maneb and Manganese-Poisoning

Early caregiving is one of the strongest influences on children's development, and among the most significant modifiable environmental factor. The aim of this study was to explore the association between quality of caregiver-infant interactions and neurodevelopment of infants living in banana-growing communities in rural Costa Rica characterized as having environmental toxic exposures. Home visits were conducted with 94 caregiver-infant dyads from the Infants' Environmental Health Study (ISA), living within Matina county, Limón province. One-year infant neurodevelopmental outcomes were assessed using the Bayley Scales of Infant and Toddler Development®, Third Edition (Bayley-III). Quality of caregiver-infant interaction was assessed with a standardized observational task: Nursing Child Assessment Satellite Training Teaching scale (NCATS) at around two years of age. Multiple regression analyses examined associations between components of caregiver-infant interactions and neurodevelopmental outcomes, adjusting for mancozeb and manganese exposure and other potential confounders. Compared to NCATS normative data for U.S. Hispanic mothers, 35% of the sample had overall caregiving interaction scores ≤10th percentile cut-off, indicating less than optimal interactions. Higher quality of caregiver-infant interaction was associated with higher expressive communication ability in infants [ß = 0.03 (95% CI: 0.01, 0.06)], controlling for pesticide exposure and confounders. Aspects of caregiving such as stimulation and growth-fostering of infants were most strongly associated with language outcomes. Results suggest an association between positive caregiving on language development for infants living in a rural agricultural area in Costa Rica, and highlight aspects of caregiving that could be targeted to improve resilience of these children who live in vulnerable conditions.

Topics: Adult; Child Development; Child, Preschool; Costa Rica; Environment; Environmental Exposure; Environmental Health; Female; Fungicides, Industrial; Humans; Infant; Infant Care; Infant, Newborn; Language Development; Male; Maneb; Manganese Poisoning; Mothers; Neuropsychological Tests; Pesticides; Resilience, Psychological; Rural Population; Zineb

The dithiocarbamate fungicides maneb and mancozeb induce a short-term stress response in a transgenic Caenorhabditis elegans strain (PC72) carrying a reporter lacZ gene under the control of a homologous heat shock (hsp16) promoter. This response can be readily monitored as induced beta-galactosidase activity, either by in situ staining or by a quantitative fluorometric enzyme assay. Particularly strong responses are induced by mancozeb (three- to fivefold above controls at 500 microg mL(-1)), causing acute toxicity at concentrations comparable to those recommended for field application (2 mg mL(-1)). Although much of this fungicide is adsorbed by soil, sufficient (ca. 6%) enters the soil water compartment to cause mild stress in the transgenic worm assay. Among possible metabolites from mancozeb breakdown, neither Mn2+ nor ethylenethiourea (ETU) is particularly toxic even at 10% of the optimum mancozeb dosage. Stress responses to a range of other pesticides are also reported, and in several cases it is clear that a nontarget soil species (here, transgenic C. elegans) may be sensitive to low-level contamination.

Topics: Animals; beta-Galactosidase; Caenorhabditis elegans; Dimethyl Sulfoxide; Dose-Response Relationship, Drug; Fungicides, Industrial; Maneb; Manganese; Manganese Poisoning; Organisms, Genetically Modified; Soil; Stress, Physiological; Toxicity Tests; Zinc; Zineb