The definitive host of T gondii is the
house cat and certain other felidae.
domestic cats are a source of
toxoplasmosis because oocysts are often present in their feces.
Accidental ingestion of oocysts by humans and animals including the cat
produces a proliferative infection in their body tissues.
Fecal contamination of food and water, soiled hands, inadequately cooked or infected meat and raw milk can be major
source of human infection
All mammals including humans can transmit the infection
Transplacelta trasmission usually takes place in the course of an
acute but innaparent or undiagnosed maternal infection
New evidence indicates that the number of infants born in the US each year
with congenital T gondii infection is considerably higher then the 3000 previously estimated.
Congenital toxoplasmosis can result in
CNS malformation, prenatal mortality
in infants who are serologically positive at birth many fail to display
generalized illness at birth
Toxoplasmosis acquired in utero can result in
blindness, encephalomyelitis, mental retardation, convulsions and death in infected neonates.
in as many as 75% of congenitally infected newborns not serologically diagnosed at birth, the disease remains
format, only to become be discovered when other symptoms become apparent such as choriorentitis, unilateral blindness and severe neurologic sequelae
The best evidence for current infection is a significant
change in two appropriately timed specimens
(paired acute and convalescent specimens)
and when both tests are down in the same laboratory at the same time
The diagnosis of toxoplasmosis can be established by
serologic tests, polymerase chain reaction
indirect fluorescnet antibody
isolation of organism.
Many consider enzyme-linked immunosorbent assay (elisa) to be the method of choice for the detection
of IgM antibodies in toxoplasmosis
Any positive result in pregnant patient confirmed as positive by a
second reference laboratory should be evaluated by amniocentesis and PCR testing for T gondii
A negative result result does n
not rule out the presence of PCR inhibitors in the patient specimen of T gondii DNA concentrations below the level of detection of the assay.
PCR amplification is used to
detect T gondii DNA in body fluids and tissues
PCR can be used to detect the presence of absence of
T gondii DNA in fresh or frozen biopsy tissue CFS , amniotic fluid, serum, plasma