North American Fruit Explorers mailing list at ibiblio

[Mauch1@aol.com]

>The disease that is dangerous to the human fetus is 
>toxoplasmosis. There 
>is a lot more of this organism around than most people 
>realize, Many 
>people have had it and don't know it (I've heard, from vets 
>and doctors, 
>estimates of twenty to fifty percent of the human 
>population). My 
>medical encyclopedia says that the most common way for humans 
>to catch 
>it is by eating undercooked meat from an infected animal. I 
>believe you 
>can also catch it from contact with soil containing the 
>organism. You 
>can also get it from contact with feces from an infected cat. 
>If you've 
>had it once I don't think you can get it again. Usually there 
>are no 
>symptoms, or symptoms are minor and mistaken for a cold or 
>flu. If a 
>woman catches it during early pregnancy it can cause serious 
>damage to 
>the fetus, which is why pregnant women should not handle cat 
>pans. In 
>very rare cases it can turn into a serious illness otherwise. 
>Your 
>chances of getting into serious trouble with toxoplasmosis, 
>whether or 
>not you keep cats, are a lot lower than of getting into 
>serious trouble 
>with a car accident.

Text from a link from the CDC provided by Joe Hecksel last month:

Rats are intermediate hosts for another parasite, a single-celled, protozoan 
called Toxoplasma gondii. T. gondii begins and ends its life cycle in 
domestic cats. The immune response that cats mount against this parasite 
forces the parasite into very tough cysts that are shed in cats’ feces. The 
cysts survive in soil for years waiting for an intermediate host, a rat, to 
eat them. Inside the rats, T. gondii resumes its life cycle. The ultimate 
goal of the parasite is to complete the cycle by returning to its primary 
host, the cat. Cats do not have a great fondness for dead animals. So T. 
gondii doesn’t kill its rodent host. But rats have a general fear of cats and 
avoid the scent (and urine) of cats at all costs, which slows the 
transmission of T. gondii. To overcome this bottleneck, the parasite has 
learned to make rats crazy. Rats infected with T. gondii show no fear of cat 
urine. This is not because they have no sense of smell, because some of these 
rats develop an attraction—an often fatal attraction—to cat urine. They go 
mad and seem to invite their own deaths. Again, no dysfunctional family, 
birth defect, or blow to the head made these animals crazy. This madness has 
an infectious cause.

T. gondii infects people too. Gardening in cyst-infested soil, handling 
infected meat, or emptying litter boxes used by infected cats can result in 
infection. In fact, nearly half the people in this world have T. gondii cysts 
in the brain. T. gondii has never figured out a way to make humans palatable 
to cats, but that doesn’t mean people are unaffected by the parasite. In 
psychological tests, women with T. gondii cysts in the brain were more 
outgoing and warm-hearted than uninfected controls, and men infected with the 
parasite were more jealous and suspicious than uninfected men—behavior with a 
twist, a protozoan twist.


Chris Mauchline
SE PA, zone 6
40° 5' N    75° 51'W
~650 ft elevation