From: wentzell@ace.acadiau.ca (LEEANN WENTZELL)
Date: Tue, 30 Mar 1993 15:34:39 GMT
Newsgroups: sci.med
Subject: Toxoplasmosis

>From: sude@isoit109.BBN.HP.COM (#Susanne Denninger)
>Date: Mon, 29 Mar 1993 06:45:18 GMT
>Since I haven't received any responses last time, I'm posting this again.
>Nobody out there knowledgeable about this desease ?

>Since I read a quite frightening article on Toxoplasmosis recently,
>I'd like to have more info on that desease :

>1. How dangerous is it ? From whom is it especially dangerous ?

>2. How is it transmitted (I read about raw meat and cats, but I'd like to
>   have more details) ?

>3. What can be done to prevent infection ?

>4. What are the symptoms and long-term effects ?

>5. What treatments are availble ?

>Susanne Denninger

What I know I found out after a friend of my miscarried because of
this.  Toxoplasmosis is a small parasite which lives apparently
harmlessly in the GI tract of cats. It can be transmitted through the
feces to humans, where again it appears to be harmless and usually
undetected, unless the human host is a pregnant woman. The parasite
will attack the fetus, usually leading to spontaneous abortion early
in the pregnancy. My friend, who has three cats, found out after her
miscarriage that she had this, through a blood test. She was advised
to wait to become pregnant again until after her system cleared of the
infection. This took, in her case, almost five years.  She has since
delivered two healthy babies, but she no longer changes the litter box
for the cats.

What surprises me is how few people know about this problem. I have
many friends with cats who are pregnant or planning to be, yet have no
clue.  Shouldn't some literature be made available at the vets'?

Standard Disclaimer: My knowledge of this is from about 7 years ago,
so I might be a little off on the monor details. A good parasitology
text should provide you with accurate info.


Lee Ann Wentzell        "Her ego wrote out cheques incredibly fast
Biology Department       But her personality didn't have the cash..."
Acadia University                         The Northern Pikes
Wolfville, NS, CAN

From: barkdoll@lepomis.psych.upenn.edu (Edwin Barkdoll)
Date: 30 Mar 93 22:50:58 GMT

Susanne Denninger writes:
>[...]
>1. How dangerous is it ? From whom is it especially dangerous ?

        Not very unless you happen to be an unborn fetus or
immunosuppressed.

>2. How is it transmitted (I read about raw meat and cats, but I'd like to
>   have more details) ?

        Cats are the definitive hosts (Toxoplasma can complete its
sexual cycle in cats, not in you, cows...).  Briefly egg-like oocysts
are passed in the feces of in infected _oocyst-shedding-cat_.  These
oocysts are NOT infective immediately but require 2-3 days before they
become infective.  In other words, fresh cat feces are not infective.
If fecal material containing infective oocysts is eaten the oocysts
"hatches" releasing the next stages which can migrate to various sites
in the body -- brain, eye, fetus, muscle, etc.  Although teh sexual
cycle does not occur in animals other than the cat, infected tissue
(meat) from nondefinitive hosts is infective.  The actual infectious
stage tho is different depending upon whether you are infected by
ingesting cat feces or raw/undercooked meat.  Cats themselves usually
get it from predation or eating uncooked meat from some other source.

        BTW, the majority of cats have + titers to Toxoplasma,
however, cats are in general infective only for a short time post
infection, about 1-2 weeks after which time they are rather resistant
to reinfection.  In other words most cats have been exposed but very
few are shedding oocysts at any one time.  If you eliminate your
contact with 2-3 day old cat feces the chance that you will get it
from a cat is nil.

>3. What can be done to prevent infection ?

        Cooking and freezing (!) meat is said to kill Toxoplasma.
        Do not feed raw meat to cats.
        Clean the litter box DAILY.
        Always wear gloves when gardening (your garden is just one big
litter box to the neighborhood cats).
        If you are pregnant get your husband/lover etc to clean ou the
litter box DAILY.

>4. What are the symptoms and long-term effects ?

        Most infections in immunocompetent humans are asymptomatic.
My parasitology book states that in certain areas up to 25% may have +
titers.  Same source say that the majority of congenital infections
are also without signs, although more serious consequences result when
infection is early in the pregnancy.  Possible consequences include
abortion, stillbirths, nervous system damage, visual abnormalities.

--
Edwin Barkdoll
barkdoll@lepomis.psych.upenn.edu
eb3@world.std.com

From: richard@woof.demon.co.uk (richard wheeler)
Date: Wed, 31 Mar 1993 12:10:00 +0000

In answer to your questions re TOXOPLASMOSIS: The following was told
to me last night by my wife who is a vet. Any mistakes are due to my
lack of understanding of what she told me.

1)      Toxoplasmais only seriusly dangerous to certain categories of
people such as pregnant women due to the effects that transplacental
transmission can have on the foetus, and immunodeficient or
immunocompromised patients such as AIDS sufferers. The rest of us
suffer temporary signs such as malais, fatigue, headaches, myalgia and
lympadenopathy which disappears once our immune system has got its act
together.

2)      It is transmitted in humans by ingesting infected
oocysts(eggs) usually from infected meat but also from infected faecal
matierial. In humans and other intermediate hosts it can only multiply
asexually and this causes inflamation and reactive changes in various
parts of the body but importantly, in the placenta. The cat ( and
other members of the felidae) is the only definitve host in which the
sexual phase of the toxoplasma life cycle can occur and it multiplies
in the small intestine producing male and female cells which are
excreted as fertilized oocysts. The oocyst is not infective for 2 to 4
days but after this time it can remain viable in the ground for up tp
18 months in the form of sporozoites - there are 8 of these in each
oocyst. The cat only sheds oocysts until its own immunity to the
protozoan parasite develops or , rarely afterwards, if its immune
system is depressed or gastrointestinal infections allow it to
proliferate again.

3)      Prevention of infection is mainly common sense and hygiene.
Direct contact with the cat has not been implicated as a mode of
transmission although infection can occur indirectly. Don't eat raw or
undercooked meat. Don't touch catlitter trays if pregnant. Wash hands,
implements and surfaces after handling uncooked meat(freezing meat
kills most cysts). Cover sand pits. Wash fruit and veg. Wear gloves
when gardening.  Wash hans after handling animals.

4)      Symptoms have been mentioned earlier however the most serious
aspect is in the effects of transplacental retardation and
chorioretinit is in children. There is a controversial view that it
might be advantageous for women to be exposed to the parasite early in
life so as to develop immunity before becoming pregnant.

5)      Treatment in humans is usually by chemotherapy i.e. antibiosis.

As an addendum it is not good to destroy all cats to control
toxoplasmos but better to encourage responsible cat ownership such as
not feeding uncooked meat to cats and preventing cats from hunting
where practical; and to employ simple hygiene.

I do not accept responsiblity if the above is incorrect. I am not a
vet!  It also affects sheep but that is another story.

--
From: jcb (Jim Becker)
Date: 1 Apr 93 01:27:16 GMT


   Subject:  Re: Toxoplasmosis
   From: barkdoll@lepomis.psych.upenn.edu (Edwin Barkdoll)
   Sender: news@netnews.upenn.edu

   In article  sude@isoit109.BBN.HP.COM (#Susanne Denninger) writes:
   >[...]
   >1. How dangerous is it ? From whom is it especially dangerous ?

        Not very unless you happen to be an unborn fetus or
   immunosuppressed.

i had a pretty terrible time with toxoplasmosis back in 1975 when i
contracted it. (probably from an undercooked hot dog).

at that point in time, they didn't know what it was. at least my
doctor. i spent some time in the hospital, seemingly close to death.
after release, it took about eight months before i was back in terms
of strength and coloration.

don't think i was immunosuppressed, as generally i'm resilient to
problems. correct diagnosis certainly would have helped.

-jim