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Rubella+chicken pox
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Rubella+chicken pox

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    Rubella+chicken pox Rubella+chicken pox Presentation Transcript

    • RUBELLA Dr Kamran Afzal Asst Prof Microbiology
    • Rubella virus
      • Family – Togaviridae
      • Genus – Rubivirus
      • Enveloped
      • Spherical virus carrying hemagglutinin
      • Virus multiply in the cytoplasm of infected cell
      • Rapidly inactivated by chemical agents, ultraviolet light, low pH and heat
    •  
    • Pathogenesis
      • Respiratory transmission of virus
      • Replication in nasopharynx and regional lymph nodes
      • Viremia 5-7 days after exposure with spread to tissues
      • Placenta and fetus infected during viremia, in a pregnant female
    • Clinical Features
      • Malaise
      • Low grade fever
      • Morbilliform rash
        • Rash starts on face and extremities
        • Rarely lasts more than 5 days
        • No features of the rash give clues to definitive diagnosis of Rubella
      First described as distinct clinical entity in German literature – ‘ German measles’
    • Clinical Features
      • Incubation period 14 days
      • Maculopapular rash and lymphadenopathy occur 14 days after exposure
      • The clinical events occurring in the neonatal age are more important and divided into two major groups
      • 1. Post Natal Rubella
      • 2. Congenital Rubella
    • Transmission in Adults
      • Acquired, (i.e. not congenital), Rubella is transmitted via airborne droplet emission from the upper respiratory tract of active cases
      • The virus may also be present in the urine, feces and on the skin
      • There is no carrier state
        • The reservoir exists entirely in active human cases
    • Systemic events
    • Laboratory Diagnosis
      • Positive serologic test for Rubella IgM antibody
      • Significant rise in Rubella IgG by any standard serologic assay
        • enzyme immunoassay
      • Isolation of Rubella virus from clinical specimen
        • nasopharyngeal swab, urine
    • Serology
      • Detection of Rubella specific IgM in a single specimen
      • A 4X rise in Antibody titers between two serum samples taken 10-14 days apart
      • ELISA tests are of greater importance
      • HAI test for Rubella is of diagnostic significance
    • Serology
    • Interpretation of Serology
    • Isolation and Identification of virus
      • Nasopharyngeal or throat swabs taken 6 days prior or after appearance of rash are a good source of Rubella virus
      • The virus can be cultured on continuous cell lines Rabbit kidney cells
      • (RK 13)
      • and
      • Vero cells
      • Cell cultured antigens can be detected by IF methods
    • Complications
      • Arthralgia or arthritis adult female children
      • Thrombocytopenic purpura
      • Encephalitis
      • Neuritis
      • Orchitis
      up to 70% rare 1/3,000 cases 1/6,000 cases rare rare
    • Congenital Rubella Syndrome (CRS)
      • Infection may lead to fetal death or premature delivery
      • Severity of damage to fetus depends on gestational age
      • Up to 85% of infants affected if infected during first trimester
      • Maternal viremia with Rubella infection during pregnancy may result in infection of placenta and fetus
      • The growth rate of fetal cells is reduced
        • Lead to deranged and hypoplastic organ development
        • Results in structural damage and abnormalities
      • Deafness
      • Cataracts
      • Heart defects
      • Microcephaly
      • Mental retardation
      • Bone alterations
      • Liver and spleen damage
    • Classical Triad
      • Classical Triad
      • Deafness / Microcephaly
      • Cardiac abnormalities
      • Cataract
    • Diagnosis of CRS
      • Demonstration of Rubella IgM antibodies in a new born is of diagnostic value
      • IgM does not cross the placenta, they are produced in the infected fetus
    • Rubella in various trimesters
      • 1st trimester infections lead to abnormalities in 85% of cases and greater damage to organs
      • 2nd trimester infections lead to defects in 16%
      • >20 weeks of pregnancy, fetal defects are uncommon
      • Rubella infection can also lead to fetal deaths, and spontaneous abortion
    • Treatment and Prevention
      • Rubella is a mild self limited illness
      • No specific treatment or Antiviral treatment is indicated
      • Clinically missed Rubella in the 1st 3-4 months of pregnancy is associated with fetal infections
      • CRS can be prevented by effective immunization of the young children and teenage girls
    • Rubella Vaccine
      • Composition Live virus (RA 27/3 strain)
      • Duration of Immunity Lifelong
      • Schedule At least 1 dose
      • Should be administered as MMR or MMRV
      • INDICATIONS
        • All infants 12 months of age and older
        • Susceptible adolescents and adults without documented evidence of Rubella immunity
        • Emphasis on non-pregnant women of childbearing age
    • EPI
    • CHICKEN POX
    • Herpes Viruses
      • V-Z Virus (HSV-3) is member of Herpes virus family
      Lymphoid tissue RKV HSV-7 HSV-8 Lymphoid tissue HBLV HSV-6 Gland, Kidney, Tissues CMV HSV-5 Lymphoid tissue EBV HSV-4 Neuron V-ZV HSV-3 Neuron HSV-2 HSV-2 Neuron HSV-1 HSV-1 ORGAN AFFECTED COMMON NAME VIRUS
    •  
    • Chickenpox virus in the body
      • Viral infection through aerosol droplet; systemic infection
        • local infection in lymph node(s) (of the neck)
        • lymphocyte associated viremia
          • Fever, malaise
        • Spread throughout the body
        • Shed in respiratory tract secretions and
        • Skin vesicles (small blisters of clear fluid)
          • Recovery with virus latency in neurons
          • Life long immunity
      • May re-emerge as shingles and spread to others
        • vesicular skin lesions
    • Infectivity
      • Incubation period is 7-21 days
      • Affects children less than 10 yrs, commonly 5-7 yrs
      • Source of infection is a case of chickenpox / herpes zoster
      • Infectivity period is 1-2 day before appearance of rash till scabbing of rashes occur
      • >90% of population infected by 15 yrs
      • Attack rates 90% for household contacts
    • Pathogenesis
    • Clinical features
      • Starts with prodromal symptoms such as mild-moderate fever, malaise, anorexia, headache
      • Rashes appear on day one of fever
      • Rashes appear mainly on trunk
      • Mucosal surfaces are involved (buccal, pharyngeal, vaginal); palms and soles usually spared
      • Rash progress as macule, papule, vesicle, and scab
      • Vesicles are dew-drop like and surrounded by erythematous area, vesicles may be up to 10 mm in size
      • Patients have itching
      • Sub-clinical varicella is very rare
      • Rashes may be hemorrhagic in immunocompromised patient neonates and infants, patient on steroid, pregnant women
    • Chickenpox vs Smallpox
    • Complications
      • Sec. infection (5%) caused by Gp A Streptococcus and Staphylococcus
        • Early manifestation is erythema at base of new vesicle
        • Infection can cause bacterial sepsis, pneumonia, arthritis, osteomyelitis, cellulitis and necrotising fasciitis
      • Pneumonia more common in adult, occurs 3-5 day after illness
      • ITP
      • Encephalitis
      • Cerebellar ataxia
    • Investigations
      • Leucopenia occurs in 1st 72 hrs followed by lymphocytosis
      • TZANK Smear --- poor sensitivity and specificity
      • IgM
      • Four fold rise of IgG antibodies are confirmatory of acute infection
      • VZV can be identified by direct fluorescence assay of cells from lesions and by PCR amplification test
      • LFTs deranged in 75% cases
      • Lab investigations have not been considered necessary in healthy children
    • CHICKENPOX TREATMENT General & Symptomatic Specific
      • Hygiene
      • Soothing agent
      • Calamine and oatmeal bath
      • Itching
      • Diphenhydramine
      • Cetrizine
      • Fexofenadine
      • VZIG
      • Antiviral
    • Prevention
      • VARICELLA VACCINE
      • Live attenuated
      • Available in two forms
      • monovalent
      • polyvalent MMRV
      • Recommended after 12 month of age
      • 12 month – 12 yrs --- single dose
      • >12 yrs --- two doses at least 4 wks apart
      • CONTRAINDICATED WHEN CMI is decreased
      • ZOSTAVAX Vaccine for HERPES ZOSTER
      • It is live but weakened version of varicella vaccine
      • Given as single dose to prevent herpes zoster at >60 yrs
      • It reduces complications —
        • post herpetic neuralgia, scarring and vision problem
      • POST-EXPOSURE PROPHYLAXIS
      • VARICELLA VACCINE
        • if given within 3-5 day after exposure
      • VARICELLA ZOSTER Immunoglobulin
        • within 96 hrs of exposure
    • Who should be vaccinated?
      • YES
      • > 1 year of age
      • varicella susceptible
        • no history of chicken pox
      • no contraindications
      • NO
      • < 1 year of age
      • immunodeficient
      • pregnancy
      • mild natural chickenpox
    • Chicken pox reemerges as Shingles Causes: Stress, radiotherapy, drug therapy, or a developing malignancy
    • Herpes zoster
      • Unilateral vesicular eruption within a dermatome in a Pt with H/O varicella
      • Pain in dermatome may precede 48-72 hrs before rash
      • Occurs due to reactivation of VZV in dorsal root ganglia
      • Lifetime risk of zoster to individual with H/O VARICELLA is 10-15%
      • Rare in healthy children of age less than 10 yrs, it may occur where CMI is decreased
      • Commonly involve T3-L3
      • Herpes zoster Oticus (Ramsay-Hunt Syndrome)
      • Herpes zoster Ophthalmicus
    • Varicella in fetus
      • Intrauterine infection more common in 1st trimester
      • Congenital infection
        • scarring, limb deformities, cataracts, CNS involvement, chorioretinitis
    • Varicella in neonates
      • During maternal varicella 24% of fetuses get infected transplacentally
      • Infant mortality up to 30%
    • Varicella in pregnancy
      • Pregnancy alters cellular immunity needed to fight viral infections
      •  pneumonitis
      •  mortality
      •  maternal complications in 2nd and 3rd trimester
        • premature labour/delivery, IUGR
      • What To Do?
      • Prevent infection
        • VZIG
        • infection control
      • Diagnose early and treat infection
      • PREGNANT MOTHERS EXPOSED TO CHICKENPOX
        • VZIG within 48 hrs of exposure to varicella
      • PREGNANT MOTHERS HAVING CHICKENPOX - chances of varicella pneumonia are high, need treatment
        • Acyclovir x 7 days
      • NEONATE & INFANT WITH CHICKENPOX
        • Acyclovir x 14 days
      • NEONATE & INFANT EXPOSED TO CHICKENPOX
        • VZIG + IV Acyclovir