Pesticide Exposure and Neurodevelopment in the Fetus - PowerPoint PPT Presentation

Loading...

PPT – Pesticide Exposure and Neurodevelopment in the Fetus PowerPoint presentation | free to download - id: b3973-OGMwZ



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Pesticide Exposure and Neurodevelopment in the Fetus

Description:

Exposure to pesticides has been linked to preterm birth and reduced fetal growth ... In utero exposure discovered that higher levels ... DDE exposure in utero ... – PowerPoint PPT presentation

Number of Views:119
Avg rating:3.0/5.0
Slides: 29
Provided by: rebeccae2
Learn more at: http://steer.uthscsa.edu
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Pesticide Exposure and Neurodevelopment in the Fetus


1
Pesticide Exposure and Neurodevelopment in the
Fetus
  • Marcel Elizondo
  • July 2009 STEER Student
  • UTHSCSA-Harlingen

2
Pesticides
  • What is a pesticide?
  • According to the EPA, a pesticide is any
    substance or mixture of substances intended for
    preventing, destroying, repelling, or mitigating
    any pest
  • What about pests?
  • Pests are living organisms that occur where they
    are not wanted or that cause damage to crops or
    humans or other animals4

3
Looking at mosquito larvae at the City of
Brownsville lab
4
Pesticides
  • Some examples of pests include
  • Pests include mosquitoes, beetles, ants
  • How do pesticides kill pests?
  • Pesticides attack the nervous system of the pests
    which in turn leads to their untimely demise5

5
Elimination of Pesticide Use
  • Stockholm Convention on Persistent Organic
    Pollutants
  • This agreement was signed by 90 countries in 2001
    to eliminate the use of 12 POPs including DDT
  • The World Health Organization made an exception
    in 2006 to back the use of DDT to control malaria
    in certain countries2

6
Pesticide Use
  • In the US, our agricultural areas use more than
    75 of conventional pesticides
  • Exposure to pesticides has been linked to preterm
    birth and reduced fetal growth
  • A popular pesticide used to be dichlorodiphenyltri
    chloroethane (DDT), which was subsequently banned
    in the US in the 70s
  • Currently, replacement pesticides for DDT are
    insecticides such as organophosphates.1

7
Effects of Some Pesticides
  • Organochlorines (i.e. DDT)
  • Excitation of central nervous system which leads
    to tremors, hyperexcitability and convulsions
    (both tonic and clonic)
  • Organophosphate (i.e. insecticides)
  • Act by inhibiting the acetylcholinesterase in
    synaptic clefts1

8
Inhibiting the Acetylcholinesterase
9
Inhibiting the Acetylcholinesterase
10
Organophosphate Detection
  • Exposure to organophosphates is usually measured
    by nonspecific metabolites in urine known as
    dialkyl phosphate (DAP) metabolites1

11
DO NOT offer your friends pesticides as a home
remedy for cough.
12
Human Studies
  • Center for the Health Assessment of Mothers and
    Children of Salinas (CHAMACOS)
  • Research is funded by NIH and EPA
  • Four objectives of CHAMACOS
  • Six hundred and one pregnant woman were recruited
    in 1999-2000. They were at least 18 years old
    and were less than 20 weeks in their gestation
    period2

13
CHAMACOS
  • Neonatal neurodevelopment was tested using the
    Brazelton Neonatal Behavioral Assessment Scales
    (BNBAS)
  • Maternal serum samples of DDT and DDE were higher
    than the National Health and Nutrition
    Examination Survey reference population
  • A minor negative association was observed between
    maternal DDE serum levels and abnormal infant
    reflexes2

14
CHAMACOS
  • Most other studies conducted had similar results
    to the CHAMACOS study
  • One exception was a study in North Carolina with
    a birth cohort of 912 infants
  • In utero exposure discovered that higher levels
    of DDE in the cord serum and breast milk led to
    hyporeflexia
  • This exception is noted because a similar
    (although smaller) cohort in Oswego, NY was
    conducted and the North Carolina findings could
    not be replicated2

15
Spanish Study
  • Cohort of 92 children
  • Exposed to high levels of DDE
  • Had lower social, mental and psychomotor
    development (assessed using Griffiths Scales of
    Infant Development and BSID-II)2

16
Mexican Study
  • DDE exposure in utero
  • Study found a decrease in psychomotor development
    using BSID-II at 3, 6 and 12 months2

17
Common theme
  • The common result from the CHAMACOS, Spanish, and
    Mexican studies suggests that DDE may have a
    negative effect on psychomotor development in
    infants less that 12 months of age
  • Only the North Carolina cohort had a positive
    association with decreased mental development at
    6 months of age2

18
How Bad can Pesticide Exposure Be?
  • First, we need to determine what the
    environment in relation to pregnancy
  • One known example of a hazardous environmental
    toxin is tobacco smoke
  • The neonatal environment can include nutrition,
    adequacy of prenatal care, smoking, alcohol use,
    maternal age and socioeconomic conditions
  • Two or more of these factors might be related or
    synergistic3

19
Physical Environmental
  • A mothers physical environmental is what most of
    us are familiar with
  • Air, water, food, soil and a number of consumer
    products
  • A mothers placenta is thought of to protect a
    fetus against any toxins encountered, however
    some cases have shown the placenta to actually
    magnify hazardous maternal exposures3

Santa Ana Wildlife Reserve
20
Physical Environmental
  • For some persistent and bioaccumulative exposures
    (i.e. organochlorine pesticides), fetal exposure
    can occur as a result of maternal body burdens
    from years of preconceptional exposures
  • Fathers are just as accountable for exposures
    since their preconceptional exposures contribute
    to the risk through a mutagenic mechanism
    involving the sperm3

21
Neurodevelopmental Effects
  • Not specifically targeting pesticide exposure,
    environmental contaminants have been known to
    have adverse effects on brain and neurological
    development
  • Some developmental disabilities include ADHD,
    learning disabilities, autism, mental retardation
    and effects on the nervous system
  • Studies have shown that the window of
    susceptibility is with prenatal exposures
  • Toxicological studies link both prenatal and
    postnatal exposure to organophosphate pesticides
    to neurodevelopmental effects3

22
Limitations
  • This research focused on prenatal exposure and
    not on adolescent or adult effects

23
Future Research
  • Due to limited human population studies of
    pesticide exposure, more research is needed
    particularly with preconception exposures. This
    research should include both maternal and
    paternal exposures.

24
Recommendations
  • One recommendation for the detection of
    pre-exposure to the fetus
  • Include a questionnaire during prenatal care
    about possible environmental exposures for the
    expectant parents
  • This environmental assessment should be
    particularly conducted in agricultural
    communities where pesticide exposure is more
    prominent

25
You too can be a basketball star without
excessive exposure to pesticides.
26
References
  • Rosas, L.G. and Eskenazi, B. (2008). Pesticides
    and Child Neurodevelopment. Current Opinion in
    Pediatrics, Vol. 20, 191-197.
  • Eskenazi, B., Rosas, L.G., Marks, A.R., Bradman,
    A., Harley, K., Holland, N., Johnson, C.,
    Fenster, L., Barr, D.B. (2008). Pesticide
    Toxicity and the Developing Brain. Basic
    Clinical Pharmacology Toxicology, Vol. 102,
    228-336.
  • Stillerman, K.P., Mattison, D.R., Giudice, L.C.,
    Woodruff, T.J. (2008). Environmental
    Exposures and Adverse Pregnancy Outcomes A
    Review of the Science. Reproductive Sciences,
    Vol. 15 (7), 631-650.
  • US Environmental Protection Agency. About
    pesticides. 2006. Available at
    http//www.epa.gov/pesticides/about/index.htm.
    Accessed July 25, 2009.
  • American Pregnancy. Pesticides Exposure During
    Pregnancy. 2009. Available at
    http//www.americanpregnancy.org/pregnancyhealth/p
    esticides.html. Accessed July 25, 2009.

27
This presentation was created in memory of Dr.
Kirby K.C. Donnelly
28
Questions?
About PowerShow.com