How to Prevent Toxoplasmosis

How to Prevent Toxoplasmosis

August 16, 2019 86 By Bertrand Dibbert


“How to Prevent Toxoplasmosis” The brain parasite toxoplasma
“is responsible for considerable disease and death in the United States.” It is the second leading
cause of foodborne-related death in the U.S., after Salmonella. It can invade through the placenta so can be especially
devastating during pregnancy, leading to miscarriages, or
blindness, or developmental delay. It can impair cognitive
function in adults too, which explains why
those who are infected appear to be at increased risk for getting
into things like traffic accidents. Multiple lines of evidence indicate
that chronic “toxo” infections “are likely associated with
certain psychiatric disorders”— it may even increase the
risk of developing leukemia. OK, OK, how do you prevent it? Well, the parasite can
get into the muscles; so, from food animals people can
get it through meat consumption, but in a non-food animal like a cat, you get infected through
contact with feces. Thankfully, in cats, the
“danger of infection exists only when the animal is actively
shedding [the parasite.]” They get it from eating infected rodents; and so, cats that are kept
indoors, that don’t hunt, and are not fed raw meat
shouldn’t pose a threat. Though if feral cats are turning your
local playground sandbox into a litter box, that could be a problem. As many as 6 percent of stray cats
or those with outdoor access may be actively infected at any one time. They only shed the parasite
for a few weeks, though; so, if you adopt a cat at a shelter,
it should be safe as long as they didn’t just come in. Many women have heard about the cat
connection but may be less aware about the risk of foodborne infection. “Only [about one in three] may
be aware that [toxoplasma] may be found in raw
or undercooked meat. Nevertheless, a high percentage of
women indicated that they do… [try to] practice good [hygiene]…
such as washing their hands after handling raw meat, gardening
[where cats may be pooping,] or changing cat litter.” What’s the riskiest type of meat? “Cattle are not considered
important hosts for [the parasite;]” it’s more pigs and poultry,
as well as sheep and goats. The prevalence of infection among
factory farmed pigs varies from 0 to over 90 percent,
though ironically, the likelihood of toxo infection
in organic meat may be higher because the animals
have outdoor access. Who undercooks pork
and poultry though? Surprisingly, about
one in three Americans may undercook meat across the board, in terms of reaching necessary
pathogen-killing temperatures, and a single slice of ham can end up with more than a thousand
parasites per slice. Current meat inspection at the
slaughterhouse can’t detect them. There are tests you can do, but
there is no widespread testing. The risk from a single serving
of meat, though, is really small. The average probability of
infection per serving of lamb, for example, was estimated
to be 1 in like 67,000. The reason there are 16 times the
number of cases attributed to pork is not because pigs are more infected; in the U.S. we just happen to eat a
lot more pork chops than lamb chops. Is there anything we can do if
we’re one of the approximately one in four Americans
already infected? Well, one of the problems with
having these parasites in our brain is accelerated cognitive
decline as we age. This study evaluated older adults
every year for five years, and the executive function of those
testing positive for toxoplasma seemed to drop quicker over time, as did a measure of their
overall mental status. Another thing that’s associated
with cognitive decline is reduced folate availability,
and the two may actually be related, as recent evidence suggests that
toxoplasma may harvest folate directly from our nerve cells,
sucking up folate from our brain. So, beyond dopamine production,
which is why we think toxo increases the
risk of schizophrenia, the parasite may be sucking
folate out of our brain. But enough to affect our
cognitive functioning? Perhaps so. Here’s a measure of cognitive function across a range of folate concentrations. Among those uninfected, it
doesn’t seem to matter whether they have lots of folate or little. They obviously have enough either way. But those who are infected have
worse scores at lower levels (higher is worse on this test). The same thing with vitamin B12. So, it’s important to get
enough B12 and folate. For B12, the official recommendation
is that all people aged 50 or over start taking a vitamin B12 supplement or eat vitamin B12- fortified
foods every day. And anyone on a plant-based diet should
start taking that advice at any age. And folate is found
concentrated in beans and greens. So, following my Daily
Dozen recommendations will get you more than
enough as, for example, a half cup of cooked lentils
gets you half the way there, as does three-quarters of
a cup of cooked spinach.