ENVELOPED RNA VIRUSES (POSITIVE SENSE) Flashcards
Under CORONAVIRIDAE
Coronavirus
Coronavirus
Reservoir
Immediate host
Transmission
Spectrum of disease
Reservoir: horseshoe bat
Immediate host: civet cat
Transmission: respiratory droplet
Spectrum of disease:
1. Common colds (2nd to rhinovirus)
2. SARS
3. MERS-COV
4. COVID-19
FLAVIVIRIDAE
Dengue virus
Hepatitis C virus (HCV)
Zika virus
Yellow virus
West Nile Virus
Dengue virus
Transmission
Spectrum of Disease
Diagnosis
Transmission: bite of female Aedes aegypti mosquito (A. albopictus)
Spectrum of Disease: Dengue fever Breakbone fever) and Dengue hemorrhagic fever
Diagnosis: NS1 antigen, RT-PCR, Dengue IgM and IgG, and CBC (platelet count)
Hepatitis C virus (HCV)
Transmission
IP
Spectrum of disease
Diagnosis
Treatment and Prevention
Transmission: (major) blood-borne, IV drug users; (minor) NSI, during birth and sexual
IP: 8 weeks
SD: Acute infection: milder than infection with HBV
- Hepatitis C resembles hepatitis B
- HCV infection also leads to significant autoimmune
reactions and extrahepatic manifestations
- HCV is the main cause of essential mixed cryoglobulinemia
Diagnosis: anti-HCV antibodies, recombinant immunoblot assay (RIBA) and PCR (HCV-RNA)
Treatment and Prevention:
1. Acute hepatitis C: Peginterferon alfa
2. Chronic hepatitis C: combination of Peginterferon alfa-2a and ribavirin
Zika virus
Transmission
Spectrum of disease
Complications
Treatment and prevention
Transmission: Aedes mosquito bites, sexual and vertical transmission (possible)
Spectrum of disease: conjunctivitis, low-grade fever, muscle and joint pain, headache, and photophobia.
Complications: microcephaly and Guillain-Barre syndrome
Treatment and prevention: supportive care
Yellow virus
Reservoir
Spectrum of disease
Diagnosis
Treatment and prevention
Reservoir: monkey or human
Spectrum of disease: characterized by jaundice and fever
- Prostration and shock occur, accompanied by upper gastrointestinal tract hemorrhage with hematemesis (“black vomit”)
Diagnosis: Councilman bodies (liver biopsy)
Treatment and prevention: mosquito control and vaccine (live, attenuated)
West Nile Virus
Transmission
Spectrum of disease
Transmission: bites of Culex mosquito
Spectrum of disease: encephalitis
is an acronym for arthropod-borne virus and highlights the fact that these viruses are transmitted by arthropods, primarily mosquitoes and ticks.
Arbovirus
Most arboviruses are classified in three families, namely,
togaviruses, flaviviruses, and bunyaviruses
TOGAVIRIDAE
Rubella virus
Rubella virus
Transmission
Spectrum of disease
Prevention
Transmission: respiratory droplets and transplacental
Spectrum of disease: RUBELLA / GERMAN MEASLES / 3-DAY MEASLES and CONGENITAL RUBELLA SYNDROME
Prevention: MMR vaccine
RUBELLA/ GERMAN MEASLES/ 3-DAY MEASLES
IP:
period of communicability
Prodome
Clinical significance:
Most characteristic clinical feature
Enanthem
Incubation period: 14-21 days
Period of communicability: 1 week before up to 1 week after the appearance of rash
> Prodrome: malaise, fever and anorexia for several days; may be accompanied by mild coryza and conjunctivitis (children may not have a prodrome)
Clinical Significance: Cephalocaudal appearance of maculopapular rash
- polyarthritis caused by immune complexes (especially in adult women)
Clinical feature: Postauricular lymphadenopathy
Enanthem: Forchheimer’s spots (petechiae on soft palate; not pathognomonic)
CONGENITAL RUBELLA SYNDROME
- Risk is greatest early in fetal development when cell differentiation is at a peak
- Rubivirus infected human embryo cells demonstrate
Body areas affected in congenital rubella include:
Heart:
Eye:
CNS:
- result of dermal extramedullary hematopoiesis
- first trimester
- chromosomal breakage and inhibition of mitosis.
Heart: patent ductus
Eye: cataracts
CNS: mental retardation, sensorineural deafness - “blueberry muffin” appearance
First disease
Other names for the disease
Etiology(ies)
Other names for the disease:
Rubeola
Measles
Hard measles
14-day measles
Morbilli
Etiology(ies)
Measles virus
