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Measles
Micro WQ18 Exam 6 (Rubella =
German Measles
Incubation period…
Measles
Micro WQ18 Exam 6
Classic Measles =
Rubeola
- Incubation period: 10-14 days
- Formation of infected cell syncytia (giant cells)
--> allow for direct cell-to-cell infection
- Multiplication in respiratory epithelium + lymph nodes + urinary tract + blood vessels + CNS
- Viremia, dissemination via monocytes
- Immune system antibody not FULLY protective
Symptoms:
- Prodromal stage (1-12 days post infection)
- High fever
- Coryza, persistant cough, conjunctivitis (3 C's)
- KOPLIK'S SPOTS - buccal mucosa (BEFORE THE RASH (2-3 days) đź‘„
- Rash (3-4 days after initiation of prodrome)
- HIGHEST fever
- Begins below ears --> spreads over forehead + face --> extends down to neck, trunk, extremities in 3 days
- Resolution
- Rise in antibody titers = viremia stops
- Rash fades in same order it appears
-
:pill: Treatment:
- Supportive care
- No antivirals
- Vitamin A supplementation
Prevention:
- MMR vaccine (live attenuated), 2 administrations
- 12-15 months = 1st fose
- 4-6 years = 2nd dose
- BayGam immunoglobulin if within 6 days of exposure to prevent/limit disease (unvaccinated or immunocompromised patients)
Contraindications:
- Egg/neomycin sensitivity
- Pregnancy
- Immunocompromise (Cancer)
Complications:
- PNEUMONIA = life threatening
- Diarrhea
- CNS attack = acute symptomatic encephalitis
- Subacute Sclerosing Panencephalitis
- Immunosuppression (altered lymphokine production, decreased oxygen radicals/neutrophil chemotaxis, DTH suppression, TB exacerbation)
-
Paroxymyxovirus
- ssRNA (-): brings in RNA polymerase
- Enveloped
- NON- SEGMENTED
(decreased variability)
- Expresses F proteins - infection spread
Expresses H protein -
hemagglutinin for attachment to host cell
CHILDREN
- Spring, low humidity
- Human ONLY reservoir
- Heavily popular areas at risk
- Vitamin A deficiency can make it worse
Transmission:
Respiratory droplets
Patient communicable until 4-5 days after rash errupts
- MAX infectiousness = late prodrome: coughing + sneezing
Diagnosis:
- Rash + KOPLIK'S SPOT
- IgM ELISA
- Serology = 4x titer increase
- FA test (swab of pharynx, nasal, buccal)
- MULTINUCLEATED GIANT CELLS
Atypical Measles
- Patients who received formalin-inactivated vaccine --> later exposed to virus
- Denatured viral F proteins --> patients did not develop anti-F antibodies --> sensitized to viral infection
- Antibody would BIND but NOT NEUTRALIZE
Symptoms:
- UNUSUAL rash on palms/soles with centripetal spread
Rubella =
German Measles
- Incubation period: 14-21 days
Symptoms:
- Prodromal stage
MINIMAL prodromal symptoms
- Mild fever
- Malaise
- Conjunctivitis, coryza
- Lymphadenopathy
- Rash
Maculopapular rash appears first on face --> spread downward
- Confused with scarlet fever
:pill: Treatment/Prevention:
- Supportive care
- Isolated hospitalized patients - 7 days
- Exclude children from school - 7 days
Togavirus
- ssRNA (+)
- Enveloped
- SMALL
Transmission:
Respiratory droplets
- Not as contagious as classic
OLDER kids (5-9 yo), adolescents, young adults
- Spring
- Human ONLY reservoir
Patient communicable 5 days prior to 5 days after rash appears
- Need: close + prolonged contact
Congenital Rubella Syndrome (CRS):
Maternal infection (viremia) --> placental infection --> fetal infection
- ESPECIALLY 1ST TRIMESTER (50% risk)
Symptoms:
- Cardiac defects - pulmonary artery stenosis, PDA
- Eye defects - CATARACTS, glaucoma
- Hearing loss
- CNS involvement
-
-
Diagnosis:
- Serology
- IgM - 4x titer increase