group gametocyte carriage was similar before and after SMC administration in children that received at least the first dose of SMC treatment (OR 0.6, 95% CI 0.14–2.51; p = 0.48) and in those that adhered to all 3-day doses of SMC treatment (OR 1.0, 95% CI 0.20–4.95; p = 1.0).ConclusionIn this study with relative low gametocyte prevalence prior to SMC treatment, no evidence was observed that SMC treatment increased gametocyte carriage in asymptomatic P. falciparum malaria infected children.

Comparative Analysis of Symptomatic and Asymptomatic SARS-CoV-2 Infection in Children

In this study, a comparison of clinical, epidemiological and laboratory parameters between symptomatic and asymptomatic children with SARS-CoV-2 infection was performed. Data from all children with laboratory confirmed SARS-CoV-2 infection admitted to KK Women's and Children's Hospital (KKH), Singapore, from January to May 2020 were analysed. Of the 39 COVID-19 children included, 38.5% were asymptomatic. Household transmission accounted for 95% of cases. The presenting symptoms of symptomatic children were low-grade fever (54.2%), rhinorrhoea (45.8%), sore throat (25%), diarrhoea (12.5%) and acute olfactory dysfunction (5.4%). Children of Chinese ethnicity (37.5% vs 6.7%), complete blood count (45.8% vs 6.7%) and liver enzyme abnormalities (25% vs 7.7%) were more common in symptomatic versus asymptomatic children. All children had a mild disease course and none required oxygen supplementation or intensive care. The high proportion of asymptomatic infected children coupled with household transmission as the main source of paediatric COVID-19 infection underscores the importance of early screening and isolation of children upon detection of an index case of COVID-19 in a household. Symptomatic children were more likely to have abnormal laboratory parameters but they did not have a poorer outcome compared to asymptomatic cases.

Monocyte dysregulation and systemic inflammation during pediatric falciparum malaria.

Inflammation and monocytes are thought to be important to human malaria pathogenesis. However, the relationship of inflammation and various monocyte functions to acute malaria, recovery from acute malaria, and asymptomatic parasitemia in endemic populations is poorly understood. We evaluated plasma cytokine levels, monocyte subsets, monocyte functional responses, and monocyte inflammatory transcriptional profiles of 1- to 10-year-old Kenyan children at the time of presentation with acute uncomplicated malaria and at recovery 6 weeks later; these results were compared with analogous data from asymptomatic children and adults in the same community. Acute malaria was marked by elevated levels of proinflammatory and regulatory cytokines and expansion of the inflammatory "intermediate" monocyte subset that returned to levels of healthy asymptomatic children 6 weeks later. Monocytes displayed activated phenotypes during acute malaria, with changes in surface expression of markers important to innate and adaptive immunity. Functionally, acute malaria monocytes and monocytes from asymptomatic infected children had impaired phagocytosis of P. falciparum-infected erythrocytes relative to asymptomatic children with no blood-stage infection. Monocytes from both acute malaria and recovery time points displayed strong and equivalent cytokine responsiveness to innate immune agonists that were independent of infection status. Monocyte transcriptional profiles revealed regulated and balanced proinflammatory and antiinflammatory and altered phagocytosis gene expression patterns distinct from malaria-naive monocytes. These observations provide insights into monocyte functions and the innate immune response during uncomplicated malaria and suggest that asymptomatic parasitemia in children is not clinically benign. Support for this work was provided by NIH/National Institute of Allergy and Infectious Diseases (R01AI095192-05), the Burroughs Wellcome Fund/American Society of Tropical Medicine and Hygiene, and the Rainbow Babies & Children's Foundation.

Asymptomatic ratio for seasonal H1N1 influenza infection among schoolchildren in Taiwan

BackgroundStudies indicate that asymptomatic infections do indeed occur frequently for both seasonal and pandemic influenza, accounting for about one-third of influenza infections. Studies carried out during the 2009 pH1N1 pandemic have found significant antibody response against seasonal H1N1 and H3N2 vaccine strains in schoolchildren receiving only pandemic H1N1 monovalent vaccine, yet reported either no symptoms or only mild symptoms.MethodsSerum samples of 255 schoolchildren, who had not received vaccination and had pre-season HI Ab serotiters <40, were collected from urban, rural areas and an isolated island in Taiwan during the 2005–2006 influenza season. Their hemagglutination inhibition antibody (HI Ab) serotiters against the 2005 A/New Caledonia/20/99 (H1N1) vaccine strain at pre-season and post-season were measured to determine the symptoms with the highest correlation with infection, as defined by 4-fold rise in HI titer. We estimate the asymptomatic ratio, or the proportion of asymptomatic infections, for schoolchildren during the 2005–6 influenza season when this vaccine strain was found to be antigenically related to the circulating H1N1 strain.ResultsFever has the highest correlation with the 2005–06 seasonal influenza A(H1N1) infection, followed by headache, cough, vomiting, and sore throat. Asymptomatic ratio for the schoolchildren is found to range between 55.6% (95% CI: 44.7-66.4)-77.9% (68.8-87.0) using different sets of predictive symptoms. Moreover, the asymptomatic ratio was 66.9% (56.6-77.2) when using US-CDC criterion of fever + (cough/sore throat), and 73.0 (63.3-82.8) when under Taiwan CDC definition of Fever + (cough or sore throat or nose) + ( headache or pain or fatigue).ConclusionsAsymptomatic ratio for children is found to be substantially higher than that of the general population in literature. In providing reasonable quantification of the asymptomatic infected children spreading pathogens to others in a seasonal epidemic or a pandemic, our estimates of symptomatic ratio of infected children has important clinical and public health implications.

Variation in haematological parameters in children less than five years of age with asymptomatic Plasmodium infection: implication for malaria field studies

During the season of high malaria transmission, most children are infected by Plasmodium, which targets red blood cells (RBCs), affecting haematological parameters. To describe these variations, we examined the haematological profiles of two groups of children living in a malaria-endemic area. A cross-sectional survey was conducted at the peak of the malaria transmission season in a rural area of Burkina Faso. After informed consent and clinical examination, blood samples were obtained from the participants for malaria diagnosis and a full blood count. Of the 414 children included in the analysis, 192 were not infected with Plasmodium, whereas 222 were asymptomatic carriers of Plasmodium infection. The mean age of the infected children was 41.8 months (range of 26.4-57.2) compared to 38.8 months (range of 22.4-55.2) for the control group (p = 0.06). The asymptomatic infected children tended to have a significantly lower mean haemoglobin level (10.8 g/dL vs. 10.4 g/dL; p < 0.001), mean lymphocyte count (4592/µL vs. 5141/µL; p = 0.004), mean platelet count (266 x 103/µL vs. 385 x 103/µL; p < 0.001) and mean RBC count (4.388 x 106/µL vs. 4.158 x 106/µL; p < 0.001) and a higher mean monocyte count (1403/µL vs. 1192/µL; p < 0.001) compared to the control group. Special attention should be applied when interpreting haematological parameters and evaluating immune responses in asymptomatic infected children living in malaria-endemic areas and enrolled in vaccine trials.

Duration of Shedding and Secondary Household Transmission of Shiga Toxin-Producing Escherichia coli O26 During an Outbreak in a Childcare Center, Oregon, October-December 2010.

We assessed shedding duration and secondary household transmission of Shiga toxin 1-positive Escherichia coli O26 during a childcare-associated outbreak. No severe illness was noted. Shedding duration was 15-46 days (median, 29). No secondary transmission to household members was identified. Value of isolating asymptomatic infected children with this low-virulence infection remains uncertain.

Non‐invasive Genotyping of Helicobacter pylori cagA, vacA, and hopQ from Asymptomatic Children

Helicobacter pylori infection is usually acquired in childhood, but little is known about its natural history in asymptomatic children, primarily due to the paucity of non-invasive diagnostic methods. H. pylori strains harboring cagA and specific alleles of hopQ and vacA are associated with increased risk for gastric cancer. Many studies of H. pylori virulence markers in children have the bias that symptomatic subjects are selected for endoscopy, and these children may harbor the most virulent strains. Our aim is to genotype cagA, hopQ, and vacA alleles in stool DNA samples of healthy Colombian children residing in an area with high incidence of gastric cancer, to avoid selection bias resulting from endoscopy. H. pylori status of 86 asymptomatic children was assessed by (13) C-urea breath test (UBT) and PCR. H. pylori 16S rRNA, cagA, hopQ, and vacA genes were amplified from stool DNA samples and sequenced. UBT was positive in 69 (80.2%) of 86 children; in stool DNA analysis, 78.3% were positive by 16S rRNA PCR. cagA, vacA, and hopQ were detected in 66.1%, 84.6%, and 72.3% of stool DNA samples from 16S rRNA-positive children. Of the children's DNA samples, which revealed vacA and hopQ alleles, 91.7% showed vacA s1 and 73.7% showed type I hopQ. Type I hopQ alleles were associated with cagA positivity and vacA s1 genotypes (p < 0.0001). Using stool DNA samples, virulence markers of H. pylori were successfully genotyped in a high percentage of the asymptomatic infected children, revealing a high prevalence of genotypes associated with virulence. Type I hopQ alleles were associated with the presence of cagA and the vacA s1 genotype.

Double‐blind Randomized Trial of Quadruple Sequential Helicobacter pylori Eradication Therapy in Asymptomatic Infected Children in El Paso, Texas

We assessed the efficacy of a novel quadruple sequential 10-day eradication therapy, its compliance, and reported adverse events in a sample of asymptomatically Helicobacter pylori-infected children in El Paso, Texas, as part of a study aiming to assess the influence of this infection on the levels of markers of iron stores. Using a double-blind randomized trial design, 110 asymptomatic children ages 3 to 11 with H pylori infection were randomly assigned to receive either a 10-day course of sequential eradication therapy plus 6 weeks of iron supplementation, eradication therapy plus placebo, iron supplementation plus placebo, or placebo only. H pylori infection status was assessed ≥45 days after treatment using the urea breath test. Analyses compared the proportion of subjects cured according to assignment to and completion of the sequential eradication therapy. Intent-to-treat and per-protocol analyses indicated that 44.3% and 52.9%, respectively, of the children receiving the novel quadruple sequential therapy had their infection eradicated compared with 12.2% and 15.4% in the arms receiving iron or placebo only, respectively (P < 0.001 in both analyses). Study medications were taken with no or only mild adverse events in most children. A quadruple sequential regimen eradicated H pylori in only half the asymptomatic children receiving this treatment. There was no difference in the cure rates of those receiving iron supplementation and those receiving placebo.

Physical and intellectual development in children with asymptomatic congenital cytomegalovirus infection: A longitudinal cohort study in Qinba mountain area, China

Background Although about 90% of congenital cytomegalovirus (CMV) infection is asymptomatic in newborn, some of them could show sequelae later in life. Qinba mountain area is a place with high incidence of mental retardation and a high rate of CMV intrauterine transmission in China. The correlation between asymptomatic congenital CMV infection and developmental outcomes of children in this area remain unclear. Objectives To investigate the impact of asymptomatic congenital CMV infection on physical and intellectual development of children during the first 6 years of life in Qinba mountain area. Study design Longitudinal cohort study. Forty-nine of all the 54 children with asymptomatic congenital CMV infection were followed prospectively in a study for surveying physical growth and intellectual developments. Results Either in neonatal or in infant period, no significant difference was noted between the asymptomatic congenital CMV infection children and the controls in average weight, height and head circumference (both p > 0.05). The intellectual development was disproportion in asymptomatic congenital infected children. Compared with the control group, both global development quotient (DQ) and full-scale intelligence quotient (IQ) scores of asymptomatically infected children were worse ( t = 2.19, p = 0.031; t = 2.48, p = 0.015), especially on language DQ scores ( t = 3.25, p = 0.002) and verbal IQ scores ( t = 3.88, p = 0.000). However, the incidence rates of mental retardation (DQ/IQ < 70) were similar in two groups ( χ 2 = 1.03, p > 0.05). Conclusions Although asymptomatic congenital CMV infection did not have significant influence on the neonatal physical development or incidence of mental retardation later in life, it is obviously an important factor correlating with long-time cognitive outcomes, especially on the development of language. It is necessary to survey CMV congenital infection and monitor the early intellectual development of children with asymptomatic congenital CMV infection in this area.

Treatment of pediatric HIV infection

HIV-infected children require a peculiar management when compared to infected adults. Antiretroviral therapy has been quite well adapted to children, but new studies are needed to answer many unsolved questions, such as when to start therapy in asymptomatic infected children. Recently, several guidelines have been updated. In this review, we compare these recommendations together with the latest studies concerning the treatment of HIV in children. A triple-drug combination therapy based either on nonnucleoside reverse transcriptase inhibitors or protease inhibitors is the recommended initial therapy. After treatment failure, a second-line therapy should be based on switching between these two regimens. Antiretroviral therapy should be managed by an expert in pediatric and adolescent HIV infection. The importance of children's adherence to therapy is a crucial point, particularly in adolescents.

Longitudinal assessment of Plasmodium falciparum var gene transcription in naturally infected asymptomatic children in Papua New Guinea.

Sequestration and antigenic variation are essential for Plasmodium falciparum survival in vivo contributing to severe pathologic findings and, also, chronic infection. Both are conferred by P. falciparum erythrocyte membrane proteins encoded by ~60 var genes. To study the dynamics of var gene expression, we conducted a 4-month longitudinal study of semi-immune children from Papua New Guinea. By use of magnetic bead-anchored reverse-transcription polymerase chain reaction analysis performed over 5 var regions, as well as cloning and sequencing, the longitudinal distribution of full-length var transcripts was analyzed. We identified a dynamic picture of var gene expression with rapid switches but with identical var transcripts recurring for up to 10 weeks. The number of var transcripts was correlated to the number of infections, with a mean of 1.7 var transcripts identified per sample and infecting strain. Analysis of 158 different Duffy binding-like 1 alpha sequences confirmed the recombinogenic nature of var genes. This is the first report of the dynamics of var gene expression in chronically infected children.

Preemptive treatment with oral ganciclovir for pediatric renal transplantation.

This prospective study examines 42 children in the first year after renal transplantation. They all received intravenous ganciclovir prophylaxis for cytomegalovirus in the immediate post-transplant period. Quantitative antigenemia (pp68) determinations and blood, urine and throat cultures were done on a scheduled basis to detect cytomegalovirus. Infection was detected in 22 children (52.4%) within an average 44.31 +/- 27.38 days; 5/22 were symptomatic. The antigenemia was positive (+) in all the infected patients, and so were blood culture in 68.2%, urine culture in 59.1% and throat culture in 31.8%. A positive antigenemia was the earliest finding in all cases but 1. The 5 children with clinical symptoms received intravenous ganciclovir. Asymptomatic infected children received oral ganciclovir at an average dose of 47.64 +/- 8.10 mg/kg/day (median 46.58 (range 33-58.7) mg/kg/day) for an average of 58.47 +/- 27.76 days (median 58 (range 26-211) days). No patient developed disease or ganciclovir resistance during the treatment. No patient presented acute graft rejection or renal dysfunction and their glomerular filtrate rate at 1 year was similar to that of noninfected children (90.38 +/- 26.51 vs. 93.93 +/- 36.24 ml/min/1.73 m2). We conclude that preemptive treatment with oral ganciclovir is useful and safe in children with renal transplantation and that monitoring blood antigenemia is a sensitive and early method to detect and control CMV infection.

Height, weight, and growth in children born to mothers with HIV-1 infection in Europe.

Height, weight, and growth in children born to mothers with HIV-1 infection in Europe.

Ophthalmological findings in children with congenital toxoplasmosis. Report from a Swedish prospective screening study of congenital toxoplasmosis with two years of follow-up

Congenital toxoplasmosis may lead to severe visual impairment or neurological sequelae in the child. The authors studied the severity of the primary and late ophthalmological dysfunction during a prospective incidence study of congenital toxoplasmosis in the Stockholm and Skane counties. Blood collected on phenylketonuria (PKU) cards from 40,978 consecutively born children were investigated for antitoxoplasma antibodies. Children with verified congenital toxoplasmosis were treated for 12 months with antiparasitic therapy and followed ophthalmologically, neurologically and serologically every third month. Three children had congenital toxoplasmosis. Two of these were asymptomatic at birth and would have escaped early detection without screening. One child had unilateral severe visual impairment and CNS involvement. The incidence of congenital toxoplasmosis was less than 1:10,000. The authors conclude that neonatal screening is important to diagnose asymptomatic infected children with congenital toxoplasmosis as treatment has been shown to reduce long-term sequelae. Ophthalmological investigations should start early and continue in co-operation with pediatricians.—Thomas J. Liesegang.

Natural outcome of Helicobacter pylori infection in asymptomatic children: a two-year follow-up study.

It is known that Helicobacter pylori can be acquired in early childhood. There is not enough data to know whether or not infected children should be treated. A better knowledge of the natural outcome and implications of H pylori infection may provide evidence that eradication therapy is beneficial in childhood. This prospective study looks at clinical symptoms, endoscopic, microbial, and histologic changes during a 2-year period in infected asymptomatic children. It is hoped that some prognostic indicators will be found that select out the children that later need therapy. During epidemiologic study of the prevalence of H pylori infection, 18 children aged 7 +/- 4 years (mean +/- 1 SD) were discovered to have H pylori infection and enrolled in the 2-year follow-up study. These patients had received no eradication therapy because they were asymptomatic. The follow-up for each patient consisted of an initial assessment, a clinical examination every 6 months, and an endoscopic reevaluation at the end of the first and second years. Gastric mucosal samples were analyzed for bacteriologic and histologic changes. Various factors were initially recorded: individual factors included sex, age, and housing conditions; microbial factors included bacterial load and the presence of the CagA gene. Inflammatory changes were also noted, such as the presence of active gastritis and nodular formation, and these were correlated with the histology which was described using the Sydney classification. Typing polymerase chain reaction-restriction fragment length polymorphism was performed to check the persistence of the same strain of H pylori in each patient. All of the children were still infected after 2 years with the same strain as in the initial assessment with the exception of 1 child whose infection cleared spontaneously. The density of antral and fundal mucosal colonization with H pylori also remained stable. There were progressive inflammatory changes in this cohort, particularly between the first and second year (histologic score, 3.5 +/- 1.3 vs 5 +/- 1). Active antral gastritis occurred in 3 out of 14 and 1 out of 8 children during the first and second year, respectively. Gastritis became active in the fundus in 2 out of 14 and 2 out of 8 children during the same period. Increases in the histologic score were found particularly in male children, and children colonized by cagA- strains of H pylori during the follow-up. The frequency of nodular gastritis significantly rose from 11% (2 out of 18 children) to 64% (9 out of 14 children) after 1 year, and to 80% (8 out of 10 children) after 2 years. These findings demonstrate a deterioration in the histologic features of the gastric mucosa of infected children despite stable H pylori colonization and the absence of symptoms.

Aeromonads in acute diarrhoea and asymptomatic infections in Nigerian children

Stool samples of 616 asymptomatic and 296 diarrhoeic school children were compared for the recovery rate of Aeromonas spp. on ampicillin (10 micrograms/ml) sheep blood agar. Culture filtrates of isolates were tested for haemolysin production with 1% freshly washed rabbit erythrocytes. Stools of 9 (3.0%) diarrhoeic children yielded five strains of A. hydrophila and four of A. veronii (two each of biotypes sobria and veronii), compared to 12 (1.9%) (p > 0.01) asymptomatic children who harbored seven A. hydrophila and five A. caviae strains. Isolates from-diarrhoeic stools were exclusively from children < or = 5 years, while all infected asymptomatic children were > or = 6 years. Culture filtrates of all nine diarrhoeic strains were uniformly enterotoxigenic (intestinal weight ratio > 0.083) and produced haemolysin titres > 128. These phenotypes where variable in carriage strains of A. hydrophila but were not detected in A. caviae. The recovery of A. hydrophila, and A. veronii biotypes from diarrhoeic stools of children < or = 5 years may suggest their involvement in diarrhoea causation in the absence of other diarrhoeagenic agents.

Controlled trial of Giardia lamblia: control strategies in day care centers.

Strategies for control of Giardia lamblia in day care differ in numbers of children treated and in costs to parents and day care operators. The effectiveness of these strategies has not been systematically evaluated. We conducted a prospective randomized controlled trial comparing three strategies for control of Giardia in infant-toddler day care centers: Group 1, exclusion and treatment of symptomatic and asymptomatic infected children; Group 2, exclusion and treatment of symptomatic infection only; Group 3, exclusion and treatment of symptomatic infection, treatment of asymptomatic infection in the center. The study included 31 day care centers with 4180 child-months of observation. Giardia prevalence was determined before intervention and 1, 2, 4, and 6 months later; new infants and toddlers were tested on admission. Initial Giardia prevalences were 18% to 22% in the three groups. Giardia was identified in 10.5% of 676 new infants and toddlers entering study day care centers during the 6-month follow-up. Giardia prevalences by intervention group were 8%, 12%, and 7% at 1 month, and 7%, 8%, and 8% at 6 months. The stricter intervention resulted in greater cost in terms of child day care and parents' work days lost, but did not result in significantly better control of Giardia infections in this day care environment.