viral infections of the bone, muscle joints II Flashcards
smallpox symptoms
- abrupt onset of high fever >101 F
- malaise, headache, muscle pain, nausea
- lesions- starts in mouth and then goes thru to skin- face and extremities (centrifugal distribution)
- COMMON TO HAVE PALMS OF HANDS AND SOLES OF FEET INFECTED(DIFFERENT FROM CHICKENPOX)
- SYNCHRONOUS EVOLUTION OF LESIONS -UNLIKE CHICKEN POX THAT VARY
Evolution of small pox
starts as macule and then turns into a pustule and then scabs over
what causes smallpox
- variola virus
- poxiviridae
- large dsDNA
- REPLICATES IN THE CYTOPLASM (like moluscum contageosum)
- USES A LOT OF ITS OWN ENZYMES FOR REPLICATION
- STRICLY HUMAN VIRUS
transmission of smallpox
- fomites, contact with lesions, rarely spread aerosol
- individuals are virulent until scabs fall off
what does variola/smallpox cause
- bacterial infection of the skin
- arthritis
- encephalitis
- respiratory tract infection
- fatality of 30%
- hemorrhagic and flat forms of smallpox
small pox vaccine
- NOT LIVE-ATTENTUATED
- IT IS THE LIVE STRAIN OF VACCINIA VIRUS (another member of the poxiviridae family) THAT ALLOW CROSS PROTECTION FOR SMALLPOX
- Vaccine stopped in 1972
how are smallpox and chicken pox distinguished?
- smallpox has centrifugal infection - infection on outter extremities- lesions on hands and feet, lesions all in same phase
- chicken- has centripetal infection- infection of core- no lesions on hands and feet, has crops of lesions meaning many lesions in different phases
what sort of prophylaxis is available for postexposure to small pox
- vaccine within 3 days- prevent or significantly lessen disease outcome
- vaccination at 4-7 days- partial exposure or lessening disease
progress of disease of measles
- prodrome for 2-4 that include fever and 3 C’s:
cough, coryza (runny nose), conjunctivitis **
-also have KOPLIKS SPOTS IN MOUTH = MEASLES
-rash for 5-6 days that starts at the scalp and spreads down
-anorexia, diarrhea, lymphadenopathy
what is measles virus?
- ssRNA
- enveloped
- F gene important for FUSION
- HA PROTEIN IMPORTANT FOR ATTACHMENT
- one antigenic type
measles transmission
- respiratory- can last up to 2 hrs in the air
- shed in nasopharynx from prodrome to 4 days out
- HIGHLY CONTAGIOUS
- Incubation is 10-12 days
diagnosis of measles
- koplicks spots- rash in mouth lasting more than 3 days- white spots with red boarder
- confirm with lab
when an adult gets measles, what is it usually a result of? a kid?
adult- due to measles virus
kid- usually due to bacterial superinfection
complications of measles
- diarrhea, otitis media, pneumonia, encephalitis, seizures and death
how are measles prevented?
- IG within 6 days following exposure
what qualifies for resistance for measles
- document receipt of 2 doses of live measles vaccine
- lab evidence of immunity
- documentation from a doc verifying you had it
- born before 1957-assumed anyone got it that time
measles vaccine
vaccine schedule
-live attenuated
-prepared in chick embryo fibroblasts
- combined with Mumps and rubella
-schedule: kids- at 12-15 months and adults whenever traveling or post HS or health care worker
those born after 1957- one dose
german measles
- maculopapular rash that looks like measles but FAINTER
- DOES NOT COALESCE
- prodrome- fever, lymphadenopathy, URT symptoms
- sometimes associated with arthralgia or ARTHRITIS
what are german measles caused by?
-caused by infection of rubella virus
Congenital rubella syndrome
- obtained when mom has rubella
- baby has DEAFNESS AND CATARACTS, CHF, retinopathy
- purpura- hepatomegaly, jaundice, microcephaly, meningoencephalitis, radiolucent bone disease
rubella virus
- togaviridae fam
enveloped - RNA genome
how is rubella transmitted
- respiratory route and primary replication in nasopharynx and regional lymph nodes
- viremia 5-7 days post infection
- time for infection to rash is 2 weeks
rubella vaccine
- live attenuated
- grown in tissue culture cells
fifth disease/erythema infectiosusm
- slap cheeks
- fever
- characteristic rash that begins at cheeks and goes to hands
- caused by B19 parvovirus
what is B19 parvovirus
-causes fifth disease
- ssDNA
-grows only in mitotic cells
utilizes host enzymes for genome transcription and replication
at does B19- fifth disease cause in terms of symptoms
- fever, rash in LACELIKE PATTERN
- usually self resolves in 2 wks
- 50% of people are serotype pos
- GROWS IN HEMATOPOETIC CELLS IN BONE MARROW
When can B-19 virus be a problem?
- with patients who are always anemic- sickle cell people- can cause aplastic ctisis
- it can cause arthritis
- pregnancy complications and increase of CHF and hydrops fetalis (swelling of fetus)
roseola infantum
-caused by herpes virus 6- dsDNA present in almost everyone
herpes virus 6- replicates in T and B cells
-high fever that last 4 days FOLLOWED by rash that last 24-48 hrs
-*characteristic timing
-
herpes virus 7
-replicates in CD4 T cells
- present in saliva of approx. 75% of adults
infection occurs after HSV6
