Measles is caused by a
Correct Answer: Single stranded RNA enveloped virus
Description: Answer: a) Single stranded RNA enveloped virus (PANIKER 9th EDITION P-305)DNA virusesFully double strandedPartially double strandedSingle strandedNaked DNAHerpesvirusPoxvirusAdenovirusPapovavirusHBVParvovirusCircovirusParvovirusAdenovirusPapovavirus RNA virusesDouble stranded RNA virus: Reovirus, PicobirnavirusSingle stranded RNASS - Enveloped RNASS- Nonenveloped RNAPositive sense* Picorna* Toga* Calci* Flavi* CoronaNegative sense* Rhabdo* Orthomyxo* Paramyxo* Arena* Bunya* Arena* Retro* Filo* Bunya* Orthomyxo* Paramyxo* Toga* Rhabdo* Corona* Picorna* Calci* ReoMEASLES (RUBEOLA)* Measles virus (Paramyovirus) - hemagglutinin present; neuraminidase absent* Measles is a winter disease* Children 1-5 years are mostly affected* Source of infection is a case of measles* No carrier state* No animal reservoir* IP: 9-lldays; 7 days following vaccine* Secondary attack rate 80%* Communicability 4 days before and 5 days after the appearance of rash* Pathognomic feature - Koplik's spots in the buccal mucosa appears 2 days before rash, opposite to lower first and second molars, fade with the onset of rash; sometimes seen on the conjunctiva and intestinal mucosa* The red maculopapular rash first appears on the forehead and spreads downwards* In malnourished children it can cause hemorrhagic rashes - black measles* Most common complication - otitis media* Most common life-threatening complication - bacterial pneumonia* Streptococcus pneumoniae and H influenzae type b - common causes of bacterial pneumonia* Giant cell pneumonia - serious complication in those with deficiencies in cell-mediated immunity* Protracted diarrhea may occur in children* Spontaneous abortion and premature delivery can occur in pregnant women* No congenital anomalies reported* Children may develop acute vitamin A | and treated with vitamin A which reduces morbidity and mortality* Multinucleated giant cells called Warthin-Finkedly cells are pathognomic of measles* Acute encephalitis occurs 1 in 1000 cases* Subacute sclerosing panencephalitis (SSPE) or Dawson inclusion body encephalitis is a rare complication> Develops 5-15 years after initial measles infection> Frequency 1 in 10000 to 1 in 100000 cases.> Progressive mental deterioration, involuntary movements, muscular rigidity, coma.> Usually fatal within 1-3 years after onset> Defective measles virus in brain cells seen> Demonstration of high titre measles antibody in CSF and serum is diagnostic> Most often develops in persons infected with measles virus at <2 years of ageCell surface receptors for Measles virus* CD46 complement regulatory protein that inactivates C3 convertases)* SLAM (Signaling lymphocytic activation molecule)* Nectin 4 (adherens junction protein)Measles vaccine* Live attenuated vaccine (Edmonston Zagreb strain)* One dose of vaccine gives 95% protection; Vaccine efficacy is 85%* No spread of virus from vaccinees to contacts* Susceptible contacts over 9 months can be given the vaccine within 3 days of exposure, as IP of measles induced by vaccine is 7 days compared to 10 days for the naturally acquired virus* Toxic shock syndrome occurs when the vaccine is contaminated or the same vial is used for more than one session on the same day. The vaccine should not be used 4 hrs after opening the vial* Eradication of measles requires immunization coverage of 96%* Atypical measles - measles infection due to formalin inactivated vaccine; rash begin in palms and soles* Modified measles - in individuals who have received serum Ig after exposure to measles virus.
Category:
Microbiology
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