Measles virus overview, Schemes and Mind Maps of Microbiology

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MEASLES VIRUS

OVERVIEW

TAXONOMY, STRUCTURE,

PATHOGENESIS, DIAGNOSIS,

TREATMENT, AND PREVENTION

Family: Paramyxoviridae

TAXONOMY

Family,Genus,Species Genus: Morbillivirus Species: Measles virus

Carries RNA- dependent RNA polymerase cDirect cell-to-cell fusion → syncytia Replication in the cytoplasm (not in the nucleus) PHYSIOLOGY Cell lysis releases new virions

PATHOGENICITY FACTORS

H protein → binds to CD150/SLAM receptors F protein → promotes entry and syncytia formation Causes immunosuppression Facilitates secondary bacterial infections

Highly contagious: R₀ = 12– 18 No surface or food transmission Airborne: respiratory droplets/aerosol TRANSMISSION Incubation: 10 – 12 days Contagious: 4 days before to 4 days after rash

Upper respiratory tract Lymphoid tissues & bloodstream Skin Eyes CNS Immune system initial infection viremia rash conjunctivitis encephalit is, SSPE immunosuppr ession ORGANS AFFECTED wich organs are affected by measles?

Specimens: nasopharyngeal swab, blood, urine RT-PCR: viral RNA detection ELISA IgM: recent infection ELISA IgG: past infection/vaccination Viral culture: Vero/B9 5 a cells Microscopy: syncytia (not routine) MICROBIOLOGICAL DIAGNOSIS

Typical signs + epidemiology (unvaccinated) Triad: fever + rash + cough/conjunctivitis/rhinitis Koplik spots: early and specific Lab confirmation: PCR or IgM Mandatory reporting to authorities CLINICAL DIAGNOSIS