Prenatal Infx Flashcards
Listeria Monocytogenes
Prenatal Infx • Short, *Gram+ rods • Weak *β-hemolysis on blood agar • *Catalase+ • *CAMP+ • "tumbling motility” • *Actin Comet Tails • *Facultative intracellular pathogen - found in soil & decaying vegetable matter, dust, numerous human food products, animal feed, water, sewage & GI tract of animals & occasionally humans Virulence - *Internalin - *listeriolysin O (LLO) - *ActA Manifestations - causes listerosis • Pregnant women: flu-like symptoms,miscarriage, stillbirth, premature delivery or life-threatening neonatal meningitis or meningoencephalitis with septicemia Transmission • Consumption of contaminated food • Transmitted in utero from mother to fetus due to bacteremia.
Parvovirus B19
Prenatal Infx
• *Single-stranded, linear DNA genome
• Replicates in the nucleus
• Icosahedral
• Naked (non-enveloped)
• Small (18-26 nm)
• transmission via fomites)
Disease Manifestations
• Erythema infectious
o Fifth disease (fifth childhood exam)
o “Slapped cheek” syndrome
• Fetal death or non-immune hydrops fettles
o Edema of the fetus (large placenta.)
• Transient aplastic crisis or chronic anemia
Transmission
•Infects primarily *erythroblasts; uses blood *group P antigen (globoside) as receptor
• Respiratory secretions
• Congenitally (via transplacental transmission)
• Blood transfusion
• Fomites (because non-enveloped virus)
Rubella
Prenatal Infx
• Single-stranded, positive-sense linear RNA genome
• Replicates in the cytoplasm
• Icosahedral
• Enveloped, spherical (sensitive to environment)
• Medium (65-70 nm)
• Includes Rubella virus, Chikungunya virus
Disease Manifestations
• German measles (adult/child)
o Rash is milder than measles; “three-day measles”
• Congenital Rubella Syndrome (CRS)
o Microcephaly, heart defects, cataracts, deafness, “blueberry muffin” skin lesions
Toxoplasma Gondii
Prenatal Infx
• Sporozoan (apicomplexa),
• uses “gliding motility”
• Obligate intracellular parasite
• Alternating cycles of sexual & asexual reproduction
• Felines are the definitive host (sexual reproduction)
• Humans as well as virtually all warm-blooded animals are intermediate hosts (asexual reproduction)(*tachyzoites )
Disease Manifestations
• Pregnant women:
o Miscarriage, stillbirth
o Congenital toxoplasmosis (chorioretinitis, hydrocephalus, intracranial calcifications
Treponema Pallidum
Prenatal Infx
• Pathogenic spirochetes
Disease Manifestations
• Primary = Smooth painless genital sore (chancre)
• Secondary = Rash on palms/sole, flu like symptoms, and painless highly infectious condyloma latum .
• Tertiary = Neurosyphyllis, Cardiovascular syphilis, and gummas (rubbery lesion)
o Note: latency period between secondary and tertiary where there are no symptoms.
• Congenital (also has several different stages)
o Late term miscarriage or stillbirth
o Early & late manifestations
o “Hutchinson triad”
• Deafness
• Impaired vision
• Notched incisors
Transmission:
• Strict human pathogen transmitted by sexual contact or congenitally
• *IgM: can be detected during primary and secondary syphilis
• *VDRL/RPR
Cytomegalovirus (CMV)
Prenatal Infx • Double-stranded, linear DNA genome • Replicate in the nucleus • Icosahedral • Enveloped, spherical to pleomorphic • Large (150-200 nm) • Can code for their own DNA polymerase (anti-viral target) • *Tegument: viral and cellular proteins that they carry with them • Latency established in monocytes/macrophages, and in endothelial cells Disease Manifestations • Congenital CMV o petechial rash, microcephaly, and jaundice Labs o Nuclear inclusions = “owl’s eye” o Perinuclear cytoplasmic inclusions o Enlargement of the cell = “cytomegaly”
