Parasites VI Flashcards
What is the TORCH complex?
classic organisms that can result in severe disease is transmitted mother to fetus
toxoplasma, treponema pallidum, rubella, cytomegalovirus, and herpes simplex 1 and 2.
What are some features of toxoplasmosis?
obligate intracellular protozoa
two forms: motiale tachyzoites (rapidly dividing) or bradyzoites in tissue cysts (slowly dividing)
What is the definitive host of toxoplasmosis?
cats
What happens following toxoplasmosis oocyte ingestion?
formation of tissue cysts filled with bradyzoites
What are the sings and symptoms of postnatal toxoplasmosis infection?
adults: typically asymptomatic, though can be a problem for the immunocompromised (brain abscesses, ecephalitis, disseminated disease)
ocular problems
What are the signs and symptoms of congenital toxoplasmosis infection?
chorioretinitis, cerebral cacifications, and hydrocephalus (get all three)
other signs: paralysis of upgaze (setting sun sign), convulsions, retinal scars, rash, hepatosplenomegaly, low birthweight, hearing loss
spontaneous abortion
How do you diagnose toxoplasmosis infection?
PCR analysis of amniotic fluid
post-birth: comparison of materal and fetal IgG reactivity or immunoabsorbant agglutination
treponema pallidum: general features
spirochete
poorly staining
vertiacl transmission in untreated mothers nearly 100%
signs/symptoms of postnatal tremonema pallidum infection
primary syphilis: chancre- painless
secondary- maculopapular rash on palms/soles
tertiary- CNS involvement, gummas, CV involvement
signs and symptoms of congential treponema pallidum infection?
fetal/perinatal death common
cuvred tibia, saddle nose deformities, hutchinson teeth (notched incisors), mulberry molars, olympia brow, painful jts
juvenile paresis, sensorineural deafness
potental for blindness, rash, condyloma lata (wart like lesions)
snuffling, hemolytic anemia
How do you diagnose treponema pallidum infection?
VDRL and RPR- false positives, but become negative when infection clears
or, TPHA (agglutination assay), FTA-ABS, and TPPA- more specific but remain positive with treatment
Rubella: general features
enveloped ssRNA
togavirus
very low incidence due to immunization
transmitted by respiratory droplets
rubella signs and symptoms of postnatal infection
non-specific- low grade fever, lymapdenopathy, headache, fatigue, coalescing rash on the face/neck that migrates downward
What are the signs and symptoms of congenital rubella?
almost all organ systems can be affected. triad: congenital heard disease, cataracts, and deafness. blueberry muffin rash
rubella diagnosis
IgM assay or PCR on kid
monitor mom for seroconversion if she is exposed
cytomegalovirus general features
enveloped dsDNA, herpes family
high prevalence: direct contact transmission
signs and symptoms of congenital CMV infection
;greatest risk if mom has primary infection during pregnancy
can cause microcephaly, intercranial cacifications, chorioretinitis, and sensorineural hearing loss.
some get inclusion disease- jaundice, hepatomegaly, coagulopathy, prematurity, growth restriction
how do you diagnose CMV infection?
viral culture or PCR
HSV 1 and 2: general features
enveloped dsDNA virus
common
What are the signs and symptoms of HSV postnatal infection/
painful vesicular rash. most severe with primary infection. also cause dysuria, headache, and fever
Signs and symptoms of neonatal HSV infection
usually transmitted during vaginal birth process (transplacental transmission very rare and usually leads to spontaneous abortion, premature deliver, intrauterine growth restriction)
can begin as vescicular lesions and progress to encephalitis and or disseminated disease. mortality of disseminated disease 90% if untreated
How do you diagnose HSV?
viral culture is gold standard
PCRalso used
start acyclovir based on clinical suspicion because disease is serious- 90% mortality to baby if untreated.
