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Paraquat and Parkinson's Disease
Numerous studies reveal possible links between exposure
to the
pesticide Paraquat and the development of Parkinson’s Disease
The title and subtitle of this page were taken from a
report
by the German Pesticide Action Network. (92 kB PDF file)
There are many instances of reports that cover the connection between
Paraquat use and the incidence rate of Parkinson's Disease in agricultural
workers. Unfortunately, many reports published by the research
community that address that connection are accessible only through paid
subscriptions that provide the only access to those reports.
That leaves out almost all normal mortals. Nevertheless, the abstract of one of those reports is quoted in the
following.
Age-related irreversible progressive nigrostriatal
dopaminergic neurotoxicity in the paraquat and maneb model of the
Parkinson's disease phenotype.
Thiruchelvam M,
McCormack A,
Richfield EK,
Baggs RB,
Tank AW,
Di Monte DA,
Cory-Slechta DA.
Department of Environmental Medicine, University of Rochester School of
Medicine and Dentistry, Rochester, NY 14642, USA.
While advancing age is the only unequivocally accepted risk factor for
idiopathic Parkinson's disease, it has been postulated that exposure to
environmental neurotoxicants combined with ageing could increase the
risk for developing Parkinson's disease. The current study tested this
hypothesis by exposing C57BL/6 mice that were 6 weeks, 5 months or 18
months old to the herbicide paraquat, the fungicide maneb or paraquat +
maneb, a combination that produces a Parkinson's disease phenotype in
young adult mice. Paraquat + maneb-induced reductions in locomotor
activity and motor coordination were age dependent, with 18-month-old
mice most affected and exhibiting failure to recover 24 h
post-treatment. Three months post-treatment, reductions in locomotor
activity and deficits in motor coordination were sustained in
5-month-old and further reduced in 18-month-old paraquat + maneb groups.
Progressive reductions in dopamine metabolites and dopamine turnover
were greatest in 18-month-old paraquat + maneb and paraquat groups 3
months post-treatment. Increased tyrosine hydroxylase enzyme activity
compensated for striatal tyrosine hydroxylase protein and/or dopamine
loss following treatment in 6-week-old and 5-month-old, but not
18-month-old paraquat and paraquat + maneb mice. Numbers of
nigrostriatal dopaminergic neurons were reduced in all age groups
following paraquat alone and paraquat + maneb exposure, but these
losses, along with decreases in striatal tyrosine hydroxylase protein
levels, were progressive in 18-month-old paraquat and paraquat + maneb
groups between 2 weeks and 3 months post-exposure. Collectively, these
data demonstrate enhanced sensitivity of the ageing nigrostriatal
dopamine pathway to these pesticides, particularly paraquat + maneb,
resulting in irreversible and progressive neurotoxicity.
PMID: 12911755 [PubMed - indexed for MEDLINE]
The report by PAN Germany that is identified at the beginning of this
page mentions what the abstract in the subsequent quote focuses on, the
synergistic effect of the use of Paraquat in combination with other
herbicides, fungicides or insecticides.
syn·er·gism
Pronunciation: 'si-n&r-"ji-z&m
Function: noun
Etymology: New Latin synergismus, from Greek synergos
: interaction of discrete agencies (as industrial firms),
agents (as drugs), or conditions such that the total effect is
greater than the sum of the individual effects |
 |
It is not only the synergism of the use of Paraquat in
combination with other toxins in relation to the incidence rates of
Parkinson's Disease that should concern us but that Parkinson's Disease
affects men and women disproportionately.
21: Br J Psychiatry. 2005 Dec;187:583-4.
Epidemiology of intentional self-poisoning in rural Sri Lanka.
Eddleston M, Gunnell D, Karunaratne A, de Silva D, Sheriff MH, Buckley
NA.
Department of Clinical Medicine, Faculty of Medicine, PO Box 271, 25
Kynsey
Road, Colombo 8, Sri Lanka.
eddlestonm@eureka.lk
We investigated the epidemiology of intentional self-poisoning in rural
Sri
Lanka by prospectively recording 2189 admissions to two secondary
hospitals.
Many patients were young (median age 25 years), male (57%) and used
pesticides
(49%). Of the 198 who died,156 were men (case fatality 12.4%) and 42
were women
(4.5%). Over half of female deaths were in those under 25 years old;
male deaths
were spread more evenly across age groups. Oleander and paraquat caused
74% of
deaths in people under 25 years old; thereafter organophosphorous
pesticides
caused many deaths. Although the age pattern of self-poisoning was
similar to
that of industrialised countries, case fatality was more than 15 times
higher
and the pattern of fatal self-poisoning different.
PMID: 16319413 [PubMed - indexed for MEDLINE]
It is of course politically incorrect to admit that more men
than women die of suicide, which is why we commonly find many reports like
this one from less objective and more politically correct sources:
Indeed, ‘safety’ rules don’t even get the simple things
right. It has long been known that the diet and drugs taken by a woman
can affect her children and grandchildren. But multi-generational
pesticide testing is rare. We all know that animal tests deemed
thalidomide harmless. Yet a pesticide’s ‘safety’ is judged on animal
tests and on calculating its effects on adult men – ignoring the
vulnerability of women, the old, the unborn and children. (Link
to Source)
As to the respective propensity of men and women to commit
suicide, the evidence is incontrovertible: In all countries of the
world men are from about three to more than ten times more likely than women
to commit suicide, yet, politically correct sources of statistics pertaining
to suicides of the sexes persistently search for exceptions that they then
imply are the rule:
The Australian National University
Demography and Sociology Program
Research School of Social Sciences
Pacific Island Suicide in Comparative Perspective
Heather Booth
Abstract All available data for 13
Pacific Island Nations are used in a comparative analysis of suicide
levels and characteristics. Age, sex and and method of suicide are
examined in detail. Global comparison shows that Pacific rates are
amongst the highest reported. Female youth rates exceed male rates
in Western Samoa and amongst Fiji Indians. Method of suicide
(paraquat ingestion) is instrumental in determining high rates in
Western Samoa, especially in females. The broad causal theme is
social transition. Commonality and diversity are discussed. (Link
to Source)
Nevertheless, globally, men are more likely than women to
die from Paraquat poisoning, whether the poisoning is deliberate, accidental
or on account of professional exposure. Exceptions such as those found
by Heather Booth from the Australian National University are a far cry from
being the rule. Although some reports present a more objective and
less politically correct view of Paraquat poisoning, the authors of some of
those reports apparently feel compelled to distort even objective
statistics, unless they happen to be numerically illiterate.
Twenty-five cases of Paraquat ingestion were identified;
of these, 16 died and 9 survived. Twenty 60%) of the cases were men.
There were 16 cases for whom questionnaire information was available
(interview cases); sex and age of interview cases were similar to those
of noninterview cases. Eleven of the 12 male interview cases were
agricultural workers, and I described himself as a day laborer. The 4
female interview cases were described as housewives who were married to
agricultural workers. All interview cases were literate. (Paraquat
poisoning in southern Mexico: a report of 25 cases; Archives of
Environmental Health, March-April, 1993 by Roberto Tinoco, Rolando
Tinoco, Julie Parsonnet, David Halperin)
Twenty out of 25 cases do not constitute 60 percent but
80 percent of the cases investigated. As the following
quote from a WHO report shows, men are identified as being involved in about
70 percent of all acute pesticide poisoning cases.
Acute pesticide poisoning according to variables of
interest
In people under 15 years of age, 816 cases of APP were registered (5.7
per 100,000 population under age 15) and 27 deaths (0.2 per 100,000) in
the Subregion in the year 2000. This risk is smaller than that
registered for the total population. Underreporting affecting the entire
situation analysis deserves special attention in this age group, even
more so because this group is highly vulnerable to exposure to these
substances. Acute pesticide poisoning impacts a greater proportion of
men, who represent approximately 70% of all cases, with a very similar
pattern in all the countries....
Conclusion
One important point to mention is the progressive increase in
pesticide importations in the Region [the Central American Isthmus] over
the last decade. This increase was registered in many countries and when
the pesticides are classified by type of organism it is designed to
control, herbicides show a rising trend. Compared to the WHO estimates
of an average pesticide burden at the global level of 0.6 kilograms per
person, the burden in the Region remains very high. For 2000, the
Regional incidence rate was close to 20 cases per 100,000 populations
and the mortality rate was 2.1 per 100,000 populations. Cases of acute
poisoning and mortality also show a rising trend. This trend may reflect
a better registration system or problems due to a poor management or a
greater dangerousness of this type of substances. Nicaragua and El
Salvador show the highest risk. However, given the increase in imports
of these substances in countries such as Guatemala and Honduras, the
lowest risk may reflect an underregistration problem. The case fatality
associated with pesticide poisoning is high. In 2000, 11% of the APP
cases resulted in death. As a response, health personnel should be
trained in the management of these situations, and strict prevention and
control activities should be put in place. Major efforts should be made
to develop and implement strategies that lead to a drastic reduction of
the use of synthetic pesticides, to the development of alternatives and
subsequently to the protection of human health and the environment.
Different initiatives supported by PLAGSALUD in the Centroamerican
Isthmus are presented in
Box
1. Source:
Epidemiological Situation of Acute Pesticide Poisoning in the Central
American Isthmus, 1992-2000, from Epidemiological Bulletin, Vol. 23
No. 3, September 2002
See also:
Incidentally, not only herbicides but pesticides as well are
dangerous to people. On account of its plant origins, Rotenone is a
pesticide that is deemed safe by many and therefore is permitted to be used
in organic farming practices. Still, it is also considered to be one
of the pesticides that are most dangerous to humans. Not only that,
but Rotenone, too, is linked to Parkinson's Disease.
Acute toxicity
Rotenone is classified by the World Health Organisation as a moderately
hazardous, Class II(18). The LD50 for rats (the amount of the chemical
lethal to one-half of experimental animals) is between 132 and 1,500 mg
per kilogram(19). One factor in this wide variation may be the
differences in the plant extracts used(20).
The acute oral toxicity of rotenone is moderate for mammals, but
there is a wide variation between species(21). It is less toxic for the
mouse and hamster than for the rat; the pig seems to be especially
sensitive. Recent studies have shown that in rats, rotenone is more
toxic for females than males. It is highly irritating to the skin in
rabbits(22), and to the eyes. In rats and dogs exposed to rotenone in
dust form, the inhalation fatal dose was uniformly smaller than the oral
fatal dose(23).
Rotenone is believed to be moderately toxic to humans with an oral
lethal dose estimated from 300 to 500 mg/kg(24). A lowest lethal dose of
143 mg/kg has been cited in a child(25). Clinical experience seems to
indicate that children, in particular, are rather sensitive to the acute
effects of rotenone(26).
Human fatalities are rare, perhaps because rotenone is usually sold
in low concentrations (one to five per cent formulation), and because
its irritating action causes prompt vomiting. If the dust particle size
is very small, and can enter deep regions of the lungs, rotenone’s
toxicity when inhaled may be increased. Acute local effects include
conjunctivitis, dermatitis, sore throat, congestion, and vomiting.
Inhalation of high doses can cause increased respiration followed by
depression and convulsions(27). On the basis of rabbit studies,
absorption through the intact skin is low(28).
Chronic effects
Studies on dogs at high doses produced adverse changes in blood
chemistry(29). In dogs fed rotenone at 10 mg/kg per day for six months,
weight loss and haematological effects were found. A No Observed Adverse
Effect Level (NOAEL) of 0.4 mg/kg per day has been determined for rats
(2-year study), and dogs (16-month study)(30). (Link
to source)
It needs to be mentioned here that Paraquat is, as is Rotenone,
classified by the WHO as being moderately hazardous (Class II).
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Posted
2006 04 22 |
