Reinfection In Children Research Articles

Effect of hygiene promotion on the risk of reinfection rate of intestinal parasites in children in rural Uzbekistan

A controlled prospective cohort study was designed to assess the effectiveness of hygiene promotion on the risk of reinfection by intestinal parasites in children in 276 rural Uzbek households over a 1-year period. The study included three groups: seasonality (no medicine, no hygiene promotion activity), treatment (medicine provided, no hygiene promotion activity) and hygiene promotion (medicine provided and hygiene promotion activity). The Participatory Hygiene and Sanitation Transformation methodology was utilized as the key tool in hygiene promotion activities. Three hygiene behaviors were targeted: hand washing with soap, safe feces disposal and boiling drinking water. On average, more than 80% of all children tested were infected with Enterobius vermicularis, Hymenolepis nana, Ascaris lumbricoides, Giardia lamblia or Entamoeba coli. There were statistically significant differences between the three groups for the risk of reinfection rate: the risk of reinfection by parasites was 30% lower in the hygiene promotion group than in the treatment group and 37% lower than in the seasonality group. If properly designed and carried out, hygiene promotion is an effective tool in reducing the risk of intestinal parasite reinfection in children, thus improving children's health in rural communities.

High Rate of Helicobacter pylori Reinfection in Children and Adolescents

Primary Helicobacter pylori infection occurs predominantly in childhood. The aims of this study were to establish the rate of H. pylori reinfection after successful eradication in children and adolescents and to determine the risk factors associated with reinfection. This retrospective study involved 45 children (20 girls, 25 boys) who met the following criteria: eradication of H. pylori confirmed at least 4 weeks after the completion of therapy, and the search for reinfection at least one year after control of eradication of H. pylori. Demographic data, socioeconomic status and living conditions were recorded. Forty-five children aged 1.2-17.6 years (median, 10.9 years) at the time of H. pylori treatment were reviewed 1 to 9 years after H. pylori eradication. Eight children (18%) had been reinfected (5.4% to 6% per patient-year). Six of 25 (24%) children older than 10 years at the time of diagnosis became reinfected. None of the studied risk factors was associated with reinfection. However, having a sibling younger than 5 years was found in four of seven (57%) reinfected children versus five of 24 (21%) nonreinfected children (p = .08). Children become reinfected more frequently than adults. Adolescents become reinfected, whereas acquisition of primary H. pylori infection occurs predominantly in early childhood. Close contact with young children, especially siblings, younger than 5 years could be a more important risk factor than the age of the patient at the time of treatment for the high rate of reinfection in childhood.

Helicobacter pylori Status and Symptom Assessment Two Years after Eradication in Pediatric Patients from a High Prevalence Area

To establish the rate of Helicobacter pylori reinfection in children from an H. pylori high prevalence area, possible clinical features predictive of reinfection and the usefulness of re-treatment. 65 consecutive children attending the authors' department between 1998 and 2000 who had proven successful H. pylori eradication were enrolled; 52 took part. Patients and family members were invited to undergo C-urea breath testing and to complete a simple questionnaire regarding symptoms and socioeconomic status. Patients with H. pylori reinfection were offered treatment; eradication was assessed by C-urea breath test 8 weeks after completion of treatment. Of 52 children, 15 (28.8%) were H. pylori positive. Variables predictive of reinfection were age at primary infection and presence of an infected sibling. Although reinfected children were more frequently symptomatic than non-reinfected patients, no specific symptom was associated with reinfection. Of the nine re-treated patients who returned 8 weeks after completing therapy, the bacterium was eradicated in five (56%). The 12.8% per year reinfection rate in childhood at 2 years that we observed should prompt a re-evaluation of H. pylori status even after a successful eradication. Living in an H. pylori high prevalence area increases the annual risk of reinfection by approximately fourfold over the annual risk in H. pylori low prevalence areas.

Prevention of intestinal amebiasis by vaccination with the Entamoeba histolytica Gal/GalNac lectin

Prevention of intestinal infection by Entamoeba histolytica would block both invasive disease and parasite transmission. The amebic Gal/GalNAc lectin mediates parasite adherence to the colonic surface and fecal anti-lectin IgA is associated with protection from intestinal reinfection in children. We tested if vaccination with the E. histolytica Gal/GalNAc lectin could prevent cecal infection in a C3H mouse model of amebic colitis. Two trials using native lectin purified from the parasite and two trials using a 64kDa recombinant fragment (“LecA”) were performed with a combined intranasal and intraperitoneal immunization regimen using cholera toxin and Freund’s adjuvants, respectively. Two weeks after immunization mice were challenged intracecally with trophozoites, and 4–12 weeks after challenge mice were sacrificed for histopathologic evaluation of infection. Vaccination prevented intestinal infection with efficacies of 84 and 100% in the two native lectin trials and 91 and 34% in the two LecA trials. Mice with detectable pre-challenge fecal anti-lectin IgA responses were significantly more resistant to infection than mice without fecal anti-lectin IgA responses. These results show for the first time that immunization with the Gal/GalNAc lectin can prevent intestinal amebiasis in mice and suggest a protective role for fecal anti-lectin IgA in vivo.

Where are We with current therapy?

Despite intensive research and widely publicized recommendations from consensus meetings in different continents, the public and primary care physicians are relatively slow in picking up the impact of Helicobacter pylori infection and identifying optimal therapies. The treatment of H. pylori infection has evolved from bismuth-containing regimens, 2-week proton pump inhibitor (PPI)-dual therapies, and now, the widely accepted PPI/ranitidine bismuth citrate (RBC) single week triple therapies. There is a wealth of evidence showing that these regimens are highly efficacious and well tolerated by patients. The MACH-2 studies have confirmed that the addition of a PPI to two antimicrobials has significantly improved the cure rate of H. pylori infection and reduced the impact of antimicrobial resistance. Attempts to use shorter regimens ranging from 1 to 3 days should be resisted because of their unacceptably low therapeutic efficacy. In the United States, there are some indications that 10-14 days of treatment may be required. While the first-line therapies for H. pylori infection is well established, we are still struggling with the choice of optimal regimen in retreatment after the first attempt fails. Quadruple therapy combining PPI with bismuth, metronidazole and tetracycline has achieved a respectable success of around 85%. Switching between metronidazole and clarithromycin seems to be a sensible strategy as these two are the most effective anti-Helicobacter agents. Changing between PPI and RBC in the triple therapy would not make much difference without replacing some of the antimicrobials. Rifabutin-containing regimens and high-dose PPI-amoxicillin dual therapy deserve more studies with large-scale studies. Data on anti-Helicobacter therapy for children are few. Most studies based on bismuth derivatives in combination with amoxicillin or tinidazole and were limited by the small number of cases. Recent studies showed 1-week bismuth-based triple therapy and 2-week PPI-based triple therapy are highly efficacious. Reinfection in children > 5 years of age after successful cure is rare. It is worthwhile to refine the optimal therapy for children as the treatment of this group would, theoretically, prevent the development gastric cancer in the long term.

Low rates of Helicobacter pylori reinfection in children

Background & Aims: Reinfection after treatment for Helicobacter pylori is uncommon in adults. It is more likely to occur in children because they acquire primary infection. The aim of this study was to determine whether children are likely to become reinfected with H. pylori and if there are any risk factors for reinfection. Methods: A prospective study of children who had documented evidence of successful treatment for H. pylori infection was performed. Sixty children were eligible for inclusion; results for 52 are presented. Children, parents, and siblings underwent [13C]urea breath tests. Details of family size and socioeconomic status were documented. Cox logistic regression analysis was used to determine the risk factors for reinfection. Results: The duration of follow-up was 103.8 patient-years (mean ± SD, 24 ±14.0 months). Forty-six (88.5%) of the index children remained clear of infection, and 6 (11.5%) children were reinfected. The mean age of those who became reinfected was 5.8 ± 5.6 years compared with 12.3 ± 3.0 years for those who remained clear of infection (P = 0.00001). Only 2 of 46 (4.3%) children older than 5 years of age were reinfected, although 80.8% had 1 infected parent and 65% of siblings were infected. Reinfection rate was 2.0% per person per year in children older than 5 years. Living with infected parents and siblings and low socioeconomic status were not risk factors for reinfection. In logistic regression analysis, age was the only risk factor for reinfection. Conclusions: Reinfection with H. pylori occurs rarely in children older than 5 years of age regardless of socioeconomic group or number of infected family members. These findings also indicate that it is not necessary to treat all family members to achieve long-term eradication of H. pylori.

Homotypic and heterotypic serum neutralizing antibody response to rotavirus proteins following natural primary infection and reinfection in children

Worldwide trials of rotavirus vaccines are currently in progress, but the basis of cross-reactive immunity between rotavirus serotypes is yet to be elucidated. The involvement of the outer capsid proteins, VP7 and VP4, in the production of cross-reactive neutralizing antibody (N-Ab) is unclear, and may be important for the success of animal rotavirus-based candidate vaccines that lack a VP4 of human rotavirus origin. In this study, VP7- and VP4-specific N-Ab was assayed in sera from children experiencing primary (27 children) and/or secondary (14 children) rotavirus infections using human-animal reassortant strains. These reassortants contained genes encoding the major G- and P-types found in human infection, including G1, 2, 3, and 4; or P1A[8], 1B[4], and 2[6]. After primary infection, the N-Ab response to VP7 was generally serotype-specific, whereas the response to VP4 was heterotypic. After reinfection (with the same or different serotypes) there was a significant increase (P=0.0313) in the number of VP7 serotypes seroconverted against with no broadening of cross-reactivity to VP4. Increases in homotypic N-Ab titer, following both primary and secondary infection, were greater against VP7 than VP4, with the seroconversion against VP7 being significantly greater upon reinfection than following primary infection (P=0.0280). In summary, heterotypic N-Ab produced following primary infection appears to be primarily against VP4. However, upon reinfection, VP7 becomes increasingly immunodominant both in terms of cross-reactive N-Ab production and increases in N-Ab titer.

Homotypic and heterotypic serum neutralizing antibody response to rotavirus proteins following natural primary infection and reinfection in children

Homotypic and heterotypic serum neutralizing antibody response to rotavirus proteins following natural primary infection and reinfection in children

Analysis of influenza A virus reinfection in children in Japan during 1983–91

The epidemiology of influenza A in Japan was studied during 1979-91 and viruses isolated from reinfections during 1983-91 were analysed. Of 2963 influenza viruses isolated from reinfections during 1983-91 were analysed. Of 2963 influenza viruses isolated during this period, 922 and 1006 were influenza A(H1N1) and A(H3N2) viruses respectively; the others were influenza B viruses. Influenza A(H1N1) and A(H3N2) caused 5 and 6 epidemics respectively, most accompanied by antigenic drift. Seventeen reinfections with H1N1 and 17 with H3N2 were detected during our study. The primary and reinfection strains isolated from 7 H1N1 and 10 H3N2 cases were studied by haemagglutination-inhibition, and amino acid and nucleotide sequences of the HA1 region of the haemagglutinin. Most of the primary and reinfection strains were antigenically and genetically similar to the epidemic viruses circulating at that time. However, in 4 out of 10 cases of reinfection with influenza H3N2 virus, reinfection strains were genetically different from the epidemic viruses.

Ascaris lumbricoides: reinfection in children bearing an established worm burden

To clarify the existence of reinfection in children bearing an established Ascaris lumbricoides infection, the authors evaluated the weight and the length of worms collected from ten cases of ascaridiasis. The worm burden was greater than 27 worms in nine cases. In seven cases the weight and the length of worms showed little variation, with unimodal distribution of values, suggesting that all the worms in each case belong to the same population, originated from a single brood infection or from successive infections over small time intervals. In three cases there was great variation in worm size indicated by the different values for the means and medians and by the high values for the standard deviation and coefficient of variation. In these three cases there was a bimodal distribution of worm's size suggesting the coexistence of two distinct populations: one, less numerous, composed of mature worms and the other, more numerous, composed of immature worms, in two cases, and two distinct populations of immature worms in one case. The existence of worms in different stages of maturation indicates that the less mature population was acquired when the mature worms were established in the gut. These results indicate that the reinfection with Ascaris in children bearing an established infection is not rare and resistance induced by a preexisting infection is not the rule.

Plasmodium falciparum Reinfection in Children from a Holoendemic Area in Relation to Seroreactivities against Oligopeptides from Different Malaria Antigens

The rate and densities of Plasmodium falciparum reinfections were investigated in children five to 14 years old from one village in Tanzania with a high transmission rate. Initial parasitemias were eradicated by a curative treatment with quinine, a drug with a short elimination half-life, to minimize the effects of residual drug on reinfection. The seroreactivities to seven oligopeptides, representing T and B cell epitopes from the ring erythrocyte surface antigen (Pf155/RESA), the clustered arginine-rich protein antigen (CARP), and the circumsporozoite (CS) proteins were determined in the children at the start of the study and after 28 days. All children were reinfected within 42 days (mean 27 days). The geometric mean maximum parasite density at reinfection was 308 parasites per microliter (range 4-13, 920). The antipeptide antibody levels showed high interindividual variation, with a significant mean decrease (16%) between days 0 and 28 for the blood stage antigens, but not for the (NANP)6 peptide from the CS protein. This suggests that the absence of blood stage antigenic stimulation had already influenced the antibody levels within this short period of time. The mean reinfection day was not influenced by the levels of antibodies to any of the peptides. However, the children with higher antibody levels to (EENVEHDA)2(EENV)2 developed significantly lower parasitemias than those with lower antibody levels (P less than 0.05). This suggests that this subunit of the Pf155/RESA molecule is an important B cell epitope for protective antiparasitic immunity.

Evaluation of the adult carrier state in juvenile tinea capitis caused by Trichophyton tonsurans

The anthropophilic dermatophyte Trichophyton tonsurans is an occasional cause of scalp ringworm in adults. An asymptomatic adult carrier state also has been described. In this study the parents and/or grandparents of 50 children with proved T. tonsurans tinea capitis were evaluated. Cultures were obtained from the scalps of 46 asymptomatic adults; 14 of the cultures grew T. tonsurans. This population may provide a source for continued reinfection in children.

Two-year follow-up of Schistosoma mansoni infection and morbidity after treatment with different regimens of oxamniquine and praziquantel

Three study groups in the Rusizi plain (Burundi) were examined parasitologically (duplicate 28 mg Kato slides) and clinically (history, abdominal palpation) 0, 1·5, 3, 6, 12 and 24 months after treatment for Schistosoma mansoni infection. Infected subjects in Maramvya (n = 430) were treated randomly with oxamniquine 20, 30 or 40 mg/kg; those in Bulinga (n = 457) with praziquantel, 20, 30 or 40 mg/kg; those in Bulamata (n = 333) with praziquantel, 30 or 40 mg/ kg. In children (<20 years) in Maramvya and Bulamata, infection rates and intensities returned almost to pretreatment levels one to 2 years after treatment. In Bulinga, reinfection in children was much less intense. Hardly any reinfection occurred in adults in Bulinga and Maramvya; in Bulamata, half of the cured adults were reinfected, most of them lightly, 2 years after treatment. The initial parasitological advantage of the higher dosages of both drugs disappeared generally 3–12 months after treatment. There was no indication of predisposition to heavy reinfection after treatment of subjects with initial high egg counts. Little relation between pre-treatment egg count and morbidity was observed. The impact of chemotherapy on hepatomegaly was limited and observed only in adults treated with 40 mg/kg of either drug. Spleen rates in children and adults were not affected. Abdominal pain was reduced in almost all treatment groups for 3 to 24 months. The frequency of bloody diarrhoea decreased dramatically in children and adults from all 3 villages. This effect lasted 24 months in Maramvya, 12 months in Bulinga and 6 months in Bulamata, and was not dose-dependent. It is concluded that: (i) repeated population chemotherapy combined with sanitation is necessary to achieve lasting impact on infection rates; (ii) retreatment intervals should be adapted to age group and, possibly, local endemicity levels; (iii) the morbidity impact of population chemotherapy in these conditions was greater on intestinal than on hepatosplenic disease; (iv) lower, cheaper treatment schedules may in the long term be as effective as those with high cure rates.