hey everyone and this is where I'm talking about toxoplasmosis
toxoplasmosis is caused by an infection with the protozoa species known as
Toxoplasma gondii what i want you to take from this is it is a protozoa
species that's causing the infection and it is an obligate intracellular parasite
here is a picture of that protozoa species now Toxoplasma gondii has a
worldwide distribution. cats and livestock act as hosts for this
protozoa and mice act as intermediate hosts now there are several different
sources by which a person can be infected with this protozoa
one is through cat feces so in this source or in this transmission the
person gets exposed to the Toxoplasma oocysts the second source is through
undercooked meat and in that source is the tissue cysts there's also horizontal
transmission this can include through organ
transplant or a blood transfusion from an infected person in the fourth source
is vertical transmission from mother to child and this leads to something known
as congenital toxoplasmosis we'll talk more about this in the next few slides
but what I want you to take from these sources is that the first three sources
lead to what is known as acquired toxoplasmosis and the fourth leads to
congenital toxoplasmosis and we're going to talk about the differences between
acquired and congenital a little later on so as we mentioned before the hosts
include cats and livestock and humans can be infected from cats through fecal
oases and humans can be infected from livestock through undercooked meat
ingesting tissue cysts so again the sources are cat feces with
fecal oases and undercooked meat with tissue cysts so when someone ingests
either fecal oocysts and or tissue cysts they transform into
what is known as tacky so White's shortly after ingestion these tackies
all whites then enter the muscle and neural tissues of the individual and
become a bright as a white cyst now what is most concerning is that in a
pregnant woman who is exposed to cysts these tackies all whites can pass
through the placenta and infect the developing fetus leading to what we call
congenital toxoplasmosis so what is the clinical presentation of toxoplasmosis
we're gonna first talk about congenital toxoplasmosis and congenital
toxoplasmosis has a classic triad of three signs and symptoms we're going to
use a mnemonic device c-h-i or Chi like the energy force Chi or you can use hick
HIC as in hiccup which ever helps you remember these three signs and symptoms
the first one is chorioretinitis, the second one is hydrocephalus and the
third one is intracranial calcifications so the classic triad again is chorioretinitis
, hydrocephalus and intracranial calcifications congenital toxoplasmosis
can also lead to microcephaly and in Toxoplasma or toxoplasmosis is actually
one of the TORCH infections that you might have learned about before the T in
torch is actually toxoplasmosis and this is one of the infections that leads to
an intrauterine growth restriction generally during pregnancy the woman
will actually be infected with Toxoplasma in the third trimester
however can happen at any trimester and being in fact
in the first trimester leads to worse outcomes for the infant and when we mean
or when we talk about infection during pregnancy we actually mean primary
infection if a woman has actually been infected prior to pregnancy
they have already either clear the infection or have suppressed the
infection and it is not a concern it is more of a concern when this is the first
time a woman has been infected with Toxoplasma so if the first time a woman
is infected with Toxoplasma is during their pregnancy with their child that is
when we get concerned so the primary infection is actually what we worry
about now this is all in contrast to acquired toxoplasmosis acquired
toxoplasmosis is generally asymptomatic it can be latent so it can basically be
in a suppressed form and have no symptoms at all but the person is still
infected with Toxoplasma it can persist for the life of the person and generally
immunosuppression can lead to reactivation so when a person is
severely immunosuppressed as in aids this can lead to in reactivation of
Toxoplasma leading to toxoplasmosis and it can lead to an acute systemic
infection we're going to talk about more about these symptoms of acquired
toxoplasmosis in the next slide with acquired toxoplasmosis there are a wide
variety of signs and symptoms that we can see with an individual that is
infected with Toxoplasma one is again this acute systemic infection this acute
systemic infection generally occurs at five to 23 days after an infection
it can occur in immunocompetent individuals most of the time it's
asymptomatic but some individuals can have symptoms those who do develop
symptoms have a benign and generally self-limited course that lasts for a few
weeks to months cervical lymph adenopathy is the most common symptom in
acquired toxoplasmosis it is a bilateral and symmetrical non tender lymph
adenopathy of the neck this usually happens within weeks of infection a
subset of individuals about 20 to 30 percent will have generalized
lymphadenopathy and there can also be constitutional
symptoms such as fever chills and sweats and this usually occurs for two to three
days other symptoms of acquired toxoplasmosis can include headaches
myalgias, pharyngitis, hepatosplenomegaly so an enlargement of the liver and
spleen and in rare cases toxoplasmosis can lead to pneumonitis myocarditis and
pericarditis so myocarditis is the inflammation of
the cardiac muscle and pericarditis is an inflammation of the pericardium that
surrounds the heart you can also lead to polymyositis hepatitis and sefa lightest
or a posterior uveitis and having said all of this again
majority of immunocompetent individuals are asymptomatic for toxoplasmosis but
in some individuals we can see some of these symptoms and especially in those
with a reactivation due to immunosuppression so how do we diagnose
and what do we use to treat toxoplasmosis for diagnosis we use
serology looking for antibodies to Toxoplasma gondii with CSF we can do a
Wright-Giemsa sustain and we can use PCR to look for genetic evidence of Toxoplasma
gondii i an immune compromised patients the patients we worry about the most for
either symptomatic toxoplasmosis or a reactivation of toxoplasmosis we can do
a head CT scan and we can do up to Lyme up thermo logical examinations and how
do we treat it what do we use to treat toxoplasmosis again because oftentimes
this is a benign self-limited infection and a lot of times individuals are
asymptomatic we often do not require a treatment for toxoplasmosis however
there are special considerations during pregnancy we would like to use
Spira Meissen or para methylene in sulfadiazine for HIV patients we can
also use pure methylene and sulfadiazine as well in 4i disease related to
toxoplasmosis we can use cortical steroids so anyways guys I hope you
found this lesson helpful that was a lesson on toxoplasmosis and looking at
the differences between acquired and congenital toxoplasmosis I hope you
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lessons like this one and it's always think is much for watching and I'll see
you next time