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Background: Many studies have documented lower vaccine efficacy among children in low-income countries, compared with their counterparts in high-income countries. This disparity is especially apparent with respect to oral vaccines such as rotavirus and oral polio vaccines. One potential contributing factor is the presence of maternal antenatal helminth infections, which can modulate the infant's developing immune system.Methods: Using a multiplex immunoassay, we tested plasma immunoglobulin A (IgA) or immunoglobulin G (IgG) levels specific for antigens in 9 routinely administered childhood vaccines among 1639 children aged approximately 13 months enrolled in the ECUAVIDA (Ecuador Life) birth cohort study in Ecuador. We compared vaccine responses in 712 children of mothers who tested positive for helminth infections in the last trimester of pregnancy to responses in 927 children of mothers without helminth infection.Results: Plasma IgA levels specific for antigens in rotavirus vaccine and oral polio vaccine containing poliovirus serotypes 1 and 3 were all significantly higher in children of helminth-infected mothers, compared with children of uninfected mothers. Plasma IgG levels specific for diphtheria, tetanus, pertussis, measles, rubella, and Haemophilus influenzae type b vaccine antigens were comparable between the 2 groups.Conclusions: Antenatal maternal helminth infections were not associated with reduced antibody responses to infant vaccines, but rather with modestly increased IgA responses to oral vaccines. [ABSTRACT FROM AUTHOR]

Background. Although norovirus is the most common cause of gastroenteritis, there are few data on the community incidence of infection/disease or the patterns of acquired immunity or innate resistance to norovirus. Methods. We followed a community-based birth cohort of 194 children in Ecuador with the aim to estimate (1) the incidence of norovirus gastroenteritis from birth to age 3 years, (2) the protective effect of norovirus infection against subsequent infection/disease, and (3) the association of infection and disease with FUT2 secretor status. Results. Over the 3-year period, we detected a mean of 2.26 diarrheal episodes per child (range, 0-12 episodes). Norovirus was detected in 260 samples (18%) but was not found more frequently in diarrheal samples (79 of 438 [18%]), compared with diarrhea-free samples (181 of 1016 [18%]; P = .919). A total of 66% of children had at least 1 norovirus infection during the first 3 years of life, and 40% of children had 2 infections. Previous norovirus infections were not associated with the risk of subsequent infection. All genogroup II, genotype 4 (GII.4) infections were among secretor-positive children (P < .001), but higher rates of non-GII.4 infections were found in secretor-negative children (relative risk, 0.56; P = .029). Conclusions. GII.4 infections were uniquely detected in secretor-positive children, while non-GII.4 infections were more often found in secretor-negative children. [ABSTRACT FROM AUTHOR]

To investigate the role of mast cells in treatment-associated adverse reactions in patients with onchocerciasis, changes in plasma tryptase levels and skin mast cell counts were examined in 2 groups of Onchocerca volvulus-infected subjects after ivermectin treatment. After treatment, an increase in tryptase levels was observed concurrent with the onset of blood eosinopenia and preceding the appearance of plasma eosinophil-derived neurotoxin (EDN) and interleukin-5. Tryptase levels were correlated with development of peripheral eosinopenia and markers of eosinophil activation and degranulation. Dermal mast cell numbers increased transiently at 24 h after treatment, preceding the onset of dermal eosinophil infiltration and the development of clinically apparent inflammation. Local reactions were strongly correlated with leveis of plasma tryptase and EDN, and the severity of systemic reactions was correlated with levels of tryptase, EDN, and interleukin-5. The data indicate that mast cells play a role in initiation of tissue inflammatory reactions after ivermectin treatment of onchocerciasis. [ABSTRACT FROM AUTHOR]

Presents information on a study which examined the association between Onchocerca volvulus infection and cellular immune responses. Types of cellular immune responsiveness; Methodology; Results and discussion.

Investigates the cytokine and antibody response to adult and larval stages of Ascaris lumbricoides in infected young adults living in an endemic area of Ecuador. Frequencies of peripheral blood mononuclear cells secreting interleukin (IL)-10, interferon-gamma, IL-4 and IL-5 in infected young adults; Levels of A. lumbricoides-specific antibodies in plasma from infected individuals.

Studies the vibriocidal antibody response to the oral cholera vaccine in children infected with Ascaris lumbricoides as well as the effect of albendazole pretreatment on the postvaccination response. Greater postvaccination rates of seroconversion in the treatment group that received albendazole; Greater rates of seroconversion and mean titer observed in the albendazole groupin subjects with non-O ABO blood groups.

Assesses the safety and biologic effects of recombinant human interleukin-10 in acute systemic inflammation using the antibiotic-induced Jarisch-Herxheimer reaction of Louse-borne relapsing fever. Pathogenesis of the systemic inflammatory response syndrome; Consequences associated with uncontrolled production of potent mediators; Onset of spirochete destruction.

Analyzes the role of eosinophil activation and sequestration in the development and severity of adverse reactions after treatment of Onchocerca volvulus infection with ivermectin. Decline in eosinophil counts in ivermectin-treated groups; Increase in the circulating levels of interleukin-5 and eosinophil-derived neurotoxin; Slin microfilarial densities before and after treatment.