Fw: Possessed by Parasites

[Guest guest]

 

You learn from your mistakes...Today I hope not to learn_too_ much. 

Sent: Saturday, July 7, 2012 12:40 PM

Subject: Possessed by Parasites

Possessed by Parasites: a Twilight Zone Story

Schor, ND, FABNO

www.DenverNaturopathic.com

July 7, 2012

The news reports from early July that tell us infection with a common parasite

increases risk of suicide in women sound more like a science fiction plot than

science.    After all, the idea that a microorganism can take over our minds

and control what we do is only half a step removed from zombies and

vampires.    Yet the science is good and this story is for real: infection

with the parasite Toxoplasma gondii changes our thoughts, and for the worse.

The July issue of the Journal of Nervous & Mental Disease reported that women

infected with this parasite are more likely to hurt themselves or attempt

suicide.  Researchers had analyzed data from a group of 45,000 Danish mothers

who were part of an earlier study that had screened their newborns for this

infection.  About one quarter had tested positive. Over the next 11 to 14

years, the infected women were about 50% more likely to cut, burn, or otherwise

hurt themselves than uninfected women.  They were 80% more likely to attempt

suicide.

The disease called toxoplamosis, caused by this parasite Toxoplasma gondii, is

quite common; it is estimated that about one third of the world’s human

population is infected.

Toxoplasma gondii lives an odd life; it spends the first portion of its life

living in rats but to complete its lifecycle and reproduce it must live inside a

cat.  In fact the cat needs to eat the rat. This presents a challenge as rats

instinctively avoid cats, making the interspecies jump a challenge. Yet

according to researchers, although healthy rats shy away from even the odor of

cats, infected rats not only lose their wariness but are actually attracted to

cat fragrance.

Back in 2007 Stanford University researchers writing in the Proceedings of the

National Academy of Sciences explained how the parasite achieves this. When the

time is right, the parasites migrate into the rat’s brain, in particular the

amygdala, the part of the brain that controls conditioned responses and fear. 

The parasites are able to damage the amydala in such a way that all fear of cats

is erased, but other fears are left intact. The rats still avoid other hazards,

but not this particular feline one.

While Toxoplasmosis infection is generally thought to be asymptomatic in humans

there have been numerous reports going back all the way to the 1940s that it

impacts psychology.  This current study on suicide rates in infected women is

only one of a growing list.

If Toxoplasma can make a cat look attractive to a rat, how much could our own

thinking be the result of an infection influencing our thoughts?   

People infected with toxoplasmosis score themselves differently on

self-administered personality profiles than non-infected people do.   

Infected men seem more dogmatic, less trusting of others, less respectful of

rules and more jealous.  Some say they are more macho.  In contrast, infected

women are likely to be warm-hearted, easy going, conscientious, persistent

insecure and moralistic, have many friends and more romantic partners as well as

like to shop for clothes more than non-infected women. Infection reduces ability

to focus on a task, for example driving. 

The strongest association is between toxoplasmosis and schizophrenia and

suggests that infection may trigger schizophrenia in predisposed individuals

Then add in suicides. A 2011 study in Schizophrenia Research associated suicide

attempts with infection, increasing risk in younger patients by 59%. Four

separate studies have shown infection increases risk of traffic accidents.

Infected people are nearly three times more likely to crash their cars.  The

statistics in these studies suggest infections may indirectly contribute to

about one million deaths from traffic accidents a year.  Estimates suggest an

equal number of occupational injuries may also be caused.  This bug may be

having a bigger impact on our health than we might have guessed.

Infection is associated with a number of other problems. Mother’s of children

with Down’s syndrome are 2 ½ times as likely to be infected as women with

normal children.  Infection also appears to change sex ratios in populations

increasing the women to men ratio. The percentage of people infected decreases

with increasing age.  One troubling explanation for this is that it is caused

by the premature death of infected subjects.

While the effects of infection on mice and rats are spectacular, in humans they

are often more subtle.    In humans personality shifts occur and they

increase in intensity the longer the person has been infected.  Over time

people actually change in other ways. Infected men are taller.  Their fingers

get longer, particularly their fourth fingers of their left hands [i’m not

making this up]. 

The number of people infected by Toxoplasma varies widely in different parts of

the world.  In some areas, it is rare and in others almost everyone is

infected.  One researcher in particular, Lafferty, a scientist working

with the US Geological Survey, has reviewed and compared published data on

culture and personality from countries where data on Toxoplasma incidence is

available.    He has concluded that this microorganism has helped shape

human culture.  In a paper he presented in 2006 at the Royal Society in London,

Lafferty wrote,

“In populations where this parasite is very common, mass personality

modification could result in cultural change.  The geographic variation in the

latent prevalence of Toxoplasma gondii may explain a substantial proportion of

human population differences we see in cultural aspects that relate to ego,

money, material possessions, work, and rules. "    

Comparing the data, Lafferty concluded that, “….the parasite's subtle effect

on individual personality appears to alter the aggregate personality at the

population level.â€

Countries with high Toxoplasma levels have a higher aggregate neuroticism score,

and Western nations with high prevalence also scored higher in the " neurotic "

cultural dimensions of " masculine " sex roles and uncertainty avoidance.

" There could be a lot more to this story. Different responses to the parasite by

men and women could lead to many additional cultural effects that are, as yet,

difficult to analyze, "    

The February 2012 issue of Biology Letters reported an association between

infection and adult brain tumors, infected adults have an 80% higher risk.   

Rates of mortality due to brain cancer are higher in areas with higher incidence

of Toxoplasma infection. 

Climate affects how long Toxoplasma lasts in the environment and how many people

get infected. The parasite's eggs live longer in humid, low-altitude regions,

especially at mid latitudes where they do not freeze. Rates of infection vary

with cultural sanitation practices but especially with how many cats are around.

In many Mediterranean countries, feral cats are everywhere.  As I write this,

memories come back to me of watching cats with my daughter from an apartment

window in Jerusalem many years ago. At the time she was just learning to count

and we stood there counting cats out loud. They were everywhere.  I recall my

daughter counted upwards of 27 cats prowling the refuse cans in the back

courtyard.  A fair percentage of those cats were probably infected.  Not

surprisingly human rates of infection vary by where people live. An study

published in the Israeli Journal of Medical Science compared infection rates

between Arab villagers and Jewish kibbutzim.  On average, 22% of the kibbutz

members were infected compared to 58% of the villagers.  Infection rates of

both groups increased with age so that 43% of the kibbutz members over 60 years

old were infected and over 74% of the Arab villagers were infected by age 40. 

How does this stack up to the rest of the world?  About one quarter of the US

population tests positive for infection.    In northern Iran, infections

rates typically run at about 78-80%.    In Croatia they average about 36%. 

In Iceland, the infection rate is about 10%.    It can go as high as 50% in

parts of Sweden where evidence suggests that infection increases risk of

developing asthma.    In Mexico, 29% of schizophrenic patients in a

psychiatric hospital were infected compared to just 9% of a control group of

blood donors from the same area.

The seemingly suicidal feline attraction that infected rats experience can be

treated one of two ways.    Feeding the rat antibiotics that kill off the

parasite stop the behavior.  So do anti-psychotic drugs.      Gnaw on that

thought for a while.

How much of the seemingly irrational behavior we see in the nightly news is due

to a little parasite nibbling away at people’s brains?  One has to wonder.

Technically we have always been outnumbered in our own bodies. If we count

ourselves as the being comprised of cells sharing similar DNA from our parents,

then there are far more parasites, bacteria, fungi, and viruses that live within

our body than there are cells that belong to us. In fact, they outnumber

‘us’ nine to one.  We do not really want our bodies to operate as a

democracy where each entity gets a vote.  We would prefer to limit

decision-making power to cells that share our genes and share our own goal for

survival.

That doesn’t seem to always be the case though and Toxoplasma may be a case in

point. 

How much of the way we see the world results from a microscopic parasite bending

our thoughts to its own needs?  How many of our views and perceptions are some

other organism’s agenda masquerading as our own thoughts.  Perhaps most

importantly, how much of what appears to be irrational human behavior is the

result of these distorted thought processes? 

Thinking along these lines, one must wonder how many of the difficulties in

human interactions on both an individual, national and international level might

be better addressed through reducing parasitic infection rates?  While we

assume that the conflicts we see result from political, religious and

nationalist ideologies, perhaps what we are really seeing are the end results of

too many Toxoplasma eroding the amygdala of too many people? 

.................................................................

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